Machine shop called me yesterday, and it seems they measured\calculated the
compression ratio at around 11:1 which seems kind of high to me.
This engine has the .020" cooper S pistons and a scatter pattern SPvp3 cam
both from APT. Jack from APT says that 10-10.5 :1 is where it should be to
run on pump gas. This still seems high to me, can anybody confirm this? The
pistons do not rise past the deck of the engine, so it seems this head was
really skimmed or something. The pistons are taller and have smaller dishes
than the original pistons but this difference in ratios is concerning. So I
am going to go down there and actually measure the volumes with some mineral
oil to make sure, and if it is indeed 11:1, the machine shop is going to try
to get a bit more combustion chamber room to lower it down to 10 or so :1.
Intresting confusing stuff.... I hope it works out. Any suggestions are
welcome.
Toby
who does NOT want to use Octane booster on a daily driver.
69 Sprite
69 Midget
71 Toyota Land Cruiser.
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