Water-cooled alternator woes

[jicaino]

Hey guys. My cheap junkyard alternator that lasted 2 years seized like welded.
No biggie, I thought, as I had one brand new oem genuine unit in the shelf.

Turns out that the back shapes are different and the unit doesn't fit. Replacing all the new stuff into the old alternator is not an option because winding is absolutely messed up.


Does anybody with involved M62TU experience recalls if that doughnut shape in the back of the timing/alternator case can be hogged off with a rotary file? I don't recall if there's a corresponding contoured shape in the back and I risk perforating the case or if I could just mill it off

[killian665]

Why not just get an alternator that fits

[jicaino]

Why not just get an alternator that fits

Same reason that's compelling you to not answer what's at question

I have to import a part that's not stocked in our country nor anybody rebuilds.properly while I'm sitting on a new genuine unit that lasted for 15 years. If I can make it fit milling that recess I'm back on the road tomorrow. If not I'll be a pedestrian 20+ days and dish out 2x whatever you guys dish out for said piece

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[jicaino]

Just answering myself in case anybody with the same question needs an answer.
It cannot be milled off
here's a picture of the back of the lower timing case.

[S50ti]

I had a water cooled unit in my 4.6is fail...found a hole-in-the-wall, old timey alt rebuild shop (in the phone book, weren’t on any web searches) that was quite familiar with rebuilding them. $300USD and they even warrantied their work for 2 years. I’d seriously call around to every place you can find.


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[geargrinder]

Juan, are the stator windings are permanently bonded to the housing so you can't just swap the back-casing?

I mean that's a DUMB question cuz I'm sure if they came out you'd have swapped 'em and never made this thread so I'm sure "YES" is the answer... just trying to understand how these go together... I've seen 'em open but never so far as to try to pull the stator or anything.

Less-Dumb Question: What's the other design from? X5? Land Rover M62? Non-BMW version of that Bosch W-C alternator?

[jicaino]

Juan, are the stator windings are permanently bonded to the housing so you can't just swap the back-casing?

I mean that's a DUMB question cuz I'm sure if they came out you'd have swapped 'em and never made this thread so I'm sure "YES" is the answer... just trying to understand how these go together... I've seen 'em open but never so far as to try to pull the stator or anything.

Less-Dumb Question: What's the other design from? X5? Land Rover M62? Non-BMW version of that Bosch W-C alternator?

Hey! I have a 180A water cooled for some N62 and all N73 cars (E65/66/67 and RRs)

Stators aren't permanently bonded but in my case, the 180A stators are longer than the 150A case so they don't fit in the back casing that fits in my car. I guess I was as SOL as to get the only scarcer alternator than the already scarce water cooled alternator our cars use...

As a side note, it's incredibly how beefy those alternators are inside. The weak points being the bearings. If this thing would have better bearings, like present day bearing technology, they'd be pretty much a lifetime alternator. I think I'll build a ceramic bearing alternator out of this just for fun. I'd have to rewind the thing so that'll take time, but I'll remachine for angular bearings or flat roller bearings or something better. I will have to dig and study thru a pile of bearing catalogs so it will be slow, but since I'm keeping my ice-stoned, almost-too-far-gone-more-than-just-once 540i, it will be fun.

[JimLev]

The rear bearing is smaller than the hole in the back of the case that the bearing fits into. There is a plastic ring insert that takes up the space between the case and the OD of the bearing that can easily break just looking at it.
While your at it you may want to consider finding a slightly larger OD bearing so you can ditch the plastic ring or machine a ring out of metal.
Good luck.

[jicaino]

The rear bearing is smaller than the hole in the back of the case that the bearing fits into. There is a plastic ring insert that takes up the space between the case and the OD of the bearing that can easily break just looking at it.
While your at it you may want to consider finding a slightly larger OD bearing so you can ditch the plastic ring or machine a ring out of metal.
Good luck.

Hey Jim. I've rebuilt 2 of them and while I hated the plastic sleeve on the back is there for a reason: the amount of distortion the casing has is huge (and this is normal, I mean, the amount of dimentional change the back casing sees due to the nature of design). And I mean, huge. The only way to use an interference fit bearing back there would be using a large tolerance bearing instead of de double zero it has. I've replaced the flimsy sleeve with a machined aluminum one and it seized when hot. Moved to rulon-J and it was better than the cheap plastic one without interfering with normal run-of-the-mill operating conditions.

I'm wondering if removing the return line is a wise move... I mean, you know, I replaced the atf/coolant exchanger and went to a regular pre-VANOS ATF/air cooler in front of the radiator using OEM parts, then disposing of the various piping lines using a VANOS manual set of hoses and a plug for the back of the alternator coolant casing. I wonder if having the return line back there increases flow around the alternator, causing it to run somewhat cooler...

In theory it shouldn't be a huge difference otherwise M62TU manual cars would fry alternators more often than automatics, but then again automatics puts brakes and alternator thru a harder task than manuals... Something to ponder about.

[topaz540i]

this is exactly the reason I converted my car to solar.

[itsbrokeagain]

I know you said you didn't want to import one but how long do you think it would take to get one from the states?

[jicaino]

I know you said you didn't want to import one but how long do you think it would take to get one from the states?

I ordered a new one and it should be arriving next week. I would have liked to keep the car running, but it is what it is... I can't blame my poor car for us being in a banana republic where no official dealer, or parts store has a new unit.