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I'm having issues with the belt being 1 rib too far forward on the damper. I bought the ATI Damper brand new from Summit Racing. Engine is a new LS2 block, stock GM crank, GM timing chain, Melling Oil pump, GM crank sprocket.
When you install the belt, it will stay put for a minute or 2 then jump forward 1 rib and stay there. I'm using the same OEM belt tensioner, water pump (electric), power steering pump as I did for many many years with no issue. I do have a new alternator but its the same physical size and pulley as my original one. The belt is riding on the same spot as before on the pulley by the alt and balancer. I even tried my original belt as well, no luck.
I'm at a loss, I'm beginning to think that I may have the wrong front to my ATI balancer. I called ATI and they said I have the right part number, at least the one on the box and said they have never heard of my issue before.... When you compare the ATI to the stock one, the ATI has a slight gap on both sides of the belt which the OEM one does not. The ATI really doesn't have a defined lip to hold the belt in place like the OEM balancer does.
I would pull the pulley off and set it on a flat surface and set the OEM one next to it on the flat surface. Set them both on the snout of the pulley that goes up and into the timing cover, not the front of the pulley, and see if they line up or if there is a height difference.
Or, start with a picture of the power steering pump pulley, can you take a picture of how far the pulley is on the ps pump shaft and post it? I had a LS truck come in with the PS pump pulley not on quite far enough and cause alignment issues at the crank pulley.
And since you have the alternator down low and not up top like a truck the alt can do it to, is that a stock alt pulley? Have you compared the alt pulley to stock?
Power steering pulley has been on for well over 12+ years. The alt pulley is identical except it's chrome plated. I've had my belt jump once on my car a few years ago but never fell off, the classic OEM belt tensioner issue. I was using the SLP Powerbond pulley since 2011 and never had this issue. It's defiantly related to the ATI Damper.
Worst case, yes I can remove the ATI Balancer but it's a real pain with the turbo in the way plus water pump = mess and more $$$ (seal, gasket, crank bolt). If all I have to do is swap the front part, I can get to all the bolts and replace it without uninstalling things.
If you end up pulling it back off. There should be part numbers on each piece. You can look at ATI's catalog on their website and it lists each part number, what it fits and the part numbers for a each vehicle.
I would do that before calling ATI. Their customer service ******* sucks. We use their stuff on pretty much everything and I hate actually having to talk to them.
Well I found the problem. It ended up being the Alternator pulley. Shortly after I posted this thread, my Alternator died. So now I have 2 problems. Once I removed the bad alt, I compared it to my original alt on the bench and found a .080" difference in height. I contacted Tuff Stuff to get a new alt and explained to them the pulley height difference. After giving them some measurements of my stock alt pulley, they mailed me a new alt with the "proper" pulley.
Once I received the new alt, I compared all 3 I had and the new one was better but still off by .050. ugh.... After discussing the issue again with them, we decided it may be best to just use my stock alt pulley. I installed my stock alt pulley on the new alt and reinstalled it back into the car.
NO MORE BELT ALIGNMENT ISSUES. Yeah !!!! I put about 100 miles on the car since the install and all is good, the belt stays put, even after hammering on the car a bunch of times. Hopefully the new alt will last longer than 200 miles....
I think someone mentioned taking that alt pulley off and comparing it to the stock one.
You sure did. once the alt died, perfect time to check it since it had to come out anyways. I'm glad I didn't have to pull the ATI off, much more pain in the azz...
I hear ya man. Glad you got it figured out and it wasn't the damper itself.
I have a 50 page alternator thread due to the extreme failure rate of replacement F body alternators.
I have no idea if tuff stuff is good, but if it already failed it sounds like it has the issue all the F body alternators had that I went through.
For what it's worth my thread is due to me having 10 f body alternators fail in 1 year. One lasted 5 minutes, longest one worked properly 2 weeks, the others I nursed through until I could change them out.
Turned out the problem was the off the shelf replacement alternators. I tried 4 different brands, tried the new and rebuilt ones from each store, and none of them lasted long at all. My original OEM one lasted a long long time and I changed it because I was concerned it may be failing, then all my problems started immediately after. I tried Napa, Autozone, Oreilly, and a private supplier we use through the shop. None lasted longer than a couple weeks. I finally tried a truck alternator I got from the junk yard and I never had a failure again. Also the truck alternator was a 145 amp and I loved the extra capability of it so my thread is all about recommending the 145 amp truck alternator. It bolts up in the stock location, uses the same wiring and all. You can even reuse your belt that you are currently running. It should solve your alternator failure issues and give you a bump in electrical stability since it has a higher capability.
The only other option is buying a dealership alternator (if those are even available) or getting something like a mechman alternator that is about $500. If you do choose to do a truck alternator and get it from a parts store, just make sure to get a good brand name like AC Delco. In my thread I recommended getting a junkyard alternator because chances are high it will be an OEM alternator, and those are about $500 new. You can get them from a scrap yard for $50 and most guys that were doing the swap were putting them on older F bodies so new and pretty didn't matter much.
I cleaned mine up with a wire brush attachment for a drill, and painted the pulley and it looked new. I understand on a build like yours you wouldn't want an ugly junk yard alternator, but it did work for more people than I can count. Not sure how many people but the thread has over 1000 responses if that gives you an idea.
One thing I did notice is that after I had put 4-5 on there, is that I could keep them mostly alive if I didn't take them over 6k rpm. But I had a 6900 rev limit that the car saw daily so I would kill them every time the saw that rpm. So the first handful died the day I put them on. Or would get to where they wouldn't charge once the car warmed up.
With the truck alternator I could do whatever I wanted, it never cared how many rpm I threw at it or how hard I blared the system with the a/c headlights and everything on.
Last edited by 00pooterSS; 07-22-2019 at 05:25 PM.
Ugh, that sucks you went through that many alternators, thanks for the insight.
I will say that Tuff Stuff was super nice about swapping it out for me since it was about a year old, even took care of S&H both ways. They even admitted that they had issues as well. The guy told me they changed a process and used either more or different epoxy inside around the slip rings.
If this one doesn't hold out, then a truck Alt it is. It's too much a pain in the azz to swap out since I went turbo.
The worst part was is I'm a tech and I kept applying the mindset that parts don't just fail and if they do multiple in a row failing means something is causing them to fail. I checked everything on my car multiple times. Ohmed out wiring, checked amp draw etc etc. I was surprised when it came out it was just **** parts in the alternators. The baffling part was that it was among pretty much all brands of standard replacement alternators. When I made that post tons of other guys came in saying they were having the same problem. So that lead me to believe all the manufacturers/rebuilders are using the same parts and one or several of the parts is junk.
That's awesome that tuff stuff gave you no crap, I had to literally get into a loud argument at NAPA trying to return on of my alternators..
If they recognized they had a failure point and came up with a fix, I'm willing to bet you're gonna be fine. If not, you know what to do.
06-03-2019, 11:54 AM
ATI 917264 Belt Alignment Issues - OEM Diameter - FBody ** SOLVED ** 
So now I have 2 problems. Once I removed the bad alt, I compared it to my original alt on the bench and found a .080" difference in height. I contacted Tuff Stuff to get a new alt and explained to them the pulley height difference. After giving them some measurements of my stock alt pulley, they mailed me a new alt with the "proper" pulley.
I put about 100 miles on the car since the install and all is good, the belt stays put, even after hammering on the car a bunch of times. Hopefully the new alt will last longer than 200 miles....
