M90 Rotor Bearings

**Cyko** · 05-21-2008

Okay, so the problem with my car wasn't in the nose, as I previously thought, and someone on here (I think it was Reptile) had said that my problem sounded to him like my rotors. I assume he meant the Rotor Bearings, as that's the only replacement part that I can find.

The question at hand is, does ANYONE know how to install/replace these things, and can I get to them WITHOUT having to remove the ENTIRE s/c from the top of the engine? I'm told they're in the rear or the supercharger main housing (already doesn't sound good) and are evidently not that hard to replace... getting to them may be another story.

An ebay search for "Eaton M90 Rotor" returns one listing and one listing only: eBay Motors: Eaton M62 M90 M112 Supercharger Rotor Bearings GM Buick (item 130223024829 end time May-22-08 20:28:07 PDT)

Do these seem like the right part? And could that be what Reptile was talking about? Help? Please?

**GR8racingfool** · 05-21-2008

If thats what you want to replace, then yes, those are the case needle bearings.

You have to remove the blower from the car, tap two already drilled holes, thread in a modified bolt/zert tool thats usually self made, and press them out using pressure from a grease gun.

Most likely this will not solve your problem.

There are two bearings ON the rotor assembly them selfs that wear out, and will cause massive play in the rotors causing them to "knock" together when they run. These will need to be replaced most likely, where you remove the drive and driven gear from the ends of the rotor shafts, press out the rotor shafts with the rotors being careful to keep them in time, and then press out the bearings and seals and press in new and then put it back together again, making sure you keep the rotors in PERFECT time and you should be good to go.

Many cannot rebuild the rotor assembly them selfs, or find ny shop willing to do it so thats why they find a good used set with low miles and install those.

But you can always email or PM Brian and see what he says.

~F~

**Cyko** · 05-21-2008

Would it be easier to just goto a U-Pull-It yard and just get a whole new blower with low miles, and swap everything out of it? Cone and coupler and internals and everything? I've seen 'em at UPullIt yards not far from here for pretty cheap.

**Sabrewings** · 05-21-2008

Unless your case is ported, I wouldn't worry about swapping the internals. If you find a low mileage blower, just use the whole thing.

**Reptile** · 05-22-2008

Originally Posted by Cyko

Would it be easier to just goto a U-Pull-It yard and just get a whole new blower with low miles, and swap everything out of it? Cone and coupler and internals and everything? I've seen 'em at UPullIt yards not far from here for pretty cheap.

It's not really necessary to get an entire blower, but if you can find one cheap enough you can pull everything out without breaking the seal and swap it....I would be interested in any blower cases you run onto though, since they make good porting candidates.

Scour the classifieds, it seems that there's always someone selling rotors.

**Cyko** · 05-22-2008

Thanks for the info Reptile.... if I DO come across a set of Rotors, so you think you could PM me a quick walkthrough of what I'd be doing, and maybe a list of parts I'd need (gaskets, seals, bolts, whatever)? Also, I'll keep an eye open in the area for Blower cases for ya too... I know for almost a fact that there's a Upull yard like 45 minutes from here with a couple full M90's offa rear-totalled cars from the mid to late 90's (all the info I could get from the guy).

**Reptile** · 05-22-2008

I can do that, no problem. It's really pretty easy.

**BADAZGTP** · 05-22-2008

How common is it for these bearings to go out? Around a certain milage or you don't know until it happens. Just curious. Any way to check to see if they are on the way to wearing out?