stevieturbo

Would it really be so difficult to do what I asked ? and answer my question ?

Video the actual impeller during shutoff.

And does your alternator have a clutched pulley ?

The Alchemist

iTrader: (19)

Relax. He decided to pull it and physically check it, and it checked out fine, so obviously the sound is coming from somewhere else. He probably figured that in order to find a root cause, he'd have to remove the blower to be able to get to everything on the front of the motor, so he went ahead and pulled it up front.

Just for kicks, try starting the car now without the blower on it and see if this still happens.

97WS6SCharged

iTrader: (1)

Sounds like one of the carrier bearings is spinning on one of the shafts. Is your bypass valve functioning?

baycityrides

yep, i decided to just remove the blower and bench rest it, instead of risking loosing a finger or something falling in the impeller i figured since i had the resources i may as well strap it to a bench and recreate the situation that way. and like i had said the blower works fine on the bench, as soon as i stopped the drill the blower stopped too... i tried it 1st with a 700RPM drill and then a 1100RPM drill, both gave the same result. i then pulled every drain plug on it and put a LED light in it and very slowly looked at every bearing, gear and seal i could see and they all seemed fine. all the bearings are properly moving and they arent blued as far as i can tell, but this is also at a super slow speed. right now a buddy has the unit at his machine shop (hes a CNC machinist) and he is dis-assembling the blower to check all the seals and bearings for me.ill post what he finds... but i dont think he will find anything. today after some sleep (i worked untill 7am) ill be going out to the pole barn to check the harmonic balancer, and every pulley in the car. i will figure this out!

baycityrides

in that pic in referance to mine, i could see all of those bearings and they all seemed to be spinning properly, no missing bearings. and yes the bypass is working, in that video the charge pipe is off the car.

Bob@BruteSpeed

iTrader: (16)

Don, have you tried running the car without the blower as The Alchemist suggested? This would rule out the possibility of anything else being the problem. Bob

stevieturbo

Yes, and applying just a little bit of common sense can save a huge amount of work.

baycityrides

doesnt make the sound without the blower, internal supercharger had 2 bearings that were iffy... my machinest buddy located both bearings and is currently installing them. the bearings werent totally gone but showed some ware so we figured better safe than sorry... but outside of those 2 bearings that had a little ware everything else checks out.

Bob@BruteSpeed

iTrader: (16)

Hopefully that takes care of it Don. Bob

97WS6SCharged

iTrader: (1)

Yeah, I was just pointing out that there isn't much inside the case that can make that kind of noise so the bearings were kinda obvious.

Might want to have your mechanic friend check the case halves and the shafts to make sure they're not showing undue signs of wear where the bearings ride. Though I'm not sure if ATI will provide you with the clearances they're supposed to have or not.

I ask about the bypass valve because between air backing up when you slam the throttle closed (assuming the bypass isn't operating) and the engine trying to decelerate the impeller via the belt system you can put a lot of loading stress on the bearings.

baycityrides

so looking at the part number on the bearings we removed from the blower procharger is causing these failures!! my F1A is rated at 74K... the bearings inside are rated to 60K!! gee i wonder why the bearings are cashing out!! my blower runs at 70K roughly at max rpm with my pulley setup!! and fyi im making a call in the morning but i think i found these bearings for 100 a pop which isnt a bad price for a 6203 abec 7 bearing!

silver_82

So even if the bearing is "gritty" or whatever, why would it cause a noise after its shut off? If the bearing race is turning in its bore then the bore is wiped out. Even if the race was turning I dont think it would make all that noise either

Man you really needed to make 100% sure if the impeller or pulley was still spinning.

conor.davis

iTrader: (20)

Don't those bearings have a higher rating when combined?

97WS6SCharged

iTrader: (1)

It takes a few seconds for a bearing to stop spinning once it's accelerated to 10,000 rpm. I doubt the outer rings of the bearings were turning in the case bores as they have a lot more contact area than the inner inner rings that contact the shafts (assuming the case was machined properly).

If the impeller is freewheeling then that means either the teeth are stripped off the gears or the shaft is broken in which case it wouldn't spin when the motor was running anyway. It's literally not possible for the pulley to continue to spin because of the belt connecting it to the crankshaft.

ringmaster72

iTrader: (8)

When you combine those bearings, they are rated for more RPM.

silver_82

I understand what your saying, my point is the gun was jumped before he verified if it was or wasnt spinning. The wheel is pretty large and has some mass, it may have enough grip to spin but when its suppost to stop instantly maybe the wheel is slipping and winding down. How hard did the OP try to turn the wheel to see if it was slipping??? Why was the unit quiet when he bench tested it with a drill or whatever he used???

There is a correct order to diag a problem and it wasnt followed, Im not trying to be rude or anything, just dont want to see anyone spend time/money on something by "throwing" parts at it and hoping for the best.

97WS6SCharged

iTrader: (1)

I don't agree that he jumped the gun. On page 2 he said it makes boost which means the supercharger is operating (ie. spinning). At that point all he needed to do was pull the belt to see if it was the supercharger that was making the noise or one of the other accessories.

I'm not entirely sure what you mean by "wheel". If you mean the pulley is slipping (which it should never do at idle) then the belt is generally worn or loose and it should chirp at the worst. If it's to the point that the pulley is literally turning for several seconds after the engine stops then the blower should never be able to make any boost. If you mean the impeller then that really isn't possible because everything inside the case is gear driven. If the belt is tight then you shouldn't be able to turn the impeller or pulley by hand.

As far as the blower being quiet while tested with a drill the OP likely wasn't able to spin the blower fast enough. A 700 RPM drill applied to the input shaft would spin that shaft at 700 rpm and the impeller at around 3700 rpm.

forcd ind

iTrader: (7)

I guess I got lost in all this just what was spinning after the engine was shut off-if the belt doesn't move, is it the pulley, or what-kind of strange

9t8z28

iTrader: (19)

Subscribed. I wanna hear the cause if this

haulass350

iTrader: (2)

so what was it?