PDA

View Full Version : need help with MPX



Nate_V6
09-12-2009, 10:38 PM
So what would you do if you bought a MPX and this is what you received.
Case is scratched up and the seals were bleeding oil as well as the bearings were so wore the rotors can be shook. Apparently it's normal for them to have oil in the IC tubes and in the case, my stock m90 IC tubes had some oil in them.....but I didn't know it's supposed to almost empty the reservoir in less then 300km.

http://i12.photobucket.com/albums/a217/Bedfear/090910165700.jpghttp://i12.photobucket.com/albums/a217/Bedfear/0909101700002-1.jpg
http://i12.photobucket.com/albums/a217/Bedfear/090910170000-1.jpg

The pics are with my cell but you can see the marks on the rotors and in the MPX. The person in question said to take pics and bring it to the forums to see what people who drive and work on these cars thought. It's supposed to be a brand new GTP rotor pack with uncoated rotors and only have 6 dyno pulls, 5 1/4 mile passes.

I'm pretty sure those scratches are going to drop performance. and I had to find another rotor pack as well, not to mention orange RTV is not supposed to be used I believe. oh and yes that is a hammer mark im sure on the edge in the orange RTV.

Pablo94SC
09-12-2009, 11:10 PM
First off, GTPs had coated rotors like the 94/95. Second, you're supposed to seal the blower case with anerobic sealer, otherwise it WILL leak. Looks and smells a lot like sweet and sour sauce. Anyway, it's likely the blower's snout bearings were shot and resulted in the rotor pack's gears to wear unevenly, increasing the lash. That would cause the rotors to have slop and wear the coating off as well as rub the case.

Case doesn't look that bad from the photos, but if there is a lot of slop in the rotor pack gears, I'd replace the rotor pack when you get the snout rebuilt. Find yourself some anerobic sealer to seal it all up and you should be good to go.

Nate_V6
09-12-2009, 11:23 PM
wow so you think the snout needs rebuilt as well? are you 100% on that? because that sucks even more, but I don't know if I need a new mpx case now with those scratches, and I know what to seal it with but I'm pointing out what I purchased that was supposed to be a brand new pack with 6 dynos and 5 1/4 passes........I think I'm due for a refund wouldn't you think?

Tony8470
09-13-2009, 01:10 AM
Rotors look fine to me. Alot of members use copper RTV. I have used it on more than a few of my blower(s) rebuilds. GTP rotors have a grey powdercoat on them. Case doesn't look bad either.

Kevin Leitem
09-13-2009, 07:44 AM
the case will be fine, I had a case in MUCH worse shape, and when i put a new case in, I saw no improvement. I would say the rotor pack is junk, if it is leaking alot into the blower then the rotor pack is worn. if it is leaking out around the pulley area then the snout is worn. I have always used RTV. Of the many many I have put together I doubt i used as much as what is on that one!

XR7 Dave
09-13-2009, 10:38 AM
I agree with Kevin on that one. The rotor pack, while definitely a GTP rotor pack, can hardly be a brand new set as you can't buy just a GTP rotor pack new. Obviously it was a pack from a used GTP blower (as all are) and therefore no one can know how many miles are on it. The fact that the coating disintegrated completely suggests that the rotor pack may have been a little on the old side when it was installed. I don't think there is any way that anyone could have known that in the beginning.

Buying parts that have been used in a race car is not the way to get A1 grade parts. Racing by it's nature is the most abusive form of use one can possibly get from a part. Buyer beware in this case. Anyway, rotor packs and snout rebuilds should be considered normal maintenance on a high performance, 25% overdriven M90 blower. Get a rotor pack from a decent M90, check all your clearances when you re-assemble, and go with it.

Nate_V6
09-13-2009, 01:34 PM
Well then he should not have posted that they were a brand new set. But if you think the case will be fine that is good. I was just upset that he kept denying any problems with the MPX altogether.....even I can tell that the rotors were bad and that was the first one I've seen apart. I found a rotor pack but now I think I might need the snout rebuilt.....but HOPEFULLY the case won't have any problems like you guys said.

Pablo94SC
09-13-2009, 03:57 PM
My rotor pack became sloppy because the snout I used was shot. You may have just gotten an old rotor pack. And if that is a rotor pack from a GTP, then it looked nothing like the GTP rotor pack I got. Mine had a nice coating on it and yours looks bare. The case looks fine however. Worst case scenario... rebuil the blower with the new rotor pack and see if you have any noise/play from the snout. If you do, tear it back down and have the snout rebuilt or install a known good one.

Nate_V6
09-13-2009, 05:16 PM
well the scratches might be deeper then what they look like on in the pics, but if others have seen worse and no issues then that makes me happy! I have a rotor pack now from a 89-93 M90, so I'm all good.

Nate_V6
09-21-2009, 05:38 PM
So apprently because I found another rotor pack and that i'm feeling better about the MPX scratches, that makes everything ok now! and I even got the rolleyes emoticon!!!

