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Guest Anonymous

Alternator questions for 318i replacement...

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Guest Anonymous


I just got an alternator out of a 318i to replace my worn stock alternator. I was wondering if anyone had any info on the alternator. Also do I have to grind the nut on the front? Any other issues with installing clearance-wise? For the wiring..has anyone done this? Is the unit self regulated? Where do I hook up the wires from the 3 prong plug since it is differnt? There are 3 wires the same, De, +, -, but then there is a 4th wire on the new alt. that I cannot figure out. Any and all help would be greatly appreciated so I can get out on the road for some fun driving. Thanks,


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Guest Anonymous

If you go back to the home page here and look under Electrical/Ignition, subheading "alternators"...there's a step by step for this install that should answer all your wiring questions. I just did this a few weeks ago and had no problems with the wiring following those instructions. As for the clearance between the front nut and the fan...I wound up grinding mine out of impatience, I'm sure there are much better remedies, but I wanted to drive it "NOW"'s working fine so far...FWIW...

Good luck, and enjoy...


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Guest Anonymous

i just went through this procedure. The 318 alt is a great

upgrade but requires some Mods. For the wiring, use this



The physical hook up is different though. First, you need to

make sure you have the 318 mounting bracket. The nuts and

bolts from the 318 help too.

Replace the mounting bracket and bolt up the Alt like the old


The catch:

The area where the Alt bolts to the slider/adjuster bracket

doesn't match up correctly. The 318 Alt is wider then the

stock Alternator.

Here is my solution though I am not sure it is the best

one..yet. I had a piece of steel fabricated from joist hangers

(home depot) welded into a shape like this:



The bottom part bolts to the slider bracket. The top part bolts

to the Alt.

The problem is that the bracket sits under the Alt instead of

up to the side where it should bolt. I'll try to take some digi-

photos and post them on my site. i am having a hard time

trying to put the procedure into words but if you saw it, it

would be pretty clear what the problem and possible solution


My first solution was to extend the bracket out from the

engine with a longer bolt and some spacers. the bolt was

almost bending and didn't look like it would hold up for long

term purposes. I took a photo of that a long time ago:

You can see the area and parts that I am talking about.


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