Head Gasket FAQ

[kirkMKIV]

There are TOO many posts being made asking the same questions over BHGs! :) How about we have ONE thread where we can keep all the questions and answers... and NO FLAMING!!!

Here is a REALLY helpful website which lists symptoms and diagnostics.

http://www.pcrealm.net/~howardh/supra/headgasket/background/bhg-repair-bg.htm

Any questions please ask them in here !

[BlackDevilSupra]

Originally posted by kirk_mk3
.....

Here is a REALLY helpful website which lists symptoms and diagnostics.

http://www.pcrealm.net/~howardh/supra/headgasket/background/bhg-repair-bg.htm

Any questions please ask them in here !

How gosh,
Where the heck did you find this page, I've never ever advertised it. Believe or not, it took me 3 yrs to complete that section, which fully explains why the page is incomplete :( (no coments Dave).
Well, this is incentive to place some impetus under my a$$ to wrap this page up.

Sorry fellas for the incompleteness. Bear in mind, my comments are exactly that, just my comments based on personal experience; 2 BHG's. So, it's not law, or the case for the general MkIII population.

Howard.

[Da Kine Guy]

Originally posted by Beef
BTW I have questions of my own.... what is the best way the test if the block needs work while it is still in the car...... I am trying not to remove the block at all costs. The Head on the other hand is getting a good once over... PT Cleaning ect.....

Visually inspect and feel the surface for roughness. You will also need to get ahold of a precision straight edge to check how flat (or warped) the block face is. I borrowed one from where I work but I've heard they are not cheap. Best to go to a machine shop and ask if you can borrow it for a day. Using the straight edge I found my block dips .001 inch in the middle with a feeler gauge. That's within factory spec and I was using a new OEM gasket. My head was perfectly flat on the other hand.

[jdk_ii]

This is the definitive source for head/block surface preparation and smoothness.

Cylinder Head Refinishing (http://www.babcox.com/editorial/us/us59826.htm)

[travlavelle]

First ,I would like to say thank's to all who take the time to look at the age old thread and help the new Supra guy's! These two links below are the best info sights I have found so far!

http://www.babcox.com/editorial/us/us59826.htm
http://www.supras.com/~riemer/HKS/hksgaskets.html


Now, I have a question about lapping.
- Glass -
Is it really a good idea to do the lapping (polishing) with glass?
Glass produces a RA (Roughness Average) of 3-4. If I understand
correctly it is rec. that you have a minimum of 30 RA so that you
will get a good "bite" between the head and the block, and thus
prevent lat. shearing. On the other hand you do not want the
shearing to tear the gasket apart. I understand that the metal
gasket requires a smoothe surface, but how smoothe should you
go?

Also torqe is a factor. I know it has been beat to death on this forum. If you read these links you can see that too much torqe will distort the head and cause the combustion chamber (chambers) to be slightly deformed causing premature gasket failure, and as we all know too little torqe will cause the same problem.

I gather that the HKS bead gasket is reliable as any on the market, with proper prep. This is probably what I will go with as I plan to do all the proper prep.

I would appreciate all the info you guys can give on your experience with this matter. Thank's

[kirkMKIV]

Here is a great website explaining how to properly lap the head and block on the 7M prior to installing a metal headgasket.

http://users.ev1.net/~mdw/lapping%20the%207mgte%20head.htm

[pmpaluda]

How many have repaired a BHG without block/head machining?

[Da Kine Guy]

Originally posted by pmpaluda
How many have repaired a BHG without block/head machining?

I did with a new Toyota OEM gasket. Took off the head, cleaned the head surface and block surface and scraped all the residue off. Borrowed a precision straight edge from the machine shop at work. Got out my feeler gauges and found the head to be completely flat (my smallest feeler is .001 inch thick and I couldn't stick it anywhere under the straight edge in all directions). My block had a .001 inch dip in the middle, Toyota spec is .003 inch. Visual and touch inspection of both surfaces came out that both surface where extremely smooth with no pitts, cracks, or stratches. I then just stuck the new HG on and put it all back together. This was at the end of last August. I drove the car until I discovered the clutch was worn out which was about Sept. 7th.

Since getting the clutch replaced on Sept. 17th I've been driving the Supra to and from school everyday, taken two 200+ mile trips, been to two Supra meets with a mountain drive, and doing various errands. The car is flawlessly performing. I've taken it up to redline maybe 4 times and nothing adverse has ever happened. Mind you I put in many other new things while doing the HG job, but it was all maintainence stuff. Boost gauge reads somewhere around 6-7psi at WOT (stock gauge is pretty vague, eh?).

So, I'd have to say that in my case the repair was successful. I highly recommend using a straight edge to determine how flat your head and block surface is, it'll tell you if you need machining or not (and in some cases whether you have an excuse to get a MHG :))

[Beef]

Originally posted by SUPRAIWAMOTO
heres my question about arp headbolts... do they stretch? and if so when should you replace them? also if im decking my block for the first time and had my head shaved a few time already what size mhg should i go with or is this a dumb question?

All bolts / studs stretch I wouldn't reused the stock Head bolts. I know of a couple guys that have reused thier ARP studs without any problems...

Stock gasket size is 1.2mm just take however much you shave or plane off and add it to 1.2 to get your new gesket size...

Example - you have had .15 mm shaved from your head and .15 mm shaved from your block.... just take .15 + .15 = .3 + 1.2 = 1.5 mm

HTH

[rbrt_88supraT]

i dont know if anyone has posted this link yet but here it is anyway..it gives alot of good info on the surface of the head and how flat it needs to be ect...http://www.babcox.com/editorial/ar/ar119862.htm {not the same as the other site "seal tight"}

[Beef]

Originally posted by 8supraman8
Hey i changed my headgasket about 6 months ago but put a stock headgasket and torqued to 60 pounds with a rebuilt head i was just wondering if i can open it again and put a metal head gasket without rebuilding the heads again??? By the way i have only put less than 800 miles since it was done due to clutch problem.

You can just make sure the head and block surfaces are near perfect and smooth.....

[makenzie71]

Need to post this because I have yet to see it here, I have also searched throughout the forum and have not found it...so here it is:


TOOLS REQUIRED TO CHANGE HEADGASKET:
(in no specific order)

Wrenches:
10mm 12mm 13mm 14mm 15mm 18mm 3/4" (few others I'm forgeting)

Various flathead and phillips screw-drivers

large and small pully-puller

Feeler guages

Large pair of channel locks

Standard and Long nose pliers

Wire cutters

Bailing wire and Duct tape

various vice-grips (one large and one small pair should do)

Hex tool (9mm, I believe)

Large flat head or pry-bar

bully-bar or breaker bar

1 Friend

band-aids

this is all I cn think of right now...but that should cover it.

Also, I would sugest a couple of things while the head if off. Remove the TB coolent lines, cleans the engine up a little. Also, do the knock sensor rewire, it's much easier if the head is off.

[flubyux2]

Hey Girl...you may have a Bad heater core. If you can smell the coolant really strongly, theres a chance that the heater core is leaking itself. If you say there arent any leaks or puddles on the ground after it sits, then the only other places it could be leaking into are: Oil pan, cylinders, or interior.

To check to see if theres coolant in your oil, Take your oil cap off and look on the bottom of it. If it has a milky brown, Wendy's frosty kinda looking crap on it, there is a leak from your head gasket. If it checks out ok, and no milky brown stuff, pull your Dipstick next to the turbo. See if there is any milky brown crap there. If not, there is no cooalnt getting into your oil.

To check for Coolant in the cylinders: You will have a rough idle, excessive steam from the exhaust, Overflowing coolant bottle, swishing sounds inside the dash, and over heating engine, WATCH YOUR TEMPERATURE GUAGE!

To check for leaking heater core: feel the carpet under the glove box. if its wet, stiff, or sticky, that will indicate that the heater core IS leaking or HAS leaked before.

If you keep having to refill it like you say, its got to be going some where. and it sounds like you have added alot of coolant so far, and i doubt you have an Inch of coolant flooding your interior...so its probably a minor (soon to be Large) leak in youe head gasket.

good luck!

Heres my question:

What gaskets do you really need to replace when doing a HG job?

Intake manifold to head gasket
Exhaust manifold to head gasket
Water pump gasket?
Thermostat housing gasket?
Cam cover gaskets?


Im a little scared of doing a HG job in the parking lot of our Apartments... mainly cuz im worried about not having all the tools i need to do it.

Is there usually a problem of the Original HG sticking to the head and/or block when disassembling? If so, how do you clean it up so there is a nice clean surface to work with?

Is the FelPro set even worth using, or is the OEM stuff from the Dealer a better choice?

Thanks
Chris

[flubyux2]

Guess what i heard...after getting spanked by an MKII w/ a 6MGTE?

The guy who does all his work, and gets it tuned by Brian @ Race Related in Tampa (i think), says his Redneck buddy has an MKIII and does the most slipshod,slapdash work in the world...(i think hes also a ford owner). His buddy blew a HG on his MKIII, and ended up getting an MHG and some ARP studs, but didnt prep the block at all. All he did was clean the old gasket off w/ the spray solvent, then took the MHG and sprayed it w/ the Permatex Copper gasket prep spray, then slapped the bitch on, and torqued the studs down to 90 ft/lbs, and has been driving it for years w/ no problems. He blew his stock CT a few months ago and is doing a 60-1 upgrade from t-netics i think. Apparantly the guy hasnt had any problems w/ it.

I was suprised that there wasnt ANY prepwork for the MHG...but its obviously working for him.

My other friend who works at Defcon uses the same spray, i remember him putting intake and exhuast gaskets on a 7MGTE and spraying both the gasket and the head...maybe it works..

[makenzie71]

stuff works great but it isn't for someone wanting to run 20lbs+/- of boost. I used that stuff several times on other vehichles...like fords, who use MHGs stock and require an ultra-low RA. No prepping just gasket it...it's just not a performance-based product.

[makenzie71]

costs really vary:

I did mine alone....$111.76 including vac line caps to plug vac lines

local shop.....$6-700.00 including all parts and labor. Most shops are more...esp. if turbo

Dealer wanted more than the car is worth

[Thermactor]

Originally posted by makenzie71
Look on ebay....you'll find gaskets from a seller called ming sung...he sells the complete gasket kit from Apex...about $100. They're decent but you can't run much boost. Apex gaskets = CRAP.


CRAP.


Spend another 40 bucks and get real Ishino Japanese gaskets from thepartsbin.com

[makenzie71]

flubyux2...basically the way I kept the costs so low is by investing the 12 hours (total) actual time and did it myself. I had all the tools I needed and enlisted the help of a couple friends to help lift the head when I needed to.

