Tequila

Member
19 hours on top end rebuild. Head machine shop renew W /new valves, springs guides seats etc. new rings, everything else in engine was well within specs. Runs good for a few hours, then next start only hits on couple cylinders until warm. Twice now a push rod came out of tappit. Rods are bent. I have adjusted tappits three times to manual specs. I am kinda stumped. I have restored 8 tractors, this is the only Oliver, I really like the 550. Anyone out there got an answer I am missing????
 

If the push rods are bent they are going to continue to bend more and the clearances will keep changing forever. Were the push rods straight BEFORE the head rebuild?
 
Are all the bent push rods for the exhaust valves? If this is the case the machine shop probably has the guides to tight. Just a thought, Chuck
 
Chuck is likely correct. Were the new guides cast or bronze? Different coefficients of expansion. Bent push rods are likely because valve was pushed to open position and stuck
there, allowing the pushrods to get displaced and then bent. Were seals put on these valve stems? They may be grabbing due to lack of lube, but I have only experienced stuck-
open valves as the engine warmed (valves directly in cast iron head). Removing the stem seals sorted it on that engine.
 

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