Choosing a headgasket - 4g64 vs g4cs vs 4g63

[Tre3zy]

Hey guys,

I was looking through the forums but couldn't find any info on the bore size of the 4g64 vs g4cs vs 4g63. I have a 4g63 bored .080 over (yes yes, i know) and since they don't make headgaskets for the 4g63 with that much bored over I was wondering if I could use a g4cs or a 4g64 head gasket that's made for a .020 over bore.

Thanks!

 

[juanpac0]

I'm also interested in this, any input guys?

 

[snowborder714]

4G63 - 85mm stock bore
4G64/G4CS - 86.5mm stock bore

So if you're running a 4G63 with a .080" bore (2.032mm), then you'd need an 87mm head gasket.

Here's a few options.
EXTREME PSI : Your #1 Source for In Stock Performance Parts - Fel-Pro PermaTorque MLS Head Gasket: Mitsubishi Eclipse 90-99 (only in 87mm bore)
EXTREME PSI : Your #1 Source for In Stock Performance Parts - Cometic Head Gasket (1.3mm): Mitsubishi Eclipse 90-99 (87mm option)
EXTREME PSI : Your #1 Source for In Stock Performance Parts - Cometic Head Gasket (1.6mm): Mitsubishi Eclipse 90-99 (87mm option)

 

[Tre3zy]

cool thnx bro.... that helps alot.... appreciate it...

 

[gyd23]

not to thread jack but didn't want to start my own and this is the closest i could find to what i need.
i have a G4CS block bored .040 over and a 4G63 head its all built.. good some day for 500HP and i need a head gasket, and for the life of me cannot find an 87.5mm gasket that can withstand that kind of power. anyones input is appreciated, thanks.

 

[gyd23]

does anyone have any info on Felpro perma torque headgaskets?

EDIT: Nevermind, they don't make an 87.5mm HG either.

 

[WizardTSi]

Holy-expensive-Felpro-headgasket batman. I was shocked at the price for some reason haha.

 

[Aproductions]

gyd23, Try giving cometic a call, they can make you a custom one for your car. They made my .020 over .075 thick MLS for me.

 

[gyd23]

gyd23, Try giving cometic a call, they can make you a custom one for your car. They made my .020 over .075 thick MLS for me.

alright thanks i will do that..
out of fear for the block not being completely flat (my engine got to 240 degrees not too long ago and has been pushing water/lost compression ever since.)
i will have the head re-surfaced but what can i do about the block? seeing how i cannot just pull it out and send it off to get that re-surfaced unlike the head..
unless someone suggests a fel-pro composite HG will be a bit safer on my application? at times almost 500hp on 30psi.

EDIT: Also what does the differences in thickness have affect on the engine or performance? what are pro's & con's of a thicker MLS gasket vs. a thinner one?

 

[WES_393]

I'm bringing this one back due to a similar situation. I recently got my block bored to 86mm and I'm trying to source the parts. I don't want to go MLS for various reasons, but can't find a 86mm composite head gasket. So it seems my only option is going factory composite, but which one should I go with? 4g64 (86.5mm) or 4g63 (??mm)?

Some say that factory 4g63 HG's should allow up to 86mm, but I'd like to see some actual data rather than words like "should" before buying one.

As for the 4g64 Headgasket, it should work no problem, right? It's only .5 larger and the 4g64 has more oil drains than the 4g63 so I wouldn't be blocking anything. Someone correct me if I'm wrong.

 

[Sewey_GSX]

The Felpro and Mitsubishi composite gaskets have bores that are larger than 85mm. I dont have one here to measure, but Im almost positive that its 86mm+. So try a factory gasket, it should work just fine for you.

 

[WES_393]

Cool, thanks for the reply.

 

[WES_393]

I used a stock composite Mitsu headgasket for the 4g63 on my 86mm bored block. The headgasket was a perfect fit so I wouldn't recommend using the stock gasket with anything larger than 86mm.