Pretty much all I payed for was the gasket set, vacuum hose plugs, and about 3ft of oil line for a hose I broke.

Also, I am not defending Apex gaskets but I will say this:
My car is N/A, and the Apex HG is very similar to the OEM one (I couldn't tell the difference). The various other Apex gaskets and seals were identical to oem gaskets. Since installing the gasket I have checked the compression 3 times and it remains consistant (700 miles so far). Also, what other manufacturer can you get a COMPLETE head gasket set for $100??? It contains all the needed gaskets and it;s budget friendly.

[Beef]

Ok since you have a NA this is what I would do:

Of course get all new belts
Get all new gaskets for the head incuding the the stock HG (This is the invoce for the parts I have ordered for my BHG plus alittle more) http://users3.ev1.net/~hmillerjr/beef/parts/invoice1.jpg
Get some ARP Head bolts... I wouldnt reuse the stock ones....

With this setup all you need to do is clean the head and block mating surfaces so you can just leave the block in the car. I wouldn't go for the MHG unless you were really going to go turbo.. Also tourque the ARPs down to 70~80 ftlbs....

HTH

[Rajunz]

To answer your question about changing your own gasket, it really depends how comfortable you are with mechanics. It's not all that difficult of a job. Study the TSRM (http://www.cygnusx1.net/supra/library/TSRM/) to figure out if you feel you can handle it. I would encourage you to do it yourself, just so you learn more about your car. The keys to a proper job are cleanliness and organization. What you don't want is a bunch of crap in your engine, so clean it thouroughly before you open it up, and use a bunch of rags throughout. Keep things organized so they go back properly. Most important, don't be a cheap ass. If you're gonna boost it later, go MHG and ARP bolts. Regardless of what gasket you use, get the head re-surfaced, that's not very expensive.

[ONyX]

i did it sunday in my drive way on my buds 87 took me 7 hours ehh long day. If your comfertable with your mechanic skills then giver. you will need 2 people to lift the head out if you leave the turbo on it.

[Sethron71]

The only thing to really pay attention too is the timming set up. The 7-mgte version of the distributor(forgot name) is a pain in the ass to get just right if you don't mark it upon take off. Other then that, everything comes off easy and then falls back into place easily!!! I you need some assistance via internet, PM me.

[ma71supraturbo]

It seems as though reading through five pages of HeadGasket posts is too much for some people as the same questions keep popping up. Here is a compilation I just made in an attempt to keep redundant posts to a minimum. Feel free to comment on my answers as I will be updating this post...


How much will fixing it cost?
This depends greatly on a number of things, including your area, what work you intend to have done, how much work you do yourself, and what parts you use. You could theoretically buy a $50 headgasket and try to reuse all the other gaskets (not recomended), doing the work yourself. Or you could have a shop pull the engine, machine head and block, and install ARP studs with the most expensive headgasket. Check out the various prices for parts, and call around to see what labor would run in your area... The basic answer is you'll get as many answers to this question as people who take the time to reply...


Can I change the headgasket myself?
This depends on three main factors. 1. Do you have a good general knowledge of automotive parts? 2. Do you have the proper tools (outlined elsewhere in the FAQ)? 3. And do you have the time?
1. The hardest part of this job (for me) was reassembly. The many vacume hose and electrical connections can easily confuse the unprepared. Take note of where things go when you remove them. Pictures are worth 1000words (digital cameras are great!). You also abide by the proper torque specs. I highly recommend having a TSRM (http://www.cygnusx1.net/supra/library/TSRM/) on hand, but you can use one online.
2. The full tool list is elsewhere, but basically you need a full metric set of sockets and wrenches, a good torque wrench, and a handful of specialty tools depending on how much work you do while changing the headgasket (like replacing the valve stem seals, timing belt, or waterpump).
3. Book time I believe was ~6-7 hours for a MKIII turbo. It’s been a while since I looked that up. Some guys can swap a headgasket in a few hours. Others do things very slowly and take a month. I would plan on having your car down a week in case the unexpected happens. My head, for example, sat at the machine shop 2 days before they got around to it. Some people only buy a headgasket instead of the full kit, and have to wait for a special gasket to come in when they discover a leaky intake manifold gasket.


I have a gurgling sound coming from my dashboard ("waterfall in dash"). What could it be?
This means you have air in your cooling lines, probably from a leak. The short-term fix is to "burp" the system, parking the car on a hill with the radiator as high as possible. With the car cold (coolant system not under pressure), open the radiator cap and let the car idle, filling the radiator as air is purged... When the radiator level stays at the top, put the cap back on, and doublecheck the coolant overflow level.


I just "burped" my supra, but the gurgling came back XX days later. Where is it leaking?
If you have a clean engine bay you might be able to spot a leaking radiator hose. Otherwise you can take your car to a shop where they can put dye in the coolant. They'll run the car for a while (maybe even have you drive it for a couple days), then they will hold up a special light which illuminates the dye. If you have a soggy carpet, your heater core may be bad.


Does (insert problem here) sound like a BHG?
Many cooling system problems could be a BHG. Instead of describing various symptoms to some random person on the internet and getting an uncertain answer, just go have a test done... If you have reason to believe your supra has a BHG, you can either take it to a shop and have them perform a block test (call around for your local rates, they are $25-$30 in my area), or you can go to Napa and buy a block test kit for around $50 (which you can, and probably will use many times over the life of the car).


When I first start up my supra, I get white smoke out of my exhaust. But once I drive it, the smoke goes away. Do I have a BHG?!?!
Again, if you suspect a BHG, test for it. White smoke does not always mean you have a bhg. Often when a car is cold (especially in the winter), white steam will come from the tailpipe. Thats normal condensation and water is a byproduct of combustion... But if it steams when the car is warm, and you're overheating, its likely a BHG. Test to be sure...

I have the BHG engine on the stand right now, and I left it there for about a month or two, will the pistons or the block rust because of the BHG?
Sure it’s possible. But if it’s on a stand, chances are you have the coolant drained. If the engine is inside a garage and not exposed to the elements it probably is fine. But if you leave an engine sitting with a half a cup of water sitting in a cylinder it'll rust...


Are there any precautionary measures I can take to make sure I get the most out of my stock HG?
There are two schools of thought. The first is to leave it alone ("don't fix it till it’s broke"). The second is to retorque the head to the higher torque advised by Supra Guru Reg R. Many people discourage a retorque, and it will by no means solve an existing blown head gasket. It *may* even cause blown head gaskets, especially on old, original head gaskets. This topic is wildly debated especially on the SOGI email list, and I don't have a strong belief one way or the other. If you decide to retorque your headgasket, I do recommend following procedure to ensure a proper torque. Remove one headbolt, lubricate the threads with assembly lube, and reinstall it to stock torque (~55lbs). Repeat for the remaining 13 bolts, removing only one at a time, and torquing it down before the next bolt is removed. When all the headbolts have been removed, lubricated, and are back at stock torque then you can proceed to increase the torque. Move up in 5lb increments following the TSRM torque pattern. Stop at 70lbs.


Also, what is the typical cause of a BHG on a 7M? I know there are many causes like Too much Detonation, overheating/warping, improper torque sequence, improper torque values, etc. But what is so fundamentally wrong w/ the 7M that causes the OEM HG to go bad in the first place?
There may have been something wrong with the original headgasket design, and the stock headbolt torque spec is too low. The original headbolts can safely be torqued to 70lbs (once). This was discovered about the same time as the redesigned headgasket hit the market (late '90s). With a properly torqued new headgasket, the 7m can achieve the "normal" (good) Toyota reliability.


Also, we heard that the headbolts Toyota put on this car are not really strong enough and that ARP makes a stud set for the car for $125, anyone think it is worth it?
The stock headbolts can be safely torqued once to 70lbs. Some have had success using them multiple times. But it is generally accepted that after they've been torqued over stock value (~55lbs), they should be replaced. If your bolts have already been torqued to yeild, you can either buy new Toyota bolts (good for one use), or you can buy ARP bolts or studs (good for multiple uses and capable of 80+lbs of torque).

Should I just use a stock HG, or should I buy a MHG?
More often than not, this comes down to money. If you use a MHG, you will almost definitely have to resurface the head, and might have to resurface or lap the block (depends on how much it was overheated and how long its had a BHG). If the car is just transporation and is not going to be modified much, I'd go with a stock HG. Stock headgaskets are a lot more forgiving about engine finish... But if you plan on boosting over fuel cut, or are going all-out in an NA, I would definitely go with a MHG.


Should I go with ARP headbolts, or ARP studs?
The bolts are just fine, but studs are generally accepted as being the stronger option. You may have difficulty installing the studs if the block is still in the car, but it can be done (search for the topic, it came up a few months ago)


I'm having a problem with overheating and I’ve already changed the thermostats, what other possibilities could it be before I declare it a blown headgasket.
Again, if you have reason to suspect a blown headgasket, just have it tested. Other possibilities for overheating include a leak introducing air in the lines, old or cheap nonToyota thermostat, old or cheap nonToyota radiator cap, clogged radiator, bad water pump, old coolant, bad fan or clutch, missing fan shroud, and missing engine undercover.

[driftinsupra]

I have a question that doesnt seem to have come up yet. Or maybe my skill in using the search button isnt too great yet. Anyway my supra came down the the standard BHG. Well due to several other problems with the engine (rod knock, burning and leaking oil, high miles) I have started to start fresh and have a JDM engine on its way. I plan to install a MHG in it and my question is, normally will a JDM engine require the block to be resurfaced? I plan on spending about $2500 on getting everything set up and I think having to resurface the block will toss me over the endge and I have heard it is not usually necissary. Anyone do you guys think I will need to resurface the block? I will be checking the smoothness of it of course but I am kinda cureous if most JDm engine that come over have that need.

[makenzie71]

You may, strong emphasis on "may", be able to slide without resurfacing the block. Just be sure to check it out thoroughly before getting too involved in your project. The head will almost certainly need to be resurfaced. Now, one thing you could do, which is highly NOT recomended but does work pretty well, is to use Permatex Copper Prep spray one the gasket before assembling everything. I have used it on lates 90s fords, which require an RA of about 10...lol...with no surface prep and the cars all still run fine...but it's not good for very high boosting.

[ma71supraturbo]

I had two JDM engines come, and both required block machinework. The bearing surfaces looked great and suggested low mileage, but unfortunately the coolant passageways seem to get eaten away on the 7m's. You *may* get lucky, but I would plan on machinework (or at the least lapping -- discussed on the sonic HKS headgasket link...)

