Z06Vette.com - Corvette Z06 Forum

johnryanbuilder · 07-04-2009, 10:32 PM

Hello, all, and thanks in advance for any advice offered. I have not had this 02 Z very long, and have noticed that the main drive belt is "jumping" out of line by a groove. Anyone else had this happen? Is this an alignment issue? I've found it this way twice. It is simple enough to get back in line, but I want to get to the root cause. Thanks again.

Subdriver · 07-05-2009, 10:09 AM

I've lost a few belts at the track. Common cause seems to just be the belt and not any misalignment of any of the driven components. Everytime I've had the same problem, I put a new belt on and its good for quiet a while. I recommend a new belt for you. But, when the belt is off, I'd check the driven components, such as the alternator, for excessive longitudinal play (e.g. in line with the shaft which would cause it to be out of line with the belt).

RocketSled · 07-05-2009, 11:33 AM

I agree with SubD. There's not a lot that can get misaligned in a stock LS6 accessory belt system. But the belt can jump due to a soft tensioner, and/or a stretched belt, particularly when you're hitting the shifts *hard*. You're new to the car, so you might not have any maintenance history, but it costs little to just replace the belt. That being said, I know that a Kevlar OEM-sized replacement is available - I'd get that if I could find it someplace. The kevlar backed belts are substantially stronger and more resistant to stretching than the standard belt.

My setup is far from standard, and I had a problem with the belt jumping, not due to alignment, just due to the loads being placed on the belt combined with my style of driving. When I finally switched to a kevlar belt, my problems disappeared. I keep a spare belt in the car just in case, but I haven't thrown a belt in 2 years.

Pit Man · 07-05-2009, 02:48 PM

Quote:

Originally Posted by RocketSled

I agree with SubD. There's not a lot that can get misaligned in a stock LS6 accessory belt system. But the belt can jump due to a soft tensioner, and/or a stretched belt, particularly when you're hitting the shifts *hard*. You're new to the car, so you might not have any maintenance history, but it costs little to just replace the belt. That being said, I know that a Kevlar OEM-sized replacement is available - I'd get that if I could find it someplace. The kevlar backed belts are substantially stronger and more resistant to stretching than the standard belt.

My setup is far from standard, and I had a problem with the belt jumping, not due to alignment, just due to the loads being placed on the belt combined with my style of driving. When I finally switched to a kevlar belt, my problems disappeared. I keep a spare belt in the car just in case, but I haven't thrown a belt in 2 years.

Where are you finding the Kevlar belts ?

Pitt

RocketSled · 07-05-2009, 09:12 PM

I think I ordered mine from Vortech, since the problem was in large part due to the Blower and an effect called "reflected inertia" (when the engine speed changes suddenly, all the spinning accessories have inertia that must be overcome by the belt. The blower adds a *lot* of inertia to the system. The effect on the belt is as if those accessories continue to "push" the belt faster than the motor wants the belt to be moving and that causes the belt to stretch and go slack on the tensioner side of the loop). But if I recall, it's a "Gates" manufactured belt, it ought to be available other places besides Vortech (the Vortech belt routing is radically different from OEM, but Vortech had the courtesy to keep the same overall belt length as stock).

Last C5 · 07-08-2009, 03:59 PM

While you're at it replace your stock tensioner with an LS2 tensioner. They have taller sidewalls and accomodate the Zs sometimes erratic belt movement. My buddy's 02Z was doing what yours is doing and that solved the problem completely. It's a direct bolt on replacement.

johnryanbuilder · 07-15-2009, 11:21 AM

Thanks for the info guys. So far so good with a new belt. The tensioner seemed fine so I went ahead and left it on more out of curiosity to see if it was the belt or tensioner causing the problem. Once I'm satisfied, I'll go ahead and replace the tensioner just as a precaution, and I'll try the LS2 unit.