We have a sb Chevelle (307) that's newly rebuilt for street use. It runs smoothly, but I noticed a slight wobble in the crank pulley.

Even though we knew better, we did use a hammer to "install" the hamonic balancer and so it's possible that we bent the crank slightly in the process. There is als a very small leak around the crank seal in the timing chain cover that could be another clue.

First of all, how do we know for sure that the crank is bent? And second, what is the downside of not replacing the crank if it does turn out to be bent?

Thanks!

I doubt you bent the crank that way. More likely it's either the balancer itself with a crooked rim or the pulley is bent or not on straight. If you peened over the edge of the center hole in the balancer while using the big F*ord tool the lip on the back of the pulley woun't seat in the hole in the balancer. It'll run crooked. I doubt the oil leak is related.

Tom

I'm sure the crank wouldn't be bent by installing a harmonic balancer with a hammer. Thrust surface of the rear main bearing maybe. I've installed more than a few harmonic balancers with a hammer, in fact that is pretty much how you have to do it with a 283 or early 327.

If you really need to know if the crank is bent, you'll have to use a dial indicator.

Mike

As Tom said, no way you will bend the crank "installing" the damper.
As Mike posted, almost all the early 283/327 cranks along with most of the 6 cylinders had no threaded hole & the early factory service manuals gave installation instructions which included a rather large hammer & block of wood or big chunk of steel depending on which manual you had ;)

You are not supposed to beat on the damper with the hammer. You put a block of wood or steel on the damper & whack the crap out of that with the "other" tool.
It was a "tool" in almost everyone's "special" tool box drawer.
Mine was a big round chunk of steel about 4" long & 4" around smile.gif

I don't recommend this as an installation method especially with a $300 ATI damper, better to have a hole drilled & tapped in the crank while it is at the grinder but it will work if you don't have a threaded hole with a stock damper.

BTW, There is also no way you are going to hurt the thrust . ;)

I've most often used either a solid rubber mallet or a rubber dead-blow mallet to install the balancer and have had fine results everytime. If I can used a balancer installer with a threaded crank snout I will do so as it is much easier with less guesswork.

Pull the crank pulley and have someone crank the motor over (don't start it) while you watch the end of the crank. If the crank is bent, the wobble will be obvious. My uncle piled his stock car into the wall a few years bank, and we noticed the bottom pulley was crushed while repairing the damage. We removed the pulley and cranked the engine over, and sure enough, the crank was bent too.

Checking the crank snout with a dial indicator would probably be best to verify if the crank is straight. I've looked at quite a bit of front end collision damage and the cranks do bend on impact. Though a collision impact I'm sure is more powerful than a hammer blow. I've put on about 12 with a hammer and block over the years and never had any problems. The factory balancers do go to hell with age though, and some people aren't to easy on them when pulling then out or rolling a used engine around on the floor before teardown and rebuild.