Don,
I'm fairly certain that your pistons are not cast from iron...Aluminum
is usually preferred.
Using 93 octane fuel you can increase the ratio to about 10.5:1,
depending on peripheral equipment, (camshaft, carbs, exhaust, etc.),
without problems!
The compression ratio issue brings up a number of questions pertaining
to variables that must be known.
It will not be a good idea to drastically raise the CR without
considering the reasons. The duration of the intended, "HI-Performance",
camshaft plays a big role in determining the correct CR.
Static compression and CR are two different things...totally unrelated
to each other.
Too much static compression and you will get dieseling. This will
destroy your pistons!
If you would like a long drawn out explanation...send me an e-mail
off-list...I will be glad to elaborate.
Best regards,
Jim Swarthout
-----Original Message-----
Subject: Greater than 9.5 compression ratio
List,
A very knowledgeable person told me that I should not go higher than
9.5:1 with standard (cast iron?) pistons. He said the unleaded gas burns
much hotter, and increasing the compression ratio beyond 9.5:1
could/would increase the piston temperature to undesirable levels --
could damage the pistons -- maybe warp them?
Anyone heard of anything like that?
The guy who said it is probably on the list so... I'm not trying to
start anything, but just have never heard that before, and was about to
go to 9.8:1 and wondered if there was general agreement on not exceeding
9.5:1 because of combustion temperature.
Thanks,
Don
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