Supercharger failed, eaton M54 on mini cooper froze

At 125K mi I replaced my original supercharger on my 2003 Mini Cooper S with a rebuilt unit. The rebuild didn’t last a year. The nose / snout bearing seems to have froze. The most likely cause would be that it ran dry and this could be the case however the underside of hood and the engine bay did have a fair amount of oil coating them after the incident. I returned the super charger to the re-builder only to be told that they would not cover it under warranty because I over heated it by running it too lean. This smells like BS to me. I dont understand how, even if I was running too lean, that could cause the nose bearing to seize and squirt its oil all over without causig some other heat related damage like melting the spark plug wires or the rubber boots on the supercharger inter-cooler.

What are your thoughts on causes for an eaton m45 supercharger on a mini cooper to have a snout bearing failure? Am I being screwed by this rebuilder?

Sounds like BS to me. Your mini is fuel injected and the computer controls the fuel mixture. If you had a carb you could adjust it to lean.

Is your vehicle modified tune or stock?

How are SC bearings lubricated? Sealed system? Does it have oil lines that use external source of oil? You have replaced it before so you should know. Or did you pay a shop to do it and are unsure? Bottom line? SC supplier says NO. Not a whole lot we can say to make them change their mind.

If the rebuilt unit is OEM, rebuilt to BMW specs, and you provided no other enhancements, the shop i full of it.

A lean air/fuel mix did not cause this. It was a loss of oil due to a leaking seal and the seal could have been leaking due to:
Wear groove on the rotor shaft which no seal will cure and should have been resolved during the rebuild.
(Do a net search about Speed-Sleeves to understand how things like this can be cured.)

Someone used an inferior seal during the rebuild or damaged it during the installation. It’s been a while since I’ve been into one of these SCs but I remember the proper seal as being Viton and care should be used while fitting it.

Too much end play on the rotor shaft could possibly cause a seal leak. This is also something that should be caught during a rebuild and if correct from the start could possibly increase due to loss of oil.

Bottom line is the bearing seized due to lack of oil; not because of a lean condition.

I think we can all agree here that the rebuilder is full of beans. They won’t stand behind their work and offer a bogus explanation to how it failed.

@sentiens Here’s a last ditch idea

Find out the corporate address for the rebuilder (if it was some kind of chain)

Send a registered sign-on-delivery letter giving them all the details (dates, model of car, model of supercharger, exact dollar amount spent, etc.) and that you’re extremely unsatisfied that their product didn’t last a year and that the rebuilder refuses to warranty it.

If nothing else, someone high up in the company may call you or write you a letter.

These guys sound less than reputable, so you have nothing to lose at this point.

@sentiens, if you know a lawyer, maybe he will sen the lette that @db4690 suggests. I had a friend that did this with a Jaguar XJS that stalled randomly. Jaguar replaced the engine ASAP, and no more problems. It helps to have friends that know how to present your issues in just the right way.

like many shops trying to rebuild the M45, that MINI walked away from years ago, most are not being rebuilt right or even well. whoever rebuilt the unit messed it up. Like many of those shops they have “Warranty” rules that really limit the true coverage of the work and parts they sell. Feel free to send me a message here if you would like any other help. A simple google search for M45 rebuilders will give you links to the limited shops doing this job right.

Sc leaked out oil? You said engine compartment was wet with oil? What part leaked? Shaft seal? Sounds like unit was not rebuilt right? What was warranty? 3-6-9months? 1 yr? No warranty?

Hi all. Thanks so much for your responses. I need to figure out how to get emailed when someone replies. I will try to answer everyone’s questions in this one post.

The shop in question is Way Motor Works, Way outsourced the rebuild - I never got to talk directly to the re-builder. They held my SC hostage for 4 weeks while I waited to get a response that they would re-build it for $100 less than the original cost, 795 instead of 895. As you can imagine that is infuriating.

The car is modified: Ported and flowed head/intake manifold. 15% reduced SC pully, 380cc injectors over stock 250cc (380cc is the OEM performance size) CAI and full exhaust.

Due to mods remapping the ECU was required, it was running RICH! (stinky) and knocking hard. The re-map did lean it out a bit but it still stinks a bit like its richer than stock. I provided AFR charts from the dyno to Way upon his request but he did not comment on them.

It was the nose/snout seal that ultimately failed - that is where the oil that leaked came from. The stock SC (non-rebuild) lasted 130k mi, the rebuilt unit with the cyl head and tune lasted 10k mi.

I just cant imagine if the car was running lean how the SC snout would be the first thing to fail. If it was that hot wires would have melted or something. If intake temps were that hot I would have had a loss of power and the mini was still jamming when it happened.

Pursuing an equitable resolution is going to be the tough part. Based on the feedback I have received here and in person, even at the dealer, all indicators point to me being lied to - that the rebuilder did a poor job and the snout spit its oil out and then foze.


Thanks for the update

Don’t get mad at what I’m about to say, please.

The fact that your car is HEAVILY modified may very well decrease the chance of the rebuilder helping you out. He may very well say that “the added stresses” put a severe load on that blower and drastically shortened its life.

Good luck

@db4690 I wouldn’t say ‘HEAVILY’ - no cam, stock pistons and crank etc. All the mods are used by Way Motor Works and he builds cars intended for the track all the time for guys who race, and claims his rebuilt supercharges don’t fail in them. I go to track days but I do not race.

I think a better question might be ‘could any car, no matter how heavily modified, cause a nose bearing in a super charger to fail by running to lean?’ I think the answer is no.

If something on my car did cause the failure I want to know so I can prevent it but I’m just not seeing how that could be the case

I have a replacement SC on now and I have not measured more than 140f at the intake and no more than 14psi boost.

Thanks for your comments.