I'm just getting around to replacing my harmonic damper and I was checking out the SC and I am curious if this is normal.

Should the SC spin freely like a turbo compressor wheel, where you can spin it and it keeps moving once you let go? I can turn mine with two fingers, but it doesn't spin like a turbo.

I also noticed when I turn it, it squeaks.

Also, if I turn it back and forth, it makes a sound similar to the sound a transmission makes when you spin a rotor by hand back and forth.

There's no play in the pulley at all, however.

 

When you consider that you are rotating two geared impellers, a power-take-off coupling, and a water pump it is not surprising that it does not 'spin freely.'

 

Yep. I've had a fresh, factory rebuilt one on the bench without the water pump attached and it does not spin easily.

 

Without water pump attached spins easily, just tried my spare SC.

 

Cool thanks guys!

 

The SuperCharger should spin without binding. They do have resistance and will not spin as freely as a turbo unit. That is why superchargers need engine power to turn which they call "parasitic drag". So if you are getting resistance than it is normal. Any noises you get like squeaking, clicking grinding sounds is not normal and they should at least be investigated.

 

Smoothly....not freely is the important term here!! If you here grinding, feel excessive binding, etc, then there might be an issue.
I have a Spare 7000 mile SC...it does have some resistance....but is smooth...with no water pimp mated. If it was installed...with water in the pump, and no place but a stopped motor to pump the air to from spinning the SC, I would imagine it would be hard to turn.

 

Close...but no cigar....the term parcistic drag is used because the SC consumes some of the HP that it creates...to make more HP......the Turbo uses mostly waste energy (at the price of a bit more backpreasure) to make more HP...so it is more of a multiplier effect. Tolerances must be tighter in a SC due to the need for higher efficeny, and slower speeds.
In the turbo...tollerances are compartivly loose...due to space needed for more thermal expansion, and the higher speeds involved. So yes, when not connected a turbo will often have less drag....
Just making sure future readers have the correct info!!

 

Well I pulled my SC today and the gears looked perfect and the fluid level was good.

Rear:


Front:


Not a single metal chip in either.

My only concern is when I am rotating the charger by hand, at very random intervals I will hear an occasional metal on metal sound. I can rotate it 30 times and then it will do the sound once, then rotate it 5 times the the sound, then 100 times, etc.

Is this normal? I don't understand why the metal sound would be so random. This happens without the nose and rear, so I am assuming it is the rotors. Is it time for a rebuild?

 

If you go GM... They sell the special SC oil.....I would definately use freash if you do seal it back up. I'm not sure about you question...but if it was fine before you took it off...I would not worry. It is still makes good boost...great...but I can say grayraven did see a nice performance boost with the newer coated SC (he had a few other items fixed too, so it is tuff to tell howcmuch came from just the fresh SC).
I guess it is a cost vs risk thing...you seem handy...you can reinstall it... Run it till convienant, the swap it out...rebuilds can take a few weeks if they don't have a unit to exchange. For this reason I found a very lightly used SC cheap off a wreck..heck, a high millage one might be cheap enough to rebuild and keep as a standby!!

 

Your SC looks great! How many miles?

 

79,200 back from 2002

I think I'm going to seal it back up and hope for the best. Don't really have the funds for a rebuild right now. Should I use anaerobic sealer or try out a thin bead of rtv?



EDIT: I also found out the clanking from moving one direction to another was simply the little bit of play between the water pump and supercharger "external forks" or whatever they are. The squeeking is also the water pump. Is this normal?

 

the manual says anerobic sealer...my Mini Guy says gray RTV works better, and is a bit better at sealing the two mating surfaces...I have not yet decided which way I'm going....I'd be interested to hear opinions too!!

The water pump does use plastic impellers.. ..look to see if the water pump shaft shows any sign that seal has wear...maybe a bit of dried coolant stains....
If putting on a new/rebuilt SC I would put on a new pump...

 

Ended up using anaerobic sealer and 6 oz of fluid in the snout and 2 oz in the rear. I set it down on a clean surface for the night and didnt see any leaks. I think either way will work fine, anaerobic or rtv.

 

Good to hear that you are getting ready to re-assemble things....the weather is getting nice!! I'm sure it will be worth it when done!

 

Well, not quite yet. Upon pulling the head, I found this nice crack running from the spark plug hole to the ex. valve (about 2'oclock).



It hasn't hit the seat yet, but I would rather replace the head now instead of having to do it later once the cracks reaches the seat. For the price of getting it welded, regrinding the seat, etc. I'd rather just pick up a good, used head for $400.