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hi all I am assembling a 97 1.8l BP. In this motor there will be Supertech 11.0:1 pistons with weisco rings at a 83.50mm bore. I am seeking advice on what I should run for piston ring gap for the top and 2nd ring. The vehicle will start out a N/A application but will shortly after move to a turbo application running around 5-6psi. The Supertech piston sheet recommends a ring gap of 1mm (.039”) top ring and 1.2mm (.047”) 2nd ring. The seems extremely excessive to me even being turboed and high compression. I was looking at the ring spec sheet for it and was doing the math of bore x .0045” top or .0055” 2nd ring and it was coming out to a .016” top and .018” bottom which I know is to small for this application. I am confused at how much ring gap I should be aiming for and am wondering if anyone has experience with this or advice. I know the turbo guys with the 9.5:1 run around .020-.023” which is what I am leaning towards but am unsure of.
what do y’all think I should do? Follow the Supertech piston sheet? Or stick to what is known to work?
thanks In advance! Attached is the Supertech sheet and weisco ring sheet
I'd do .022-.024, maybe even a hair bigger. If I were building it for myself, not caring about oil consumption. A hair tighter if that is a street engine and that is a concern. Usage is important.