Hi guys,
I've noticed on my idler pulley a small thin band of rubber like this:



It looks like my belt isn't completely laying flat on the pulley when I go to boost. I can't figure out how that could happen. Any ideas?

 

does it smell like its burning.

 

I think the belt is loose or jumped a rib on the pulley, it seems as if it cut a "rib" out of the belt....

Clean off the pulley, make sure the ribs aren't chipped, and replace the belt. Make sure you tighten it enough so that when you give the throttle a blip, the belt doesn't jump off the tensioner pulley.

 

I checked the main pulley and the belt is online. I haven't lost any belt ribs either. It just looks like I have more tension on that side of the idler pulley which explains that rubber residue. The belt is running ok on the tensioner pulley. I did tighten it a smidgen because of belt squeaking (slight slippage) on first start in the morning.

A thought just occurred to me: Maybe I need some washers on the mounting bracket to compensate for the belt angle? Well, not the mounting bracket but the mounting posts for the blower. I'm thinking about putting them on the posts closest to the front of the car.

 

Negligable smell there. Not like its smoking.

 

I dont get what problem your explaining.

Your 6 rib belt should take up the entire surface of the idler pulley.

You DEFINTLY shouldnt need any washers

-matt

 

I was just thinking out loud here, matty. I'm trying to eliminate some belt slippage that's happening when I boost.

Here's another diagram of what I'm thinking:


I exaggerated the belt angle in the pic. In reality it does lay flat. My thinking is because there's more tension on that side of the belt that would explain why there's rubber residue on the inner side of the idler pulley.

Matty, the only reason why I mention washers was because I had to use them on my V2 plate when I first had it installed. As people say, not every engine is quite the same and this looks like one of those cases.

Update: Please ignore that belt I drew at the top of the pulley. The belt runs underneath the pulley, not on the top.

 

The belt does not run parallel to the idler pulley but it should be flat (V pattern formed from both ends of the belt as you look from the side as drawn). You should be able to see that on the "wear pattern" on the pulley when you take it off as it is actually wider than the belt itself.

I'm guessing the rubber is just "worn wear" from the belt surface with use though I don't remember seeing it on my steel ASP one... If the pulley metal surface is still good and the belt looks fine, I don't think there is much to worry about. If you had an actual picture of the pulley with the build up, that might help.

 

I'll get a pic of the pulley and post it tomorrow. Tonight I'm going to adjust the belt tension just a touch to find the spot where it doesn't slip.

 

Here's a couple of pics I took last night:

Idler Pulley:


Belt:

 

When I checked the belt it didn't feel as taunt as before. That surprised me because the nut holding down the belt tensioner was tight as can be. Anyhow I retightened the belt and its taken away most of the belt slip squeekies. Another 1/4 turn more should do it.

 

New belts will stretch a bit initially... only tighten down enough to get rid of the squeal.

I can't tell if there is any weird wearing on the pulley and belt from the photos but there doesn't appear to be any big problem IMO...

 

Thanks Chunger. Maybe I overreacted about the belt and its stretching as you said.

Just wondering now if the belt stretches when the weather is hot because the belt squeekies almost disappeared when the weather got overcast and cold.