MTFCA Forum

I know that the parts dealers say the new style head gaskets won't work with an aluminum head but I just wonder why? They also say that steel adapters for using 14mm spark plugs are not for use in aluminum heads.--Just wondering. bobt

Robert

Generally those new 'silicone' strip gaskets aren't recommenced on the high compression heads is for the possibility of leaks. The sealing area on the silicone ( you can't add any gasket sealer to these like Copercoat) is a very thin line, that is risky for higher compressions, and/or block and head that haven't been surfaced to flat square and smooth.

Note too, the silicone red sealing strips aren't between the cylinders, where risk of blow-out is a concern.


Note the narrow red lines (silicone strip), that is the only sealing area on the silicone gaskets.

As for adapters, typically those extend into the compression chamber and run the risk of putting the plug or adapter too deep, affecting performance or interference.

DanTreace wrote: ↑

Tue Nov 02, 2021 9:07 am

Robert

Generally those new 'silicone' strip gaskets aren't recommenced on the high compression heads is for the possibility of leaks. The sealing area on the silicone ( you can't add any gasket sealer to these like Copercoat) is a very thin line, that is risky for higher compressions, and/or block and head that haven't been surfaced to flat square and smooth.

Note too, the silicone red sealing strips aren't between the cylinders, where risk of blow-out is a concern.


Self sealing silicone head gasket.jpg


Note the narrow red lines (silicone strip), that is the only sealing area on the silicone gaskets.

As for adapters, typically those extend into the compression chamber and run the risk of putting the plug or adapter too deep, affecting performance or interference.

Thanks for the pix. I had not seen the new gasket. You have done me a service & the following is in no way directed in your direction To be clear.
This is absolute BS!!
Anybody ever run a champion X ? The bottom of the plug & the electrode extend a good 1/2" below the threads. Long enough reach 14mm plugs are hard to find where the electrode extends out of the adapter. At least in the adapters I made for years. Could current adapters be so wrong?

The "silicone" gaskets I have came from T Carrnagie? They look like the top of the line felpro head gaskets. Could have been made by felpro.
I dont recall a lack of sealing between the cyls. Will check tonite.

If these new gaskets wont work with a new hi compression head, they wont work on a stock head either. BANK ON IT! CARRY EXTRAS ALWAYS!
My fuse is lit, spittin nails. Jumping to a conclusion.
At a time when we are in critical need of a usable/functional head gasket, we are handed a POOR QUALITY COUNTERFEIT POS. Will this kill Toms gasket sales to boot?
There is too wide a disconnect between the manufacturer/dealer & actual, real life users/consumers of the parts they offer. Thanks for nothing. (Crappy stuff that displaces good parts) SHAME ON YOU! I wag my finger.

Dealers at least offer a workable solution!!! But that means lost sales when we dont regularly have to replace gaskets.
I need a double med dose today.

I do offer a possible solution to this gaskets failings. An old overhead (GEMSA) trick. I do this on copper head gaskets for all heads.
Place a thin copper wire between both thin cylinder walls to add extra sealing pressure to the gasket. Helps to lay on a very thin smudge of ultra black.
Done for now. bring it on.

I've seen a lot of pictures of Model T and Model A engines that show evidence of coolant seepage from the head gasket. Some of the pictures are of otherwise clean, recently built engines, and some are obviously engines that have seen a lot of service. In decades past, people often re-used head gaskets, but I assume most all of the recent builds have used new gaskets of one kind or another.

I can't tell you the "whys" and "wherefores", but one of our chapter members ignored the caution note and used the new style gasket on his aluminum high compression head, (twice!). It did not go well for him...

John

My post on the silicone style gaskets comes with no experience, but observation only of the design, and on one post a while ago, a silicone red ribbon stripe style gasket was shown blown. Don't have the details, may have been wrong application or fitting.

My experience with high com. head, both 'Z' and Prus, is very good using copper sandwich gaskets and CopperCoat on the surfaces.

The mfg. instructions for the silicone note to not use it on the 'Z' head for the reason the silicone red ribbon stripe could get exposed and prevent sealing, and Lang's web site carries this added statement from a user on the webpage catalog:
This gasket has a steel crush ring around the combustion chamber that must be sandwiched between the head and the block. Most high compression heads have a different shape on the deck so that it exposes the silicone directly to the combustion chamber which will not work.

The other comments written were positive on the use of this silicone gasket on stock heads and blocks. Other than it is a single-use gasket due to the silicone that becomes squished and flattened and stuck to the surfaces. I don't think the supplier will lose many sales due to non-application to high compression heads, as many use high compression pistons, so this silicone gasket should work for that application too.

Hadn’t kept up with the new silicone head gaskets so my question is will they work on the standard heads which aren’t high compression. I guess I like the copper standard type like others. The old copper sandwich type could be used for a few times. My Grandfather had several he kept for emergencies that were good ones. He would coat them with a light coat of grease and use them again.

Aluminum and cast heat and cool at different rates so the silicone can not move with the heat like copper does.

I’ve been using these gaskets under my 7.25:1 aluminum Sherman head for several years now with good results. The cam profile causes this motor to generate 165 psi cranking compression, and the head and block are nicely surfaced.

I used to run solid copper shim gaskets for many years as the combustion chamber shape was altered to accommodate 1.720” intake valves. I found myself needing to reduce the compression due to detonation issues, and so was tried thicker solid copper gaskets. No luck! Couldn’t seal the water as material thickness variations increase with material thickness. I eventually tried a silicone gasket as the fire ring is much easier to remove and reshape than a laminated copper version. The silicone gasket crushes to about .050” (50% thicker than my solid gaskets), and was enough to lower my compression and relieve some detonation

The concern about the “Z” head is probably the combustion chamber shape, causing the fire ring to not contact completely. I use no sealant, and have no noticeable water or combustion leaks. The gasket is not reusable as the graphite paper will stick to the surfaces and delaminate as the head is removed. Always keep a spare around...

As this thread has progressed, I have grown suspicious of some aspects & did my homework.
The original statement is incorrect. The vendors have a warning about using with a Z head specifically, Not high compression heads. My older silicone gaskets have a similar warning. Understandable. Z heads are known to blow out copper gaskets also.

The silicone gaskets I got from Tom Carnagee 10+years ago look similar, but the red lines may be wider. The base is a darker olive brown & stickey like a varnished/silicone coat. They dont appear or sound the same as the new style. Are the new offerings a poorer quality counter fitted product that will displace a better part? Cant be sure enough to say now. If I get my hands one one, ill know for sure. May ask T.C.
Why dont they have a line of silicone around the chambers?? The recommended torque is #45 for aluminum heads. Sounds light.