Ring end gap
 

I got a 12.5hp flat head Briggs with a cast iron sleeve. I didn't want to put much money in the mower as it's getting old so I just thought I'd rering it, cut the seats and grind the valves. I've been boring cylinders for many years in my shop but never much Briggs stuff. So I put it in the tank and went about tweeking it as little as possible. I didn't know where to measure the piston on the skirt so I just went off the bottom. I stopped at around .0065. should work but loose. I figured I'd just get a set of std rings and "hope" the ring gaps wouldn't be too far out. I get the new rings and the oil ring has been updated, it's now a spring and a cast ring around it, so the factory manual the dealer had was no help at that point with end gap. What I can't figure, being that it's now got .0065 skirt clearance now, I figure new it probably had somewhere around .003 on it so how could I now with the new rings have gaps #1 at.015, #2 .018 ? I can live with those but the new updated oil ring has only .010 on it ? How can this be ? I if anything it should be out of specs. I called the co. and all they can give me is a reject size ? Ring end gaps are not wear points ? The only thing that can make it get bigger is a bigger bore or grinding it bigger. So I have no minimum to work with here. IMO .010 on a cast air cooled one piece ring in a roughly 3.5" bore is asking for trouble. I'm thinking it should be at least .015. So can anyone tell me just why there are no min specs ? and any opinions on just how much is asking for trouble ? If not I'm going to grind it out to .015 and call it good.