Q: I have lost the harmonic balancer three times in this engine (327). The first time they repaired it but it came off six hundred miles later. The second time it came off they tried to weld it (spot weld). Now I am told the best way is to drill the crank and use a 7/16 in. bolt with a thick washer. Some say this can be done and other people say no. Why is this not holding when it is "repaired"? Do I need a new crank? Should there be a hole in the end anyway?
There is about 5k miles on rebuilt engine. (it has Dart heads a mild cam, bored .40 over and a few other things that I dont think have much to do with this problem.)
A: your crankshaft is most likely worn slightly. On these engines it was a pressed fit. I have drilled and tapped the crank in two of these engines, and it cured the problem. I would try tapping it out before i replaced the crank. After all, youre only out a few hours of time for the trying.