Moss / Lucas Alternator Conversion.....

[justaguy]

Hi All,
I while back my generator on my 1967 Midget (1275 CC) finally gave it up so I decided on an alternator conversion …. I ordered the Lucas kit from Moss & installed it. Alternator would not charge the battery. I took it off & had it tested, Alternator was bad… I got in touch with Moss & they were great, sent a replacement. I installed the new one & it was sending a charge to the battery. BUT now I am having other problems… When running, the tach, & fuel gauge will randomly stop working. Also, when I park the car, there is a constant drain on the battery which completely kills the battery in a very short time.
I have re-checked all of the connections that needed to be done for the regulator re-wiring & everything is secure & correct per installation instructions. It is driving me crazy & making me wish that I had not went with the alternator conversion. The car spends most of its time sitting now because I cannot trust it to consistently charge the battery if I go somewhere. I spent a ton of money on the kit & not been able to drive the car since.
I am not sure but I am thinking that the trouble is somewhere in the voltage regulator end of this??? The regulator is new & worked fine with the generator.
Is it possible to eliminate the regulator all together & go with a one wire alternator? If so, does anyone know what “One Wire” alternator will be the right size to bolt to the brackets that come with the Lucas kit?

Thanks!
J

 

[Trevor Jessie]

The generator voltage regulator should not be used with an alternator that has an internal regulator.

 

[justaguy]

The generator voltage regulator should not be used with an alternator that has an internal regulator.

Agreed, the Moss / Lucas kit came with instructions to re-wire the voltage regulator. I followed the instructions. I do not know the story on the kits alternator but assume that it still required the regulator to stay in place. I would have no problem eliminating it if I knew how to re-wire the car to do it & had an alternator with an internal regulator. The car is LOTS more fun when it is not sitting in the garage.

 

[Trevor Jessie]

Most likely the instructions actually wired around the old regulator(bypassing it and making it superfluous). I suspect that the tach/fuel gauge is unrelated to the alternator swap. When the car is off (and key is removed) I'd unplug the alternator and start looking for a voltage drain. You can do this by disconnecting a battery cable and placing a test light in series between the removed cable and the battery. If it glows then you have some sort of battery drain. Then you start unpluging things one by one until you find what makes the test light go out. Then you figure out why it is causing the battery to drain.

If you have no drain with the alternator unplugged, try it with the alternator plugged in.

Also, double check your wiring around the regulator box.

 

[Guest]

That alternator does (or should) have a regulator in it. To the best of my knowledge there is only one readily avalible one-wire alt.

 

[TR3driver]

The generator voltage regulator should not be used with an alternator that has an internal regulator.

Or even with an alternator that requires an external regulator. The requirements are different and in particular, running an alternator through a cutout relay (which is found in all generator voltage regulators) will likely damage the alternator.

But it is very unlikely that you have an alternator that requires an external regulator. I'll second Trevor, and suggest removing the old regulator entirely, since the bad connection might possibly be inside the box. (I had a similar problem on my TR3A, although it wasn't intermittent.)

If the tach & fuel gauge quit working randomly, then you have a bad connection somewhere. They should continue working for a long time (hours) even if the alternator quits working entirely.

The constant drain could also be a wiring problem, although it might be the alternator. Does the drain stop if you disconnect the wires at the alternator? If so, get the new alternator tested as it may be bad (again).

There are several choices for "one wire" alternators. Unfortunately, I have no idea which one will fit with your conversion kit. But wiring up a more common 3 wire alternator is (or at least should be) trivial. The heavy wire goes to the battery (perhaps through the ammeter if you want to go that way). One of the other two wires goes to the light on the dash; the third wire also goes to the battery (bypassing the ammeter if you went that way).

 

[justaguy]

Or even with an alternator that requires an external regulator. The requirements are different and in particular, running an alternator through a cutout relay (which is found in all generator voltage regulators) will likely damage the alternator.

But it is very unlikely that you have an alternator that requires an external regulator. I'll second Trevor, and suggest removing the old regulator entirely, since the bad connection might possibly be inside the box. (I had a similar problem on my TR3A, although it wasn't intermittent.)

If the tach & fuel gauge quit working randomly, then you have a bad connection somewhere. They should continue working for a long time (hours) even if the alternator quits working entirely.

The constant drain could also be a wiring problem, although it might be the alternator. Does the drain stop if you disconnect the wires at the alternator? If so, get the new alternator tested as it may be bad (again).

