Pulley Installed - Belt looks off by about 1mm

[neilgj]

I installed a 15% supercharger pulley today. I slipped on a new belt as well. After I had everything put back in place, I started up. Nothing happened. I panicked until I realized I didn't reconnect the ground wire. Oops I reconnected the ground wire and started it up again and everything sounded great. No weird noises no bad lights. Then I went around to look at the pulley and I noticed that the belt was about 1 mm over the edge of the pulley. The belt was perfectly set on the crank pulley, the alternator, the a/c but was off a bit on the tensioner and supercharger pulley. I expect that is not a desirable thing. I got out the belt adjuster tool and pushed the belt over. I started it up again and the same thing happened. I adjusted the belt one more time. Same thing. The belt hung off about 1mm just over the outer lip of the supercharger pulley away from the engine.

If this is truly undesirable, how do I figure out what's wrong? How do I fix it? If it doesn't matter or it will just go away then I'll shut up.

[CoolCarStuff]

Hi

Did you try the belt on the pulley before you fitted it? Just to check that the fit is good?

Unless you have the belt one groove out (unlikley but might just be your problem...) I guess it will be ok....

The only other thing to check is that the pulley is located right on the SC shaft to ensure that no side load is on the pulley bringing it over...

Could you post a picture?

Most belts running off make a noise....so it may be ok....

I can fully understand why you are nervous.....

DJ

[GTT 280]

If you have run the belt at an off-angle i would be concerend that the internal tension material of the belt may have been exposed to lateral damage i.e. not designed to be twisted.

Just a thought.

Over time, your belt may snap prematurely.

K.

[Capsaisin]

Surely the pulley has grooves, so the belt is either located centrally and correct or is located in the wrong groove and there will be an "empty" groove at the other side to the overlap.
If your belt "jumps" across, leaving an empty groove and is overhanging the edge of the pulley, I would think you have installed the pulley too far over the s/c shaft toward the s/c.
Correct fitment depends on the type of pulley. For example Alta pulleys are supposed to be self aligning against the end of the s/c shaft, but some other types depend on the fitter correctly positioning the part that fits on the s/c shaft.
I suggest you get the pulley alignment checked, or carry a spare belt with you at all times.

What type of pulley did you fit?

[neilgj]

It is the missing information that sometimes holds the key to wisdom. After putting on the SC pulley, I thought I would also change out the crank pulley. I used a (relatively cheap) harmonic puller and managed to strip the center bolt while pulling. So, I decided that I had better get a sturdier puller. Since it looked like I hadn't budged that pulley a bit, I bolted it back on and buttoned things up. Well, I finally got the new crank pulley on and - guess what - the belt's in perfect alignment. I must have budged the crank pulley a wee bit before I stripped the bolt and caused the belt misalignment.

Let that be a lesson to me.

[Tit]

Same thing has happened to me. Had a BMW dealer fit it (a pro-mini two-piece pulley), and they didn't even say anything to me about it when I picked it up. After checking through the engine bay, apart from finding that they'd scratched paint off a whole lot of areas where they worked and seeing that they hadn't re-tightened some things properly, I saw this:



I was about to move to another city, so I got it re-fitted by the dealership in the new city. They couldn't make it fit right, and it went back on the same way (I tend to think they just sat the car in the back of the shop and didn't touch it) - are you getting an impression of how I feel about BMW in Australia? Anyway....I've run on this for about 10,000km now, and there's been no apparent damage. The belt seems fine and everything seems to be running normal. It still sorta bugs me sometimes though....has anyone seen this before? (I have no other after-market pulleys etc)




BTW, those stains on the tensioner are evidence that I've had TWO engine mounts explode in there as well....also...can you see the scratches in the paintwork below the blue tag? They did that in a few places in the engine bay!

[Tit]

Quote: Originally Posted by Tit (original)

They couldn't make it fit right, and it went back on the same way (I tend to think they just sat the car in the back of the shop and didn't touch it) - are you getting an impression of how I feel about BMW in Australia? Anyway....I've run on this for about 10,000km now, and there's been no apparent damage. The belt seems fine and everything seems to be running normal. I

Well...I was wrong...

And my suspicions were probably fair:









Thank god for good friends like Stumpmeister and Jirrupin - they saved me in the middle of the night!