Originally Posted by Horsehockey
Thank you Professor Disston. Maybe this explains the big difference I noticed in how difficult it was to remove and reinstall the wrist pins the three times I've done that on an airhead. Sometimes easy, sometimes harder n' hell. Sounds like the alignment on them things can be off by more than I thought.
That phenomenon is mostly not about the twist in the rods. It's varying interference fit in the pistons and varying pin/bushing fit and bushing bevel. I have sized enough wrist pin bushings on a Sunnen rod honing machine to know for sure that if you get that down to .0003 or .0004" like it is suppose to be sometimes you would swear the pin is never going to go in with the rod and pin right there in your hands! Then you try and try again and it falls right in with plenty of room to slide back and forth.