Single Nut Lifter Woes

[John Stone]

I had this problem several years ago. I center punched the threads and it still loosened up. Did this a couple times. Then pulled the pan and found the mushroom was wearing off. Case hardening wasn't there. Did a hardness test and it was soft like cold rolled steel. Put in a new set of "single lock" lifters and the car is still running with those giving no problems. I saved the lifter as an example of bad reproduction parts.