Cyl. Head gasket material

[irsq4]

If someone know or is working on...?

Which stainless steel material is used for multi layer cyl head gaskets (f.e. ISO 10N, 19N)? Which material (probably kind of termo-elastomer) is used for coating gasket metal surfaces?

[riff_raff]

Laminated head gaskets for production auto engines are likely made from a low cost austenitic stainless steel sheet that is easily formed. Maybe something like 309 or 316 cres. The elastomers bonded to the gasket to seal coolant and oil passages are probably fluorosilicone for high temp areas or something like EPDM for lower temp areas.

[marcush.]

The sealing is provided through viton coating ,material is Stainless SS301 as I understand.
At least that´s what i was told back then when I used the then state of the art Cometic MLS head gaskets which did a tremendous job in combination with ARP head bolts.
their current web site does not give away much Detail These days..

http://www.cometic.com

[riff_raff]

The primary seal around the cylinder bore for combustion gas does not use viton or any similar elastomer. The primary combustion gas seal relies on a seamless metallic ring sandwiched between the outer stainless steel face sheets. The gasket surfaces are usually coated with something like teflon to prevent fretting damage due to relative sliding from CTE mismatch between the block, gasket and head faces.

[strad]

I would have thought they would have O-Ringed the block

[TurboLag]

I have a HKS MLS gasket for my SR20, and I'm pretty certain it does not have a solid ring facing the bore.. I'll get a picture tomorrow

[TurboLag]

as promised..

no seamless ring, full metal sandwich

[riff_raff]

Maybe you can post another picture of the gasket construction around the bore.

Here's the gasket construction I'm talking about:

[TurboLag]

Coming up!

No ring, seamless integrated or separate facing the bore either. This is the same as for example original Mazda B and F series which has OEM 4 layer MLS gaskets

[Brian Coat]

High performance derivatives of this gasket type do often have a combustion sealing ring feature due to the higher temperatures and pressures.

The reason not to do so in a lower performance engine, of course, is cost. It adds material and processing steps.

In racing engines, varying the head gasket thickness can also be used to fine tune critical clearances.

[TurboLag]

No ring, and this gasket is designed to hold well above 800 hp, at boost pressures exceeding 50 psi.

I've been around and watched the building process for several 1000 hp boosted 2-3L engines using mls gaskets, and none of them has had rings facing the bore.. I don't say that "ringed" high performance gaskets with rings don't exist, but I have never seen a mls with them.

[strad]

The head gaskets used in building my high performance small blocks had a ring incorporated in the gasket around the bore, but not exactly like O-Ringing the block like we used to do on blown engines.

[TurboLag]

Cooper/Willis rings? or pyramids maybe? I would call them techniques rather than seals, because the ring itself isn't used as seals since they cut into the head and is used to keep a standard type gasket in place and prevent blowouts when the combustion pressure acts on the head. (Sorry, long sentence)