Supercharger noise - not coupler

[swat0712]

Ok. I had the blower and stuff off the car and just got it all back on. While I was in there I replaced the coupler with the zzp one....Now it is like a steady and loud knocking sound. Any thoughts??

[swat0712]

Also, Idk if it makes a difference or not, but when I put a sstethoscope on it the noise seemed to be at it's loudest closer to the pulley itself.

[Mitchstrp]

well its not the pully because they have no bearings, it could be the needle bearings inside the cone, which are fairly cheap but since ive never done it, i dont know how difficult it is to do one. you can buy the bearings at ZZPerformance.com

[SeanGTP]

With that said... needle bearings aren't really that close to the pulley. Did just check the belt?

[swat0712]

What do you mean by just check the belt? Also, needle bearings, are you talking about down inside the blower, as in I have to take it all apart again? I have a "free" day tomorrow and I'd like to get at least an idea of what I need to fix.

[SeanGTP]

Check the belt for any sort of deformation. It's unlikely, but it never hurts to check. Can't really say without hearing the sound first-hand.

[The Chad]

Does it sometimes switch from steady to random? I'm assuming it increases with RPM's?

[swat0712]

Ok...I checked the belt it looks good, no noticeable imperfections. The sound is pretty steady, kinda weird whine that goes along with it...Here's a video of it running...

Without belt on

YouTube - DSCN3446

with belt on

YouTube - DSCN3448

[TLSheff]

Dam that sounds brutal... Sounds like mine when I spun the bearing on Cyl#1

Altho, mine didn't matter belt or no belt it still did it. With the belt off and it not doing it, Id say one of the pulleys or something in the SC itself

[alkygto]

Did you feel anything when you spun the supercharger over by hand? You could have possibly unevenly torqued it down slightly distorting the case and letting the rotors rub, they are pretty tight tolerance.

And the snout has roller, not needle bearings. The needle bearings are on the inlet side of the blower case.

[Fivefingerdeathpunch]

sounds like the rotors are having a party inside there.

[swat0712]

When I "spin" the pulley it seems to move freely, I mean there's resistance and it doesn't exactly spin, but it doesn't sound like anything's knocking/rubbing together?

[Mitchstrp]

holy sheet! :O

[The Chad]

Hey Swat, dumb question I know, but did you put the S/C oil back in it after changing the coupler?

Anyway, did you really have to torque on anything when you did the coupler, anything that took too much force and made you wonder if you messed something up/bent something? Shouldn't be much resistance when you spin it. It may have been over torqued and causing rub like Alkygto said. Drain the oil again, loosen the snout, look in there and inspect for debris of any kind, and retorque it to 15 ft.lbs. max. Put the oil back in, and see if it helps.

If that doesn't work, you may have to remove the S/C itself and take it apart (not too difficult). Once the S/C is off, spin it and see if it sounds like this
YouTube - Eaton M90 Rotor Failure

Was the S/C oil ever changed to your knowledge, and was it black when you drained it or were there any shavings or anything inthe snout? If so, then your bearings may be jacked. http://www.grandprixforums.net/repla...ngs-20376.html

[swat0712]

Chad, yup I put two bottles of the GM supercharger oil in there. I don't think the car has ever had it changed...It was literally almost dry when I took the snout off..Like completely...There weren't any shavings or anything resembling abnormal wear though...I haven't actually had the supercharger belt on the car for probably more than four months now because I knew the coupler was going bad and I didn't want to put any more stress on it then I had to...The oil being basically gone was not something I was expecting to find

As far as I can remember I didn't have to put much force on anything. I put the coupler on the pins on the rotor side and then lined up the snout with it and as I tightened it down it pressed on.

I'll drain the oil and check it today hopefully...

[swat0712]

So I haven't drained the oil and checked the snout itself yet, I did check the bolts holding the blower case down and they're all good...Also, Idk if this makes a difference or not, but when the belt is off the supercharger, whenever the pulley still spins under throttle/rpms I can here it spinning/the air/whatever, but there's no knock...So even when the pulley spins it doesn't knock, only when the belt's on...Like it's pulling the snout out of place or something.

[vsl67]

you need to remove the rotors completely and check for marks especially at the rear of the blower case near the bearings ,Its sounds like you could have stuffed rotor block bearings which has thrown the timing out and you wont be able to feel it spinning the supercharger by hand because its needs some Rpm and air moving to put some load on the rotors to unbalanced them and take notice if your rotors are coated in a film of grease or oil ,

Did you notice any usually high boost readings before this happened?

[The Chad]

Vsl67 will know more about this than most of us will. Glad to see that he chimed in on this thread! Remove the rotors like he said, and it's really not too complicated. You'll just need to carve out some time to do it. The S/C is very simple machine with reletively few moving parts. Let us know when you're going to do it so someone can try to be available to help answer questions.

[rolyat]

Your rotor pack bearings are probably bad which is allowing the rotors to hit each other. The seals on the rotor pack may be bad too if the blower was almost out of oil. Check your oil level again to see if it has gone down any.

[swat0712]

Ok...well I'm hopefully going to start working on it tomorrow morning. Start with draining oil. Get the snout off and then impeller plate/rotors out, right? I'm going to try and video/take pics so I can give you guys a better view of what's up instead of trying to guess on my terminology. Thanks again everybody for your help so far!