What Thickness of Head Gasket?

Davie Houston

Davie Houston

Member
Am currently in the middle of building another forged engine for my car, and just have the head gasket to get for it.

Its either a cosworth (no worries about making dowel holes bigger) or HKS one, which either one i can get quicker basically.

The block will be decked and will be running CP 8.5:1 pistons, and the gasflowed head has had a skim before.

So if am thinking right the 2.0mm one will be better choice over the 1.2 / or the 1.5mm cosworth one?

What do yous guys think?
 
Trondelond

Trondelond

Active Member
That would depend on your intended use for the car, power levels, boost, and how much the head has been skimmed, I'd think. :)
 
stevepudney

stevepudney

GTiROC CHAIRMAN
Staff member
Trondelond said:
That would depend on your intended use for the car, power levels, boost, and how much the head has been skimmed, I'd think. :)
Click to expand...
Have the head and block ever been skimmed because of overheating damage ? if not and they have only been skimmed to clean up the mating surfaces then for a road car i would always go for the 1.2mm option.
If your unsure how much in total the head has had removed you can use the spec's in the manual to measure the height of the head.

Another good point to remember (to often forgotten) is when removing/skimming material from the block is to always remove equivalent material from the top of the oil pump cover, otherwise when refitting the head and torquing it down you will put unnecessary stresses on the oil pump cover which can lead to oil leaks or crack the oil pump cover.
 
Davie Houston

Davie Houston

Member
The engine was fine, till i melted number 4 on its orignal engine.
So just building another forged engine to replace my existing one.
The block has never been touched before, it has just been decked and bored to 86.5mm and was decked with the oil pump fitted.

The head had got a clean up pass before, but was fitted to a standard head gasket.
But now its going onto a metal one, so will be getting checked and skimmed flat, so all surfaces are nice and flat.

Car is an all rounder, but mostly it just gets abused.
It shall prob be getting a Gt2871r or a 3071 stratpped t it within next couple of months, once its been run in.

Once finished with it, am looking for between 350 and 400 ish.

Was just thinking on a 2.0mm gasket due to head been skimmed before and block been decked also.
Or is the 2.0mm one over kill?
 
Davie Houston

Davie Houston

Member
Offft man, rather u than me, am bad enough in inverness for 3 days!!!!
A have eventually got my finger out and got in about the tin can.
Stripped the orignal engine and number 4 is mangled lol.

Crank is immaculate, and the shells that came out are brand new looking too :)
Engine had been looked after before i got it lol.

So just got standard shells to get, either from nissan or a machine shop for some standard acl ones.
Put the racing ones in the current engine and i bet their guffed already lol.
 
vss irvine

vss irvine

Well-Known Member
youll be up and running in no time then, ive been buying the last of the bits to get our car together.

lots of nice bits to get it finished before may!
 
Davie Houston

Davie Houston

Member
Yeah hopefully mate, need to get the seals done on my standard T28 its a wee bit smokey, but the shaft is still perfect, no play at all in it.

I have a turbo dynamics roller bearing one their too, needing the seals done, but not paying 500 quid for it, when i can get a new turbo for a bag of sand.

Just trying to find time to do all the build up is anightmare. End up out on the sauce all weekend and lie like a burst ball all day lol
 
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