There are several choices for "one wire" alternators. Unfortunately, I have no idea which one will fit with your conversion kit. But wiring up a more common 3 wire alternator is (or at least should be) trivial. The heavy wire goes to the battery (perhaps through the ammeter if you want to go that way). One of the other two wires goes to the light on the dash; the third wire also goes to the battery (bypassing the ammeter if you went that way).

Thank you... Would you be able to tell me how to remove the regulator all together? It has a bunch of wires going to/fom it & I do not know which ones to splice/connect to others, ect...

 

[Trevor Jessie]

So... was your car previously positive ground?

 

[justaguy]

So... was your car previously positive ground?

Yep.... converted it a bunch of years back...

 

[Trevor Jessie]

The Moss instructions look correct to me. Does your regulator have spade terminals or screw on?

 

[justaguy]

The Moss instructions look correct to me. Does your regulator have spade terminals or screw on?

Spade

 

[John Kuzman]

Do not know if this will help, but several years ago I helped a friend do a Moss Kit conversion on a '68. Same problem you are experiencing. I took a shot at lifting the ground wire off of the original regulator ( IIRC it was the "E" terminal) and all was fine. Seemed like somehow the Moss wiring allowed a leak to ground through the old regulator.

 

[Trevor Jessie]

If you used that "clip-on-splice", then I would change it to a crimp/solder connection.
Also, does the "ignition light" come on with the key and go off once the car is running?

 

[Trevor Jessie]

Good point John. The Ground connection is certainly not needed for a non-functioning box.

 

[justaguy]

Do not know if this will help, but several years ago I helped a friend do a Moss Kit conversion on a '68. Same problem you are experiencing. I took a shot at lifting the ground wire off of the original regulator ( IIRC it was the "E" terminal) and all was fine. Seemed like somehow the Moss wiring allowed a leak to ground through the old regulator.

I will give it a shot. Do you know if there is any reason at all to keep the existing regulator in place? If it is no longer doing anything useful, I'd like to just remove it completely & splice the wiring together. Extra / un-needed parts just bug me & also provide an extra place for problems to grow...

 

[TR3driver]

It has a bunch of wires going to/fom it & I do not know which ones to splice/connect to others, ect...

Sure, I'll take a stab at it. I've never owned a Midget, but the generator wiring is the same. You'll need to securely bond together all of the wires from the A and A1 terminals, which according to the Midget diagram I found https://www.spritespot.com/Downloads/Workshop Manual/Nc Wiring Diagrams.pdf will be brown and brown/blue. This connection carries power to the entire car, so make sure it is a good, solid connection. Solder or a good clamp-type connector is a must, IMO, this is not the place to be twisting wires or relying on crimp connectors. Something like this would do https://www.madelectrical.com/catalog/cn-1.shtml but I would still solder the wires to the terminals. (Sorry this isn't a very good shot, but hopefully you get the idea)

Disconnect the two brown/yellow wires from terminal D and connect them together (this will become the indicator lamp wiring from the alternator). Or if it is in poor condition as they usually are, you can replace the section to the alternator with new wire.

The black wire (terminal E) can be disconnected and tucked somewhere, or clipped off if you are certain you'll never want to go back. It is just a ground wire, so it doesn't need to be insulated. The brown/green wire (terminal F) can be discarded or ignored.

According to the diagram there is no ammeter, so make up a new heavy gauge wire (10 AWG will do, I used 8 AWG) to run the alternator output to the terminal on the starter solenoid where the battery cable connects. If your alternator has a 'sense' input, you'll need a new wire from it to the solenoid as well (or if you want, just jumper it to the output terminal at the alternator).

Obviously (I hope), you have already converted to negative ground.

 

[justaguy]

I will give it a shot. Do you know if there is any reason at all to keep the existing regulator in place? If it is no longer doing anything useful, I'd like to just remove it completely & splice the wiring together. Extra / un-needed parts just bug me & also provide an extra place for problems to grow...

Sounds easy enough... Time to break out the soldering gun! Thanks a bunch!

 

[nomad]

Not uncommon to blow a diode in the alternator by accidently shorting the hot lead from the alternator or accidently hooking up wiring backward's. My first guess would be a blown diode in the alternator. I believe Lucas alternators are especially sensitive.
Just my .02 but easy to check. If the alternator is disconnected the battery would not drain down. [As mentioned a test light between alt and wire after disconnect will tell you in a hurry.]

Kurt.