Hello, kinda new to the forums but after scratching my head and staring for a while im gonna ask for assistance. I recently purchased a DuPont Restoration, and the guy I purchased the tractor from said it had a knock in the clutch, and was having trouble keeping the clutch adjusted. I ended up pulling the clutch completely out of the tractor and replaced all of the toggles dogs, t bolts facings springs pressure plate and driver to no avail on fixing the knock. I then got into the crank case, took the rod caps off and wiggled the connecting rods, flywheel side had no movement back and fourth, but the clutch side had about a half of inch of play in the wrist pin. Ended up tearing the tractor down, and the piston wrings feel apart as I took the pistons out, and could tell that there was a lot of taper in the block in addition to seeing a lot of block sealer in the engine. Took the block and had it bored .090 over, to new aluminum pistons with .012 skirt to wall clearance to allow for expansion, took the head down and found cracks in the exhaust valve seats the ran all the way to edge of the cyclone part of the head, so I purchased a crack free head, and put new valves guides and springs, in addition to having it milled to flat. Put the whole thing back together and fired it and was pleased it didn't take much to here her come to life, but the knock was still there, no where near as bad, and when the engine gets to operating temperature the knock seems to go away completely. Checked the flywheel clearance and everything is ok there other than the splines on the fly wheel are shot and the guy I purchased it from put jb weld in the splines to keep it from moving (will be getting a new flywheel here soon) and I also took a slow motion video of it to see if it really was rocking in and out which it wasnt. Sorry this is so long but from what I read everyone usually puts a back story to there, and just curious if this is normal for a cold engine that has been bored out or if I am missing something. Thanks for all of your help...