some of you may have seen my thread a few days ago showing a bunch of scratches and scarring in one of the cylinders in my h22... Ive made some progress on my first engine rebuild but I'm still not sure exactly what was causing the pistons to scrape against the cylinder walls

ive got the pistons out now and 3 of them look fine but the one that came out of cylinder #3 (the scratched one) looks pretty much how i expected it to... its pretty beat up







Im not sure if I knocked it loose while working on it but one of the thrust washers was dislocated when I got to the crankshaft. This also has some significant wear on it, as does the bearing that was right next to it.





I did ended up getting a drill hone and did some work on the bad cylinder and it seems to be a lot smoother now... I noticed however that one of the pistons does not fit comfortably into each of the 4 cylinders. Its pretty strange because it fits into cylinder 1 and 3 just fine with the correct orientation (IN marking toward the intake side). However it only drops into cylinders 2 and 4 if it's rotated 90 degrees (IN marking towards flywheel or crank pulley). Although once its down in the bore I can rotate it back to how it should be... Is this an indication that the cylinders are warped or not within specs?





IDK how much I actually want to do, my plan right now is just hone all four cylinders, re-ring the pistons, replaced the bearings, throw all new gaskets on, and cross my fingers that I still get somewhat normal compression. Even if just the misfiring stops Id consider it a success... But if anyone has some input for me Im definitely in a little bit over my head here... Ill post some other pics in case theres something that jumps out...



The two cleaner pistons werent like that when I took them out, I just cleaned all the carbon buildup off of those two and havent gotten to the other 2 yet...

 

it looks like you lost oil pressure and the oil squirter didn't keep the piston cooled off and it let it scar up like that. make sure you put the piston back into the cylinder that it came out of. that should help a little. but from what your saying about getting the piston in the cylinder either the piston is damaged somehow or there is a burr inside the cylinder that is causing the piston to get hung. i would go ahead and hone the rest of the cylinders a little. don't over do it. make sure you use plenty of oil.

 

Where's the oil filter?!? Just kidding, it looks like you're doing fine. Just read the relevant sections of the helm manual and go by that. Honing with a drill is not ideal, but it's far better than having scratched up cylinders. When you're done honing the cylinder it should be very smooth (600 grit iirc), you don't want any visible cross hatch on FRM. Good luck!