iamvandemon

hey ya,

my s. belt jumped track and half of it was chewed up. I bought a new belt but then thought better of installing it and decided to figure out why it jumped in the first place.

I was looking at all my pulleys as the engine idled, and noticed that the crankshaft pulley seems to be wobbling a little. the belt visibly wanders on the idler pulley, but it doesn’t look like the idler pulley or tensioned is bad.

how common is it for a crankshaft pulley to go bad? I have never had this happen before, and cant think of any reason why it could/should.

any insight you can offer would be great.

thank
van

93' d350; a/c; intercooled
(the idler pully is metalic- i'm guessing aftermarket?)

rlyons

The pully is two piece with rubber in the middle to absorbe vibrations. They will go bad and wobble or worse yet fly apart. Get it changed quick before it flys through your radiator or hood.

iamvandemon

thanks! that makes good sence.

now, does anyone have especially strong fealings about who they would buy a replacement crankshaft pulley from? like cummins dealer vs gettozone?

van

rebal

I would get a cummins part if it is the pully, but first check out the idler pully real close, if it has any wear on the plastic washer that is moves on it will eat belts.it can work even bad but it starts eating the inside edge of the belts off.

iamvandemon

thanks for the advice. I will pay particular attention to that once I take it all apart and after.

cheers
van

Underpsi

are the 91.5/intercooled trucks the ones with the two piece crank pulleys? If so would it not be posible to just buy the one piece and put it on and then never have to worry about it again?

iamvandemon

if your asking me, I have no idea.

but, it was mentioned in another thread, that I was reading over tonight, so tomorrow I will talk to the Cummins parts supplier about it.

thanks for the suggestion.

cheers
van

bgilbert

You check the torque on the 4 bolts holding it?

iamvandemon

i replaced the belt tensioner and crank pully/balancer.

i dont think the crank pully/ballancer was bad because the new one wobbles just as much as the old one. i am not exited about that but maybe its supposed to..?

does your balancer have any movement on the outside face when its spinning?

Tuckerdee

Is your truck a standard shift or an auto? There was a thread just a week or so ago about this very problem. His thrust bearing on the crankshaft is worn out and his crank shaft will move (front to back) about 1/4". This is more of an issue with a standard transmission since pushing in on the clutch wants to move the crankshaft forward. After 300,000 miles of that the thrust bearing says "Enough!". Maybe check to see if you can move your crankshaft backwords with a prybar.

Edit: Here's the first thread: https://www.dieseltruckresource.com/...ad.php?t=93016

Here's the second thread:
https://www.dieseltruckresource.com/...ad.php?t=94909

apwatson50

That was me and just hope that your crank won't move in and out. I'm in the process of pulling the oil pan and i've had to remove the tranny t/case so far and the whole engine is going to have to be lifted up at least 6 inches. So it might just come all the way out.

So now i've bought a new clutch($400), new crank pulley(200), main bearings/rod bearings oil pan gasket(200), and some other stuff. Its getting kind of expensive, guess its still cheaper than a new truck. haha and it'll be ready for another 300k when i'm done.

iamvandemon

yeah, i got a stick.

aarons description sounds exactly like what i got going. shelling out for parts is one thing, but having to half pull the engine to install them doesnt excite me one bit.

thanks for pointing me towards aarons threads and such.

van