Hi Compression Head

M

Maurer1929

Member
How can you tell if you have a high compression head? On my 1929, which seems mostly an original engine it has a "23" stamped in it near the front top and also has a small diamond shape on front top of the water port.

Also if it is a high compression head, it the timing set different from a normal head?

Thanks
 
not sure on your head , but the timing is all the same . i have a 6-1 & i set it as normal . 5* retard & 35* advance . if you get in a spot & hear the motor ping , retard it a little ....................
 
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When I replaced my engine, which had a HC head, I could tell instantly when the replacement head was a standard just by the way the way the car drove. I had
an O/D ****** and the H/C head didn't ask for fifth gear until about 55 MPH, and the standard started asking for O/D at about 45-50. If you have a standard ****** this probably won't help you much.....sorry.

Jack
 
Do a compression test.
I believe 55 to 65 pounds is about right for standard head while around 100 pounds should be right for high compression head.
I believe though timing procedures are the same, a high compression head should be driven with the advance in a much more retarded position due to pre ignition.
 
Maurer1929 said:
How can you tell if you have a high compression head? On my 1929, which seems mostly an original engine it has a "23" stamped in it near the front top and also has a small diamond shape on front top of the water port.

Also if it is a high compression head, it the timing set different from a normal head?

Thanks
Click to expand...
Sounds like a stock head. I find all or most original cast parts on Model A's have a small rectangle or diamond cast in. The head is cast in the top of the water pump mounting where you indicate.
 
I recently purchased a 1930 cabriolet and the head has a "B" on it. I have been told that the B signifies a Higher Compression Head used by police cars?....What are the odds of that :-))
 
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