I don't know about you guys, but I farkin pissed off here since I paid for something that was no where near what was specified in the post. He wouldn't have been able to sell it for the price I paid if people knew the condition it was really in.

XxSlowpokexX
09-22-2009, 12:01 PM
Nate unfortunately it happens. My MPII imploded..Recently rebuilt...

The snout is easy enough to check. If it wasnt spraying fluid chances are it wasnt bad.

And a set of 100,000 GTP rotors can hav ea perfect coating on them. As has been said none will know exactly how many miles it had or if teh previous owner changed out the GM non synthetic oil when they should have. Take those rotors that look new and overdrive them >>>And the coating can come off real quick...Happened to me on several of my rotor packs. The biggest problem with the MP blowers isnt the blowers themselves but the unknown quality of the rotor packs being used. The blower is as old as the rotors.

And youll likely not notice an issue with the scratches unless they are real bad. I probably would have went over them however with a very fine emery cloth to smooth out any rough edges. And you may want to replace those rear bearings just because..

And Ive never had a leak issue with sealant. Im with Kevin on that one

WhiteThunder
09-22-2009, 01:22 PM
Nate unfortunately it happens. My MPII imploded..Recently rebuilt...

The snout is easy enough to check. If it wasnt spraying fluid chances are it wasnt bad.

And a set of 100,000 GTP rotors can hav ea perfect coating on them. As has been said none will know exactly how many miles it had or if teh previous owner changed out the GM non synthetic oil when they should have. Take those rotors that look new and overdrive them >>>And the coating can come off real quick...Happened to me on several of my rotor packs. The biggest problem with the MP blowers isnt the blowers themselves but the unknown quality of the rotor packs being used. The blower is as old as the rotors.


I had a set of used GTP rotors in my supercharger. The coating was perfect when I installed them. They always sounded like rocks in a tin can. Pulled them out recently. One rotor had so much front to back play it was rubbing the back of the case. The coating was around 50% gone (I'm overdriving 15%). I was told that all the oil was gone out of the snout because the rotor pack seals were shot.

Put a set of Ford rotors from an '89 - '93 supercharger - I'm using a ported '94 supercharger case. Nice and quiet now. (Also used a spring loaded coupler this time, instead of a solid coupler.)

eddie
'90 5-speed SC
'97 LX sport

Nate_V6
09-22-2009, 01:43 PM
I replaced the entire rotor pack now, and I'm using ford's synthetic supercharger oil......was more expensive then I though but I'm assuming it's better then GM's stuff since it's not synthetic.

Kevin said he has used worse cases though without performance loss......So I think this winter I'll rebuild the rotor pack and snout and spin it to 25%......I'll work on the case too and see what I can do with it....might just sell the case on it's own for 300 bucks and get a new one with a raised top.

XxSlowpokexX
09-22-2009, 02:09 PM
I dont think its worth buying a new one.

David Neibert
09-22-2009, 02:25 PM
I replaced the entire rotor pack now, and I'm using ford's synthetic supercharger oil......was more expensive then I though but I'm assuming it's better then GM's stuff since it's not synthetic.

Kevin said he has used worse cases though without performance loss......So I think this winter I'll rebuild the rotor pack and snout and spin it to 25%......I'll work on the case too and see what I can do with it....might just sell the case on it's own for 300 bucks and get a new one with a raised top.

I wouldn't be too concerned about that case. My MPII ingested two stainless steel screws from the throttle body while at WOT on a dyno. It hung the throttle wide open and I had to turn off the ignition to stop the motor. Installed two new screws in the throttle plate, started it back up and made two more pulls. Much to my surprise the HP didn't change (pulled 369 rwhp), so I drove the car for another year before I even took the blower apart.

It made a mess of the rotors and gouged the case pretty bad, but it didn't really have any noticible effect on boost or HP.

David

S_Mazza
09-22-2009, 03:17 PM
If the rotors have front-to-back play, that is because of worn bearings at the front of the rotor pack. The bearings at the rear only locate the rotors perpendicular to the axis of rotation, not front-to-back.

An oil leak at the snout may be because of a bad snout seal. However, it could also be because of bad seals at the front of the rotor pack.

Worn out gears could cause the rotors to scuff against each other, but should not cause any play front-to-back, because the gears are straight-cut. For what it's worth, they seem to be pretty sturdy.

If anyone finds an error in the above, let me know and I will correct it.

Nate_V6
09-22-2009, 03:21 PM
wow that's good to know. Well then I guess I'll just rebuild the pack and snout this winter before I run 25% OD.

and there was play moving side to side LOL and you could slide them a bit front to back, but you could defiently make them slide back and forth. (by that I mean the ends would angle left to right, like tilt? they were just super loose all around)

But Dyno is now booked for thursday at 5pm so should have the vid up thursday night!!!!

S_Mazza
09-22-2009, 03:36 PM
The rotor pack I am using hasn't given me any problems. But I did notice a slight amount of "wiggle" or "tilt" in the rotors when I had it apart. I think a minimal amount is okay, but I don't have a spec. When installed, the rear case bearings take half of the load anyway.