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MG MGB GT V8 Factory Originals Technical - Which Alternator?

What kind of alternator is everyone running? Are there any Lucas alternators that are short enough to run off the factory V8 alternator bracket?
Thanks
Jake

Iskra alternator, 85A. Brandnew. Runs off the factory V8 bracket.

Frank
Frank de Groot

Frank,
Can you send me more details on this alternator? a picture of it on the car even?
Thanks
Jake
Jake

No problem. Iskra is perhaps not well known, but is OE equipment for Opel. They used to make alternators for tractors. Now they took over part of Bosch. It is a very good alternator, with bearings to modern standard. Will send you details and picture.
Your reminds me of last year, when my "factory original" Delco alternator broke down yet again, after reconditioning. I decided to dump the thing, but finding a new one proved to be difficult. Especially because I wanted more amperage, reliability and modern bearings.

Frank
Frank de Groot

Frank,

What do you mean by ‘modern bearings’?

Geoff
Geoff King

Geoff,

Will give details tomorrow. While having a testflight to the electronics-dealer the right hand side exhaust blew of my manifold. So right now I have other things on my mind. More on alternators tomorrow.

Frank
Frank de Groot

Okay, on the bearings. The place where the bearings really matter is at the back of the alternator. At the front you tension the belt. This puts power on the front pulley. This pulley pulls the axle on which the rotor is mounted down. So the rear of this axle will create an upwards force, resulting in wear at the rear bearings. That's why the design of the rear bearings has great impact on longevity of the alternator.
But lets remember that the old Delco stems from a time where it was considered normal to check your car every week; look at the manual what you are supposed to do!
First the Delco. The Delco (OE on Rover V8 in the MG B GT V8) has needle bearings in the back. The axle on which the rotor is mounted rotates on these needle bearings. What has happened when you hear noise from the alternator? The bearings are worn. But also the axle itself! Grease is not contained that well, and the axle rotates on the needle bearings themselves. So you can replace the needle roller no problem. This is normally - given the overall age - a partial solution, as the axle is worn as well! But not many people want to replace the axle with the rotor: expensive solution.
How do modern alternators handle this problem? With "industrial" bearings. More or less solid. So the grease stays in. Part of the bearing is pressed on the rotor axle, so there is no wear on the axle itself (as with the Delco). Together with a higher amp output this creates a product that will last longer with less maintenance.

On amperage the sky seems the limit. Look at new Mercs with all electric seats and other gizmo's. They have 1500 dollar alternators that produce in excess of 150A and are watercooled. Can we use this? No. Remember the power is generated by pulling a belt over the pulley of the alternator. High amperage will need a high pulling power from the engine being transferred to the alternator. With the normal OE belt this engine-power will not result in power from the alternator, but in a belt slipping over the alternator pulley. This puts a limit on things; around 75-85A max is recommended.

The Iskra I used last year is know has a number ending on 811. You have to make sure that is has both a terminal for bolt-on pos/neg as a normal plug-type terminal. Over here in Holland the price is around 150 euro's. As far as I know this includes VAT at 19%. Comparison: a month ago the VW TDI from my parents needed a new alternator (and batteries). Only option was OE alternator, at close to 315 euros.

Of course I'd like to know what others use; the Iskra works for me, but surely there are other options?

Frank

Frank de Groot


I prefer the late model 1990 and up GM 65 Amp to 180 Amp or more. This alt is small simple to adapt and has extra leads to run a relay etc. Known to go above 200k miles. Some auto parts have a lifetime warranty, so save your receipt.
Bill

Bill,
Does this alternator have a provision for an igintion light? Ive heard that some of the 1 wire delco's can be used if you want one.
Jake

Jake wrote:

"Does this alternator have a provision for an igintion light? Ive heard that some of the 1 wire delco's can be used if you want one."

A "true" one wire CANNOT be used with an indicator light. Sadly, far, far too many parts store clerks don't really know what a one-wire is, and will sell you a three-wire, claiming it to be a one-wire. Many people mistakenly believe that ALL Delcos are one-wire, but this isn't the case. If it is a one-wire, it only takes ONE wire to hook it up - from the alternator to the battery. If it takes more than one wire, it is not a one-wire. A three-wire Delco will work with the indicator light.

I don't know what the wiring hookup is on the alternator in question, but I have an article on the internet about alternators that may be of some help, at:

http://www.vtr.org/maintain/alternator-overview.html

The alternator of concern will be wired very similar to that shown on this web page.
Dan Masters

This thread was discussed between 09/02/2003 and 12/02/2003

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