Are these rings loose or what, bore is 81mm, but the rings are coming out at .022-.023 for the first ring and .025-.026 for the second rings. Are these supposed to be that loose ?

 

I don't think they should be that loose, have heard of this being an issue for others.

I encountered something similar with Nippon and Hastings rings recently for 81.5 pistons. I ended up buying file to fit rings which came tighter at .014-.015 for the top rings.

 

Yeah, that's looser than I'd want for most types of builds. Get another set of rings.

 

Where did you get the file to fit rings? I’m also having issues. My first Hastings set had oversized, out-of-square gaps. The second set had decent gaps but was old 2022 stock with a different second ring design I wasn't confident in running. Third set I went with NPR, but now I’m unsure about proper end gaps. For example Hastings and Wiseco use bore-based formulas, while NPR gaps are "for reference” and based off wide bore ranges. Having trouble finding clear info.

 

I'd just go with the standard .004/bore-inch top ring and .005/bore-inch second ring if it's totally a stock rebuild. Add an extra .0005/bore-inch if you're planning to beat the crap out of it or if it's a good bit higher performance than stock. If it's strictly a race car and you don't care about making 100k+ miles or burning a little oil, add another .0005 again.

NPR claims that theirs are specific to the bore they are listed for and that they don't want you filing them. Obviously not an option anyway if they're coming out with gaps like OP listed. Here's their tech doc: https://www.npramerica.com/attacheme...roduction1.pdf

File to fit are obviously going to be listed for a range of bores with the expectation that you the user are going to do the final fitting. Maybe the happy spot is to order the NPR rings 1 oversize beyond what you are bored to and then file the rest? FWIW the NPR rigns, in my experience, are better than the other aftermarket options out there (Hastings, GNH) so I think you're on the right track sticking with theirs.

 

My b series npr rings were way out of spec as well. Some just within the far end of acceptable according to honda but most were out of service limit new.