Crank pulley wobble

[Farrell5.0]

Since I've had the car (an 87 gn), I noticed the crank pulley wobbled, but not the balancer. I should also note the engine is bone stock and never been opened. I finally got around to investigating it and pulled just the pulley and left the balancer on.

It looks like the pulley is made of 2 pieces, am I wrong? If that's the case, could it be some play in the pulley?

I put an indicator on the face of the balancer and cranked the engine over, it has .02" of runout, so maybe the length of the pulley is exaggerating it. It looks like the balancer has warping where it was cut on the backside.

Again, bone stock, unopened motor.

How should I approach this?



Sent from my SM-N950U using Tapatalk

 

[turbo89]

Since I've had the car (an 87 gn), I noticed the crank pulley wobbled, but not the balancer. I should also note the engine is bone stock and never been opened. I finally got around to investigating it and pulled just the pulley and left the balancer on.

It looks like the pulley is made of 2 pieces, am I wrong? If that's the case, could it be some play in the pulley?

I put an indicator on the face of the balancer and cranked the engine over, it has .02" of runout, so maybe the length of the pulley is exaggerating it. It looks like the balancer has warping where it was cut on the backside.

Again, bone stock, unopened motor.

How should I approach this?



Sent from my SM-N950U using Tapatalk

you shouldn't ... clean it up and put it back together .. leave it alone

 

[TURBOTIMMER]

Take Your serpentine belt off and check to see if you harmonic balancer came loose. I’ve seen that big bolt back out of an unopened motor.

 

[Farrell5.0]

you shouldn't ... clean it up and put it back together .. leave it alone

That's what I was leaning towards lol

Sent from my SM-N950U using Tapatalk

 

[Farrell5.0]

Take Your serpentine belt off and check to see if you harmonic balancer came loose. I’ve seen that big bolt back out of an unopened motor.

The bolt is still tight.

Sent from my SM-N950U using Tapatalk

 

[TurboTnZ06]

Pull the balancer. The part that you can't see may be cracked. Had that happen to a stock one once. If you don't fix it, it can damage the snout of the crank wobbling around like that. Buy a new used balancer and slap it on.

 

[Farrell5.0]

Seems used is my only option. Nobody sells a stock replacement? That sucks.

Sent from my SM-N950U using Tapatalk

 

[Nick Micale]

Pull the balancer. The part that you can't see may be cracked.............

I have experienced many stock balancers that have cracked or worn shaft bores.

In short order it will beat the snot out of the crank, which will render it un-useable.

 

[TURBOTIMMER]

https://turbobuick.com/threads/nos-harmonic-balancer-never-mounted-or-used.456493/


Good price considering used ones go for $40-60.

 

[Farrell5.0]

https://turbobuick.com/threads/nos-harmonic-balancer-never-mounted-or-used.456493/


Good price considering used ones go for $40-60.

Good looking out, thank you.

Sent from my SM-N950U using Tapatalk

 

[Farrell5.0]

I've read that the bolt requires 200+ ft-lbs, how do you actually apply that torque without spinning the motor?

Sent from my SM-N950U using Tapatalk

 

[Nick Micale]

I've read that the bolt requires 200+ ft-lbs, how do you actually apply that torque without spinning the motor?................../QUOTE]

Clamp a vise grip on the flexplate,

 

[TurboTnZ06]

Vise grip on flexplate works, or jab a 18 inch 3/8 socket extension thought a flexplate hole up under the oil pan flange....

 

[Farrell5.0]

Ah, good idea. Thanks!

Sent from my SM-N950U using Tapatalk

 

[turbo89]

No no no .. Geez guys .. there is a flexplate wrench .. its only $20 bucks goes right on the flywheel teeth ..
Either have a buddy come and help you or you can position it so it grabs a solid when you turn the bolt.

If you need a stock balancer I have a few that I can get you .. but I thought you said the balancer was good and only the pulley was wobbling ?

 

[Farrell5.0]

No no no .. Geez guys .. there is a flexplate wrench .. its only $20 bucks goes right on the flywheel teeth ..
Either have a buddy come and help you or you can position it so it grabs a solid when you turn the bolt.

If you need a stock balancer I have a few that I can get you .. but I thought you said the balancer was good and only the pulley was wobbling ?

When the motor is running, the balancer appears to run straight, but when I put an indicator on the face of it, it was nearly .02" of run out. So I'm not sure if the pulley is the problem, or if the wobble of the pulley is exaggerated from the balancer runout due to it being several inches long.

Looking at the face of the balancer, there is no crack. I took the bolt out yesterday, but the balancer is stuck on there and I didn't have time to mess with it yesterday any further, so I'll be getting back to it today to pull it off to inspect the back side.

Sent from my SM-N950U using Tapatalk

 

[turbo89]

When the motor is running, the balancer appears to run straight, but when I put an indicator on the face of it, it was nearly .02" of run out. So I'm not sure if the pulley is the problem, or if the wobble of the pulley is exaggerated from the balancer runout due to it being several inches long.

Looking at the face of the balancer, there is no crack. I took the bolt out yesterday, but the balancer is stuck on there and I didn't have time to mess with it yesterday any further, so I'll be getting back to it today to pull it off to inspect the back side.

Sent from my SM-N950U using Tapatalk

just to make sure ... do you mean .002 " or is it in fact .020" runout ?

 

[Farrell5.0]

just to make sure ... do you mean .002 " or is it in fact .020" runout ?

It's .020" on the surface that the crank pulley bolts to. It's .026" at the largest diameter on the face.

 

[captndave737]

The torque spec is 219 lbs.ft Minimum.

 

[earlbrown]

.020" on the balancer face is a mile. That hub should be dancing all over the place.


I'm kinda amazed the belt tentioner has kept the belt from flying off and taking out the hoodliner.