Crank pulley shaking at idle

gilly02le · Post by **gilly02le** » Fri Apr 23, 2010 3:22 pm

had my car idling in outside the house today, and noticed my crank pulley seemed to be shaking. On further inspection it looks almost like my crank is a bit warped... since the crank pulley bolt is spinning out of round as well.. When i rev the car up even a little, it smooths out, but i notice when its idling, you can feel the shake throughout the car.

Any suggestions on what the problem might be? At this point im thinking my crank bearings may be toast..

heydockyle · Post by **heydockyle** » Fri Apr 23, 2010 4:10 pm

Is the bolt tight? Have you had it off? Is it pressed on all the way (I assume it is since it isn't throwing any belts)

It could also be bent, or if someone has had it out multiple times, the it could be messed up from people heating it to help get it off.

gilly02le · Post by **gilly02le** » Fri Apr 23, 2010 4:26 pm

im going to have to check the bolt to see if its still torqued. But yea i have had it off once when i installed a new timing belt/tensioner, But i used a proper tool and it come and and went back on with no issues. Odd that it spins smooth when i step on the gas.

heydockyle · Post by **heydockyle** » Fri Apr 23, 2010 4:36 pm

I think the centers are part rubber, so thats a possibility.

How did you put it back on?

Post by **occasional demons** » Fri Apr 23, 2010 5:21 pm

The outer ring is bonded to the inner hub via an elastomeric ring. But the outer ring would wobble if it was ready to go into orbit, taking the belts with it.

Possibly it is just an illusion from the engine shaking at idle, giving the appearance of being out of round. I am not sure how you could turn it by hand, and check the runout tho. The ratchet and pulling would move the engine, so a dial indicator or fixed object from the car body would not work. If there is something that you could attach to the tensioner plate, that may work. All the plugs could be removed, so cranking with the starter is smooth. Then see how it looks, while someone cranks it over.

gilly02le · Post by **gilly02le** » Fri Apr 23, 2010 5:51 pm

Forgot to mention im running a UDP. I checked it before installing it with a micrometer and it was very very straight. Since the head of the bolt is physically turning with a warp to it, i would have to assume the problem is inside, and not the udp itself.

Post by **occasional demons** » Fri Apr 23, 2010 10:13 pm

Well a UDP is of course either a solid piece, or a hub and the pulley is attached to the hub. If the belts are not wobbling, or the outer circumference seems to be running true, I wouldn't worry too much. The head of the bolt may not be perfectly centered. Hell just remove the bolt and see how it looks. I doubt the pulley will come off. The bolt is only there as a fail safe. The interference fit is what keeps the UDP from slipping/moving. If the UDP is loose without the bolt, then the udp, and/or the crank is toast. For a 5 minute run, to see if something is out, it shouldn't hurt. Just check for looseness before starting.

heydockyle · Post by **heydockyle** » Fri Apr 23, 2010 11:24 pm

They said it would take like a 5 ton press to create enough force to get the pulley off. Or something like that. So no, you don't need the bolt aslong as it is seated on there all the way.

Post by **occasional demons** » Sat Apr 24, 2010 7:49 am

Yeah, as long as the crank, and hub are in love with each other, there is no separating them without brute force. But say, if the hub cracked, then there could be issues. I would think that would be a rare problem, but with an ebay part, it may have a small increase in risk.

gilly02le · Post by **gilly02le** » Sat Apr 24, 2010 8:07 am

Ill take the outer pulley portion of it off and see if there is any damage to the back of the pulley, or the hub it installs on.