D&C vette

Just a little history.

Car has had SL1500 on it for about 30K with zero issues.

Engine lost a lifter and took out lifter bore. I installed a forged iron block. Everything from original LS2 was put on L76. I removed the restrictor, installed larger injectors, added A&A fuel system. Off to the tuner I went. Belt came forward one initially, could not complete tune.

Brought car home, checked alignment as best I could with laser, looked one rib off. I added shims, car would drive fine until I got on it and belt would walk. I got a flip drive, rechecked alignment, shimmed a little more and same thing.

Disassemble the blower from bracket, take bracket off block. I find some small areas that are built up unevenly from powder coating. Clean off the areas, check alignment and adjust blower forward 1 shim. With car idling, after about 2 minutes, belts shredded 1 rib and walked completely off the blower and crank pulleys. WTH?????

Xtremespeed

Do you think it's possible the balancer didn't seat completely? What about the ac belt? Is it holding up or wearing/breaking?

schpenxel

Have you used a real laser alignment tool? I realize you mentioned a laser, but I want to be sure you're not trying to Macgyver something with a regular 'ol laser

D&C vette

AC belt has no issues. Laser is the Gates unit made for serp pulleys. I checked the calibration on it and it is spot on. I checked the alignment again tonight and the belt is off just slightly, still on the 2nd valley just to the back a little.

While checking things for any play, found the manual tensitioner to have about a eighth inch of play fore and aft. Gonna take head unit off this weekend and see what gives

Xtremespeed

I noticed when changing the cog belt on my flip drive the other day, when you tighten the adjustment nut on the manual tensioner, it tends to try and back the bolt out that holds the pulley. I had to pull the blower loose to tighten the bolt so the pulley didn't have any play in it. The only reason I noticed it was, when I put the blower belt back on, the manual tensioner wouldn't move far enough to get the tension where it needs to be. The pulley bolt had backed out enough that it was hitting the blower bracket. Maybe this is what yours has done.

I've also seen several posts where people have bent or broken the pulley bolt and I wonder if it backed out slightly on them when they tightened the adjustment nut and they didn't notice. It would explain a lot. I also wonder if using a lock washer instead of the nyloc nut would help. The nyloc grabs the pulley bolt and tries to turn it before the nut gets tight to the bracket.

schpenxel

I agree.. I snapped the bolt that holds the manual tensioner pulley. I didn't realize it threaded into part of the tensioner until after the bolt broke.. I thought it was just the nut until I looked at it closer

RpeterK

Check to see that the .070 thick spacers are in place. The go between the water pump and the main mounting bracket on C6 apps. I would suspect this first as they are easy to overlook. There will be tracking issues for sure if they are missing.

D&C vette

I don't have any spacers on the main bracket at all. Are these flat or wedge shaped spacers? Thanks

schpenxel

There should be spacers (looks like washers) between the mounting bracket and water pump. There are two bolts that connect the bracket to the water pump.

DOUG @ ECS

That would certainly do it. OP, let us know if you would like us to get a set sent off to you.

D&C vette

Doug, sent you a PM.