Alternator conversion for 71 Midget

[JimSnack]

I'd like to convert the generator on a 71 Midget (1275 engine) to an alternator and have found several websites explaining the procedure. I have the necessary brackets and I know I have to bypass the voltage regulator. Now I just need to get an alternator.

I have seen several suggestions regarding what alternator to use, such as a single wire GM unit or a Ford Fiesta alternator. Will I need to replace the pulley and fan on whatever alternator I choose? Can I use the pulley and fan from the old generator?

In short, which alternator should I get, and how will I need to modify it so it works?

Jim

 

[Trevor Jessie]

The Lucas unit is available at most parts warehouses. It may take a day for your local parts store to get it to their door.

Generator pulley and fan will not work on an alternator.

 

[Trevor Jessie]

Also, look here:
https://www.mgccars.com/electrical-upgrades-for-you.html

 

[JimSnack]

Thanks for those ideas. Now let me ask...if I don't want to spend more the $100, which alternator should I choose for the conversion?

 

[Trevor Jessie]

The big delco units are cheap and plentiful, but they look a bit awkward. I prefer the Lucas unit because it looks correct and supplies adequate power.

There is a nippon-denso that is pretty small and works well. There is also a bosch unit that people use.

Try the advance search feature of this forum and you can probably come up with some part numbers.

 

[vagt6]

I have a Datsun B210 alternator on my MK III Midget, came with the Datsun gearbox. It's a Denso unit, small, works great, and it's cheap.

There are plenty of others. Unless you're installing a bid stereo or for some reason need a bigger output, the stock Lucas one is fine, also.

Let us know . . .

 

[JimSnack]

I like the price on the Datsun unit. Did you have to change the pulley and fan or modify the mounting brackets?

 

[tdskip]

Guys - won't the wiring need to change as well?

 

[Trevor Jessie]

He said he had the procedure to bybass the old voltage regulator, so I assume he has that part covered.

 

[Morris]

A 71' should already have an alternator... right???

 

[tdskip]

He said he had the procedure to bybass the old voltage regulator, so I assume he has that part covered.

Once again proving that posting before the coffee kicks in is a bad idea.

Sorry.

 

[Trevor Jessie]

'72 was the first year I believe. My late '70 was still a generator.

 

[Morris]

Wow... I thought they went to alternators in the mid-60's.

 

[Billm]

BMC was NOT that advanced!!

 

[dklawson]

I went with a Motorola alternator that is a copy of a Bosch. It is a bit "big" (case diameter) but fits. I made a bracket to mount the ignition coil on the alternator so my coil would be in the same location it was with the generator. That conceals some of the alternator's size.

I used the wiring method where you gut an old control box and modify it to serve as a junction box. That makes the engine bay and wiring look stock. Should a future owner want to go back to the generator, all the original wiring is intact.

 

[Gerard]

In short, which alternator should I get, and how will I need to modify it so it works?

Jim

Also in my Tech Section along with a couple other good links.

I've done a number of these including on MGA and Morris Minor. There's very little to modify and they look correct. I don't know that you can hit the under $100 mark though.

https://gerardsgarage.com/Garage/Tech/alternatorTfisher.htm

 

[JimSnack]

Hi Gerard,

That's a good article you wrote on the topic...one of the better one's I've read so far. It looks like I might have to raise my budget! Thanks.
Jim

 

[Sarastro]

I used Gerard's article as a starting point for my conversion (https://www.nonlintec.com/sprite/alternator/). Take a look at the Wiki also; the article there is abstracted from the above article.

I think that the Lucas alternator is about 35 amps, which is enough if you don't add any electrical equipment, but it's a good idea to have a little power in reserve for possible future additions. The Fiesta (Bosch) alternator is 55 amps, which will give you another 20 for future use. It's worth doing, in my opinion.

Hooking it up couldn't be simpler. There's info on this in all the above articles.