Hi Guys:
I replaced my Lucas alternator this week end with a Hitachi 14255. I did the hook with tech help from Coolcat and Mr Livingston. I left the VR and the 3A relay in place. When I start the engine the ignition light comes on until I rev the car up. The light then goes off and stays off. The problem is that I'm not showing any charge on the amps gauge. The needle moves to the very end of the red no charge area and goes no further.
The belt is tight in the new custom bracket. The 1 yr old batttery is fully charged. I taped up all the un used wires on the standard Lucas alt wiring. I used a 14Ga wire for the direct wire from "S" connector to the "+" side of my battery. Should this have been heavier wire? Maybe a DOA alternator out of the box? I drove the car for about 15 minutes with the revs up but it didn't change. I'm stumped. Thanks for any insight.
Best/ Jack

Submitted by SC38-21185J on Mon, 07/19/2010 - 21:59

No offense to anyone, but this can-o-worm is exactly what happens when you stray away from original equipment and start cutting, mixing, omitting, and cross-connecting wires. You probably wouldn't have had any of these problems if you had just had your original rebuilt for about 50 bucks. And I pity the next owner who has to figure all this out.

Patrick

Submitted by mfrank@westnet.com on Mon, 07/19/2010 - 21:22

I'm a bit puzzled. Where is the alternator end of the AL wire? It should be installed on the "L" terminal of the Hitachi. You can plug the F+ lead (NOT the F-) into the "S" terminal, but this shouldn't be necessary. It sounds to me like you have the wrong wire plugged into L. Whatever you have plugged into L had better switch off when you turn off the ignition, or you can end up with a nice bonfire.

I've sent you a connection diagram for the Hitachi by email.

Submitted by tvtom@sbcglobal.net on Mon, 07/19/2010 - 13:06

Edited on 2010-07-24 13:39:17

Edited on 2010-07-24 13:37:24

I have never felt that I was really up-to-speed regarding the functioning of one-wire alternators so I put one-wire alternators into my search engine and selected madelectrical.com from the results. Wow, that resulted in a LOT of valuable information when I clicked on the Elecrical Tech tab there.

You may not wish to go as deep into the theory as is explored in Part 3 but Part 1 is helpful and Part 2 points out a number of things to be considered in changing from a three-wre to a one-wire alternator. Certainly not as simple as one (me included) would think.

Submitted by jack@deatonyac… on Mon, 07/19/2010 - 11:54

Hi Mike:
I took an early lunch and checked out your suggestions. With the engine running I'm getting 11.5 volts on my meter from across the battery terminals. I disconnected the AL and WL from the 3AW relay and jumped them together. Now when I start the engine the ignition light comes on and stays on. DOA alternator?
Many Thanks/ Jack Coulter

Submitted by mfrank@westnet.com on Mon, 07/19/2010 - 08:59

It's ok to leave the VR, alternator relay, and the 3AW in place. The alternator relay and VR can remain connected for appearance sake, but tape off the F+ and F1 leads at the alternator. Disconnect the AL and WL leads at the 3AW, and jumper these together. The
3AW ground can remain as is. There is no need to replace the stock B+ wire, but if you do, you want at least 10g. Make sure this wire terminates at the positive stud behind the battery. Check the gauge reading by measuring voltage across the battery terminals. It should be at least 13.5v when the car is running.

If everything is wired correctly, and you still have no charge, the alternator is a dud.

Submitted by SE98-32482CJ on Mon, 07/19/2010 - 06:25

Jack if this is your 1970 car you do not have an AMP gauge--it is a battery volt gauge and seems to reflect a no charge situation. As this is not a stock setup I will not be a lot of help but I think that you have gone to a one wire setup--correct? If so then assuming the Alt is good it is not being energized--check the relay (if used) and check the voltage at the battery while running--