im gonna run a 20g after i rebuild my engine, but i was reading and run into that some people with 20g's have their cylinders bored at .02 and others at .04, which one do u guys recomend? im gonna buy the pistons by the end of this week and i need to know which bore will benefit me the most, or is it not that important?

.020 for the first rebuild (JE Piston does not make a .040 low compression piston)

If your stock motor was rebuilt/bored, then you would be stuck buying a .040 piston.

cp has 40 over, i used to have a set.

I'd stick with .02" over, in case you ever need to rebuild it again you don't have to get a custom-sized piston.

Originally posted by DeanoD
(JE Piston does not make a .040 low compression piston)

They don't shelf a .040" over piston for our app. You have to custom order them, but the price is the same if you don't mind a slightly longer wait.

Actually. wait to buy the pistons until the motor has been checked for cylinder wear. If you have minimal out-of-round and Taper wear, you might be able to order a standard size piston. The standard size pistons will leave you with only needing to deglaze the cylinder as long as its wear pattern is within spec. You wont know until you measure the bores.



Terry

I'm one of the people that run a .040" over bore JEs. They were special ordered. I had to go .040" over because the original forged motor (at .020") blew up and caused considerable wear on the cylinder walls. This required that the cylinders be bored out more to return to clean it up. Just an FYI.

thanks dudes!!