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Discussion Starter #61
So, I've been cleaning stuff up, waiting on parts, soaking some bolts in penetrant and watching a lot of youtube.

After being so specific on getting a downpipe with a wideband bung already welded on it... I read my gauge manual and then do some research online and find that placement directly at the turbo is as far from ideal as possible.

Manual says to mount at least 24 inches downstream of turbo for more accurate read. So that was a waste, but the pipe still looks good ;) lol

Its so easy to get carried away. I was already reading up on meth/water injection and I had to reel myself in. Lets get the car back together and running, then worry about bigger turbo and shit like that 馃ぃ 馃ぃ 馃ぃ 馃ぃ 馃ぃ

I'm removing the fuel rail, a few remaining plugs and hoses...and the plan is to have the head off this week.

I've went back and fourth on rebuilding the head while its off...new springs, a valve job (not by me)...gasket match everything, polish before it goes back on. Also read a little about porting the exhaust manifold...spooling up a little quicker.....why not, ya?

Literally never ending plan change. For the better tho.
 

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Discussion Starter #62
Everything went pretty smooth.

Then it didn't.

The one bolt closest to the block on the oil return line on the turbo I can't get to, and I'm in the process of cutting the bolts for downpipe off at the cat so I can drop the downpipe and get to the last bolt on the oil return line

The exhaust bolts - half are rounded off and extremely siezed on, the other half are just siezed on. (at front and back of cat)

I was hoping time + pb blaster would get me around cutting, but it didn't.

I'm hesitant about throwing a torch under there, but that may be easier than cutting them off, idk.


Once I drop the downpipe and remove that last bolt on the turbo the head should be ready to unbolt. (I have the rest of the bolts on the turbo to manifold loose)

My tool collection after this project will have doubled. 馃お

PS detail, since I'm having to go nuclear on the bolts anyway, I'll likely throw a cheater bar on and my assumption is the bolt will either round off or the head will sheer off. If it the heads break off less to grind, but as thick as they are I am thinking they'll round off before they sheer off


If anyone has some magic tricks throw them at me
 

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If you have time to wait try putting CLR on the blot threads. You'll have to keep applying it but it'll slowly wick it's way up the bolt and eat away some of the corrosion between the bolt and nut.

Otherwise, yeah the bolt heads are going to round off.
 

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yeah I feel your pain man, it goes together so much easier than it comes apart.

I have had good luck using heat. not oxy / acetylene torch glowing hot heat...but simple propane / map (yellow can) plumbing torches. heat the head up for a few min then hit it with the clr/pb blaster. it will smoke like crazy and boil off....but it (clr) will get pulled into the bolts due to the heating/cooling cycle. it also helps to heat bc it can break up the time/rust welding that is going on. if you get one that fights like a mother I always take a break (do something else) and come back to it 1st thing in the morning when im fresh. funny how they sometimes pop right away after a break

also (more "tricks") I have welded many a cheep sockets / spare nuts onto rounded bolts. Im talking just a few tack welds with a $90 wire feed flux core. the heet from welding it on helps, and yeah it wont slip anymore and will pull the dam stud out / break it off .

...hang in there you will get it
 

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Discussion Starter #65 (Edited)
ALRIGHT!

I got everything off this morning minus the exhaust manifold (turbo is off)

A buddy is going to help me remove the head this week sometime.

I was surprised how easily the downpipe came off. My experience with long pipe in an engine bay is a headache. (Origami like, trying to get it out)

Anyhow, excited to be moving again.

Going to do some reading on exhaust manifold, if it's worth it - or if I should just do a gasket match on factory manifold. Read it will spool up a few hundred RPMs quicker with a cleanup
 

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Discussion Starter #66
I've read if you are going to go the ARP route you have to remove the cams...is this true/ and if so...

Is the ARP setup THAT much better than new factory headbolts at the proper torq?
 