[SlowMo]

7mg 1.0mm-thick 83mm-bore
7mg 1.0mm-thick 85mm-bore
7mg 1.5mm-thick 83mm-bore
7mg 1.5mm-thick 85mm-bore
7mg 2.0mm-thick 83mm-bore
7mg 2.0mm-thick 85mm-bore????

i plan on running high boost everynow and then, mostly lower boost to keep me daily driving. i will have the head port , polished
and decked. turbo trimed 60-1, etc etc, main goal of 400+ whp. what head gasket best suits me.

[HamsMKIV]

I would go for the 1.5 or the 1.0. The 2.0 is pretty agressive in dropping your compression. Given your desired mods and need for useable compression out of boost, I would say that the 1.5 would best suit your needs.

Chris

[ma71supraturbo]

Originally posted by SlowMo
7mg 1.0mm-thick 83mm-bore
7mg 1.0mm-thick 85mm-bore
7mg 1.5mm-thick 83mm-bore
7mg 1.5mm-thick 85mm-bore
7mg 2.0mm-thick 83mm-bore
7mg 2.0mm-thick 85mm-bore????

i plan on running high boost everynow and then, mostly lower boost to keep me daily driving. i will have the head port , polished
and decked. turbo trimed 60-1, etc etc, main goal of 400+ whp. what head gasket best suits me.

Again, read Regs HKS headgasket FAQ. The link is on this sticky. Basically you want the thinnest headgasket that will come close to stock compression. If you take off 0.012" from block and head in a light surfacing job, then the 1.5mm HG is perfect. The stock HG is 1.2mm, so 1.5mm-1.2mm = .3mm (.3mm=.012")

If the machine shop removes 0.032", then the 2.0mm gasket is perfect. The thicker the headgasket, the more chances for it to blow (Reg's theory), so choose the thinnest that will maintain near stock compression.

Choose the bores based on your engine being stock or overbored...

[TRD Charger + Propane]

With a 3mm head gasket, I think the compression would drop enough to enable a couple of gains for the 10+ boost league. My buddies talon runs 6.5.1. He set the idel around 1000 rpms but, when boost hits, it hits. I think this would help the motor breath with some lower compression. Turbo should spool easier. I would like some clarifaction from some who understands what's going on.

Thanks,

Kam

[SpyHunter]

I thought that I would share the great prices on gaskets, etc that I got from my local Jay Marks Toyota (aka Toyotaworld) here in Houston (11711 Gulf Freeway).

Complete engine gasket kit...LIST $392.08------SALE $294.06
Throttle body gasket.............LIST $ 4.40-------SALE $3.52
Cylinder cover gasket............LIST $ 42.27-------SALE $31.70
O-ring....................................LIST $ 4.14-------SALE $3.31
Timing Belt.............................LIST $ 31.81-------SALE 23.86

Basically, I got a 25% discount and didn't have to wait or pay for shipping. :D I believe that these prices are even cheaper than their website. I also metioned SOGI, which may have been the magic word because the parts guy immediately said "You hang out with those guys? I'll hook you up." Now I just need a weekend where I'm not either working or out of town so that I can put the parts to use...

-Winston

[stonedworm]

I got a full gasket kit for 160 CAN from toyota... turned out i only needed the HG, water outlet, exhaust mani and intake chamber gaskets so it was even cheaper:)

[supradeviouse]

Hi mi bought my car not knowing what was wrong with it (just smoked alot i wastold).i sent the heads in to the machine shop.He said the heads were warped 7 thousands of an in. end to end and to clean up the round grooves in the head from the compression rings on gasket it was another 8 thou in.So .015 in.Is that going to be ok to reuse?I have like what .060 to work with on a stock unmilled head right? Do you think that sounds like a bhg?He said while the heads were in i should get a valve job.He said it would cost $400.He also said hed clean the block,mil it,pollish the crank,hone and bore(if neccesary) cylinders etc...for another $400.How to these prices sound to you and which of these should i do 1st meaning either the valve job(havent checked lash but prob needs seals anyways) or pollishing the crank and fully cleaning block.Either way how are these prices????? I may do it all...and with arp's, hks mhg..........bulletproof. im still doing backwards detective work here as i got the car partially disassembled.To me .007 warpage isnt a bhg its in normal range right???anyways thanx and im learning soooo much i love it and thank you guys.:D

[boost4you]

do it all on one condition... make double sure that the head is milled EXACTLY and has nothing less than a mirror finish. this is needed because you are mating metal to metal. there is no room for error on this. if the motor is already apart dont worry if its a bhg. do the valve job, esp the seals, they go a lot in these cars. DON'T touch the crank, he is milking you for $$$. cranks on 7m's are over built, and can handle like 500hp. these engines have very high tolerances from factory. five thou (thickness of a hair) is pushing it. new rods and pistons may be a good idea, if you got the bucks... good luck oh and visit www.supras.com and click on the sonic link then look for the tech articles it will help you a huge amount. keep this thread going and get back to me on your progress!! hal

[X-man]

I had .010 off the block and .012 off the head on my JDM engine and am running a 1.2 mm HKS gasket with no problems to 20 psi on a TD06 turbo so far. That's alittle high the prices I think. I had my block honed and cleaned with new oil pump drive bearings installed, head(also cleaned) and block decked with a valve job with seals and the balancing on the engine checked( it was only a tenth of a gram off from Toyota) for 300.00. If they would have had to balance it, it would have cost an additional 125.00.

[supradeviouse]

well im thinking for now maybe sticking another stock gasket on er and slaping it back together with all new gaskets and cleaning the parts and putting on all new hoses and seeing how she runs.I dont want to spend too much yet in case once i get it together theres other probs costing more money.As far as you getting all that work done for $300.Where do you live????Ill drive and drop it off if i can get a shop to do it for that price.I thought8-900 was a good price for what would be a virtually "better than new" motor.But hell $300 thats even better!!!!!!!!!!!

[X-man]

I used to work at this shop. The only flaw was they weren't able to get the head and the block as smooth as I wanted it so I bought a lapping tool from Reg and finished it up for the MHG. If you are not going to heavily mod. your Supra a stock headgasket should be fine, just torque the bolts down around 70 to 75 ft/lbs.

[Pearly Whites]

what do you guys think. i bought a H.G. set so i was thinking about just using the stocker.
i plan on running probably 14 psi daily and around 19 or so when i dyno. so stocker or metal?
i dont think the stock hg would go unless there detonation right?
oh ya i also got arp bolts too.

[derK]

OEM......MHG takes a lot of money and effort to get it put in properly./

Derek

[Pearly Whites]

ya and stocker should have no problem what so ever with 19psi as long as detonation is controlled right.. anyone on her using the stocker with a higher boost setting, Dr. Jonez??

[Rajunz]

Nothing wrong with the stocker and ARP's. What turbo are you running there? If it's the stock CT, do yourself and don't boost it up over 14psi. It's already been dyno proven by MKIIISupraGuy
that anything above 14 psi and the CT is just pumping heat into your motor. He gained something like 12RWHP from 14 psi to 18 psi. That's where detonation will set in.

[Bishop92T]

I ran 1.4 bar (~20psi) for 6 months on original stock retorqued HG (75ft/lbs). HG was in decent shape when I pulled it, slight warpage in the #1 cylinder as well as a few coolant jackets warped. Probably damage done before I did the retorque. No damage to head or block, showed no external signs of BHG, very slight HG blow. You should be fine with 19psi if you control your a/f ratios properly and don't detonate :)

[OvenRude]

It all depends on your long term goals. Personally, a MHG to me is a "must do for own sanity" mod....but its up to you. Personally, I would like my car to be reliable as can be before it gets really fast.

[derK]

If you don't want to prep your block then honestly don't even think about getting a MHG. IMO i think it would be worse to put in a MHG without a prepped block and head. As everyone says, controlling detonation is the key ;)

Good luck.

Derek

[paddlenbike]

I am happy to hear such positive comments on stock HGs combined with ARP bolts...that's the setup I'm running. I pulled the cylinder head and checked it for warpage and it was under factory specs (just barely), so I did not resurface the head. I slapped in a new gasket and torqued the ARP bolts to 83 ft lbs. I run the car hard but I'm only up to 9 psi so far. It's been 6,000 miles and no problems.

I had no idea people were running close to 20 psi on stockers. ;)

[MixMasterP2k3]

The dealer told me $1800 with machine work and parts. Two other shops told me $1600 and $1700. I have all the symptons of a BHG, disapearing coolant with no leaks, rough idle, constant white smoke out the exhaust, and recently its started overheating on idle. But all the shops tell me that they will do a presure test to see if there is any cracking. Can a BHG cause cracking in the cylinders? Another thing, is the toyota gasket metal, just like the HKS gasket, and yes i have read reg's write up. I even showed the technicians a picture of the HKS gasket and told me the toyota one is the same. That is what i was told at two different shops. I have worked with head gaskets on cars at school and noticed that they are more like plastic. I have never seen a toyota gasket for the 7m-gte, so I am a little confused.

Any help is appreciated, Thanks

[makenzie71]

they lied to you...the toyota gasket is graphite or composite or whichever word the use, the HKS and such is METAL. Big difference.

[ma71supraturbo]

As for the cracked head question -- a BHG might not cause a cracked head, but the overheating that is associated with a bhg certainly could. I wouldn't expect to see it except in rare cases of abuse ("Oh thats what that gauge on the left is!").

[bcastine]

I had a fel-pro hg put in at 90k miles with the stock head bolts torqued to 72 ft/lbs. Been running 14 psi since and have had no problems and am at the 136k mile mark.

[chevydude]

I just ordered and have got the Fel-Pro kit, all I need to know is what gskt sealants do I need to get, and what is reccomended?

[makenzie71]

Just get some black silicone gasket sealer and use it on the paper gaskets.

[flubyux2]

I just got a Full Top end gasket kit for less than $130. Its made by Detroit Gasket. If i remember correctly, they are like the equivalent to an OEM gasket right? Ive used gaskets from them in my engine building class, but nothing performance related. I couldnt pass up the deal cuz of the good price and im hoping the HG will hold up well enough for my BPU plans and goal of 300 rwhp for the time being.

Has anyone heard of or used Detroit Gasket parts? I want to hear some testamonials or something.

I also saw that Summitracing has ARP head studs for $103 bucks, and have free shipping and a $7.95 handling fee. I was just curious if i can install all the studs into the block except the onces by the fire wall. and then install rear most studs w/ the head on the block by just dropping them thru the head bolt holes and tightening them into the block...and then putting the nut and washer on like normal. Do you think that would work, and be easier than unbolting engine mounts and tilting engines?

Btw, can anyone get ARP Head studs CHEAPER than $110 shipped???

[sobeit]

What is "decked"? And what if I just use the 1.4mm with no block work, what will lower compression do?

