Gasket for B block with Thomas Head

[GWO]

Hi

Manged to blow a gasket on my 1928 A on sunday. The car has a B block with a Thomas head. I have been reading here about what gaskets to use, but I was wondering what the latest views were.

Interestingly, when I bought the car it came with a few head gaskets, including 3 Fel Pro ones. These are the composite (not copper B pattern). They are new and a good option as I have them. I also have 3 period made Payne gaskets. These are copper with proper asbestos in them.

What are peoples thoughts on what to use?

Much appreciated

[Charlie Stephens]

Use the Model B gasket as it will more closely follow the combustion chamber. It will also cover and seal the two two steam holes at the center of the engine.

Charlie Stephens

[GWO]

Originally Posted by Charlie Stephens

Use the Model B gasket as it will more closely follow the combustion chamber. It will also cover and seal the two two steam holes at the center of the engine.

Charlie Stephens

thanks Charlie. Both are Model B gaskets. I was also wondering if there was a better modern offering. The one that failed was a composite one which was black with some red plastic mixed in certain places. This could have been a Snider one. Not sure though. It blew between 3 and 4. I think it had been in there for years. I had read that the Snider ones should be avoided

[Jack Shaft]

The gasket you do you needs to match the head,not the block.

[Beater]

Originally Posted by Charlie Stephens

Use the Model B gasket as it will more closely follow the combustion chamber. It will also cover and seal the two two steam holes at the center of the engine.

Charlie Stephens

the correct B gasget does not cover the steam holes in the B block


I just did this aswell, and I did use the one sniders recommends. however knowin peoples are having them blow I liberally sprayed mine with copper coat time will tell I guess I do not know what the best one to use would be

[Jim Brierley]

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It is usually wise to plug 4 of the small holes in the B block as over time the enlarge themselves. Plug them flush with the top deck in order to support the gasket. As Jack Shaft says, the gasket must match the head.

[Ernie Vitucci]

Good Morning...A Model 'A' head should be torqued once a year. After changing the head gasket, you do need to re-torque after a few miles and then after 100 miles or so. Many a gasket failed because the head had become loose. With more compression, this re-torqueing becomes more important...I normally do it with the engine stone cold.Ernie in Arizona

[Pete]

The most important thing is, the fire ring must NOT hang over ANY amount on either the head or the block. I used the copper gasket. 10.5 compression ratio. I had to do some welding on the head to correct it but I was filling the chamber completely so it was no big deal. I use aluminum spray paint for glue.

[Charlie Stephens]

Originally Posted by Beater

the correct B gasget does not cover the steam holes in the B block


I just did this aswell, and I did use the one sniders recommends. however knowin peoples are having them blow I liberally sprayed mine with copper coat time will tell I guess I do not know what the best one to use would be

Technically you are correct. The steam holes are not covered but open through the gasket to the Thomas head. Since there are no holes in the Thomas head they are sealed at that point. What I should have said is that the Model B gasket follows the shape of the Thomas combustion chamber better and the steam holes are not near the edge of the gasket and will not leak which is a good possibility if you use a Model A head gasket without plugging the holes in the block.

Charlie Stephens

[GWO]

Thanks for all the replies so far

My Thomas head has steam holes!

[Benson]

Originally Posted by GWO

Thanks for all the replies so far

My Thomas head has steam holes!

I am curious is this head an original or a Repro?

[Charlie Stephens]

My original Thomas head lacks the steam holes.

Charlie Stephens

[Pete]

Originally Posted by Charlie Stephens

My original Thomas head lacks the steam holes.

Charlie Stephens

Just curious, why does my original Thomas head chamber look different than yours?

[Jim Brierley]

Pete, Charlie's chamber looks more like the original than yours, which looks to me like maybe a Dan Price revision, and is a better design.

[Beater]

because its lower comp

[Pete]

[QUOTE=Jim Brierley;1864530]Pete, Charlie's chamber looks more like the original than yours, which looks to me like maybe a Dan Price revision, and is a better design.[/QUOTE

Could be, I don't remember where I got that pic. It was just labeled
"Orig Thomas".

The design that Dan recommended for racing involved filling the chamber completely with weld and machining it to look exactly like an Edelbrock head for a V8. Worked pretty well. I had one at Riverside.