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Discussion Starter #67
244495


I'm a huge rookie, but it appears the gasket had already failed. The piston closest to the radiator and closest to the firewall each had coolant pooled on top, and it appeared the copper (or whatever) coolant port was deformed on each as well - as in the photo attached.

Overall the pistons and walls looked decent to my untrained eye. No scoring or obvious damage
 

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It seems that cylinder 6 and 1 are the most common places for BHG. On all the 7m's that had a BHG which I worked on it was always those cylinders that failed.



I do feel that having the heater valve fully open does help a bit more with moving more coolant from the rear of the motor. Also I have done the zulu mod on the cylinder head (where you open up the cylinder head coolant passage behind the 6th cylinder where it is normally blocked off) so I am very curious on how that will help in the long term. Time will tell but so far it has been good all summer...

 

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Well what I can tell you,

the OEM hg is fragile when it comes to detonation. Doesn't take much to make it let go.

Did you retorque the head once you installed the new HG to 75 lbs-ft?

if using ARP studs, follow the instructions that came with the studs (90 lbs-ft)

rusted bolts,

couple of things you can do. One trick i found that worked even better than the wd40/rust-ez etc is to grab a plain ole plumber torch, heat just the nut and then grab a candle and apply said candle in between the bolt and the nut. It should allow it to release fairly quickly.
 

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Discussion Starter #70
I haven't reinstalled head yet.

I will be going MHG and ARP.

I am taking the head to the machine shop tomorrow for a valve job, resurfacing, and replace anything that needs it. Springs/valves etc. Guy claimed on the phone springs should be ok. Well see.

Getting to this point though, I've found several things I'm definitely changing as it goes back together (egr delete, and cleaning up as much of extra crap as I can)

I did have to cut one wire going from harness to top of transmission (manual) I'll have to connect back up. It was the last thing I had and couldn't get unplugged because it was on top of tranny. Call me ghetto for now. Lol

Advise me on this logic....

I really want a forward facing intake...because if I have to pull the head off again , seems I could just unbolt intake/exh manifold , push over and pull the head. Or am I mistaken?

And ya, I know... Stock stuff across the top isn't THAT time consuming, but it is ugly and extra bolts if you had to pull the head.
 

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I haven't reinstalled head yet.

I will be going MHG and ARP.

I am taking the head to the machine shop tomorrow for a valve job, resurfacing, and replace anything that needs it. Springs/valves etc. Guy claimed on the phone springs should be ok. Well see.

Getting to this point though, I've found several things I'm definitely changing as it goes back together (egr delete, and cleaning up as much of extra crap as I can)

I did have to cut one wire going from harness to top of transmission (manual) I'll have to connect back up. It was the last thing I had and couldn't get unplugged because it was on top of tranny. Call me ghetto for now. Lol

Advise me on this logic....

I really want a forward facing intake...because if I have to pull the head off again , seems I could just unbolt intake/exh manifold , push over and pull the head. Or am I mistaken?

And ya, I know... Stock stuff across the top isn't THAT time consuming, but it is ugly and extra bolts if you had to pull the head.
That reverse light switch connector on the top of the manual transmission sucks as you can't really get to it with the transmission fully installed. I made a small 2 wire extended harness using the factory 2 pin connector so it can be unplugged by the starter (like how the automatic transmission wiring is connected). That 2 pin style connector is very common and you will see that style connector on the alarm horn, heater valve vsv, fuel pump hanger, side markers, low brake fluid sensor plus you will find it on other 80's and 90's Toyota's in the junkyard too.

Do you plan on running a standalone? If not I would personally recommend you keep the EGR if you are running the factory ECU.

If you plan on upgrading the valve springs you should look into the COMP 975 ones. They even sell them in 12 packs for us Toyota guys but they were meant for a Chevy motor.

On the front facing intake you can leave the cylinder head installed and you can change it later to that style with the cylinder head installed. Adding a front facing intake later on is not a problem, the only problem is where to find a good one for sale. The factory intake routing may not be the prettiest but there has been some high hp 7m's with the oem intake manifolds. Also keep in mind you will need a alternator drop down bracket and depending on how the front intake manifold is designed you might have to remove the a/c compressor and or relocate the battery.