[ma71supraturbo]

It won't lower your compression that much, so I doubt you'd even notice it. But it still amazes me that people plan on putting on a MHG without doing any prepwork to the block or head. If you're lucky you may get away with it, but certainly don't plan on it.

As for your other question, in general lowering compression takes away power. But you also lower the risk of detonation, which allows you to boost higher (if you have supporting modifications). The amount your car's compression will change isn't extreme, but yes it would change cam timing slightly (very slightly)

[sobeit]

What is the very least prepwork to the block and head that you should do and what is recommend?

[makenzie71]

may want to at least lap the block...that it if it isn't warped too much.

[ma71supraturbo]

The block will almost never be warped, but you won't know what prepwork you'll need until you see it. They are almost always OK to use a stock headgasket, but every single one I've come across (4 or 5 in total) has had significant deterioration around the coolant passageways. So I wouldn't count on the block be OK to throw a MHG in. Some people have had success, many have not. I would wait until the head is off, and if the block looks really smooth and regular -- you might risk the MHG. If it doesnt look nice, throw on a composite hg, torque it properly and save up money to do the MHG job later...

[suprastylin23]

i just have a question about starting up again. Right now the cylinders are filled with coolant/oil mixture. After you remove the head and go through all the necessary steps, when reassembling the engine should i just make sure everything is clean and dry. then change the oil and coolant. Will this be enough. Or should i run a cleaner or even a flush through the engine. I guess what im asking is am i leaving anything out. thanks.

[ma71supraturbo]

Originally posted by suprastylin23
i just have a question about starting up again. Right now the cylinders are filled with coolant/oil mixture. After you remove the head and go through all the necessary steps, when reassembling the engine should i just make sure everything is clean and dry. then change the oil and coolant. Will this be enough. Or should i run a cleaner or even a flush through the engine. I guess what im asking is am i leaving anything out. thanks.

Sop up whatever you can when you have the head off. You'll probably spend quite a bit of time scraping the old gasket off the block anyway. And flushing the coolant and changing the oil should be enough. I recomend changing the oil only a short time after the head has been of since the internals have been exposed to contaminents (which the oil carries away etc). Just check the oil frequently. When it starts to change from gold to a dark brown change it (may be 100 miles, may be 1000 miles)

[88Turbo]

does anyone know of any write-ups with some pictures of how exactly to change a HG?

[sneakypete]

Yes, I believe it would help all of us out there who are and/or will be attempting to change their headgasket if there were some kind of website of instruction that gives step by step instructions on what to do. Today I received my fel pro gasket set and honestly got quite confused when i say all the gaskets and seals. I have no idea where they all go and how to install them (seals). I believe I understand the basic concept of what to do and I do also have some basic mechanical knowledge, but I dont know every part of the engine. Its the little things that need explaining, like where to start, what to remove, etc. Ive done sooo much searching through this forum (as well as other forums) and I cannot find a thread that gives a link or actual step by step instruction. So if anyone can help us out here, that would be great.
Thanks
-pete

[suprastylin23]

the online tsrm has everything you just asked for. pics and step by step explanation. i dont have the link saved on this computer(at school right now) but im sure you could find it if you just searched here for "tsrm".

[pumpkins01]

ok so ive discoverd oil in my coolent over flow tank and obviously its a BHG....so my question is how long can i drive with this? like what will happen...will my car suddenly break down while im driving or what and how long can i go with it...the only symptom i have is oil in the overflow tank.......

[89toysup]

If you have any oil in the radiator then you should not drive the car at all. Trust me on this one. You could possibly overheat the engine because oil makes for a shi*y coolant. I did this on an 85 Celica and ended up rebuilding the motor. I,m assuming the engine has lost alot of power or that you did a compression check? Otherwise you may have something else wrong.

[t4h3supra]

that permatex copper spray is the sh@@#t! it works real well and is good to put on a mhg.seals a lot better i have a t3h4 turbo pushing 18 psi no problems with the gasket.also arp studs

[adjuster]

I just bought my MHG, it's a Greddy 1.5, 83mm unit, I plan on running on stock internals. If the stock internals ever go out, hopefully just a mild bore clean up, and I can reuse the MHG. Or I'll go with a JDM motor, and use it there.
My question is about the gasket. It is slightly bent, and some of the layers of metal have warped apart. Nothing major, it came shipped between two planks of plywood, and the factory cardboard, but I'm worried about it being anything but very flat.
I understand the head will pull the gasket flat, but does anyone have some thoughts on this, or am I just worried for nothing?
BTW, the Permatex Copper spray sounds like a good idea, even if the head finish is nice, some sealant in the right places can't hurt right?

[hotcress]

I would have personally sent that sucker back. Those Greddy hgs are pretty costly and you do the mhg for reassurance. If you have to question it, might not want to use it. Think about it, the head and block surfaces have to be in perfect shape to acheive optimum sealing with a mhg as a mhg doesn't seal imperfections.Shouldn't the mhg be as close to perfect as possible as well?

[Johnny Dangerously]

i would like confirmation on this please....

When you do a MHG job and the block and head are prepped, you are supposed to torque them down to spec (72lbs or whatever) run the car for 100 miles and then retorque it, correct? to ensure a good seal, right?

[hotcress]

If I remember correctly ARP doesn't recomend retorqueing their fasteners. Someone correct me if this is a lie.

[mk3turbo]

My Supra was diagnosed with a BHG about two months back, and the cars been sitting since. Yesterday when I drained the oil to begin repairing the BHG, and about 1 litre of coolant poured out before the oil started coming out?? Anyone had this problem before?? I searched thourgh this FAQ and tried searching but I couldnt come up with anything?? Anyone know what could be wrong besides the BHG??

[rcdsupra]

Today I tried to retorque the head since I just upgraded my turbo and had the valve covers off. Anyways I have a brand new torque wrench and have torqued things on other cars to 95 lbs so I know it works, and when I tried to torque doen the head bolts they didn't budge. I tried first at 65 lbs, then 70, 75, and then 80lbs and all I got was clicks. I couldn't break them loose for anything. I tried both ways at 75 and they didn't budge, my car hasn't ran for a year, I guess I will have to retorque after they warm up and I break the car in.

[flubyux2]

The TSRM isnt as helpful as theyd have you beleive. Im trying to use it right now, and its pretty vague. and it tells you to remove and disconnect things w/ long technical names that youd never know what they are. Especialy since there is only a drawing here and there, No arrows pointing to the part in question, no description of it, now tips or tricks required to remove the part. No tips if other items are in the way and need to be removed to get at the main item you have to remove.

Does anyone know of any website that has a walk-thru or something to that effect that an amature can use? Im a Pro when it comes to DSM's, but im embarassed to say i know practically NOTHING of the MK3.

So when it says "remove the VSVR tube from the vaccume transmitting chamber" or some shit, i am totally LOST... at least give me a freakin picture w/ an arrow or finger pointing to it... not some lame ass drawing.

maybe ill go out and buy a Haynes, at least they are "based upon a complete disassembly of an actual vehicle" and have real pictures.

there is so much crap that has to be removed and then theres stuff that can be left on the head... but i dont know WHICH things i can leave on and what has to be removed/disconnected... Jesus.

Im so overwhelmed by this project, im beginning to doubt my abilities... and thats rare. maybe im just a sissy :)

[ma71supraturbo]

Originally posted by rcdsupra
Today I tried to retorque the head since I just upgraded my turbo and had the valve covers off. Anyways I have a brand new torque wrench and have torqued things on other cars to 95 lbs so I know it works, and when I tried to torque doen the head bolts they didn't budge. I tried first at 65 lbs, then 70, 75, and then 80lbs and all I got was clicks. I couldn't break them loose for anything. I tried both ways at 75 and they didn't budge, my car hasn't ran for a year, I guess I will have to retorque after they warm up and I break the car in.

From my post on Page 2:

Many people discourage a retorque, and it will by no means solve an existing blown head gasket. It *may* even cause blown head gaskets, especially on old, original head gaskets. This topic is wildly debated especially on the SOGI email list, and I don't have a strong belief one way or the other. If you decide to retorque your headgasket, I do recommend following procedure to ensure a proper torque. Remove one headbolt, lubricate the threads with assembly lube, and reinstall it to stock torque (~55lbs). Repeat for the remaining 13 bolts, removing only one at a time, and torquing it down before the next bolt is removed. When all the headbolts have been removed, lubricated, and are back at stock torque then you can proceed to increase the torque. Move up in 5lb increments following the TSRM torque pattern. Stop at 70lbs.




The reason you just get clicking is because your headbolts are sort-of seized in place. Once you break them free, they should turn more easily, but the torque specs are all given for lubricated threads (75lbs on lubed threads will turn the bolt more than 75 lbs on old corroded threads). So you need to remove one bolt at a time, then lube the threads, then reinsert just like i listed above...

[ma71supraturbo]

Originally posted by Johnny Dangerously
i would like confirmation on this please....

When you do a MHG job and the block and head are prepped, you are supposed to torque them down to spec (72lbs or whatever) run the car for 100 miles and then retorque it, correct? to ensure a good seal, right?

No, a "retorque" is only done on a car with bolts currently at stock torque... Many people discourage a retorque under any circumstances (search SOGI archives @www.supras.com)

[ma71supraturbo]

Originally posted by mk3turbo
Yesterday when I drained the oil to begin repairing the BHG, and about 1 litre of coolant poured out before the oil started coming out??

Yup. That is almost a sure sign of a BHG. Instead of coolant being burned in the combustion chamber, some of it was forcing its way into the oil passageways and contaminating your oil. Contaminated oil is not good (I suspect coolant in oil and low oil levels are the leading causes of rod knock -- but i digress).

[flubyux2]

i pulled my head and have it all stripped down. and when i pulled the springs, retainers, locks out... i sorted them all and put them in individual bags... but i forgot to put the seats in with them. Is it imperative NOT to mix up the valve spring seats.. or can they be mix-and-match items?

btw, why do i have a sort of crystalline pattern of white ash-ish stuff on my exhaust valves?

also, what do i do if my cam saddles and caps look too scored to be used as-is? is there a way to polish them w/o taking too much material away, or if the cam saddles/caps are scored, does it render the head casting worthless?

one more thing, i STILL cannot get the damn spark plug cover off, those damn 14mm bolts will not come off. its not the end of the world if it doesnt come off before sending to the machine shop for hot tank/machining?

Oh, and i dont have as socket/wrench big enough for the heater hose union on the back, is it ok if it stays on when they hot tank/machine the head?

i think thats all the questions i have for now.

