I've posted a few threads about this before, but i think i have finally narrowed down the problem. I've had a grrrrrrr. under hard acceleration in first for over a year now. it'* gotten worse recently, so i did the old listen to it through the screwdriver thing. It'* definaly comming from somewhere in/around the nose cone. When i rev the engine in park it makes a screeching noise, and when i let off it screechs down lowering in tone, then starts chunging. I can also feel the nosecone vibrate. I'm going to do the coupler soon anyways and i need to know what else to get while i'm at it. is the nosecone the front bearing for the supercharger, or is there another separate bearring like the one in the back of the charger. If there is 2, how do i go about deciding if it'* the nosecone, or the front bearing. Thanks as always.

Try this thread for starters, it has the part #'* your gonna need and a how to for the coupler. http://www.bonnevilleclub.com/forum/...ic.php?t=11686
It is more than likely the coupler, or the front bearing in the snout. Also check the Sticky at the top of the Topic and the Techinfo section on this site.

Keep us up to date

ken

Try taking the belt off and see how tough it is to rotate the pulley by hand.

So if it is hard to turn it is most definantly a bearing. Can i just buy a bearing for the front, or do i need to replace the nosecone itself. I know my coupler is bad, and i need to replace that anyways. Could a bad coupler cause that bad of noise. It'* a loud grrrrrrrr noise. very very noticable....

If it'* the bearing, it will be hard to turn, and will show symptoms at all speeds. If it'* the coupler, the pulley will have play in it when you spin it back and forth, and will make noise at idle only. You can take the nosecone apart and replace the coupler and bearings yourself, or replace the whole nosecone or even the whole supercharger.

http://www.bonnevilleclub.com/forum/...pic.php?t=2408
http://www.bonnevilleclub.com/forum/...ic.php?t=11412

Ok.. so i took the belt off, then i turned the charger. It seemed to be turning ok. When i spun it fast i could hear some noise. It was not hard to turn. I know i need a coupler... there is a lot of play in it. Do you think it is just the coupler?

Your other symptoms still worry me, like the screeching noise and the vibrating nosecone. You could try one more experiment and take the belt off the supercharger and turn on the engine (This may turn off another accessory too, I can't remember which one), and see if the screeching goes away.

You could also try spinning the other pulleys to see if you could find the culprit. Sometimes the automatic tensioners go bad and make that kind of noise. My alternator went bad once and made a whistling noise.

On the other hand, I would hate to replace the coupler, and find out later that the bearings were bad too.

Normally, the coupler will produce a rattle at idle only. I have a funny question....have you checked the oil level in the nosedrive?

The SC will make some noise while turning by hand. You shouldn't hear it while it'* running though.

i have not checked the oil level in the nose drive. I've heard that that sounds like a screw in a vacume. And that'* not my noise. I'll check it when i get home today. The grrrrring noise is even starting to do it some when i'm in second gear. Where can i get a bearing for the nose drive. I figure if i'm taking it apart to replace the coupler, i might as well at least have the part incase it needs to be replaced. If they are not that expensive, i might just do it anyways. There is no side to side play in the sc pulley either.

My biggest problem is i don't have any real good way of testing exactally where the noise is comming from, becuase it happens with over 1/2 throttle in first gear. hard to listen under the hood when the car'* accelerating.