Piston ring end gap.

I usually follow the '0.0035" to 0.0045" gap per inch of bore' rule.

I haven't checked one of these engines though. With the locator pin, it may make measuring things a little fuzzy.

If it doesn't run because the rings weren't properly gapped, I'd be very surprised.
 
I removed the piston and removed the rings from the piston, pushed the top ring in the cylinder and squared it in the bore with the piston. Measured the end gap of both rings separately in this fashion. The gap in both rings was .01 inches. Bad things can happen to the bore, piston and rings if there is to little or no expansion gap. Looks like the factory did it job correctly. Thanks for the info.
 
Well, I get that. I have built plenty of engines, but not so much little ones like these. I know ring gap is paramount to engine performance and, most of all, longevity. I was just saying that of all the issues I've seen with china girl engines, I've never heard of ring gap being one of them.

Also, as I was saying about the locator pin, the ring clamps around it at the ends. So that must be taken into consideration when checking the gap. At least that's true of the ones I've worked on. Some may be different, and your mileage may vary.
 
I'm never overly concerned about gap, as these motors are not high performance anyway. For a while, I saw some 45mm rings being sold for our 47mm jugs that had way too much gap, and have occasionally had to file the ends on some new rings that had no gap. These are all rings sold separate from piston sets - ones sold as a set with piston or top end have always reasonable so far.
 
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