[Pearly Whites]

you should NOT mismatch anything in the valvetrain. put every thing back to where it came from, even the spring seats.

with the 14mm bolts i used an old bolt with 14mm head and grabbed the threads with a beefy pair of vise grips. then use the bolt head to turn those 14mm caps. can be time consuming but it works. i had to keep on adjusting the vise grips tighter.

and the heater union can stay on i belive, so dont worry about it.

[supra1989turbo]

Well im looking at my options for a head gasket in my car .. i know the preferd one is the HKS 1.2mm

but what do you guys think about copper head gaskets. ???


let me know

Thanks.

[ma71supraturbo]

Originally posted by supra1989turbo
but what do you guys think about copper head gaskets. ???


In order to be used, the engine must be O-ringed. Only very qualified machine shops (those used to build racing engines) should perform the procedure. Suprafab (the guys at MAXX) didn't have any luck running copper head gaskets, but copper head gaskets are widely used in racing. Here are some threads of interest:

http://www.supraforums.com/showthread.php?s=&threadid=87493&highlight=copper
http://www.supraforums.com/showthread.php?s=&threadid=84802&highlight=copper
http://www.supraforums.com/showthread.php?s=&threadid=86398&highlight=copper
http://www.supraforums.com/showthread.php?s=&threadid=71006&highlight=copper
http://www.supraforums.com/showthread.php?s=&threadid=40442&highlight=copper

[steve_mk3]

you might want to check out this site. I will need to do a BHG repair and thought it was helpfull-
He goes thru the repair, I agree that the TSRM is to technical and does not have enough tips along the way

http://www.geocities.com/MotorCity/Speedway/1636/bhg.html

If you find any other please post-

[ma71supraturbo]

good link

[sneakypete]

Shorty, I will be attempting the change the headgasket in my supra. There are no reputable machine shops anywhere I live (new jersey) that offer head rebuilds. I do have some concerns about getting a rebuild head. I did some research and found a good place that does cylinder head exchanges and they give a warranty. What I've heard is that when you put a rebuilt head on an old car like mine (126,500 miles) increase of pressure could cause the lower end of the engine to blow. The explanation I got from several mechanics was that the new seals will increase the pressure on the rings will cause them further breakage. Out of the four professionals I asked, they suggested that I either get the engine rebuilt, or just replace the headgasket. If anyone has any further information on this subject, it would be greatly apprieciated. Or if anyone has put a rebuilt head on their supra without rebuilding the lower end, please let me know if its a good idea.
Thanks
-Pete

[steve_mk3]

Pete-
I just moved from S. orange to middletown. I have never changed the HG befor. I am looking at a car on Friday that has a BHG and will need to be replaced. Also has high mileage, 135000. The engine was replaced once before about 70k ago. I have found a rebuilt head but it will cost about 500. how much for the exchange? contact info? have you found additional info on doing this?
thanks
Steve

[steve_mk3]

ok -
so I am reading the tsrm, I get to page em-37 and say to myself WTF!! item #6 says remove all this wires. I have no idea what they are or where they are. When I read thru the geocities link above he makes no mention of removing all this! which is correct?
do I try to find a haynes manual?
HELP!! I want to do this, but without good instructions I will fuck it all up

[sneakypete]

steve-
the company i ordered from is called aluminum head rebuilders. if you search their name of the web you will find their website. they charged me $455 shipped plus a $100 core charge. if the engine was replaced at 70k miles, then why has it already blown its hg?

[flubyux2]

Steve, i know exactly what you are talkign about. The TSRM expects you to know what every stupid little gadget is on the car... including their ridculous technical name instead of "the IAC valve"... they call it something like Idle speed adjustment control bypass solenoid vaccum valve" or some stpuid shit ilke that. basically, disconnect every connector, even the starter wires, and remove the wire harness and lay it off to the side. try to remember where it goes, but since its allin a harness, everything should lay in place when you put it back together. Plus, they have plugs that only go onto one receptacle.. so its not that hard, it should work out.

My rebuilt head was $250, from a local toyota guy. but it wasnt fresh, it had ~5000 miles on it since the rebuild, according to the shop owner. apparantly, it was on a kids car, he wrecked the whole side of it, and the shop owner bought the car for the drivetrain. he pulled the head and i boughten it offa him. everything is in good contion, looks great. all valves are shimmed up to .005-.007 on the intake side. on the exhaust, ranges from .007-.009... so its all real nice. the cam bearing journals had a few minor score marks here and there... but, i guess ill hve to live w/ it.

Is it hard to find a head w/o any freakin score marks/grooves in the cam bearing journals??? my stock head and this rebuilt unit both have markes.

btw, the HG may have blown, cuz all the manuals (chiltons and TSRM) still say torque specs of 54 ft/lb. so if you had someone who follows instructions REAL good, then thats the reason...or a good chance that its the reason the new HG went

[steve_mk3]

Pete-
Thanks for the info
flubyux2 hit it, the 70k engin has the old hg and bolts!

Since i put the deposit down today, I will be getting the car next week. Starting the teardown soon!!
then you will see the HELP posts start :-)

Steve

[steve_mk3]

A few more questions-
1- where do I get a lapping tool?
2- how do you keep all the crap from going into oil/cooling passages?
3- I read on some post aout cleaning the pistons etc with brake cleaner fluid, again how do I keep this stuff from getting into the passages?
4 after cleaning everthing up(pistons walls) do I put oil on them?

Thanks for the help

Steve

I have found some answers
http://www.supraforums.com/showthread.php?s=&threadid=129921

[buhbye]

So Many questions and no one is answering. I thought this was a FAQ??

Ok so here's my Situation:
I'm planning on removing the turbo and doing a HG replacement. My car has 150K miles. It does NOT have a blown HG. But I plan on getting my head rebuilt (or just find a rebuildable one to minimize downtime) while I'm at it. The whole reason I'm doing the HG is to allow for peace of mind while venturing into lower ETs and Higher HP figures. I really do not want to remove the engine nor do I have the tools to do so, so I really don't want to deck the block, but suppose I would if I needed to. Now. Here's my Questions:

1. What RA does the head need to have? How do I need to tell the machine shop I need my Head done when I bring it to them? I don't wanna sound like a dope and I wanna get a good quality product here.

2. Should I be ok if I skimp on block prep?

3. WHERE do you get a lapping tool?

4. Where do I get a professional straightedge (sounds like a fancy ruler to me) and how much do they cost?

Thank You!

-Casey

[flubyux2]

I thought this was a FAQ
FAQ means "Frequently Asked Questions" not "Frequently Answered Questions" maybe thats the reason people dont answer. :)

1- where do I get a lapping tool?
2- how do you keep all the crap from going into oil/cooling passages?
3- I read on some post aout cleaning the pistons etc with brake cleaner fluid, again how do I keep this stuff from getting into the passages?
4 after cleaning everthing up(pistons walls) do I put oil on them?

1.There is a Lapping tool that you can buy from Reg i think... IIRC, i remember reading his How-to and he mentioned that he sells the kit w/ the polishing compound and everything... its lke $250.

2.Fill the tops of the holes w/ Silicone sealer. when you are done, use some tweezers and a disposable utility knife w/ the break-a-way blades to remove it.

3. You can use the brake cleaner to scrube the tops off the pistons. scrape as much off before you start using chemicals. you should have filled all the holes in w/ silicone sealeer before doing this. you could use a brass or stainless steel bristle detailing brush. i bought a 3-pack from Autozone for like $5

4. Put oil on the cylinder walls AFTER tearing it down since they will be dry, and exposing them to the atmosphere will allow the moisture to condense on them (like your windows in the early morning, and this will leave surface rust scale... not good. so get a lint-free rag, soak it in thick oil, i used 20w50. then wipe down the deck surface and the cylinder walls, lavish oil upon them... and prevent rust. I already read about a poor guy who did this, and his car was kept out on the street in front of his house, and his cylinders rusted.

1. What RA does the head need to have? How do I need to tell the machine shop I need my Head done when I bring it to them? I don't wanna sound like a dope and I wanna get a good quality product here.

2. Should I be ok if I skimp on block prep?

3. WHERE do you get a lapping tool?

4. Where do I get a professional straightedge (sounds like a fancy ruler to me) and how much do they cost?

1. For a MHG, the RA needs to be 3-8 i think. some rinky dink shops tell you that you dont need a surface that smooth and that you need 'bite', i expereienced this first hand, just as mentioned before. they just wanna take youre money and dont give a shit about what your engine really needs to be assembled properly. for a composite...~30-40 i guess. i still have fly-cutter ridges on my deck from the last time the engine was taken apart. i just scraped it clean w/ a single edge razor and brake cleaner... i had to scrape and scrape cuz black stuff kept coming off

2. for a composite gasket, you can get away w/ just scraping and cleaning... most of the time, block decks dont warp. it takes soem serious overheating to warp an iron block... youd have to be a Reeee-Tard to let something like that happen. "Just raise your hand, and Tommy will come around and hit you on the head w/ a Ball-Peen hammer because you are a REEee-tard"

3. Reg Reimer i think... from SONiC. im pretty sure it was him selling the Portable lapping tool. http://www.supras.com/~riemer/sonic/sonic.htm

4. I looked everywhere and could not find one to buy... best thing i could do is become friends w/ the local supra shop/machinest shop and KINDLY ask to borrow theirs for an hours... after bribing them w/ a 12pack of Bud... or Pabst Blue ribbon, dependnig on the age of the Bribe-ee :)

EDIT: i found it for you: Reg Reimer's How-to for MHG use (http://www.supras.com/~riemer/HKS/hksgaskets.html)

[supra-g]

hey guys my friend also just finished putting a fresh mgh
in but he is idling really high and rough....
I guessed that he just needs to get the timming right....
could he have done something else not to have gone
through this. cause im about to go in there and i am learning
from all his mistakes...
thanks,..
g

[flubyux2]

Yea, i have a feeling his timing is advanced too far. i had that problem cuz i had a hard time getting in my CPS correctly, it was always a tooth off, and idle real funky... it didnt help that i had a massive vaccum leak either though.

anyhow, when i fixed my vaccum leak, it idled smooth and real high, like 1400. When i put a light on it, it looked like it it was 27* BTDC... all i could see was that it was like 1.5" to the left of the timing marks... i twisted the CPS, counterclockwise i think, and the idle came down, and the timing mark started moving closer and closer to the marks. i set it at 13* BTDC.

I have a timing light for sale now.. BRAND new, only used once :)
$35 and you too can be a proud new owner of a NEW timing light!

[Nuke '83]

OK, now for my question; Given that I am going with ARP bolts and stock headgasket, how do I best clean the remains of the HG off the Aluminum head without scratching the hell out of it?

(Yes, I know I should send it out to a shop to have it machined, and the valves re-done, and have the block lapped, and a MHG, and...I just want to stop spending $$$ and TIME on a car that doesn't move!)

