I notice a slight vibration in my 302 @ 50-55 mph. I noticed the crank pulley is slightly out of round when at idle. Not warped but the belt is moving slightly up and down. maybe 1/4 inch or less. Could this be the pulley is off center or the harmonic balancer ? It's had this issue since day one.
MPH shouldn't play a part in the vibration. if it's motor, RPM should show where it comes in and out. JMO
What i suggest if you,re concern with pulley is to take off and inspect. While you,re there take a peak at balancer. As for the vibration you,ll have to do some process of elimination. Tire balance, driveshaft, is tranny to engine bolt all tighten? Another suggestion you can try is take note at what rpm you're at where vibs occurs. Now rev motor at rpm in park and/or neural. Anything unusual? You gotta figure out if in engine or from engine back. Hope you understand what i,m suggesting.
Easy, run it up to 60 mph or so and put trans in neutral. If vibration is still there at 50-55, ain't the engine.
Where do you feel it, in the seat, steering wheel and can you pin point the direction it's coming from? The speed you say it happens is in the sweet spot for tire imbalance so it might be the best place to start. As far as the pulley, it may have taken a hit at some point and narrowed the groove. I had that happen on a Pontiac I used to have, engine was swinging on the hoist and bumped a stationary object with it.
Have you replaced your universal joints in your driveshaft lately? Could be one of them is bad. - Matt
Driveshaft could be out of balance or bent? I had the problem of bent and out balance when I got my car; at around 60 mph got vibes. I would also check harmonic balancer for rubber isolation material integrity.
Yeah, I've done that. When in neutral at 60 mph and engine idles down, The vibration is not noticeable.
Glad you found it before I got worse. I had a slipping balancer ring knock the crank pulley off at 70mph once on one of my Cougars. It didn't really warn me with a vibration beforehand, but it sure got my attention when the pulley started to ricochet all over the front of the engine compartment.
I noticed the harmonic balancer is spinning true but the crank pulley is not. Like it's off center a bit.
