blower rotors grinding

mywhite89

Registered User
Well, I got my car driveable again, now to the next issue. When I rev it, I hear a clattering sound that I have narrowed to the supercharger. It sounds like it is coming from the rotors (possible slight binding), like they need clearanced. I put coated rotors in it a while ago, and now have read a response from Mr. Niebert that said in rare instances some people will have to use shims on their packs. I think I am one of those rare guys, but I would like to hear responses from people with the same experiences?

My other question is, if this is the case, have I ruined either the blower or the rotors or am I good to go once I check clearance? I think I still make full boost and full power but I havent really flogged it, and wont until the problem is resolved and I good a couple more miles on the rebuild diff.

Chris
 
Did you use a GM pack? If so how straight was the dowel pin pressed in and was it deformed during the press operation? I had the same issue last year, when I pressed out the pin it was deformed enough that when I pressed it back in it rubbed the case. I believe you should have .002-.004 clearance with the coated packs. Or maybe the rear rotor bearings have went out.
 
Well, I got my car driveable again, now to the next issue. When I rev it, I hear a clattering sound that I have narrowed to the supercharger. It sounds like it is coming from the rotors (possible slight binding), like they need clearanced. I put coated rotors in it a while ago, and now have read a response from Mr. Niebert that said in rare instances some people will have to use shims on their packs. I think I am one of those rare guys, but I would like to hear responses from people with the same experiences?

My other question is, if this is the case, have I ruined either the blower or the rotors or am I good to go once I check clearance? I think I still make full boost and full power but I havent really flogged it, and wont until the problem is resolved and I good a couple more miles on the rebuild diff.

Chris

Chris,

Not shims on the rotor pack, under the mounting pads of the supercharger case. If you loosen the mounting bolts and it turns freely, but binds when tightened down to the manifold, then you start measuring with a feeler gauge to determine where to shim it.

David
 
Is it like a "chuff chuff chuff" sound when you rev it right off idle?

I just installed coated rotors on my car and I am getting a "chuff". I didn't consider the possibility of a clearance issue. I thought that it might be pulsation or cavitation caused by the tighter sealed rotors sucking against the mostly closed throttle plate.

Does it sound like we are having the same issue, or different ones?
 
its caused by the rear rotor bearings being worn the rotors drop a little making them touch and also rotors toush the back of case look at rotors with intake off bet they have rub marks on the ends that face out thru inlet thatmeans rear bearings are bad
 
Well, I decided I would turn it loose on the highway just to see what happened. I opened a can of worms; the noise definetly got louder, and more pronounced. It is loud enough now that I cringed driving it home the last mile just waiting for pieces to be sucked into the engine. It really sounds like a bearing to me now, I'm going with Manny on this one. I don't feel like messing with it so I'm going to take it to the experts in my area. There is a machine shop out my way that specializes in the rebuilding, porting and all that fun stuff to the M90 blower. They should have fun studying this rare breeed of M90 with magnum powers technology.

btw, car had and still does have full power. At this point even with loud scary noises it is not affecting performance. I'm just glad I made it through the day without it making this louder sound.

Guess if I trashed it, I have to upgrade.

Chris
 
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Well, I decided I would turn it loose on the highway just to see what happened. I opened a can of worms; the noise definetly got louder, and more pronounced. It is loud enough now that I cringed driving it home the last mile just waiting for pieces to be sucked into the engine. It really sounds like a bearing to me now, I'm going with Manny on this one. I don't feel like messing with it so I'm going to take it to the experts in my area. There is a machine shop out my way that specializes in the rebuilding, porting and all that fun stuff to the M90 blower. They should have fun studying this rare breeed of M90 with magnum powers technology.

btw, car had and still does have full power. At this point even with loud scary noises it is not affecting performance. I'm just glad I made it through the day without it making this louder sound.

Guess if I trashed it, I have to upgrade.

Chris

http://youtube.com/watch?v=09BOH2DW-FA

sound like this if so it could be your snout bearings thats what mine was i changed out the snout with another and the sound went away..
 
sounds to me like your just trying to find the excuse to order an MPX :D:D:D

hope you can get it figured out before Dayton
 
lol, I wouldn't mind a MPX! All I need is a 10% crank pulley and a new tune, and I would be there. Hmmmm....

Got the blower off last night and I can see on the back side of the rotors, there is a spot on each fin where the coating has come off and they are binding up against each other slightly. Guess I'll know soon enough.

Chris
 
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