------------------------------------------------------------------------------------

I have so many issues with repairing a BHG on this engine...

First, if you can afford it and the shop will torque the head to 75+ ft-bls, just pay for it.

Second, the instructions should start with "Detail strip the engine (including the exhaust) until you get down to the engine block".

Third, what moron in design decided to route the wiring harness THROUGH the intake manifold?!?

And last, but not least, the TSRM is worse than Haynes/Chilton (which are pieces of crap). They at least have pictures (sometimes actual photographs) of the weirdly named Toyota part you are supposed to remove.

[SpeedySupra]

Hello Everyone,

I have been a member of this forum for about a week and this is my first post. I have done alot of reading in the forum and have gathered alot of great information, so for that I thank you.

I love my Supra and it is quite the rocket when you are coming out of a 79 datsun 210!!!!

Anyhow to the point. I get to join the BHG Club and have ordered the HKS 1.2mm gasket and ARP head stud kit. My question is, is there a preferred type of Gaskets for the rest of the job?(Intake, Exhaust, Turbo, Valve Cover, etc.)

Toyota? Felpro? Napa?

Thanks for the help guys.

Speedy;)

[MrBoost]

Toyota gaskets are pre'd for the rest of the motor.

FYI, the headbolts are easier to work with. The studs require the engine to be removed unless you do this one special unique trick to work em with the motor in-place. DO have the head/block surfaces fully prepped or you will be doing it again, gauranteed.

[fatboy]

I like the HKS cause it is black :D haha

[s000pra89T]

HKS here too....


BTW, were't there BHG Club T-shirts?

[supra-g]

alright guys getting ready for the tear down, got the
apr bolt and hks 2mm bead, now my question is,
is the head gasket kit that toyota sells all i need to get
started or will i need some other stuff? I dont want to have
to leave the car AT ALL while im doing this. want to have everything
so that there is nothing in my way. so should the kit be enough?
thanks.
g

[steve_mk3]

I think that depends on what you consider to be everthing?
I dont mean to sound like an ass, but I am in the middle of the teardown as well. I think that I will replace all my vacume hoses, coolant hoses, power steering lines. also while im in there might as well do the timing belt, and all the belts on the front. I think maybe also the water pump.
Just my thoughts.
from what I have read if all you want is stricktly the head then yes just the kit should sufice.
Steve

[supra-g]

yea i only want to change whats necessary, if its broke
or brakes while im there of course its being replaced.
i was talking only about the gaskets and stuff.
thanks though.
g

[adjuster]

I have a 83mm Greddy 1.5mm MHG, but my pistons will be 85.5mm bore HKS ones.
Anyone ever had any issues with a smaller HG bore that the piston bore?
I think the thicker gasket between the bores, and the coolant passesges will be better, but with the larger pistons, do I need to get a 86mm HKS gasket? (Sucks, the Greddy is brand new still.)
Also I have checked it out, and the minor bends I was worried about are nothing to worry about. (I'm just very picky, so I ask questions.)
SO, can I run, or who here has run a larger bore under a smaller MHG size? (Stock bore is 83, but many people are running larger pistons.)
I don't think the piston can "hit" the gasket, but having that much gasket stick out over the edge can't be that great.
It would keep compression up however v/s a 86mm bore gasket of the same thickness.
Thanks for all answers or thoughts.

[ma71supraturbo]

I wouldn't run the smaller bore. I would imagine that that lip would be a nice point to collect heat, helping create preignition.

[supra-g]

after the head is removed and manifolds are out, will you
need to take out the valve springs, valves, etc?
or can the machine shop shave with the things on?
just want to know how far to go....
thanks
g

[steve_mk3]

supra-g
you need to call the shop that is doing the work and ask them how they want the head delivered to them. The guy that did mine wanted it all together, but he removed valves/springs/cams etc. I would think at the very least you would need to pull the cams off so the valves are all closed.

Steve

[supragook]

was wondering on the quality of this gasket set?? i just went to an oreilly's here in town and thier gasket set was gona run me 300 bux.........now let me know on your guys' opinions on gaskets.......they all the same right? on the head gasket i'm switching to hks after i get done with the machining.....deck work etc.....
i tried to quote a earlier post........but the gasket set was ishino from thepartsbin.com

[SilkE]

Adjuster asked about running the smaller bore hg with the larger bore cylinders but I have the opposite question. I have the stock 83 piston bore but want to use the HKS hg - 1.0 mm, stopper type. It has 86mm bore. Will this cause any problems to have a 3 mm higher bore on the hg than in the cylinder?

The other question is, since this HKS gasket is coated with flourine rubber, do you think it will still be necessary to use a lapping tool? I do not have a bhg but having the hg replaced when having other work done on the motor. The motor is still intact so I don't know what condition the block and the head are in.

Last question: where can I get that copper spray that someone in this thread mentioned. Or is it not a good idea to use that?

Thanks for help!

[flubyux2]

Head machining: i had my head machined for my DSM at Clearwater Cylinder Head Exchange for $65, but that included removing the valves, springs, seats, springs, retainers and locks. the ONLY reason the guy removed them was because the head has been milled a few times already and this next pass would have actually cut into the valves. normally, the valves are recessed up into the combustion chamber far enough above the plane of the head surface that you dont NEED to remove them.. but some shops have their own preference. id take the cams out, put the cam caps back on loosely, and drop it off.

HG bore Vs. Cyl Bore: i dont think its a good idea to use a mismatched bore when referring to HG and Cylinder... if the HG bore is too small, youll have exposed HG material inside the combustion chamber, a good 1.5mm ring of gasket all the way around the chamber... now if your block has been decked, youre at a greater risk of your piston hitting your HG, but usually there is a little space between the crown of the piston and the top of the deck surface. it will raise your compression a little, but i dont like the idea of that much gasket being exposed... the melting point of elemental Copper is 1084.6°C or 1984.3°F. Combustion chamber temps can get higher than that, im quite sure... especially around the exhaust valve areas too. share edges and protrusions collect the most heat, like the sharp corner of a the gasket bore.

Copper spray: you can find it at Napa, Carquest, AutoZone, Discount Auto, Parts America, etc. Its just called Copper Gasket spray, they will know what you are talkin about. you know that stuff looks like copper cotton candy when you spray it? if it doesnt hit its target, it whisps around into little threads... weird. anywho, its usually not INTENDED for performance applications. Ford uses it for their MHG applications to save time by avoiding the Lapping process and allows them to get away w/ the normal Head and block machining process that leaves the cutting marks. I was looking for the easy way out when i thought about the spray... but, i think id much rather take the xtra time and effort to do it the right way and use the SONiC lapping tool that Reg Reimer has. see, i came to the conclusion that its damn near IMPOSSIBLE to get a machine shop that can resurface a block or head and not leave those cutting marks. ive just come to accept the cutting marks as the byproduct of your average machine shop's current level of quality/technology. If i want something done the right way, i have to do it myself..

Conditin of your block: the blocks almost NEVER warp... honestly, i didnt even check my block for flatness. I just scraped it and cleaned the shit off the surface, wiped it down w/ brake cleaner and proceded to put the HG on. Its only been a few 1000 miles, so theres no telling how long itll last... but i used ARP's and torqued them to 85 ft/lb...i think its sufficient for the next several years. the mods in my sig are only waiting on one thing: four more 550's from my friends DSM... and then i can complete all the shit in my sig, then ill find out how good the HG job really IS.

[SilkE]

Thanks very much for that reply, flubyux2! :cool:

I'm thinking the best thing for me to do is just get the OEM hg, ARP studs, torgue to 75 lb-ft and be done with it!

Hey BTW, your sig. didn't show up so I couldn't see your mods. This is probably a really stupid question but did you install the two 550 injectors you already have and run with them? I'm looking into doing the 550's but with the little bit of looking I've done found them for $95 ea. Kind of pricey!

[Supra0fDoom]

Any advantages to one of them? I have a 2.0mm GReddy MHG sitting in my room that I bought last year... and I'm finally thinking about doing a complete rebuild, would the 2.0 be a good choice?

[Level10Supra]

do you need the hg repair kit?
i hear everyone say apr/hg/machine done.....
again it could just be a given.....
lmk
thanks

[Teraka]

If the stock gasket was 1.2mm and I took off 0.012" (~.3mm) that's a 1.5mm gasket that I want (thanks to ma71supraturbo for the numbers).

Now the Greddy 1.55mm has a bore of 85mm and the HKS 1.2mm has a bore of 86mm (according to mvpmotorsports).

So other than the obvious 1mm between the two, whats the difference?

[flubyux2]

almost all the mods i was fixin to do are completed. My emange is installed, my walbro is in and hardwired, my 550's are in, my lex meter is in and my boost is cranked up... now my clutch doesnt hold all the power im making... only thing i havent installed yet is my J-tube bypass and my electric fans.

remember, the only reason people talk about torqing bolts down to 75 lb/ft is cuz the OEM bolts can only sustain that much torque... the ARP's can hold way more and you should take advantage of that and torque them down to 85-90 lb/ft and USE the ARP moly lube that they supply w/ the bolts/studs!!!!! that stuff is slicker'n Greazed Owl shit!

[Yeahdoug]

How much hp can a new designed toyota hg take. I'm buying a car that has a bhg but comes with a new stock one. Arp bolts and all other gaskets. I was thinking just to slap the new designed gasket on to learn how to drive that car ( never owned a 5 spd and rwd car). And to get the car titled I'll need to get it inspected. Can't pass with a bhg and I only have a certain amount of time to title it and until the temporary insurance runs out (not gonna insure it in the winter). Should I just wait until the new hg blows to do the headwork required to run a MHG. Will I be ok running 15 psi on the greddy kit for awhile.

[flubyux2]

really... the smart thing to do, would be to do the job right, and do it once... i know im gonna hate having to tear my motor apart later to do the MHG job... but once its MHG'd, itll last forever.

Im fixin to run 400-450 RWHP on the stock HG till it blows... thats all im shooting for honestly. and as long as i keep the oil full and the pressure up and the detonation in check, i can run it and not worry about the HG.

Detonation is the #1 thing on a stressed out motor that can hasten the failure of a HG, rod bearings, piston rings and ring lands.

[Yeahdoug]

Tearing the motor apart doesn't scare me. I have a friend who has done 3 hgs on mkiii's. So it won't take that long. I just don't want to dick around with the machining right now. The motor has really high miles and mght not even last that long.

