i'll try and make this short but i'll need as much input from others if they've seen this before.

i was at the track this weekend and blew a supercharger belt. not a big deal, i've had to change it before at the track. the reason it blew is what has me concerned. i have a 15% pulley that's been on there for a long time. it looks like the pulley is walking off of the S/C shaft. there is about a quarter inch of the inside of the two piece pully showing. i got the screws as tight as i could put on a new belt and went back on the track. after that first run the one section of belt that was hanging over the pulley "went away". now i have a slightly more narrow belt. not wanting to give up my track time i don't go over 6K rpms for the rest of the day. everything seems fine.

the next day i get an early start and loosen the pulley screws so as to try and move the pulley back to it's proper location. i get the screws loose and can't move a thing. i get everything tight again and i'm back off to the track for 4 more runs that day. i still didn't go over 6k rpms and all was well. i need to fix this. anyone ever heard of this or seen it? what did you do to fix it?

thanks

 

If you have an Alta pulley, remove all 4 screws then put two of the screws into the non-countersunk 'extra' holes. Screw them in till you feel them bottom out, then alternate turning them in about a quarter turn at a time. What you are doing is pressing the outer 'rim' of the pulley off of the internal tapered bushing. The outer part should pop loose. Remove both the outer piece as well as the bushing. Check the bushing as well as the supercharger shaft for any sort of wear or galling. If this is not found, clean the shaft, the pulley inside diameter and the outside and inside of the bushing, reassemble the pulley as if installing it for the first time. Slide the pulley onto the supercharger shaft till it bottoms, then alternately tighten the 4 screws till snug, then in a crisscross pattern to 30, then 60, then 80 INCH POUNDS of torque. Dont forget to use blue loctite on the screws to keep them from backing off.

If you are using something other than an Alta pulley, check with that vendor on how to remove it.

 

it is an alta pulley. i'll try this when i get home next week. i was wondering what those other holes were for. the pulley is the only mod to my car that i didn't do myself. has anyone else had to do this? will i be able to do this without jacking the engine up? please say yes. thanks again bear.

 

bluesmini,
First off Greatbear is right, how to remove it. But how tight were the bolts when you pulled it off? If the SC pulley is loosened and was spinning on the shaft, then you may have some problems. But all is not lost, reinstall the pulley and use a small amount of grease on the taper portion of the hub, and on the threads of the screws. Tighten to 80in-lbs if you have the SS screws, if you have the black steel screws you can go higher than that. Are you loosing any boost?

 

Thats INCH POUNDS folks

 

thanks for bringing that up. is glanced right over it and just assumed ft/lbs. that could have been ugly

 

Yes it could have been ugly

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more help please..... i took the pulley off with some trouble. i ended up going to my car shop hang out to get some longer screws. the ones that came with the pulley just weren’t long enough to make the pulley come apart. the longer screws only took a half turn to get the pulley to come apart.



after reinstalling the pulley it still didn't line up with the other pulleys. WTF..... what have i done wrong? i pushed the center piece all the way onto the pulley til it would go no more. the other half of the pulley would pull out the center piece into the correct spot. not sure how but it didn't work out. any one have this issue also. please tell me about your personal experiences.

 

Yikes!

 

regardless of the postion of the inner part, the outer part should go on until it contacts the shaft end ans stay there when you tighten the screws, drawing the taper together by moving only the inner part.

this assumes your shaft end is still in the right place and there are no burrs or other problems on the shaft or bore of the inner part.

 

i can't imagine that the shaft has moved at all. i'm thinking i'll try a different pulley just to see what happens. what else can i do?

 

I have heard of people removing the stock pulley or other pulleys, using the wrong tool, causing the SC shaft to be pulled from the SC. This seems nuts, but, a shop called us and told us they tried using a pickle fork to remove the stock pulley. This pulled the shaft from the SC. They did fix this by tapping it back in using a 5lbs hammer. Did you ever try something like this?

Also maybe there is something wrong with the SC itselft and the shaft isn't pressed into the blades tight enough. This would explain how the pulley was fine then you noticed it was walking of the end of the shaft.

The other thing it could be is a bure on the inside of the pulley, not allowing it to sit flush to the SC. Just to make sure did you remove the plastick cap at the end of the SC?

