CRANK WOBBLE!! Updated, found problem

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Coyote Jack

Coyote Jack

Member #55, I'm old
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The car has not been working the way I like it so I did a little investigating. I put on my pulleys to get 10 to 11 lbs of boost and went for a drive. Everything seemed normal until after I gave it a good hit. Nothing to extreme just wide open until after I was in 2nd gear. After that it was like it was down a cylinder. I checked all cylinders and I am getting fire using the water on the header tube method. I started looking around with the car idling and I noticed a wobble in the crank pulley. Is this normal or do I have a real problem? I have a video of it but I can't upload it to the site.

Jack
 
Hard to tell from that, but it APPEARS the pulley is what is wobbling, ballancer looks to be running true...hard to say without being there in person.
 
replicaracer43 said:
Hard to tell from that, but it APPEARS the pulley is what is wobbling, ballancer looks to be running true...hard to say without being there in person.
Click to expand...

I agree. I think the pulley is all that's off track. At least it appears that way.
 
Unfortunately that was the best video I could get. The balancer is moving just not as much as the pulley. I am going to take the pulley off tomorrow and check the balancer bolt and stick another pulley on there and check it again. Kind of scared the crap out of me when I saw it.

Jack
 
crank might be broken or cracked at snout or right behind the first main.

slow the video down to .25 speed. easier to see the balancer wobbling.
 
Do you have a dial indicator and a long stand? Check the crank snout with the balancer off. Might have to spin with the starter, or run the bolt in w a spacer and turn by breaker bar, the better way.
 
I would buy a dial indicator (if you dont have one) and remove everything down to the crank snout... then turn the crank by hand and track if the snout is bent - this would show something wrong with the crank... if it shows true then it's obviously somewhere else... put the balancer back on and repeat the process... then add the spacer... then the pulley... checking each piece as you go --- itll narrow down where the problem is.
 
aren't the OEM balancers prone to some level of failure at the bonded elastomer where the inner and outer rings are "together"? I wonder if it is failing on you and would a Fluid Damper or ?? be a better option?
 
Youtube troubles lately, any one else see this?
Screenshot_20200630-142308_Free Adblocker Browser.jpg
 
As Leroy stated, the elastomer gives out over time one the OE units, and even the performance counterparts require 'rebuilding' to replace the O Rings in the dampers.
Which is why Fluid Dampers are so popular.
BTW, if this is the case, and the damper has slipped, the wobble will grow over the length of the pulley. Basically exaggerating the runout.
The best way to confirm the issue is to put a timing light on it to see if your timing is off from your normal setting.
Also too, look all the way around the damper to see if rubber is pushing out between the hub and outer ring.
 
crackedback said:
crank might be broken or cracked at snout or right behind the first main.

slow the video down to .25 speed. easier to see the balancer wobbling.
Click to expand...

I'm thinking the same.....I just didn't wanna rain on Jack'a parade.
 
A dial indicator? Seriously? Take all the belts off, grab the crank pulley and if you can rattle it up and down, side to side, the crank's broken. Real simple. Possibly real unfortunate.
 
'63GT said:
As Leroy stated, the elastomer gives out over time one the OE units, and even the performance counterparts require 'rebuilding' to replace the O Rings in the dampers.
Which is why Fluid Dampers are so popular.
BTW, if this is the case, and the damper has slipped, the wobble will grow over the length of the pulley. Basically exaggerating the runout.
The best way to confirm the issue is to put a timing light on it to see if your timing is off from your normal setting.
Also too, look all the way around the damper to see if rubber is pushing out between the hub and outer ring.
Click to expand...
If you watch the video in slow motion it seems pretty clear the inner balancer is wobbling, making the blower pulley really wobble.
Sure looks like a bent or broken crank, especially with the running condition
 
if the crank is bent , the pulley is way out there . you won't see it wobble with your eye on the damper , its dial indicator time on the damper and rotate the motor by hand . blowers like to crack crank noses off it starts with a bent nose . and are you sure you damper is not taking a sh....t . la's are known for damper to fail to stay in good shape .
 
Unfortunately, I have not been able to get at it due to other issues around here. Hopefully in a couple of days. I can say with all belts removed the pulley does not move by hand. I will be able to tell more once I take the pulley off and can see the damper better. I will have a look with the timing light today if I can. It doesn't take long to check it. I don't think the crank has broken yet as all cylinders are firing.

Jack
 
MiradaMegaCab said:
Is the crank forged?
Is it double keyed?
Is that a stock damper?

Was the blower belt too tight?
Click to expand...

Stock forged crank, single key, stock damper. Blower belt did not appear to be to tight. The only big difference I can figure is that I was running a smaller top pulley and had the boost up to 10 to 11 lbs.

Jack
 
I found a few minutes to look at it this morning and also found the problem. SEE PHOTO My only guess is that when I upped the boost the damper couldn't take the extra stress and failed. Of all the things that could have happened this is definitely not the worst. It cracked the timing cover as well, but I have a spare one of those. The crank seems to be running true so I am not to worried about it. Anybody know where I can get a decent damper quick in Canada?

Jack

DAMPER002.JPG
 
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