Cometic head gasket questions

[Turbo V6 231]

Maybe someone can help me out in this issue I have, my motor & heads ha e been machined and engine builder that did the work said I need a .60 thick cometic gasket, my bore size is .30 over
I have searched and searched but can only find a cometic gasket that is 3.860 and .60 thick, and that have another that is 4.02 I believe, so there is only 2 variations of this gasket? Am I to use a 3.860 bore gasket on a 3.830 motor?
Any help is appreciated



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[pacecarta]

3.860

 

[Turbo V6 231]

Ok so I do go larger on the bore with this gasket, thanks for the help now I can move along, also no adhesive correct just the gaskets? And the best intake gasket to use? And valley pan?
Thanks


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[pacecarta]

i dont get the question .. for 3.8L stock bore up to .060 over thats the gasket
older cometics didnt have a raised area to the valley and those will leak oil without spray like coppertek
new cometics should not need any spray .

felpro 96033PB one peice intake /valley looks like original but blue paper coated

 

[Turbo V6 231]

Thanks for the answer, my original question was I have a 3.830 bore now, I didn't know I can use a 3.860 gasket on it, that was it, I assumed you needed to use the gasket to the correct bore, but I guess you can go up larger.


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[Turbo V6 231]

I have seen posted that some people are using the fel pro 1200 m, would this be necessary if lining up is an issue?
Does this have a valley pan as well?
Sorry for all the questions just want to buy the right stuff and be ready for install


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[pacecarta]

1200 are seperate intake gaskets used in pairs and if you run a pcv in the base of intake youll need to shield it .

 

[Turbo V6 231]

Ok thanks for the help think I may have it now, I have also heard of people cutting the shield off the one and using it with the 1200 if need be that is an option to get the shielding necessary and also if you need a thicker gasket, not sure it's correct though.


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[ek02]

MS96033 is the FelPro intake gasket that most people use. It has a blue coating on it. The 1200 gaskets are for GN1R heads or irons that have had the intake ports enlarged to the max. The MS96033 will work fine with unported GN1 heads. If yours have been ported to the max then you will need the 1200's with a MS96033 that has been modified to act as an oil shield.

 

[earlbrown]

The reason the Cometic has a 3.860" hole is because that's the maximum bore size of a 3.8 Buick. It'll clear a .060 overbore.


That being said, you CAN NOT run Cometics unless your deck surface has been MACHINED FLAT. Not wire brushed, not belt sanded, not filed, but MACHINED (and machined well). Same thing with the heads. Flat, flat, flat.

Then add, copper spray, ARP studs, and a couple GM seal tabs and you'll seal so well you can bust pistons without leaking.


Skip any of those steps and you'll be bent over the fender installing composite gaskets.

Also, are your pistons .020" out of the hole?

 

[Turbo V6 231]

Sent you a pm earl


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[TurboBuRick]

Follow the manufacturer's recommendations when installing cometic head gaskets...

 

[williamsGN]

Ran cometics on three motors, arp studs, copper spray, stock UN machined heads/block.... no issues.