M30 multi v conversion (serpentine)

E28 technical advice asked and given! Troubleshooting, modifications and more.
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Sump scuffer
Posts: 2
Joined: Jan 01, 2023 2:54 PM
Location: Nottingham

M30 multi v conversion (serpentine)

Post by Sump scuffer »

Hi all im new here but not so new to retro bmws iv had e30s and e34s for many years many years ago I built my m30 turbo now along with a few issues over the years 1 problem I have have for some time now is at high rpm it throws the auxiliary belt and evan a few times its flipped the belt when this happens the belt rubs through coolant hose that runs close to water pump pully

I have checked using a dti gauge to check for run out and end float on crank and found nothing
So my thoughts are that the belt must be panting thus why I'm considering a multi v conversion iv seen it done once on pictures but not sure whether I can use later bmw components so I'm looking for other options on what fault could be or ideas for components thanks
Mike W.
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Joined: Feb 12, 2006 12:00 PM
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Re: M30 multi v conversion (serpentine)

Post by Mike W. »

Welcome to the group!

No info on a multi Vee conversion, but I will talk about the regular belts.

I'm puzzled, I've had a bunch of M30 cars and never had a belt thrown or twisted or whatever. Broke one once and lost all 3, but that was probably with over 100K miles on the belt set. I've got to think something is out of alignment. I'm a little confused by your term Aux belt as the main fanbelt which runs the water pump is the main one. Regardless. One thing I can think of is many M30s had alternators with rubber mounts, which often (always?) compressed unevenly and caused the alt to run at an angle to everything else. Starting here in I think it was '87 they stopped that and just used a mounting hole in the alt of the correct size so everything stayed straight. So, not knowing even what model you have, let alone what they used in the UK, I'd look at that first, then next put a straight edge along the belt to check for alignment.

I think it would be a very difficult conversion as the crank pulley for the water pump and alternator is part of the harmonic dampener. Now I'm not saying it can't be done, enough time and money and energy you can do pretty much anything, but with such an unusual problem I think it would be much easier to find out what is going on and correct that rather than reinventing the wheel.

Now if you're talking the power steering belt, that might be somewhat easier. And of course make sure you have the right belts on there. Here in the US the catalogs are generally wrong for the water pump belt, they generally say 1055 or 1060, but 1040 is correct. Power steering here, uses a narrower belt than the 12.5/13 used on the water pump/alt. And trust me, I've had them at high RPM, redline with a chip on E28 era M30s, which is ~6600 and over 7K on an earlier E3.
Galahad
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Re: M30 multi v conversion (serpentine)

Post by Galahad »

I've seen someone do it over on r3v for an m20 (see here). I don't know if the same would work for the big engines - a lot of the parts he used came from an m50 - but it might be a place to look at.
1st 5er
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Re: M30 multi v conversion (serpentine)

Post by 1st 5er »

Mike Holtmeier just completed the conversion and documented it on the E28 FakeBook page. I'll see if I can find a link.
1st 5er
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Re: M30 multi v conversion (serpentine)

Post by 1st 5er »

1st 5er wrote: Jan 01, 2023 5:10 PM Mike Holtmeier just completed the conversion and documented it on the E28 FakeBook page. I'll see if I can find a link.
Oops!!! It's on his personal page.
https://m.facebook.com/story.php?story_ ... tid=Nif5oz
Sump scuffer
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Joined: Jan 01, 2023 2:54 PM
Location: Nottingham

Re: M30 multi v conversion (serpentine)

Post by Sump scuffer »

Well the car is uk model 1989 e34 535i auto or was when new
Iv ran straight edge on water pump to crank and alternator and all look to be running true
And it is the water pump alternator belt
Iv already removed power steering pump when I originally had this issue and it seems the happen at 6500rpm
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