Question about tiny hole in new piston b20

[19dabeast85]

I purchased these pistons new but from a private party 2 years ago. Just getting around to rebuilding the b20z in our crv and noticed this on one piston:

These are YCP (great reviews all over the different forums)






Will this pose an issue? Not sure how deep it goes but my concern is the piston blowing out at that point due to unknown thickness of piston wall from bottom of that hole to the other side (rod side).

Any way to repair this? It's going to be crazy difficult to track down a replacement individual piston!

I found this Lab Metal Hi-Temp which can withstand consistent 1,000*F BUT says not to use in a combustion environment. I'm wondering with as small as the hole is if combustion would actually damage the products...

[illinois_erik]

To me it just looks like a casting imperfection. Do you have a pick to probe it? I feel you'll be ok and it'll fill with carbon in no time if however you feel it'll become a problem I'm sure it wouldn't cost much to tig in a dollop of aluminum. Those are some extremely rough castings if you were inclined enough to sand and polish the faces you could make a better determination about the pinhole and get a small performance boost out of it.

[19dabeast85]

A regular A/C pick is way too big. I used a sewing needle and poked and prodded. Seems it's maybe 0.5mm deep max. I had thought about the carbon filling it and it'd be ok....I'm more leaning towards that now that I have determined there's a definite bottom to the hole.


Yeah, YCP casts these out of a better alloy and puts teflon on the skirts. They pay attention to details like sizing, durability (machine shop couldn't measure a difference in diameter between the 4 with their tools measuring to 0.0001") but finish is obviously not a concern lol. I don't have the time nor experience to touch them up though so they're going in as-is.