Disco1 alternator no charge?

[Utemad]

Hi all,

This is all on a Disco1 1994 update MY95 serpentine belt 3.9 V8.

Before I pull out and strip my Magnetti Marelli alternator, I've got a question for the good members of the board.

Problem one is it isn't charging. Driving along this morning and the charge light came on and the tacho stopped and dropped to rest position.

I have power to the back of the alternator on the battery cable but only .66v on the D+ wire.

If I connect 12v to the D+ connection then the charge picks up to about 12.8v at idle however it also makes the alternator vibrate slightly and with a dull whine while making the revs drop. It has no effect on the non functioning tacho.

This dull whine and vibration has been noticeable on and off in general driving but I thought it was clutch related for various reasons.

I also suspect it hasn't been charging properly for a little while. I have a Traxide SC-80 and the second battery (tested after the problem today) is measuring about 10.5v and the start battery at 12.1 volts. It is also sometimes a little slow to wind over. Barely noticeable but I did.

The batteries are on charge now in the car.
I've had the alternator apart about 18 months ago to change the bearings so I know how to get it all apart but just after thoughts on the problem. Would rather fix than replace due to expense and not too keen on fiddling with brackets and pulleys to fit an aftermarket job.

Quite similar to this one inside from memory. Surprisingly enough.
http://www.aulro.com/afvb/technical-chatter/25589-pics-tdi-alternator-rebuild.html

I'm getting picked up shortly, thanks to this, to go to a bucks party so won't be doing anything til tomorrow.

Thanks guys for any insight you might have.

I assume it is the regulator but I'll let you guys battle it out :)

[justinc]

Hi justin, its Justin.

The groaning noise you are hearing when you excite it is a problem with the rectifier and/ or rotor shorting to earth. It is cheaper to replace these marelli ones than repair them if the rectifier or rotor is shot.
There is difficulty finding a alternative alternator for these serpentine belt engines due to the mountings, and the requirement to have the belt length remain the same as standard.
Either a good used one, or new, is the best option.

JC

[Utemad]

Thanks Justin.

I've spoken to a mate who has one for a 300Tdi. It works but has shagged bearings apparently. I was hoping to swap out the innards from the 300Tdi alternator to the V8 alternator housing.

Is that feasible?
I guess I'll find out in the morning.

[Utemad]

I have picked up the 300Tdi alternator and interestingly it is a A127IM. The on in the Disco should be an A127 as well. In fact according to Rimmers all Disco1s are A127 something.

Different LR part numbers though. Will find out this afternoon the differences and similarities.

The 300Tdi is AMR5425 made in 02/97\A.

[justinc]

Hey Justo,

Rimmers refer to the pre serpentine belt V8 discos as Disco 1's. They call the update D1 a D2, and a D2 a D'II':mad:
An A127 will fit a non serpentine belt V8.
The A127 has an external fan, the Serpentine model a has an internal fan. You CAN buy a Bosch alt to suit the early D1, because it runs a standard V belt pulley.
Are you SURE the Alt you picked up isn't off a 200Tdi? They also run a v belt pulley and are similar to the A127 V8 ones, different orientation though.
JC

EDIT: I was Wrong, the ALT65 is the one I was thinking of, you are right, the A127 model is the right one. This isn't the first time I've confused the 2, something about similar numbers that aren't similar???

[Utemad]

It definitely came off a 300Tdi as I know the car it came off.

Also the sticker on the alternator in question says

Type: A127IM-100A
Part no.: AMR5425
Date: 02-97/A

It's an internal fan jobbie as is mine. It also still has its little serpentine belt pulley on it. Much smaller pulley than my V8 unit.

I've had both apart though and the innards are close in design but not close enough. So I've put them back together and put the original one back in the car. It charges at about 12.7v at idle with lights off and 12.2v with lights on.
So I'll shop around for another one and put the battery on charge every night til then. This should suffice as I suspect it has not been charging properly for the last week anyway and I haven't been charging it and it didn't go flat.

A guy I just met today has an EF Falcon with an AU motor in it. Said he just did his alternator too. Cost him $30. Gee thanks for that I thought.

So should I ask how much these alternators are worth? :(

[slug_burner]

try here (http://tinyurl.com/6lq6a6)

[Utemad]

Thanks. Just had a look at the website and it is quite ambiguous in regards to Discovery models but I'll ring them tomorrow.

[Utemad]

EDIT: I was Wrong, the ALT65 is the one I was thinking of, you are right, the A127 model is the right one. This isn't the first time I've confused the 2, something about similar numbers that aren't similar???

With the amount of LR part numbers floating around your head it was bound to happen sooner or later :D

Disregard the 2nd battery voltage problem too. Just discovered it is stuffed. 10.5 volts as soon as you remove the charger but it won't take any current when charger is connected and jumps straight to 12.5v or so..

[Tank]

Justin, try some Inox Battery conditioner before you dump battery, it may be "sulphated up", may restore it , Regards Frank.

[Utemad]

Thanks for all the help guys.

I'm going to replace it now.

New thread here about genuine or aftermarket. Any input would be appreciated.

http://www.aulro.com/afvb/technical-chatter/67365-disco1-v8-alternator-aftermarket.html#post853025