[Yeahdoug]

Anyway to tell the difference between a BHG, Bad rings, and oil seals on a blown turbo. I went a just drove a mk3 and at course at start up it puffs a little smoke. But then if I sit there and rev it it will puff out more smoke. The car only make 3 psi so I know the turbo is shot and it has 217k miles on it. I asked to do a compression test and through past experiences they won't allow the car off the lot without a salesman and the salesmans doesn't want to go get one done. :rolleyes: Temperature gauge doesn't work. After warming up it won't smoke anymore (15 mins) but I think the turbo is leaking oil cause when you drive it you can smell burning oil and drips a little on that side when shut off. So anyway to tell? If its just a BHG/bad turbo I'm gonna get the car but if the motors shot I don't want to replace it. The motor is also spotless unlike the rest of the car. The car is a 5 sp/targa and I think I can get it for 1000

[ma71supraturbo]

217K on the 7mgte is relatively high. whether it needs a rebuild now, or in 40,000 more miles I think is a mute point since you have to tear it down anyway for a good HG job. So if you don't want to rebuild the engine as well, find another car IMHO

[Yeahdoug]

yeah I just don't have the room to pull a motor right now. I have a garage that I could do everything else in (hg). Just wouldn't want to pull a motor in it.

I was thinkin that the motor is so clean that it might have been rebuilt or replaced. Anyway to check? THe dealership doesn't have any past history on the car at all. Does the motor have a vin on it anywhere?

[VR4yosoupraz]

Yea I just spent 30 minutes reading the whole thread so I think I've earned my questions. My moms 92 MKIII turbo has like 105k on it and it definately has a BHG. She took it back to the dealer where she bought it and they pulled up the service records saying that it had been done there before. For this reason the guy said that the head was probably already milled down and therefore they could not mill it again so her best bet would be to replace the entire engine. He said the only service they would offer her was installing a Jasper motor with a 75k warranty. Parts and labor- $5000.
I said she was nuts if she did that. If you spend 5k on a motor the tranny could go, or any other problems could happen and if you modify it in any way I'm sure the warranty would be void. I say that we can just use a thicker HG to compensate for whatever is taken off the head.

The problem is how do I know what was taken off the head during the first time? I guess I could just measure the thickness of the current gasket and add whatever is taken off. I would rather know for sure though. Is there a way to measure the entire thickness of the head vs. stock?
This car has never been modded, and it was parked right away (it wasn't driven hot). I'm trying to talk her into letting me do it. I just want to make sure I know which HG to get.

[flubyux2]

well, youd have to pull the head off to measure it first, there are usually things like 'wear indicator pads'. my DSM has this, and it is a recessed area that is the MINIMUM service limit before the head is not reusable... My DSM head has been shaved twice so far and is AT the minimum service limit right now... so if i ever have to pull it off again, its junk since it cannot have anymore material taken off it.

its hard to say exactly what the service limit is on the 7M head since i dont know what it is.

and for $5000, you could rebuild the motor yourself and have a pretty stout motor, including a metal HG, forged JE pistons w/ High temp coatings, shot peend rods, titanium valve spring retainers and seats, double valve springs, 2JZ valves (1.5mm oversize) and pay for all the necessary machine work.

but, you can get a thicker-than-stock head gasket, it would have to be a metal HKS head gasket or the like, cuz those are the only ones that i know of that will safely add space between the head and the block in order to keep the timing belt/valve train in proper order and to keep the valves from touching down on the piston domes. there are copper head SPACERS out there, i know they are available for hondas... but they are TEH DEVIL. i would recommend AGAINST them since it allows more combustion pressure to be placed on the gasket bore than should be.

hope that helps... you should be able to get a car w/ a BHG for dirt cheap... considering that it could require alot of money to fix... you odnt have to let them fix it.

[voidstar]

I've read this thread twice (great info!) but want to verify with the experts a couple questions. Background - I'm the original owner of an 86.5 NA and I'm in the middle of dealing with my first BHG @ 138K miles. I detected the BHG with a block tester- it never severly overheated (just a few wild temp gauge swings prior to testing). I've got the head off and took it to the machine shop where they measured it at .010 in warpage on the deck side, he did not check the cam journals. There are also moderate grooves in the head from the HG cylinder rings (just on the exhaust side) that I can feel with a fingernail. I'm not looking to for any performance mods, etc - I just want to get as many easy/cheap miles out of it as I can. I do not want to go the MHG route... I'm planning on using the Ishino gasket set. My questions:

o The machinest says he will have to remove about .015 in to get rid of the grooves. Will this be too much to still use a stock thickness gastket? Just how close are the valves to the pistons in this engine? Will they still clear in event of a timing belt break?

o He suggest a shim gasket but was unaware if one is available for this engine... could this be used with the Ishino gasket?

o What would be the impact of leaving the grooves, or resurfacing enough to partially remove them?

o The block deck also has some minor grooves in the same place (not as deep as on the head). Will these likely be ok? As the block is in the car I can't easily have any machine work done on it... I've just cleaned the deck surface as best I can.

o Should I use copper gasket prep spray on the Ishino gasket?

Thanks!

[flubyux2]

my head came back resurfaced but still had grooves in it from the fire rings on the previous head gasket...i installed it anyways w/ a stock-thickness head gasket and i beat on the car regularly and havent had any problems yet... i run anywhere from 1.0-1.2 Bar on the stock CT and stockc intercooler... it pulls like a Son of a bitch once i get near 1.0 Bar, plus it REALLY starts sounding like a real turbo w/ a very very audible whistle like a semi truck turbo. however, my car runs richer than rich. the plugs i pulled out the other day show no signs of leanness or detonation... but this is probably a freak occurance, especially w/ the boost i have been running.

the only thicker-than-stock gaskets i know of are the aftermarket metal HG's... like the 2.0 MM HKS gaskets. spacer gaskets or shim gaskets are generally a bad idea... a cheap fix to a serious problem. i wouldnt really recommend it, but since your NA you might be able to get away w/ it.

whatever you do, upgrade the head fastener hardware to ARP; either bolts or studs.

you CAN use the studs and install your head w/o having to unbolt your motor mount or rock your motor or any of that BS. the key to using Head studs w/ a motor that is in your car is.... REMOVE THE EGR COOLER. this will give you the clearance you need to drop your head straight onto the block w/o interference of the firewall.

the other solution would be to install the head on the dowles and gasket and install the studs thru the head... the install w/ an allen key, so you could thread them into the block and hand tighten them down snug with the head already on... then just install the washers and nuts and torque to a minimum of 85 ft/lb. with studs, i would probably go w/ 95 ft/lb in 3 stages; 30, 60, 95 and the one final pass to make sure you didnt forget anything.

w/ a composite head gasket, i would advise against the copper spray, espeically w/ the graphite-type gasket.

hth
kthxbye
Chris

[MotoFool]

has anyone ever sucesfully O-ringed the 7mgte block

with steel orings around the cylinders and usging a copper gasket around the outside or some rubber orings around the outside for colant and oil holes..

[mc17]

i really need some post-BHG, pre HG replacement info. (and i didn't find anything really specific after reading 5 pages... really specific is what i need.)

it'll be at least a month before i can have the HG replaced. what do i need to do? drain the coolant? i mean as specific as possible... drain the coolant and let it run for 15.4 seconds? then raise the front end up 2" for airflow dynamics... what the fuck ever.

the car HAS to sit for nearly a month, and it's been sitting (most likely with a cylinder full of coolant...) for about 4 days already. Am i screwed? is my cylinder rusting? my combustion chamber corroded beyond all hopes? will it be in a week if i do nothing?

any info would be spectacular.

[flubyux2]

if you have a pretty decent mix of coolant in the system, then no, your cylinder would not be rusted. Coolant itself is a rust inhibitor, or at the very least, contains rust inhibitors. but of the coolant is watered down too much, rusting could be a potential problem.

My car blew its new HG, but thats what i get for running 1.2 Bar on the stock turbo at a "normal" AF ratio. i was gettin away w/ 1.2 Bar this whole time running pig rich. but as soon as i did the J-tube bypass, my car blew the gasket the very next day. but thats what i get for not taking the time to go thru the extra work of pulling the motor, doing the machine work and using a proper MHG.

but, right now, im saving money and accumulating parts for an entire rebuild... so my car too, will have to sit for about a month before i can begin working on it... so i know what your deal is. but when im done, ill have a motor able to handle damn near 1000 HP... but ill only run about half that.

[76celicagt]

anyone have info on copper head gaskets?

[Brady89]

Hey guys I read through the thread and I have a bhg. I am going to replace it with a 1.2 hks metal head gasket. Also with some arp head studs. I am having a mechanic do it and he said I need to supply all of the nessasary material to do it. Is there a kit I need or just the hg and arp studs? I really need to know as soon as possible

THANKS

[Keo]

I think he means a head kit, which includes all the other gasket above the head i think it's around $300 at toyota

[Mo87NA]

Alright I've read the the entire thread but I just have one question. My car does not have a BHG, but just for my own sanity, I'm planning on putting one in. I'm in the process of buying a newly rebuilt head that has already had a lapping process done to it. Since there seems to be nothing wrong, do I still need to lap my block, or could I get away with making sure everything was smooth and there were no signs of pitting. I really dont want to take my block out. Any advice is appreciated. Thanks

[A Mack]

hey i am close (i guess you could say that) to getting a 87 turbo w/ 130000 miles. i cant even legally drive the car AT ALL until september 1st, so i have plenty of time to fix stuff on it and mod things until then (if i do get the car, that is). I was talking to my dad about how when i do get a supra (be it THIS one, or another one) id do alot of preventative stuff and matience before i started putting performance mods on it (exhaust, intake, etc.). i mentioned to him that if i got a turbo, i was thinking about maybe putting a MHG on to prevent a BHG, but he said that was a job 'ya only do when you get a Blown head gasket', and didnt need to be done if you didnt have a BHG. now my dad used to be a mechanic, in the 80's and hes built plenty of engines in his time (granted they were all chevelle, nova, and camaro engines from the 70s), but i cant help but think that the best preventative measure to put on the car would be a MHG.

i heard they cost like 200-300 (i could be wrong by a long shot), and my dad said to have one put on, would be close to 1000 (which i dont think i wanna spend..considering all i have is 2000 and that will be going towards the car). but i thought if it only costs 300$, and we could put it in ourselves, it would definately be worth it. i dont know how much BHG's cost to replace, but i heard it was aLOTTTTTT.

heres my question: is it recommended that i do put a MHG on if/when i get the car? and if i convinced my dad to do it himself, how hard would that be, and how long would that take?

thanks.

[malloynx]

well, it's really about how you feel. i'm running a stocker and have 0 problems with it. i'm shooting for 400rwhp. right now i have my stock ct-26 at the max and the stock HG is holding up fine.. i got arp bolts torequed to 80ft. lbs. just control detention and you should be fine.

