Thread: Can you use the guts from a Marelli V8 serpentine alternator to fit a 300 TDI Alt

Yes -
PIcs of a Tdi alternator rebuild

Although the pics are gone, the thread can help with disassembly. You'll find that the rotors are the same. The diode/regulator assembly may have to stay as they can be different according to the age of the respective units.

Thanks Langy

Originally Posted by SPROVER

Im just posting this on behalf of another member.Is it possible to swap the insides from a Rover V8 Serpentine alternator (Marelli)
to fit into the 300 TDI Marelli alternator? Just to keep as a spare or back up.They look the same but the shafts look a little bit different.

I am that other member. I was in Melb on the weekend trying to get an alternator for my 300 TDI. Sprover had one off an early V8. (I think it was a RR) which I purchased. I then picked up a known dud from a wrecker for $10 which was from a V8 disco. Both these were identical to look at except for different width pulley and mounting points. They also looked the same as my TDI except different mounting points again.

When I got home I pulled both apart and they were the same internally. I then removed the one off my disco. When I removed the plastic back it revealed that there were a few differences that would make the guts unchangeable, unless you can remove the outer windings, although I looked at this and I don't think this can be done.

As it turned out the only thing that was wrong with mine was the brushes were worn out. As the brushes are part of the regulator and cannot be removed(and the regulators were different) I was able to graft the good brushes by cutting and soldering the copper braid wire that comes out from the carbon brush. Providing that the internal heat does not melt the solder this should work ok, although I do have reservations due to the fact that they use some type of spot weld to join the braid to the terminal.

Does anyone here have any knowledge on the internal heat V solder melting temp?

Dave.

All the Bosch brushes I have seen/replaced over the years have been soldered, I can't see it being a problem.

50/50 solder starts to melt at 183 degrees C - I reckon that you should be fairly confidant it will hold together in the alternator casing.

Forgetting about the early RRC alternator ( and you've figured out the case differences) you've stumbled across the difference between the 3 bolt and 4 bolt regulator assemblies. (See the attached pics - the whole alternator is the 3 bolt type YLE10113 and the diode assembly by itself is the later 4 bolt AMR4248). The regulator & brush assembly is available although hard to find. I reiterate that I've only swapped rotors - the diode setup has to stay.

As least you'll be able to identify which alternator is which.

Originally Posted by langy

50/50 solder starts to melt at 183 degrees C - I reckon that you should be fairly confidant it will hold together in the alternator casing.

Forgetting about the early RRC alternator ( and you've figured out the case differences) you've stumbled across the difference between the 3 bolt and 4 bolt regulator assemblies. (See the attached pics - the whole alternator is the 3 bolt type YLE10113 and the diode assembly by itself is the later 4 bolt AMR4248). The regulator & brush assembly is available although hard to find. I reiterate that I've only swapped rotors - the diode setup has to stay.

As least you'll be able to identify which alternator is which.

The picture on the left is the same as my TDI 300, which is an AMR 5425.
The pics on the right are the same as the two I purchased off V8's.

Dave.