I love my 03mcs but .... 15% pulley w WMW exhaust ....
Driving happily along and made a right turn ...all of a sudden I hear something bouncing under the car like I ran over something in the road ( which I might have ) next thing I know I hear a rattleing sound like somethings jammed in the wheel and or brake . If I tap the brake it goes away for a minute but it would come and go . At one point it seemed like the engine was vibratting when I revved it.

So I pull over and cant find anything . I start driving and again I hear the noise and then its gone . I pull into a parking lot and I notice the belt is frayed a bit and seems slightly off the center of the alternator pulley .
( forgot to mention the belt started squeeling a bit several days ago when cold but didnt seem like it was rpm dependent)

I made it home and cant see any problem other than the frayed belt . No time today to pull the wheel and inner wheel well cover to check . Im hoping someone here has an idea of wtf happened

 

That belt and the entire pulley tensioning system has a very heavy duty job to do. The SC can require upwards of 30 HP that the belt have to deliver. If you see the belt running off center of the pulley, it may very well be the crank pulley is dying and requires immediate attention. There are countless threads on this.

 

Thanks for the response . Thats pretty much what I figured it was Ill know more tmo when I can look at it . If it is the crank pulley the question is which after market pulley to get . I know theres lots of threads on that as well but maybe someone can recommend one. I remember reading about one thats 1 or 2% under . Is that a good choice w a 15% on the SC

 

ATI is the only recommended pulley. You can get the under version should you choose. WMW sells both. Never go with those light weight "performance" pulley.

 

It is actually an oversized pulley, 2 % larger. Would get another 1/2 to 1 psi with it.

Be sure to check the belt tensioner pulley and the idler pulley as well.

 

Sounds like you are describing a crank pulley failure. For sure go with the ATI damper as it is the best, lighter, and still a damper. You will likely notice your car run smoother with it.
https://www.waymotorworks.com/super-...ulley-r53.html

 

Well it was the crank pulley ....belt stayed on thank God so I could get it home . New ATI 2% ,crank seal and JCW belt (15% sc pulley already installed ) on the way from WMW
Anything I should know b4 hand on installing the ATI damper?

 

It's a direct replacement so you are good.

 

What size belt is recommended for a 15% and 2% ATI pulley combo?

 

they recommended the JCW belt which is what I used

 

So much for an easy repair . The ATI pulley went in with out a hitch however....After running a few minutes I noticed the belt looked funny . What happened is for some reason the inner half of the belt stretched longer than the outer half so the belt kind of twisted . I double and triple checked it was installed correctly and all the pulleys were lined up correctly . I removed the belt and all pulleys spin and look fine . Also the alt and ac pulleys spin fine and look good . Someone know whats happening ?????

 

I looked at the belt again and I see its the back of the belt(unribbed side) that has a mark on it like something scuffed it .Seems to point to and idler pulley or tensioner pulley . Does that sound logical ??? I looked at both of them and they spin freely and look fine . Since the crank pullry broke and the only thing holding the belt was the tensioner maybe something happened to it that I cant see.
In the event I do need to replace it what do you guys recommend

 

I managed to put the old belt on although its a bit too short and is missing a rib or two and I cant see anything wrong with any pulleys . It didnt stretch weird like the other one and all the pulleys look good . I watched the tensioner carefully and it moves up and down a bit but no side to side movement . Im really stumped

 

Does not need to be to the thousands of an inch, but how far is that 15% from the supercharger?

 

I appreciate the reply but I dont understand what your asking .

 

If you mean is the supercharge pulley aligned correctly it is . Its been on the car quite awhile with no problems . The 2% ATI was the only part installed

 

OK, what about the idler on the tensioner? Was it jarred when the damper went?

Trying to picture in my head what would make the inner part of the belt stretch more than the outer. Would think if the belt was not a pulley correctly when the motor was started the outer would stretch.

 

Im getting a new belt tmo and Ill try it again . I checked really well b4 starting the car that the belt was on correctly but maybe I missed something . Thanks for the help

 

When I woke up today I started 2nd guessing myself whether it was the inner or outer streched . Thank God I took a pic on the belt while it was installed and its plain to see it was the inner part of the belt that was stretched and where the mark on the unribbed side was

 

Can you post that picture?

 

Sorry I have'nt posted sooner but things have been crazy .I put a new belt on 2 days ago and now there seems to be no issue with it stretching . It was either something I did incorrect or perhaps due to the crank pulley comming off the tensioner was out of place when I first started it . Dont know for sure but now all is good . Thanks for you help
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