I just rebuilt my bottom end. New oem rings, hone, bearings, etc, etc. The head before this had I would say 3k miles on a fresh valvejob and new OEM stem seals. During the rebuild I soaked the head in some "good" cleaner that worked excellent for removing some old buildup. I do however have concerns on if it could have possibly damaged the stem seals...

The engine smoked good before the rebuild, leakdown was 12%-30%. Obviously coming from the rings. I tore it down, simply cleaned the head, rebuilt the bottom end. I now have 120 miles on the "new" bottom end. After driving the car, removal of the spark plugs reveals "wet" piston tops and a good amount of carbon. Keep in mind it was completely cleaned when I rebuilt. I have not noticed any smoke under WOT or deep vac (car has no cat) and I have not noticed and oil loss on the dipstick in the 120 mile period of time. I am showing ~5% leakdown at this time. I am confident in the bottom end and how well the rings are sealing, but I am beginning to worry about the stem seals. Has anyone ever ran into problems with cleaners destroying otherwise new/good stem seals? I have rebuilt many engines before and they all seem to have "wet" piston tops for a short period of time, but I am a little concerned about it this time.. It doesn't appear to be going away.

 

Yeah, it sounds like you may have messed up the seals. 5% is a little high for a fresh rebuild. If you have compressed air then you can use the snap-on tools to remove the springs with head on. Also, honda seals the stem remover.