 

i did not do the original pulley install. after taking it off this past weekend i see that the plastic cap is off. can anyone tell me the lenth of the shaft that is supposed to stick out for the pulley to attach to. this would help so i don't go beating on the shaft if i don't have to.

i didn't raise the engine to remove the aftermarket pulley so tapping the shaft back into place would prove to be difficult.

 

here are some pics of my bare S/C shaft. anyone else know how this compares? please say they are equal.

 

here is a pic of the back side of my pulley. when i had the pulley off i didn't put it back together off of the shaft to see how it should look when assembled. can anyone with an alta pulley tell me if this is what theirs looks like? pardon the lighting. the pulley looks black but it's not.

thanks in advance for your help.

 

I just measured:
the shaft-to-SC casting (not bearing) is .930"
the center of the pulley groove farthest from the SC should be .970 from the casting.
the end of the shaft is about .035-.040" inboard of that same pulley groove.

 

thanks, i'll check it out when i get back home to my car.

 

my parts have come in.



my new pulley from myminiparts came in along with my new (i broke the first one) tensioner tool. i choose this pulley because it uses six screws and has a hole in the face of the pulley to see if it's up against the shaft.



i put the new pulley on and installed the new belt. i let the car run for a few mins and the belt jumped track and moved over a grove. this is what's been happening to shred my belt. the alta pulley has a big lip to keep the belt inline and if your pulley is not in the right spot that lip cuts the extra belt off.



i stopped the car and scratched my head. i read back threw this tread and decided to try the moved shaft theory. i had my buddy Joe working with me this time. it's always a good idea to have another person’s thoughts and voice of reason when you’re getting frustrated. i had warned Joe that it might be a S/C shaft issue. he was well prepared with a barrage of large odd shaped pieces of metal to get at the shaft with.



we used a very long heavy piece of iron and used it as a fulcrum. with a piece of wood against the side of the engine bay and the pulley on the other side with about a three foot leaver it wasn't long before i heard the pop of the shaft moving. we had measured the shaft to 1.1 inches. jlm had told us that it was supposed to be less than that.



i used the tensioner tool to loosen the belt and moved the belt over a groove. the car ran well after that. i haven't road tested it yet but i'll try that this weekend. feel confident that i'll push the car hard.

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So basically our pulley would have been just fine if the shaft hadn't have been pulled out. Do you know how it got pulled out? Did you have someone else do the install? The other customers that have had this problem have tried to pry the SC pulley off using a pickle fork or something to pry against the SC body.

I would really like to know why this happens once and a while. If not from installation, but from something else. I would say once a month we get someone in your same shoes, and if we can determine a fault in the car or installer, it would really help those people out.

Like your self you went through a lot of time and work, to get a new part, and find it has the same issue.

Glad your car is back to normal!

 

the alta pulley was not the problem. the problem is still unresolved. after a quick trip today the belt jumped track but the new pulley doesn't have the lip on the inside so the belt hasn't been cut. i did see that the bushing on the engine side of the pulley tension arm is gone. one of the mech's at the dealer thinks that may be the problem. i'm droping the car off on monday night.

i really hope i don't have to pay for this.

 

it's raining here at the beach but things may be sunny at the dealership.


i just got a call from the guy working on my car. he has replaced the tensioner pully arm. he tells me it was in very bad shape and most likely the cause of my problems. he's gonna take it home tonight and drive it to see how it works. after a five miles the belf hadn't jumped track.

on a side note he says i was losing some pressure from the super charger. one of the ruber gaskets on either side of the intercooler was leaking. he fixed it. i'll pick up the car after the final call.

fingers crossed.

 

bluesmini - Can you elaborate on the procedure you used to move the SC shaft back into the correct spot? I am afraid that I may have the same problem...

 

Unless you tried prying off the original pulley, I wouldn't try that. Did you do the install yourself? If you have had the pulley on for a while without problems, then I would think belt tensioner

 

Unless you tried prying off the original pulley, I wouldn't try that. Did you do the install yourself? If you have had the pulley on for a while without problems, then I would think belt tensioner

 

I would take a look at the pulley tensioner arm first. Mine had a nasty bounce in it just at idle. There is a small shock absorber on the arm. At one end of that shock the bushing was completely gone. The bushing had the diameter of about a nickel and the bolt holding it in position was the size of a pencil. With that bushing gone and just the outer housing there was a lot of play in the tensioner arm. I had the entire tensioner arm assembly replaced under warranty. That would have been very difficult to replace myself. There is just no room in there for hands to work.