supercharger 'rocks' noise

[96 SSEi]

hi all, my S/C is making the rocks noise but with the belt off, there is no play when I turn the pulley - is this common and is it that little sprocket that needs replacement?

[J Wikoff]

Run it for a minute with the sc belt off. Is the noise still there?

[96 SSEi]

no I have been running about 500 klm with no belt for s/c and no rocks

[96 SSEi]

well?. does anyone have insight?

[J Wikoff]

Any grinding when you turn the pulley? That would point to a bearing. There are nose drive bearings, rotor plate bearings, and needle bearings on the intake end.

[96 SSEi]

no, no grinding, no play and it spins smoothly.....thanks

[Roadrunner]

Have you checked the idler pulley & the tensioner pulley on the SC belt train?
It is very common for bearings in these to go bad.

[96 SSEi]

Have you checked the idler pulley & the tensioner pulley on the SC belt train?
It is very common for bearings in these to go bad.

no, but it sounds like it comes from the blower....Ill check the tensioner,,,thanks

[96 SSEi]

WELL, the pulleys are both spinning freely so the rocks are from the blower

[96 SSEi]

ok, this may be easier to answer............if I drive with the s/c running and making the rocks noise - will it damage the blower or engine?

[J Wikoff]

Well, it's not a good noise. These superchargers aren't known to catastrophically fail, but it has happened. I'd look into getting it fixed soon. My guess at this point is that it's the needle bearings. If you don't feel like replacing bearings, a used sc isn't super expensive.

[96 SSEi]

OK, THANKS, where would I get those bearings if needed

[MattStrike]

I think you can get all the parts you need to rebuild the supercharger on ebay in a kit? That might have just been for the nose, but the bearings are available on ebay for sure. The needle bearings in the case can be R&R'd without a press, but you can't R&R the nose bearings without a press.

I'd double check that the noise is not the harmonic balancer rubber failing. The noise can be similar to the blower rock noise when it first starts to fail, as is gets worse it starts sounding like rod knock. Most people don't really notice it until the rubber has completely separated from the center pulley, and you can freely move the belt back and forth a bit by hand when the motor isn't running. The last one that failed on me the rubber hadn't fully separated - the partial bond allowed it to not be moved by hand but still made the noise - which was confusing until I inspected the balancer.

[96 SSEi]

ok, thanks for input but I am positive the blower is making the noise - no noise when disconnected.

Im gonna start by changing the oil and see if the noise changes

[J Wikoff]

Unless there's no oil in it currently, or it has cooked and congealed, the noise probably won't change.

[96 SSEi]

I will diagnose as best as I can, not interested in idle chatter...thanks

[J Wikoff]

I was trying to point out that changing the SC oil will likely be fruitless.

[maxi426]

Unless there's no oil in it currently, or it has cooked and congealed, the noise probably won't change.

I agree. Also, without the load of the supercharger, a balancer just begining to make noise may not make noise with the belt off. Try a stethoscope on each end of the supercharge with the belt connected.

[MattStrike]

I agree. Also, without the load of the supercharger, a balancer just begining to make noise may not make noise with the belt off.

This was exactly what happened to me. What sounded like the supercharger ended up being the (newer) balancer.