Thread: Alternator - 3.9i V8 with 4 belts

Fear not - the MM alternator's bearings can be easily replaced. See this thread

http://www.aulro.com/afvb/showthread...ght=alternator

I know that the LA V8 is different to my MA Tdi, but when I was looking for a replacement some time ago, I found that it was the angle of the brackets on the alternator that prevented a Bosch unit being fitted. It hangs cranked to the left, whilst most other models hang cranked right or straight. That was for both V8 and Tdi, the major difference being the width of the the hanger assembly (Which is why you can't use a V8 alt in aTdi) Of course if you find a way to use a Bosch, make a thread of it.

You champion!

Mine is pretty much identical. I've hit it with a hammer before realising that I needed to unsolder the field coil tabs (deeekhead!!!) and I was too dumb to put the nut on the shaft. I spent over an hour with a rifler file set redoing the thread so the pulley and nut could be reapplied. I guess it's one of those things you only do once!

I'll leave it for not but I will try the Bosch Magna unit - will get one from a wrecker to play with before taking the plunge. I was advised by Ray at Romsey LR Service Centre that a Falcon alternator will do the job too.

If/when I get the Bosch unit sorted I'll take photos of it and then I'll strip the MM one I have.

I have a Bosch Magna 85amp on my 3.9 Range Rover.
The mods required are
1 Lengthen the adjuster with a bit of strap steel.(about 2 inches)
2 Grind a bit off the bracket and the mounting boss onthe alternator to allow it to swing in to use the standard belt.
3 Fit a field wire to run the tacho.The electrician that sold me one did this for $40.
4 the one I bought had an injection plug but the wires are obvious.

5 Mine came with a multi groove pulley. If you buy from an electrican he will have a box of pulleys. try to get the smallest. I had to lathe off the flange on the pulley and move it from the front to the back, to line up the belts. I did this myself with the pulley in a drill and holding a hacksaw blade!!!
The Lucas (MM)pulley is 60MM in diameter and no one else has one this small. I think mine is 63MM, so about 10% out on the tacho.
The mounts fit straight up, using a couple of washers as spacer. the rear mount of the alternator has a steel sleeve which adjusts to a certain extent. The bolts are a little smaller than the holes but this is not worth drilling the bracket for.
I have had mine for a couple of years with no problems.
Regards Philip A

Philip,

What vintage Magna is the alternator from?

Thanks for the tips. The trickiest thing sounds like it's going to be the pulley, but I might be able to track down one from a Rover wrecker to modify.

Cheers, Mike

I put a Bosch 120 amp alternator on my 88 Rangie3.5 and had no end of trouble. The higher the electrical load, the worse it would run. In the end I fitted a 120 amp unit of a Disco 3.9 (MM brand) to solve the problems.

I certainly don't think I need a 120 amp unit either way. Still be keen to know which series Magna alternator suits.

I am not sure which particular model it was from, but I think it was an early 90s model, about the time of changover from vbelt to ribbed belt in Magna. It was 85 amp which should make it easy to identify.
The Bosch part number is something like 1245.
My local auto electrician was cheaper than Repco at $200 even.
Sorry, cannot be any more precise, as its probably the only receipt I have not kept!
Regards Philip A

The only problem with alternators is the mounting points, macman

my local auto leccy bloke just fashioned up a longer arm for the replacement which was a tricky bosch thing and runs about a kilowatt -

simple belts are easy - ask any of the tradey people and they'll find one that fits (as in length)

eg: the real one for the x19 no longer exists but at any 'autoshop' there is a simple replacement - for about $10......

12vDC gear is simple stuff

GQ