Questionable donor motor

Carpetbagger · Dec 25, 2019

I am in the process of putting a 126 back together with a donor K301 12 horse Kohler that I know little about. I need advice on what to do to the motor while I have it apart and sort of cleaned up. It was pretty carboned up and grimy. What do I look for on the valves and pistons and rings to clue me in on possible rebuild or rattle back together? I've got new carburetor and points and have repaired a cracked oil pan. I've cleaned up the head and top of the block. Also, exactly what is the purpose of the "tin" shrouds over most of the motor? Thanks, Gearjammer

RandyT · Dec 25, 2019

The tin shrouds are to direct air flow around the engine for cooling. Check the cylinder wall just below the top of the cylinder for a ridge that would indicate amount of cylinder wear. Also look at the oil control ring to see how flat the surface is that makes contact with the cylinder wall. If there is a concave between the top and bottom edges of the ring then not too bad. If flat that would indicate excessive wear. Also make sure to change the head bolts when you reassemble. Will save you headaches in the long run. Has to to with the initial stretch of the bolt. When reused have been know to no longer match the expansion and contraction of the aluminum head to cast iron block interface causing blown head gaskets, or will cause engine to run for period of time and then die and won't restart until the engine cools