SC12 noise.. is it suposed to do this?

**AE101LEV** · 24-04-2006, 11:49 PM

pulled the pipes off my SC12 to paint it and pulled the pulley off.. put the pulley back on and then thought it would be interesting to see how the charger works so I just was turning the rotors inside it and it turns over smooth but I can kinda hear wat sounds to be a slight rubbing noise from somewhere each couple of cycles.. is that just the sides of the rotors rubing the side of the charger as inside is not lubricated? because I didnt do it before I pulled the pulley off I dont know if it was makn that noise before hand. or I have done something just worried that if I put it back in teh car it will make a loud noise or something :S but if it is rubbing a little bit i would imagine it will just wear that part away thats rubbing and my noise will be gone after a bit but yeh not sure if its a normal thing as its not lubricated as stated before. i havnt put it back in the car as the motor is not with me at the moment so i cant really find out.

**TooF** · 25-04-2006, 01:48 AM

it should make like a "woosh woosh woosh" noise as you turn it by hand. kinda hard to describe.

**Smokey228** · 25-04-2006, 02:43 AM

^^^ i like ur description...

sc12's use a electronic clutch system. so maybe its the clutches rubbing?? there is also no oil pressure wen its off, so it could be bearing noise...

if it was me, i woulda prolly left it and see'd wat happened...
but i fuck alot of things doing that. good move toymoding it...

**oldcorollas** · 25-04-2006, 03:00 AM

Originally Posted by Smokey228

^^^ i like ur description... there is also no oil pressure wen its off, so it could be bearing noise...
if it was me, i woulda prolly left it and see'd wat happened...
but i fuck alot of things doing that. good move toymoding it...

i can't see why that happens to you

your H key is broken too

bearings are self contained and not pressurised. it is not a turbo.
could doing up the pulley nut thingy have caused one of the rotors to be pulled toward the housing?

is it happening once per cycle? (ie one lobe with a high point on one part of the housing), or twice per cycle (ie both lobes rubbign on a high part of the housing)

rubbing is not so good if the coating comes off the lobes.
the lobes are designed to be either very close clearance, or slight touching, which may be the rubbing you hear.

can you see any shiny points on the lobes as you turn it over? any shiny areas on the walls of the housing?

oh and since it is a dry system (ie air, but no fuel), the lobes are not lubricated during running.

**4agte** · 25-04-2006, 05:26 AM

the rotors do touch slightly on one part of the rotors well atleast the appear to on all the sc12's ive seen leaves light scratches whether this is normal or not im not sure?

**AE101LEV** · 25-04-2006, 09:51 AM

Originally Posted by TooF

it should make like a "woosh woosh woosh" noise as you turn it by hand. kinda hard to describe.

yeh it makes that noise and yeh makes that scape noise once per cycle and it apears its coming from the side of the housing, the housing on both sides is shiny but there is no shiny parts on the rotors.

**nick.parker** · 25-04-2006, 10:56 AM

Hi,
Yep, its normal for the rotors to rub against the inside of the casing in places. This is part of the brilliance and robustness of the deisgn. The black coating on the rotors (teflon based ) prevents the rotors from ever binding (ie ally to ally would be BAD) and enables tighter clearances with minimal risk. Any dust /grit with make the sc sound a bit nasty when you spin it too, but even if totally clean you will still get some rubbing. The coating is 0.5mm thick and I'm sure as time goes by the coating gets 'tweaked' slightly by any rubbing.....

Cheers, Nick.