So my Buick bent a pushrod. Passenger side 3rd one in. Had the engine rebuilt about 5 years ago locally and about 1500 miles ago. Late last summer my idiot oil pressure gauge light came on. I didn't think anything of it because I have a gauge T in and oil pressure showed like it always has. Started running rough at the end of the year so I parked it for the winter. Started running rough out of nowhere actually. Got it home and put it in the garage until I had time. Started going through a few weeks ago, tried to start it and nope. Crawled underneath and saw the starter was cracked. Got that replaced, then saw a vacuum line plug was off. Got it plugged and started and heard a noise from the passenger side. Took valve cover off and saw the pushrod. Anyway long story short. I pulled the engine and in the process of tearing it down to see what all was damaged and what caused the damage. Piston looks good, nothing here, cam looks good but haven't gauged it. What else should I be looking for or ideas? Had a small oil leak on it 1 year after getting it rebuilt so I'm tearing it down a d double checking their work and new gaskets.
I would be looking at that lifter from where that push rod sat to see if the plunger clip has popped out . This usually takes place from a over rev. The lifter then pops the clip out, over extends and then the push rod bends. Oh, and this condition will send tons of oil out the top of the lifter most times.
Weak valve spring lost control of the valve. The lifter CAN stay together during this situation but the pushrod, being its held in position by the lifter cup and rocker arm seat/cup can jump out and get hammered/bent. You have original valve springs? How do your rocker arms look?
Original pushrods, rocker arms looked good. It's possible they reused the valve springs. I would have to find the receipt, it's been awhile.