Keep us updated on everything.
 

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Discussion Starter #72
That reverse light switch connector on the top of the manual transmission sucks as you can't really get to it with the transmission fully installed. I made a small 2 wire extended harness using the factory 2 pin connector so it can be unplugged by the starter (like how the automatic transmission wiring is connected). That 2 pin style connector is very common and you will see that style connector on the alarm horn, heater valve vsv, fuel pump hanger, side markers, low brake fluid sensor plus you will find it on other 80's and 90's Toyota's in the junkyard too.

Do you plan on running a standalone? If not I would personally recommend you keep the EGR if you are running the factory ECU.

If you plan on upgrading the valve springs you should look into the COMP 975 ones. They even sell them in 12 packs for us Toyota guys but they were meant for a Chevy motor.

On the front facing intake you can leave the cylinder head installed and you can change it later to that style with the cylinder head installed. Adding a front facing intake later on is not a problem, the only problem is where to find a good one for sale. The factory intake routing may not be the prettiest but there has been some high hp 7m's with the oem intake manifolds. Also keep in mind you will need a alternator drop down bracket and depending on how the front intake manifold is designed you might have to remove the a/c compressor and or relocate the battery.

Keep us updated on everything.
Good info here. I didn't think the egr delete would cause hiccups, but I don't PLAN on a stand alone, so I may just leave it be for the time being.

FFIM - I'm definitely keeping AC if possible, so I'm going to have to do a lot for research on this.

Looks good as hell, but if I'm going to drive the car outside of winter I want AC 馃槤

Good info guys, I will give another update when I get my head back late next week and discuss more
 

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Discussion Starter #74
A little update, the head was warped 8 thousandths according to the machine shop I took it to. I'm supposed to pick the head up in the next 2-4 days and will begin putting stuff back together.

I've been trying to match up replacement hoses while I had down time...it would so help if they had a number sequence and a picture with the kit I bought...but oh well, it was affordable. Lol
 

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Discussion Starter #75
Waiting on my gaskets and all to get here, got bit in the ass...

I told the machine shop to order the head gasket since they knew exactly how much they were taking off, to keep me at stock compression.

Very established and reputable shop

They charged me 205 for the cometic HG. cool. Except they only ordered the head gasket not the top end kit. Top end kit is like 205 in summit, with the HG.... Meh. They have strict rules on returns so ya, I just had to eat this one.

ANYWAY.

Head looks like new. The rest of my gaskets should be here Monday or Tuesday.

Gasket matching everything and then re-assembly!

On another note... Ive cheated on the Supra. I got another little toy I couldn't pass up I saw a few weeks ago.

1973 240z with a fresh RB20DET in it w/ rb25 turbo. It's a fun little car, looks like a rat rod at the moment. But the engine/engine bay is on point, needs rear LCA's but has had BC coilovers installed and it is very rigid, solid handling little car. A little video (sound is junk, I need a remote mic)

 

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Yeah, its got the insert. When I zoomed in on photo, I think I can see where they broke off the piece that's used to turn the heli-coil.
When I did my BHG, I also noticed that 2 or three exhaust nuts were loose. But, when I re-installed them, I was able to torque them down to spec. In hindsight, I should have had them heli-coiled since the exhaust threads issue seems common to 7M's.
 

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Discussion Starter #80
So, I'm slow as hell on progress, I know - HOWEVER..

I've cleaned my mating surface about 15 times now (exaggerating, but not really), gonna do 1 more final cleaning, primarily to remove residue from thread lube on studs off, but I laid the cometic gasket on and it appears correct per their instructions, however I notice the coolant ports on one side just really dont match up worth AF in my opinion. Can anyone confirm/deny if this is correct?

The coolant ports on the opposite side are perfect, all the rivets are hanging OUTSIDE the block as they should per instructions.
 

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