Ken Dowd writes:
I’ve got high compression readings of over 190 lbs on all cyls on my TR4. The head has been reworked twice that I know of, about .050 has been shaved. I got these readings after putting the engine back together with all new sleeves, pistons, rings and a head/valve job. I CCed. the head at 55cc and crunched the numbers on several online compression ratio calculators and figured my compression to be about 9.5:1 Compression ratio on the stock engine is 9:1. Would you expect to see such high compression readings with such a small increase in compression ratio?
I’ve searched the world over and cannot find a spec for compression on a healthy 2138cc TR4 engine. Do you have any experience with after market solid copper oversized (thicker) head gaskets to bring down compression? That is the only thing I can come up with. Your thoughts would be appreciated.