engine and drivetrain What head gasket to use with 92mm bore on M10 block?

[Digby]

I need some help from the M10 engine builders. I'm working thru the details of building an M10 stroker with an 84 mm stroke S14 crankshaft and custom 92 mm pistons.

Right now I'm stuck at what to use for a cylinder head gasket.

I would much appreciate any comments from people who are familiar with building big-bore M10 engines.

Thanks.

Digby

[2590402]

I used the BMP cutting ring gasket and just took the cutting ring out. The other option is a cometic gasket.

http://www.bmpdesign.com/product-exec/product_id/1176/category_id/46/search_year/1973/search_model/6

-Andrew

[Digby]

I used the BMP cutting ring gasket and just took the cutting ring out. The other option is a cometic gasket.

http://www.bmpdesign.com/product-exec/product_id/1176/category_id/46/search_year/1973/search_model/6

-Andrew

Thanks, Andrew. I've checked out your URL for the BMP cutting ring gasket. Could you provide a bit more info about the cometic gasket, though? I'm not familiar with it.

Also, what are your thoughts about using the stock 2.3L S14 head gasket with the M10 head? Not that much more expensive than the cutting ring gasket, but maybe a bit more rugged perhaps?

Thanks.

Digby

[Kidasters]

Digby,

Cometic will custom make a gasket for you. Just look 'em up:

www.cometic.com

Ken

[Digby]

Digby,

Cometic will custom make a gasket for you. Just look 'em up:

www.cometic.com

Ken

Thanks Ken.

Cometic looks like a workable solution for my problem, though there are perhaps other workable solutions as well.

Digby

[Guest Anonymous]

just use an s14 gasket

[Guest Anonymous]

just use an s14 gasket

[Digby]

just use an s14 gasket

Thanks AD.

This makes sense to me, too, though I still have a few questions in my mind as to the relative thicknesses of the stock M10 head gasket and the stock S14 gasket.

Let me ask, however, before I go trucking off into the wild: Is your answer based on personal experience, or is it strictly a personal opinion?

Thanks.

Digby

[Russell74Fjord]

my MM engine with 92mm bore, uses the S14 head gasket, with a small insert to fill the gap under the front cam gear/timing chain cover where the gasket does not quite match up. This is at the left side under the front cover, about the size a finger tip and held in place with some gasket sealer.

[Digby]

my MM engine with 92mm bore, uses the S14 head gasket, with a small insert to fill the gap under the front cam gear/timing chain cover where the gasket does not quite match up. This is at the left side under the front cover, about the size a finger tip and held in place with some gasket sealer.

Thanks much for your detailed explanation. Using the S14 head gasket appears to be an excellent way to go.

Digby

[Harv]

An acquaintance of mine used to be involved with Cometic and Weisco (used to be the same company). He said they could make a custom head gasket without a problem.

I have an S-14 HG waitting for my motor but maybe I should look into this. Maybe a group buy?

I wonder how many people would be interested in a big bore M-10 HG?

John

[Digby]

An acquaintance of mine used to be involved with Cometic and Weisco (used to be the same company). He said they could make a custom head gasket without a problem.

I have an S-14 HG waitting for my motor but maybe I should look into this. Maybe a group buy?

I wonder how many people would be interested in a big bore M-10 HG?

John

John,

I like the idea of checking into a group buy. I've checked the Cometic website and their prices are pretty high for the regular parts they list. Based on this I'd guess that one custom-made gasket would be a rather expensive proposition. A group buy, though, could bring down the price considerably.

There may be other options, too, as some specialty parts houses apparently are already purchasing small runs of Cometic head gaskets and marketing them. Here is a listing that is currently on eBay:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=002&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=120156935731&rd=1

Note that the seller specifies that this Cometic head gasket is for a 1966 M10 with a 92 mm bore. In his online store, the seller has a 90mm head gasket for the later M10 engine---1972-1988, as I recall the listing. I'm not aware of the differences in the blocks and heads where the head gasket is concerned, but at least the seller thinks there are some.

Anyway, I'd be interested in checking into a group buy for a custom Cometic head gasket as an alternative to using an S14 head gasket.

This makes 2 of us interested in checking on a group buy. Anyone else interested?

Digby

[Russell74Fjord]

I thought I should add a little about my experiences with MM engine and head gaskets - and a caveat this is only my experience - and I do not think indicitive of others, but, I bought a short block from MM and re-used the MM Head from my first MM complete engine purchase. I had the head rebuilt locally and checked for flatness and pressure testing for cracks, regardless blew a few head gaskets - NOT THE S14 one, there is another head gasket option, some other gasket that can accomodate the 92mm bore that Jim sent along with the MM short block. Not sure what this is, but it does have a water jacket cutout at the last water jacket at #4 exhaust side that is tear dropped shaped, that matches up quite closely to the water jacket shape itself and leave very little material between the water jacket and the cylinder to seal up betwen them. This area seemed to fail , since the grey gasket material here was missing once I disassembled it (after blowing gasket), only the metal backing remained. The S14 shape of this water jacket is just a circle, leaving more material to keep water from entering the cylinder, and I hope solves my blowing head gasket situation once and for all. thx all, good luck.

[Russell74Fjord]

(nt)

[Russell74Fjord]