Fan Belt jumping on AC compressor

[Diesel_Junkie]

I finally did my KDP mainenance with the timing cover off.

Put it back together, and a couple weeks later my fan belt torr off one of the ribs and jumped a groove one all the accessories.

I got a new belt, a goodyear gatorback, and when i put it on, it continually jumps 1/2 of a groove on the AC compressor everytime I start it up. It actually rides with ridge on ridge, only jumping 1/2 a groove. It also pulls out a little bit on the tensioner pully. As an FYI the belt routing is crankpully> Tensioner pully> AC compressor.... the only accessory with an issue is this AC compressor, all the bearings and end play on all the pullies seem fine.

2 questions
anyone had bad luck with a gatorback?????

One of the bolts for the timing cover has an extra long bolt and a wierd shaped spacer about 1/2" thick and about 1"OD. When i put the cover back on, i could not remember which hole this one went it..... I origionally put it one space away from the vibration damper, towards the driver side. I moved it to the hole that is right next to the vibration damper, and put an old cummins brand belt on and it works fine now. What gives? Is that spacer supposed to be some kind of belt guide????

I dont know if its the gator back, the spacer, or somethign else....

Is there any wisdom out there on this kind of thing?

Thanks,

 

[MIDNIGHT RIDER]

May not have a thing to do with your situation, but, we had an old Chevy Corsica that insisted on eating off one rib of the belt, jumping a groove in the process.

After about ten belts, we replaced the tensioner assembly and end of problem.

It may be just a coincidence that this started after your other work.

 

[2500cummins]

I've seen the tensioner cause this problem on at least four different Cummins engines, I would look there first.

 

[Mike]

Hmm, not Cummins specific. This is an issue on the PSD as well. I'd bet dollars to donuts that its your tensioner casuing you the grief.

 

[Headhunter_5.9]

Would have to agree that it's not Cummins specific, my old '95 PSD did the same thing, but mine wasn't the tensiner it was an Idler that was SHOT!

 

[rlyons]

I don't know what the spacer is for but that is the right location for it.

 

[Diesel_Junkie]

It seems like moving the spacer fixed the problem... but that is just too weird. It is on the edge of the belt leading into the crank pully, but does not actually touch the belt when it is running. The problem happens right at startup too, so i would only expect extra tension on the belt when i hit the starter motor.

 

[Diesel_Junkie]

Turned out to be the tensioner.... wierd, the bearings felt fine.

 

[2500cummins]

Its the spring loaded pivot thats worn, it lets the tensioner pulley twist slighly and pushes the belt to one side..