After having problems with the boost controller not maintaning the desired boost level and fixing it with a stiffer spring; now my alternetor belt comes off everytime I drive the car hard. The car feels stronger, but I have replace the belt like 4 times now. I never had any issues with it. I can be cruising in the car and everything is OK. As soon as I get on it, the belt comes off. Everything is align, in its place and tight. Have someone had issues with the belt, other than having the belt loose or not align?:wtf
I'm thinking on getting a UDP and replace the stock DP to see if this fix the problem.

You may be overtightening the belt or the Crank pully is not all the way on.

Terry

It may be how tight it was, I had it almost with no slack. If it was the DP not all the way in, I would had this issue long time ago. Is only if I go above 6500. What rpm are you running with the MS? Have you gone above 7200? No issues with the belt?

I had a problem similar to this before and after my AFX UDP, problem was the torque on the bolt and the alignment on the pulley... Would be fine for normal driving but after driving hard it would just fly off... Replace the belt three times total before it got fixed right. Just be patient and try and make sure everything is perfect.

Well, I guess I will re-torque the DP bolt and see if this fix the problem. I will let you know. Thanks guys!

Damn alternator belt. Keeps comming off!
I adjusted everything yesterday, use an impact gun, took it for a spin and the belt came off again. The belt sometimes flips and runs with the ridges up.
I check the alignment and it was off by maybe 1 or 2 mm. But its been like this forever. I don't know why I'm having this problem now. I know it may sonud weird, but I added two more extra injectors and turn the boost up, 28 to 30 psi. This is when I started having this issue. The DP doesn't go any further. I will try the UDP next.

I can rev to 7000 and it stays on.

I've seen this happen with cheap belts. I use Goodyear gatorbacks and I haven't had any problems. Also Gates are excellent belts too.

I actually had it happen a bunch using the gatorback...I got the cheapest belt they had at my parts store and it lasted a good week or so (a long time lol) ...but the gatorback I've put on since has lasted a few weeks or so now. Just seems some cars with the udp are very touchy when it comes to the tensioning I guess :shrug

I don't think it could have anythhing to do with the torque on the
crank pulley bolt, I never even put that bolt in and havn't had a single problem with my belts on my AFX pulley using the belts that came with it from howell

The crank pulley is the #1 reason for tossing belts. I don't torque mine anymore, I just hit it with the impact wrench until you hear the thing totally bottom out. The impact wrench starts complaining. Once the UDP/DP is seated, you can take the bolt out completely, but getting it on there all the way is the key.

Another possibility is the bearing in your tensioner is wearing out. Check the archives for a cheap bearing replacement posted by Jamesman.

Your tensioner assembly could be loose or broken too. Recheck all the mount bolts, and back the tensioner screw off 10-15 turns and inspect for stripped threads.

THANKS thedawg! I checked the left motor mount and guess what, It was loose. Adjusted the bolt and after a few runs, everything is now OK. So far, so good. WO-HOOOOOOOO!

Damn! NOT AGAIN.
Belt came off.;(

It seem that I damage the thrust bearings. Trying to force the DP into the crank with a hammer:wallbash , I damage the thrust bearing. The crnak has too much endplay. I found this after looking for a strange noise. The car was pulling great, the noise only came when I let the engine decelerate by itself. No noise when accelerating or under load. I will have to take the engine apart and replace the main bearings. Atleast there is no sign of wear in te oil.

Don't ever hit the DP to get it in place:nono, get a longer bolt and a impact gun.

LESSON LEARNED THE HARD WAY!

I hammered the shit out of mine to get it on... But I also heated it to 400* in the oven first.

When you talk about placing the DP on the oven, you mean the aluminum UDP , right. The original one has a rubber isolator. The original one was the one I was pounding into place, cold. After that I started having the noise. No vibrations.

I opened the engine. Bearings are like new; rods and mains. Normal wear, not even uneven wear. The only issue is that I felt a little play in the crankshaft moving it forward and back. Thrust bearing looks good on the crank surface, but a little wear on the sides. Check the clearance with a filler gauge and it is barely with in the limit. I'm pretty sure is the Thrust bearing. The noise wasn't always and under load it didn't make any noise.
I will spend the $80.00 and get new bearings and put the engine together. Let's see how it goes.

I had the exact same issues, so i just got a 3 rib belt instead of the 4, and it's been fine ever since..This only started to happen once i went over 15 psi boost too..wierd..

DAMNNNNN!
Guest what. It wasn't the bearings. The flexplate is crack. So long waiting on a new set of main bearings and it was the flexplate. I have wasted so much time waiting.
I guess it is good news now. Well, I got the Megasquirt so everything is going back but without the stock ecu. WoooHoooo!

Few pictures after finally got a new camera.