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MGB Alternator conversion results...

To: "MGB List (E-mail)" <mgs@autox.team.net>,
Subject: MGB Alternator conversion results...
From: "Christopher W. Reichle" <CREICHLE@bdpb.com>
Date: Wed, 26 Apr 2000 11:37:50 -0400
First, thank all of you who spent so much time looking up part numbers and
explaining how your conversion went. I found a wealth of information in the
archives and everyone who I contacted from those archives replied with help.
Really a great group of people. So here's how it went.

I have an 80 B with a bad alternator. I am installing A/C, hight watt lights
and big radio so I figured I could upgrade to a higher amp alternator. I
found references to using Bosch units from 86 VW GTI (65 or 90 amp), 80 Ford
Fiesta/Festiva (55 amp), and variouse other cars. The bosch units share a
similar if not identical 1 and 5 o'clock ear orientation, N13 plug (Fiesta),
two ear on one side, one on the other configuration... or so I thought. 

I went to Napa and Discount Autoparts to buy one of the units. To my
surprise, the units had one big ear on one side and a normal ear on the
other in the 12 and 6 o'clock positions, different wiring plug. These were
not the bosch units but the auto parts remanufacured units. I wanted to look
at one before I ordered a bosch. I figured it would have to be the same
style... So I asked those people who had done the conversion what the deal
was and one answer I got back regarding the Ford Fiesta was that I should be
asking for the import unit. I don't know if that is the story with the GTI
as well but I had a few problems finding the unit that people had sent me
pictures of.

There is also a GM unit that can be used it. I decided not to use this
alternator because it is large ( I have little room with the a/c ) and it
requires different mounting due to the large ear configuration that it has. 

I was not terribly concerned about getting a direct match for the lucas
because the lucas did not fit very well on the compressor mounting bracket
that I have for the A/C anyway. I went through a bunch of alternators at
Discount until I found one that fit my application. The only problem was
that noone could tell me what car it came from. I was not about to put an
alternator in my car and not be able to order a replacement by giving a car
that it fit into. In addition, the alternator was $200 plus a $60 core
charge. Then I had an idea... I called around to a bunch of junk yards til I
found one that pulls parts and stocks them on shelves (labeled with which
car it came from). I found that the style that I was looking for is commonly
used in Mazda autos. Since I needed a compact unit I picked one that was
from a 90's car with internal fan, and regulator. I narrowed it down to a
few choices: 93 protoge, 91 MPV, 92 Probe ranging from 65 to 75 amps. Other
cars with this style ears included 626, mx6 and various years of all. The
main differences being the width between the two ears and the amps. I called
Discount on my cell while I was at the junk yard to check on the price and
core charges for the alternators I was looking at. They are all about $100
for rebuilt and $60 for the core. I paid $40 for the junk unit (91 MPV). I
purchased a few metric bolts and washers to use as spacers and spliced the
plug that came with the unit into my harness. I had to get a slightly smaler
belt (remember I have a/c) but it bolted right in. I had decided to mount
the alternator on the water outlet bracket which is about 2" long with the
adjuster mounted to the compressor. I reamed this out from 5/16ths to
25/64ths to snugly fit the metric bolt and spaced it with washers. Aside
from having to raise the idle RPMs a little, it went very well. 

I can see things glowing on my dash that I didn't even know had bulbs behind
them! I think these alternators would also fit the stock mounting for the
lucas also with the one exception being the ears are in a 12 and 6 o'clock
orientation. This worked well for me for my mounting but in the stock
position you might need a longer or more curved J style adjuster bracket.
The MPV came with the right pully. If you use another unit that comes with a
flat belt you can get the pully changed at an alt place or possibly even at
the junk yard.

I highly recommend replacing the alt with a newer design, more compact,
internally cooled, cheaper, more durable, and more powerful unit. I
appreciate the help of all the list people that helped point me in the right
direction....



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