Supra Forums banner

1 - 11 of 11 Posts

·
Registered
Joined
·
170 Posts
Discussion Starter #1
I had my head off my car for a while, and today I finally sprayed a new Toyota headgasket with some copper gasket sealer, put it in, and tightened down my ARP's. However, I forgot to install the coolant hardlines that begin near the starter, go around the back of the engine and across the exhaust side. Now I can't fit them back on and also need to helicoil the rear exhaust manifold stud. So, it looks like I will need to take my head off again.
Let me know if I am delusional for even considering this, but how bad of an idea would it be to re-use the factory headgasket? Should I wait and see how it looks after pulling the head, or is it useless to even try?
I am in a very stubborn mood and need to hear some common sense, so don't be shy with your opinions.
 

·
Madd Tyte JDM yo ®
Joined
·
7,014 Posts
i would highly recommend against reusing a composite head gasket. since they crush when you torque them down, they dont return to their original shape. its probably not a good idea to reuse it since its been crushed and conformed to the head and block. once you unbolt it, the gasket can shift a tiny bit from the way it was installed before and might not seat the exact same way... its a risk i wouldnt take with a composite gasket. if it was MHG, id say go for it.

btw, is the engine in the car or on a stand? if its on a stand, the coolant pipe will slide forward from the rear, doesnt have to drop down from the top.
 

·
475RWHP 449TQ and climing
Joined
·
5,911 Posts
flubyux2 said:
i would highly recommend against reusing a composite head gasket. since they crush when you torque them down, they dont return to their original shape. its probably not a good idea to reuse it since its been crushed and conformed to the head and block. once you unbolt it, the gasket can shift a tiny bit from the way it was installed before and might not seat the exact same way... its a risk i wouldnt take with a composite gasket. if it was MHG, id say go for it.

btw, is the engine in the car or on a stand? if its on a stand, the coolant pipe will slide forward from the rear, doesnt have to drop down from the top.

All summed up in a nut shell!
 

·
Buddy thought I had a NA
Joined
·
2,476 Posts
ummm you can get the coolent line back on you just have to pull the motor forword with cherry picker then slap it back on
 

·
Registered
Joined
·
170 Posts
Discussion Starter #5
Unfortunately, the engine is in the car and I don't have a cherry picker.
 

·
25psi = 14" brakes :)
Joined
·
2,306 Posts
I found the factory type head gasket to be a great coatings template, but they SUCK as headgaskets if your running more than 15psi, or ever plan to. (Or have one detonation event... bye bye head gasket seal....)

Buy a metal head gasket, clean up your engine, install the coolant pipe and then coat the MHG with brake quiet on both sides, wait 10 to 15 min. till it's nice and tacky, then install the head and tourqe your ARP's to at least 85lbs for bolts, and 100lbs for studs. (My values, so go at your own risk. I belive APR reccomends the 85lbs, and there are some who think 120lbs on studs is fine. Mine are at 103 just because that's where I ended up.)

Good luck, and be happy you needed a reason to remove that crappy stock head gasket in the first place.
 

·
Madd Tyte JDM yo ®
Joined
·
7,014 Posts
i personally am starting to thing abiding by the ARP recommendations with their moly lube is what we should use. the 85 lb/ft rating with moly lube is equivalent to the 100+ lb/ft torque that everyone thinks should be applied... however, the MoSO2 lube (greg, i know youe familiar w/ how "slick" that stuff is) really cuts down on the frictional losses that attribute to reduction of clamping force when torquing down a bolt. 85lb/ft + Moly lube is equivlant to like 120 lb/ft + 30wt motor oil. the sheer strength of the moly lube really helps out on getting an accurate stretch from the bolts.

i used copper spray. the copper spray is actually an evolution of an old racer's trick from back in the 60's. what they used to do is apply silver spray paint to the head gaskets. the machining tolerances and finishes available back in the day arent what they are today. but the aluminum powder and filings in the Silver spray paint would allow the small undulations and micro-grooves to be filled in and conformed that the inferior machine work left behind. the copper gasket spray that is produced by Permatex is actually Copper filings in an industrial adhesive. Its the exact same adhesive that is used to apply "Rolling Rock" beer bottle lables. the up side is that copper is more malleable than aluminum and does a better job at filling irregular surfaces than the aluminum does in silver spray paint.
 

·
Registered
Joined
·
170 Posts
Discussion Starter #9
Although I would certainly prefer to use a metal headgasket and never have to worry about it again, I don't have the opertunity to pull the block and do everything properly. However, I don't plan to ever run more than 10psi on this headgasket, and if I ever decide to up the boost, I will be tearing down the engine anyway.
I am using moly lube on the headbolts, but it's not the stuff that comes with the ARP's. Since I'm not using a MHG I am only tightening them down to ~73 lbs. And that copper spray seems to work well, so I will probably use it again for the new Toyota gasket.
 

·
Madd Tyte JDM yo ®
Joined
·
7,014 Posts
you shouldnt really have any problems with the sealing surfaces if the head and block arent pitted. alot of times on higher mileage cars, the block deck will be pitted around the bores and under the coolant jackes. if you dont have the pitting, an MHG should seal pretty well... but it takes alot of prep work if you cant machine it. you could call a general machine shop and ask them if they could make you a 10" x 12" by 2" thick peice of steel, with a surface ground finish so its a precision flat surface. then you can get valve lapping compound and lap the surface of the block to remove the irregularites and material that is left from the old gaskets.
 

·
Registered
Joined
·
170 Posts
Discussion Starter #11
The head has been machined, but the block has some minor pitting in the areas you mentioned. Although I got most of the block very smooth, the few minor indents concern me enough to shy away from using a MHG considering their vital location. I'm sure I would be more inclined to use one if I had a better history with headgaskets and was more confident in my ability to lap the block without compromising the flatness of the deck surface.
 
1 - 11 of 11 Posts
Top