Johnoolo

Back story, going for 300 to 350whp on e85 was thinking a .021 and .024 on ring gaps. .57 ebay turbo. Okay I understand there have been countless threads on ring gaps I'd like to find pre gapped rings, I really don't like the idea of grinding down my rings. The Vitaras I want to purchase for a stock 75mm bore come with NPR rings. What I don' understand is how does the size of the ring compare to ehat the ring gap should be. The NPR rings say the first group of rings size are 1.00 the 2nd are 1.20. is this just the thickness of the ring or say the circumference as far as dnt ring gaps go? thanks a bunch

TomCat39

The 1st and 2nd ring are different thickness. And will vary between piston makes and models.

You have to grind the rings to gap them as every bore is not the same. You can't get "pregapped" rings because of this. Instead you have to custom gap each ring to the bore, just like the machinist will hone each bore to the specific piston. Each piston is not the same and the bore has to be honed custom to the piston for the exact piston to wall clearance.

This is all minute but critical details in engine building.