crank pulley


WOW, after about 6 months of messing around with this crazy car, I think I have finally solved my problem.
It all started off with this crazy miss / backfire / some times under boost and sometimes not ?
I did the normal tuneup, and thought I fixed it a few times because its started as a very intermittant problem..
Well the last few times I have drove the car it just put me in a BAD mood because it was just running terrible..It idles fine but sometims right off idle it pops and studders and sometimes only with boost""" uggggg.
Well tonight I pulled a spark plug wire and just stuck an old spark plug on the end and I was going to start and car see if the spark looked ok. I vise gripped the plug to one of the brackets and started the car. Well it sparked ok, I guess ??? not sure how much it should spark ... Im sure if I touched it , it would have knocked me on my butt..... : )
But what I did notice was a strange knock that I never noticed before while it was running with a miss from the plug wire being off...I climbed under the car while it was running and it seemed to be coming from the crank pulley area...
Well to make a long story short... I shut the car off and climbed under the car and the front pulley assy will spin back and forth about 3/4 of an inch before the converter moves...
I have worked on many s/b and b/b chevys before and they have on the crank snout a groove for the key the harmonic ballancer fits tight onto the crank with NO movement.....
MY question is ... does the buick use the same key slot system ... and if so has anybody ever had this kind of movement.....
Im sure this movement has to be the reason for this wild goose chase over the months..... Its got to be throwing off the crank sensor timing..... : )
I hope this is it...
Please anyone with some idea help......

tom in st. louis
I've seen that problem many times,

It happens more often when the balancer bolt comes loose. More than likely it's just the woodruf key and not the balancer but i have seen both wear. They use the same woodruf key as a small journal chevy (283/327)

Hope this helps.
I took the car apart today, and found the crank key was worn really bad because the balancer snout was cracked, The way this thing is cracked im susprised I didnt end up on the road somewhere : )

From what I am reading on here they dont make this balancer anymore..

Anybody know where I can get a good one ?
BHJ makes an external balance real harmonic dampener that should be able to be made to work with a stock crank but it sounds like the crank is gone. And that means that you may need an entire bottom end re-do so might as well call Full Throttle and get a complete stroker kit and be done with it.
ha ha I would love to do that , but I dont have that much cash to blow..... and besides the crank looks fine .... the only real wear that I notice is the part of the key that goes into the balancer and the balancer itself that is cracked,,,,,,,
got a balancer from someone local here in st. louis, sure hope the car runs right with I put it back together..... : )
it sounds like the crank is gone.

I agree 100%. It's going to happen again if the crank isn't replaced now.


If you just put the balancer on be sure to check and side to side and up and down movement before you tighten the bolt. If it moves the crank is toast.