My book tells me that a TR3 has 8.5:1 compression ratio with 83 mm pistons.
The TR4 has 9:1 compression ratio with 86 mm pistons. My TR3 with new 86 mm
pistons with the TR3 head will compute to 9.12:1 compression ratio as the
combustion chamber on a TR3 head has less volume than the TR4 head. (Unless it
has
be surfaced.) I think with retarding the timing and an octane booster I'll be
fine. NOW if I were to bore a TR3 with 83 mm pistons 20 thousands, the
compression ratio would change from 8.5:1 to 8.6:1. Not significant, so boring
will not change the compression ratio drastically. Maybe I'll need aviation
100
low lead fuel. JUST KIDDING Mr. EPA agent as you can only use that in
Non-Highway vehicles.
Just my 1.5 cents worth,,, unless you bore it out then it's just my 2 cents
worth.
Kent Shrack, TR3a, with the future blown head gasket.
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