check this thread for a history. https://www.honda-acura.net/forums/s...d.php?t=267866

for those that don't want to read the other thread here is an abridged version. I bought a 1990 integra gs with a blown engine. I put in a new engine. started it up. there was a knocking/ticking noise coming from the engine. I figured it was a spun bearing or a stuck/bent valve. I did a leakdown test and it showed that one of the exhaust valves was open on the #1 piston( I'm not too sure I had the piston at tdc though). I took the head off today and the exhaust valves do look like they could be stuck open just a little. there is no damage to the tops of the pistons though. the most disturbing thing that I found is the fact that once pistons #1 and #4 are at tdc I can physically push them down without moving the other pistons. #1 will move about 1/4" and #4 will move about 1/8". there really isn't any damage done to the cylinder walls though. just one or 2 vertical scratches in all 4 cylinders that you can only see, not feel. I think those are from starting up the engine after it had sat for so long. I'm not sure about that though.

so what do you guys think it could be? spun bearing? I wouldn't think the pistons would move that much with a spun bearing, or at least there would be more damage done to the cylinders. I'm kinda lost, any help would be appreciated.

 

You've already gone through the trouble to remove the cylinder head, why not drop the oil pan and check the bearings? If they are in good shape, it might be a wrist pin.

 

well, I finally made it over to my parents house today to drop the oil pan... and I have 2 spun bearings. #1 and #4 pistons had NO bearings left at all. the crank at the #1 piston looked fine, I couldn't feel any scratches on it at all. #4 had a few scratches that I could barely feel at all. do any of you think I should get a new crank? can I swap out the bearings or crank without pulling the engine again? I think I remember someone telling me I could.

 

Do not re-use that crank! Honda uses forged cranks that cannot be machined or turned. Even if you did risk grinding it, If a bearing has spun once its likely that it will happen again. Used OEM cranks in perfect condition can be had for $100 - $200.

It will take less time pulling the motor and doing it the right way than it would take to attempt working on the engine still in the car. You can't check for clearances upside down. I'm not saying its impossible, but I wouldn't even attempt. If your confident in rebuilding your block, pulling the engine should be the least of your worries.