[tunaman]

Just got an 87 N/A with 170K on it for 600 bucks. It has a BHG so i'm getting a kit from a parts house w/timing belt and tensioner.

Some people have talked about using the stock head bolts for a re-torque on turbo cars, but not on an N/A motor. I have no plans of ripping the shit out of this motor, only bringing to a max of about 5500 RPM's.

So can i re-torque the head bolts down to the recommended 72ft lbs until i save up for my 7M-GTE swap in about a year which i will put a metal head gasket in with ARP studs.

[MK3Brent]

I had some different brand head bolts on a 7mgte... didn't get the packaging...

Basically I wanted to know if there is a breaking point for stock bolts.... or aftermarket (non APR) bolts?

Just some food for thought.

-brent

[tunaman]

re-torque on NA head bolts.

opinions, experiences, anybody.

[MK3Brent]

I retorqued the replacement head bolts.... after so many miles though, the bolts are very difficult to turn...

[Supra887MGTE]

im looking at a 7mgte with a HKS MHG and arp bolts or studs, not sure. anyway the guy said it didnt seat right but the head was resurfaced and the block wasnt. it runs but looses coolant...is it possible to just take the HKS MHG off and use a stocker without any other modifications to the engine?

[MK3Brent]

A stock gasket will help with the mating of the block and head.

Metal HGs need to have a perfect flat mating surface.

If not... then you won't have the cussion that the OEs can provide.


Regardless you need to have the head milled.....make sure no warping happened.

If you're going through the trouble.... you might as well get the block decked, (lapped w/e) and have a nice MHG put on.

You can perfectly run OE gaskets with ARP hardware... and have a longevity.

[Supra887MGTE]

the head has already been milled though or should i have it done again?

[MK3Brent]

Hmmm.... not really.

It really depends on whether the head was on the block for a long period of time where there was direct detonation.

Little explosions in the cracks could induce warpage.

BUT

Both the block and head need to be SERIOUSLY mirror FLAT... for a MHG to work.

[Supra887MGTE]

if im going to use a stocker, is it a bad thing that the head was milled for a MHG and the block isnt? do i need that "bite" for the stocker to work?

[dziuggy]

Ok here i go again...........

this is my story.

I just got the car back with JDM motor 30k or less at least my mechanic was really please with it. since i got i back i probably have like 500 miles on it not more. there is no sigh of any problems but i am on stock boost and bad turbo right now. Now the bad part.

Well my mechanic is preaty smart guy but he deals with mostly rutine stuff on daily basis therefore it took him forever to replace my engine. so at some point he convinced me that JDM engine which had no BHG, does not need head/block resurfacing (also it was probably because he worked for VW for a while and VW's use metal headgaskets as well, quite common problem and they do that without resurfacing). anyways i was anxios to get me car back so i went along with it. So HKS 1.2mm MHG was installed (with ARP bolts) without resurfacing block or head so far i have no problems, and i have been told that my block and head were in great condition although it was't checked thoughly. anyways this is my standpoint:

fresh JDM engine.
HKS MHG and ARP's - no block or head prep.

what is diferent routes i can take as if right now. I red all the faq and most of them does not recomend resurfacing the block, but then laping looks like a good idea - nesecary or not???
now how about the head resurface and do valve job (3")????

or at this point i should just buy redesigned toyota HG take of the head and put it back together.??????

i am planing to run SP61GT, and i believe that this will stay my daily driver so i will be runing it 14-18psi every day.

any help/sugestions is apreciated.

aslo NOR CAL guys anyone knows good machine shop in nor cal?
some pricing would be great as well if you have done it.

Ziggy

............................................

[MK3Brent]

if im going to use a stocker, is it a bad thing that the head was milled for a MHG and the block isnt? do i need that "bite" for the stocker to work?

No.
The OEM gasket is squished between the head and block and is held in place by the studs or bolts. (Depending on whether you use APRs, or other brands)

When my 89 7mgte blew her gasket, I had the head milled, then INSPECTED the block...(Nothing serious) so I put a OE gasket on, and some 11mm allen head studs in.

Stock setting is 58 ft/lbs
Recommended is 72-80 ft/lbs (Higher for ARP hardware)


what is diferent routes i can take as if right now. I red all the faq and most of them does not recomend resurfacing the block, but then laping looks like a good idea - nesecary or not???
now how about the head resurface and do valve job (3")????

Re-surfacing in VERY necessary if you'll be running a MHG ONLY IF THE CAR HAD A BHG BEFORE THE MHG. (Very important.)

Think of the most important seal in the entire engine leaking over the period of let's say a year. That damage can and will in most cases put some type of damage to the head, and divots in the block.

In order for a hard MHG to seal properly, you need a mirror smooth finish on the block and head.

[MartyDaMan1]

If the head is taken off inproper fashion, and I have a jdm engine with only abotu 15000 miles on it, is the head still going to require resurfacing, a lot of these actiles make it sound like the shop that resurfaces it will have the head more messed up that what it was stock. I just do not see how the head woudl get warped on and engine with so few miles on it.

[Enraged]

Question:

I'm going to be doing the HG on my 88T pretty soon. I was planning on getting the head resurfaced and the valve seals done. is it necassary to get a valve grind/ valve job (for CDN$300)? is there any way to check if it has to be done? im tryin to do the HG for as little as possible (doing the work myself, new Toyota HG and ARPs).

[87TurboB]

Ive got a question, hopefully it will get answered asap? My engine is bored .020" (.5mm) oversize. Now do i have to get a mhg with bigger bore size holes or can i stick with the stock bore size on the mhg other than a 2mm thickness due to a bunch of machining that was done? Thanks.

[suprra_girl]

well i've got an hks bead type which is stock bore size but the stock bore gaskets are actually like 1mm larger than actual boresize... so in theory you should still be able to use it

i have an 83.5mm bore (20 thou over) and the gasket i've got which is a stock bore from hks is actually 84mm...

i would think it would work

[chevydude]

Don't forget to retorque the headbolts after 500miles of use. I think some people overlook that part.

[2damaxsupra]

ok i got an question i read much about sympton of BHG, but the only one i have is overflow in coolant tank after when is under heavy accelation (it overflow when the engine is at idle after boosting) Since my rad is leaking a bit so i ruled out BHG. Other than the overflow i dont have any other sympton. Anyone had this experience before? i also checked my plugs as well and they seen to be normal.

[nofear6235]

I had the same symptoms, also if I kept driving without adding the missing coolant, my car eventually overheats, since loosing coolant through the overflow bottle.
I took head off the car and saw my cyl head warped and cracked between 4 and 5 cyl on intake side. Headgasket was fine, its 2mm Greddy MHG.
I won't bet that you have a BHG or bad cyl head, but you definitely suck air into ur coolant system somewhere and push coolant out. I incline to think its related to cyl head (warp, crack, etc), since you have this problem only under the boost, when cyl pressure rise.
If I was you, I would try to re-torque the head, change/fix rad, and if its not help, just remove the cyl head, may be you can save it, before it cracks.
Do search on my tread "Bubles in overflow" it may be help to you
Good luck

[iamking]

so if u got a bgh and want to use a metal hg u gotta machine the head and lap the block?

what if u use regular OE hg's? Can u machine the head, granted they dont shave it off too much, and use a new OE hg with oe bolts without any problems? i plan on having 13-15psi on the stock turbo.

[evolvedrs]

Anyone have any links that work? I tried the ones on the first page.

I'm having an issue with mine losing coolant and missing a little at idle and steady rpms. No water in crankcase, it's not leaking, and not smoking. ???

[Caplax40]

so if u got a bgh and want to use a metal hg u gotta machine the head and lap the block?

what if u use regular OE hg's? Can u machine the head, granted they dont shave it off too much, and use a new OE hg with oe bolts without any problems? i plan on having 13-15psi on the stock turbo.


That's pretty much what I'm looking to do only with ARP bolts. Stock turbo, 13-15 psi. How would this setup work? My Turbo has never had a bhg.

[TorqueMonsterSupra97]

How much does a Head Gasket coast for a 91 mk3

[mr_incredible]

Hi guys,

I have a couple questions regarding head bolt re-torqueing. My engine was rebuilt probably about 30k ago, but im pretty sure the mechanic only torqued the head down to stock specs around 42 ft-lbs. Lately I have noticed that oil is leaking down my block and landing on my exhaust and burning. I had my valve cover gaskets replaced so i'm quite sure that it isnt leaking from my valve covers, so the only possiblility is that its leaking from the head gasket. I want to replace the stock head gasket bolts with ARP head bolts. Is it possible to replace each stock bolt with an ARP bolt one by one? Does the entire head have to be taken off to do this or can I just get him to take off all the stuff in the way and then start replacing bolts with ARP bolts torqued down to 72 ft-lbs? What sequence of replacing should he use, inside bolts first working out? Is this a reasonable solution to the oil leaking from my head gasket?

thanks =)

[nofear6235]

stock spec is not 42 ft-lbs.
If I remember correctly is 52 either 58. Anyways, before you go there, to re-torque cyl head, remove valve covers, clean everything, where v cover gasket resides (both surfaces), install a new gasket (oem Toyota) and evenly! torque to the spec (most mechanics will just missed this part and no matter how fresh valve covers job, it will leak).
HTH
Alex

[mr_incredible]

I actually just replaced my valve covers and im not worried about them.

[1988SupraDreams]

What all is involved in Lapping/Decking the block?

[TurboSupra219]

Ok, I tired to look through all the pages to see if this was covered, but am at work and can't spend too much time. So in short, can anyone tell me how much hP you can run on a stock HG. and how much a with the MHG's 1mm, 1.5. and 2mm? thanks.

[chuck norris]

Im about to take off my head and do some lapping, try to get it down to about 40 - 50 RA so I can put on a Metal Head Gasket.

I have access to a shop with mills, just wondering if you can achieve that kind of smoothness by milling it, or do you have to lap it to get that ultra-fine finish?

[90_turbo]

:english: Had a question about my mhg. I've got a set of arp head studs and a cometic gasket. Cometic reccomends that the head only be torqued to 60 some lb/ft. This just doesnt seem right considering I'll be running 14 psi. Should I leave it like this, go with stock torque, or overtorque to 80 lbs or so?

[mkiii 4 life]

has anybody had any more major problems after replacing the head gasket?

[schmall's supe]

anybody know a good write up detaling a bhg replacement job please?

[7m-gte]

I'm doing my headgasket today with arp studs Guess what it says in the arp instructions. with arp lube, use 80lbs, with a weaker lube, use 120lbs.....it has your torque right there

[7m-gte]

not much substance here, I just feel that I earned the right to post here since I just completed a hks MHG and ar