VetteVinnie

Ever since the ATI Damper went on the car, I've been spitting off A/C belts. First one just simply popped off, so we tried a smaller diameter belt (the ATI is apparently slightly smaller than the stock balancer) and readjusted the tensioner, then over the weekend it actually split the belt in two down the middle, and of course it came off again. This is only happening with high RPM spirited driving. Never did this before.

Anyone else have this problem? If so, what was the solution?

Thanks.

RedZ4me

sorry, mine is the stock ATI diameter, 3000 miles and so far ok. Common sense tells me misalignment though

LS7 BUD

I had the same problem... For me it was that my crank bolt backed out... It was a new ARP crank bolt too... It killed 2 tensioner and 2 belts before we found the problem... I bought a Katech Billet tensioner after it killed two stock ones... I have the ATI 10% under driven balancer...

VetteVinnie

Okay, thanks. Katech tensioner is on order, and I'll check the crank bolt. Mine also has a brand new ARP bolt in there.

Odd that it's only impacting the A/C belt, though.

double06

I have had some issues with high RPM situations. The stock size ATI does not have much in the way of holding it on the balancer. The factory one has a nice ridge that sticks up on both sides to keep belt in. The 10% underdrive one I think has a ridge in it due it being under size.

VetteVinnie

Interesting. Although looking at ATI's part numbers for the LS7, they only have two of them and both are stock diameter (one with A/C 4-rib and one without).

Anyone know the outside diameter of the stock balancer? The ATI Damper is 7.53". Just making sure it still takes the 41" A/C belt.

double06

The factory pulley looks like 7.65 inches wide; however, it has a lip the height of the belt grooves is .170 less on each side so if you could measure that it would be 7.30 inches with at groove width. As you can see GM put the grooves down in there so the belt would not walk which is what is happening on ours.

petsur

Did the Katech tensioner solve your issue? Makes me wonder if replacing a good stock dampener with an ATI is worth while?

VetteVinnie

Katech tensioner would have nothing to do with the A/C belt. That was just a precaution against the main serpentine belt.

What I did with mine was to replace the A/C tensioner and to use a slightly longer A/C belt. Still haven't had a chance to get the car out because the weather lately has been horrible. Supposed to be sunny tomorrow, so I may have it out tomorrow to give it a shakedown.

VetteVinnie

Update: So far, so good. I changed the belt to a Dayco belt part #5040425 and a Dayco tensioner pulley.

double06

I was having same issue. If it remains good we should probably tell ATI about it so they can put in the notes in catalog. The ATI crank pulley is definately .20 inch bigger than stock thus could use a slightly longer belt. Mine would usually have issues on dyno or very high rpms.

VetteVinnie

Same here. Still haven't done too many high RPM blasts yet (cold weather not good with summer tires). Rain chance today, but this weekend perhaps. I plan to "test" this new stretch of road that opens Saturday. It's only 3 miles up the road from me.

vvlf

Any update as far as the longer belt not coming off, or has it still been too cold to drive ......

VetteVinnie

No problems yet. But I got sidetracked from the belt recently. I've been driving it quite a bit trying to get all of the sensors to come ready. I actually had a code set (P0174) and had to tighten all of the bolts on the intake manifold that apparently came loose from heat cycling. When I reset the code, it also reset the readiness of the various sensors. Inspection sticker is out as of December.

I did get it out on 99 a few times, but way too much traffic and the detector lit up frequently. There must be more than a few people out there getting the cops ruffled.

vvlf

Hopefully that ATi hasn't been throwing any more belts. I'm finally doing my build and trying to decide whether or not to throw a 10% ATi on there

VetteVinnie

So far, so good. With the slightly longer belt and the Dayco tensioner, it has survived several high-speed blasts and even a couple of low 11 second 1/4 mile sprints.

TT32VGT

I shredded one but I think it was bc the cam sensor came unplugged..and when mine got shredded i just went with the factory belt..i feel for ya tho.. its a PITA to install the ac belt.
Ive made countless visits to the track since and had no problems.. ive got a 10% underdrive on my 600+rwhp hci c6 z06.

vvlf

Just curious, why the Dayco Tensioner and not the Katech?

VetteVinnie

Katech doesn't make a tensioner for the A/C belt. I have one of theirs on the main drive belt. Don't forget that there are two belts on these cars.

double06

basically dampner on the ati is about 1/4 of an inch bigger than stock so the longer belt is needed to reflect that. 42.5 inch is the one evil is using. Factory I think is 41.7 inch.