Head gasket

S

SDLuck

Junior Member
Hello, needed for a friend.On a 4 cyl model A are there difference thickness head gasket to lower the compression after the head and block have been shaved.Who make them?
 
How much was taken off the head and block. If they were just cleaned up I wouldn't think you need to worry about too much compression. A little more compression is a good thing. I use the Best Co. copper gasket.
 
I like the Best copper too. Best gaskets are thinner than some, but that is a good thing. Best makes a composition gasket that is the same number, so request the copper as it is easier to remove when needed.
 
I read the questions several times and still missed the "to lower" compression.
 
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On a stock model A engine , the pistons will protrude around 32 thousands or a small amount above deck height .
 
He has calculated the compression to be to high due to ping,other than retarding the timing,what do you recommended. On sbc we can order head gasket any size we need to adjust the comp if the block and the heads are shaved to much.
 
Just curious. Have you taken a compression test, just to see how high it is? Stock Model A is 65 psig. They will ping if too far advanced. Maybe enrichen the GAV a little.
 
I have a Winfield head on my engine. The deck on the block had been shaved to clean it up. At TDC the pistons are almost .100" above the deck. After having the surface counter bored .062" for the pistons, I still get 165 psi compression. The pistons are .100" over.
 
If you need more clearance, you can also use 2 head gaskets. I bought an engine at a swap meet, and when I cleaned it and took it apart I found someone had used 2 head gaskets for some reason, but it ran fine.
 
I think it would be easier to flycut the recess above the pistons. Not much meat on the tops of the pistons to cut them shorter. Most people would be trying to increase compression and adjusting the spark rather then lowering it. Have you done compression check or clearance check with clay? Right now you are asking questions with too many unknowns? Like how much was taken off both? How thick the material is left on the head above the pistons? How far do the pistons pop up above the block? etc
I am thinking the 165 above is a typeo and might be 65LBS
 
Decking or milling changes the cr very little. Check your timing. There is a timing strip available from the dealers that bolt to the front passenger motor mount bolt. Then you can actually use a timing light.
 
I've used 2 gaskets with no problems, this on a Cyclone head. It resulted in 7.4:1 compression and cleared the pistons, which is why I did that.
 
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