Custom Cometic Head gaskets

[Gly]

was speaking to a friend before my holiday in vagas,

mentioned that they deal with Cometic and can source us custom head gaskets, or any other custom gasket you may want, thickness/material as required/specified,

also deals with JE pistons, and ARP aswell.

would anyone here be interested in me pursuing this??

obviously most of you will want to know i price, but i dont have one not even ball park,
and in the end it will vary a bit if you want thicker or thinner gaskets.

but those with a serious build and money they want to spend speak up.

what i looking for is the definitely keen people and willing to put there money were there mouth is,
not the tyre kickers, and maybes.

http://www.cometic.com/custom-gaskets.aspx

[scott.mohekey]

I'd be interested. I suspect Adam.Findley will be too.

[Gowf]

I am potentially interested.... I have a company here in the UK that has already made them for the 6A13 and do offer either copper or multilayer metal. Copper is all well and good but you have to O-ring the block to get them to work properly.

The cost for the 2 gaskets is somewhere around the £270mark plus p&p

[taupodrifta]

I would be interested

[Kenneth]

What benefit would they have over the OE MLS gasket?

[Adam.Findlay]

Im in same boat as kenneth. what is the advantage over the factory MLS gasket (other then the ablilty to go thicker to decompress and run more boost lilke the RB/SR nissan boys use cometics for) as neither I nor kenneth are intrested in lowering the compression.

[Gowf]

I am not sure on the sealing ring material on the standard gaskets.... is it copper or s/s? This is what was sent to me from Ferriday engineering,

The Bi-Metal head gasket has been in existence since 2006, has been used in both road & race situations, and also by OE manufacturers during the development of new engines. Although initially developed for high power engines, the Bi-Metal gasket can sometimes be applied to more conservative environments. It is a more sophisticated, next-generation replacement for the Solid Copper gasket, but still relies on completely flat block & head surfaces with excellent finish i.e. freshly machined with a surface finish that matches or exceeds the requirements of a Multi Layer Steel gasket. There is a difference in thickness between the materials that make up the BMG, so that the majority of clamping forces are taken by the cylinder sealing rings and no other clamping mechanism should be needed. New gaskets can be completed from an OE type sample or customer drawing, though many drawings are already held on file.

Each gasket is specially made for your engine, so alterations for special applications (larger bores, off-set oil ways or bores etc) are no problem. Trade enquiries are welcomed, confidentiality is assured (a Non-Disclosure Agreement can be signed, and all files will then be marked accordingly in our computers), and individual jobs can often be completed within a few days. There are no set-up or tooling charges for new gasket drawings, minimum order is one.

As with most Ferriday Engineering products, these components are usually made for extreme applications where there is no other alternative. This means that these products will continue to be classed as “Experimental” (not yet proven in this application), and this classification will probably also apply to the rest of the engine, i.e. - a non-standard “hybrid” that far exceeds the OE manufacturers expectations & design criteria. None of our products should be considered to be as user-friendly as mass produced items, a certain amount of input from the machinist/assembler is required. Composite & MLS gasket both have the ability to conform slightly between irregular surfaces, but the solid metal sealing ring of a Bi-Metal gasket does not compress to any degree worth talking about (please read all of this info including the last paragraph “Limitations“). However, because the sealing ring is made from copper, it is able to conduct heat away from any problem areas very efficiently. Re-torquing may be required, and may be carried out more than once. Uprated head bolts may be required.

It must be remembered that sealing a cold engine on the bench is very different from maintaining that seal while the engine is running – i.e. going through the heat cycle (expanding & contracting), bending, twisting, having huge temperature variations across small distances (imagine the hot combustion chamber/exhaust valve seat area, with coolant passages just a few millimetres away), all whilst producing much more power than the engine designer ever intended. Machining, assembly, clamping system, head design, block design, cooling system design, driver care etc are all factors that can affect the initial seal.

A Bi-Metal head gasket is never the answer to a basic head gasket failure, and should only be considered when the original gasket is no longer suitable. But, as a solution to a strength problem they can be almost unbeatable providing that utmost care is taken during engine machining & preparation. Re-torquing should be considered normal, and can be carried out more than once.

Solid Copper or Bi-Metal? The Bi-Metal gasket is a more user-friendly component than Solid Copper and does not require wire rings to block or head. Occasionally a Solid Copper gasket may be more suitable, we are always happy to discuss all alternatives with the customer. We will also be happy to recommend another manufacturer’s product if we feel it is more suitable for that particular application.

Is a solid head gasket the right choice? - If a conventional head gasket is still suitable for your job then this should be used, though the Bi-Metal gasket can be especially useful for high-powered engines that have suffered failures with conventional gaskets. Although Bi-Metal gaskets are often used by customers for road use they should be considered a hard-core
competition component.

Limitations - The sealing ring of the Bi-Metal gasket is made from solid copper and will not crush under the amount of pressure that is generated by an average set of head bolts, whereas a soft composite gasket is designed to crush and “fill” surface variations. This means that in order to use a Bi-Metal gasket both block & head must be extremely flat with excellent surface finish, something that is easily achieved by a good machinist. But, at some point, depending on head design, the castings will “bow” between each bolt as bolt pressure is introduced. A simple way to visualise this is to imagine two pieces of finely machined solid steel, let’s say 150mm thick (the bottom one being the engine block, the top being the cylinder head) being clamped together with a set of head bolts. It is fair to assume that these two strong pieces of metal will remain flat as they are clamped. But if we remove the top piece of steel and replace it with a piece of cardboard and clamp that to the bottom piece you will be able to see the cardboard deform between each bolt - a
“bow” will appear. This is an extreme example, and although the thought of bolting cardboard to steel is a silly scenario, it gives an easy visualisation of how an extremely rigid casting may behave compared with one that has little strength. This is the limiting factor, and is something that no-one has control over.