What size cometic head gasket to get?

[frsh13]

Im trying to order a Cometic head gasket and ARP head studs, I just need to know which sizee Cometic head gasket to get. It seems there are different sizes, AMS has one thats .040, ive seen ones that are 1mm, and 1.2mm. Im running stock pistons and rods.

[frsh13]

no one knows?

[zanilth]

I am not sure, but I think it has something to do with your compression, and what you want to run and such.

[S13FX]

Yes thats true head gasket thickness does lower or raise your compression.

Why do you need a new one? Did your stock one blow or something?

[eazye2000]

I personally ran a .079" or almost 2mm cometic for compression purposes.

I would say the .040" would be the best for an all-around build.

[zanilth]

So with the intent on getting the brian crower stage 2 cams for the KA, which size would be a good idea to grab? Not trying to change compression or anything.

[Chezedik]

I have a .120" used for 20bux if interested. Still in pretty good shape, I am just rebuilding. This will put you in the 8.6:1 area with stock head height.

[GTR PrYdE]

So with the intent on getting the brian crower stage 2 cams for the KA, which size would be a good idea to grab? Not trying to change compression or anything.

do you need a new headgasket?

[frsh13]

Im not touching the pistons, just going to put a new head gasket and arp head studs, I think im going to go with the .040

[zanilth]

do you need a new headgasket?

When I get my cams, I am going to replace the head gasket and studs. It can't hurt.

[Florida240sx]

Ever here the saying' "If it ain't broke, then don't f*(K with it"

[zanilth]

Ever here the saying' "If it ain't broke, then don't f*(K with it"

So preventative maintenance doesn't apply?

[Chezedik]

A head gasket is major surgery, not preventive maintainence (sp?), if done wrong you can ruin a motor. It isn't hard, but not preventive at all. Unless the manufacturer messed something up, you overheat it, or overload it, it should be a lifetime part.

[zanilth]

So when swapping to arp head studs, with intention of running 350 hp, you wouldn't say it would be a good idea to change the head gasket then? Instead of waiting for it to go out, if it does?

[Chezedik]

Why would you change the head studs if you aren't rebuilding? The stockers are good for 500+hp.

[Florida240sx]

I know cars running over 15psi stock motor..

[Carl H]

the best cometic hg is the one left on the store's shelf.arp studs + stock nissan hg = winarp studs + stock nissan hg + oring'ed block = pure winarp studs + cometich hg = fail.

[frsh13]

the best cometic hg is the one left on the store's shelf.arp studs + stock nissan hg = winarp studs + stock nissan hg + oring'ed block = pure winarp studs + cometich hg = fail.

a little more evidence to support this would be nice, I dont see how a performance headgasket that proves better for so many engines would be bad for a KA.

[eazye2000]

Yeah, I know alot of people that hate on the Cometic. I think it's all in how you install it and prep your parts.I've been using mine with about 12psi for a while now. No problems yet. But it is possible to use the OEM, or a Fel Pro for upwards of 400hp no problems.

That's just my .02$ and real world experience. Alot of people will come in saying this, and that. But when it comes down to it... The information they provide may be what they have 'heard' or 'their friends have done it'.

[S13FX]

Stock hg = FTW

[Carl H]

the ka that i posted on this forum a while back orignaly had a cometic hg on it when we put it together.the block and head were both decked and cleaned but the hg kept leaking no matter what we tried, eventualy the head was pulled off and a stock hg fitted...no more leaks and holds power like a champ.i know quite a few sr guys have had problems with the cometic bits before same issues, leaks and no matter how much torque is applied to the studs it wont seal.

[klattr1]

the ka that i posted on this forum a while back orignaly had a cometic hg on it when we put it together.the block and head were both decked and cleaned but the hg kept leaking no matter what we tried, eventualy the head was pulled off and a stock hg fitted...no more leaks and holds power like a champ.i know quite a few sr guys have had problems with the cometic bits before same issues, leaks and no matter how much torque is applied to the studs it wont seal.

You must be talking about Brandon's car.

I've seen TONS of KA's have great success with the Cometic headgaskets and have seen some with leaking problems...it's one of the 90/10 situations (people usually post threads on problems rather than successes) if you know what I mean. There are always those setups that are an anomaly from the rest.

[Chezedik]

I had more than my share, and finally am just overhaulling the motor (which I found to be with my Cometic), I would just stay stock, in fact, I am going to a Felpro.

[Carl H]

on a side note, its good to have a weak link in the motor, i would rather blow a hg than destroy a ringland due to pressure/power.mhg = unyeilding = boom if detonation is occuring.composite hg = power = 'fuse' if something goes horribly wrong.

[klattr1]

on a side note, its good to have a weak link in the motor, i would rather blow a hg than destroy a ringland due to pressure/power.mhg = unyeilding = boom if detonation is occuring.composite hg = power = 'fuse' if something goes horribly wrong.

its more dynamic than that...if the detonation is severe enough, it doesn't matter what's between the head and the block.

people say "stock HG FTMFW", but most of the people saying that run less than 20 psi of boost...

so what im trying to say is that if you need the HG to be a weak link, then you need to look into different areas (not using enough octane, the tune is all jacked up, no knock feedback, too much timing, lean spots, air charge temps too high, etc).

just my opinion.

[Florida240sx]

Debating on to use my hg again or go with felpro. Got my arp studs today... spray copper gasket maker on the hg and it's good right?

[480sx]

I got my metal cometic sealed with Copper spray, it seems to be holding oil fine. I think that with a metal HG, it really maters how smooth your sealing surfaces are. I sanded both of mine down to 1000 grit, and that seemed to do the trick. I also sprayed the bottom of the head and the top of the block with just a little bit of the spray.

Dont put to much on the metal HG, just enough to coat it well, so you cant see the metal anymore. Wait till the copper stuff becomes tacky, and install your HG.

[Chezedik]

Felpro goes on dry.