Recently acquired tractor. Has a spun rod bearing and in the process of dismantling found a exhaust valve spring broke, but valve was stuck and did not drop. Found the cap but could never find the 2 small keepers anywhere. They look like a 1/4 inch lock washer cut half into. The shop manual calls them collets. They are no longer available from Ford or anywhere else I can find. Does anyone have 2 they are willing to sell? Found a guy in Ohio who has some but he wants 10.00 EACH for them, which I think is a bit excessive. Guy at the machine shop has some that are the right circumference but are thinner(.131 thickness versus the original .153), does anybody know if these will work OK? If you can help or have any advice I would appreciate it. Thanks in advance.