Are those the Chinese parts (stens)? When we had the K341 apart recently we had a chinese piston and Kohler, the kohler was definitly a higher quality item. There was a noticable weight difference in the two.
I noticed that when I ordered a "kit" for the last K 181 I did, as well; I had a new OE piston and a few other parts here just not "everything" I needed; and the "kit" was cheaper than the "rest" of what I needed on the OE level; upon comparison I repacked the box w/ the kit and returned it, spent the $$ to do it right with OE Kohler stuff;
My most recent rebuild candidate is a Briggs 289707 12-1/2HP I/C engine; alum block w/a cast iron sleeve; built w/ a mix of OE and aftermarket parts; rod was only avail in OE; (I needed a 0.020 undersize; I had to have the crank turned) I chose the "Rotary" piston/ring assy for $25 vs the OE one for $50; upon opening it ("Rotary" is Taiwanese):thSick: I found a nice looking piston and broken rings taht were still in the cellophane; so I called the place I got the parts from, and they sent me a set of Stens rings to replace the busted ones; I was encouraged to see "made in USA" on the Stens ring box;
I hope they are OK, as I have too much into this rebuild for it to go sour;
Further encouragement came when I checked the ring end gap in the freshly rebored engine and it was at the "low end" of the spec range; but the oil ring scraper seemed kinda "oval" w/"daylight" between the outside of the oil scrapers and the cylinder; God I hope that was just because of not being on the piston and not having been run yet.
and I have another 289707 on the shelf to do up next.
This engine I just built is going onto a Ransomes Bobcat 48" commercial walk behind;
I see a twin to this mower on CL as we speak that also needs an engine; with the 2nd 289707 sitting here; I may see what these Stens parts "can do".... big difference in cost vs OE B&S; I really hope I dont get bitten in the @$$ but I figured "what the hay'; I'll try them once and see.