I have a couple of loose off the car Eaton M62 Superchargers that I need to evaluate before choosing which one to use first.
One was on a '86 GT with a Series I that I heard running for a short time before I dismantled the motor to replace the head gaskets. It occasionally made some load noise, but I don't recall it was constant. I am hoping it is just a bad coupler, and not bearings. On a youtube video, it was mentioned that bad couplers can make a lot of noise.
The other M62 is one I pulled off a '95 Park Avenue Ultra parts car. It seems to be in slightly better condition. But I will eventually need to use both of them on two different GT swaps.

Is there any way to evaluate them while on the bench?

I am mostly interested in determining if there is any bearing failure.

Thank you for the help.

The 95 charger would be the better of the 2. It should be a gen 3. The biggest issue, other being M62, are the needle bearings in the back. If you have access to a stethoscope, listen for a "gritty" bearing noise right behind the throttle body while spinning by hand. Also listen at the coupler end for the front bearings. Not that I have benched many chargers, but I hook them up to an electric motor by belt. I listen for noise changes while closing and opening the throttle. You should hear compression noise, but when the needle bearings get worn the "impellers/vanes/screws/roots" start to touch and make a noise kind of like rubbing 2 pieces of aluminum together.
As long as the oil was kept up, these last a long time except for the couplers.
If you do decide to take them apart to inspect the needle bearings, mount them in something vertically so you can pull the impellers straight up. To try to help from having them drag in the bore once they come off the bearings. And you have to use the right sealers when assembling.
Don't try to rebuild unless you have access to the right tools.A press and the right bearing puller are a must. To easy to nick the bore and not get the needle bearings straight without them. They are not that complicated. Just have to have the right stuff. Personally I think the rebuild parts are way overpriced for what they are.

quote Originally posted by cmechmann: As long as the oil was kept up, these last a long time except for the couplers.

How do the these Eaton superchargers actually get lubricated?

The front bearings are lubed by the oil in the snout. The needle/rear bearings are lubed when installed. But the impellers can be removed and the bearings relubed. If they are in good shape. They are repacked with a grease for those bearings.
Note: the front bearings take most of the force of the pulley and gearing. The rear bearings are mainly to keep the impellers aligned in the bore.

quote Originally posted by cmechmann: The front bearings are lubed by the oil in the snout.

Can you tell me what the type of oil is used in the snout?

Thank you for the help on this. I will be working on this project over the weekend.

GM has special oil for it. You would need 2 bottles(8oz.). It is made from animal fats and smells like arse. Some of the speed shops also carry it. It's like $16.00 or more per bottle. Heard rummer that it is the same as Ester 100 that was used in older A/C compressors. I haven't been able to find that. There is also special sealer for the snout. Is is anaerobic sealer. Permatex/Loctite has one that works.
On the needle bearings have heard people having success with Kendel "Super Blue". It is an all purpose high temp grease. But GM has a grease with the rebuild kit that has the seals for the front bearings. If you replace the seals you will need a puller for the belt pulley.
There are several youtube vids in this. The most popular, I think the guy is a little rough with the chargers.
http://www.youtube.com/watch?v=mD-DvN7HO8M
But he makes sense.
http://www.youtube.com/watch?v=48a8QvPwbWQ
http://www.youtube.com/watch?v=EksCcU7CeNY

[This message has been edited by cmechmann (edited 09-12-2014).]

I used a stethoscope from Harbor Freight on the first Eaton M62 SC that came off the running '86 GT with the Series I swap, and did not hear any usual noises before disassembly.

I just drained the oil from the front snout, which looked nice and clean. Then I removed the snout to clean, and replace the coupler.

I also want to look at the needle bearings in the back end, and add some 500-10GRT Needle Bearing Grease that I got from ZZPerformance when I bought the new coupler.

Again, thank you for the help on this project.

[This message has been edited by hdryder (edited 09-14-2014).]