Alternative Alternator

GRTV8

Well-Known Member
#1
Ive just picked up a new unboxed alternator for my 72 P6b
old one has a worn stator , is not charging ,so is basically snafu.
Local Repco agent have matched old with new alternator except it chucks out 65amp. wich is 15amp more than my old one.
Is this extra power output OK?
Limited knowledge on electricity and dont want to create a problem in the harness or other dark place that carries hot wires.
thanks
Gerald
 

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Tom W

Active Member
#2
It will only supply what the car needs, so nominally, it should be fine. The maximum output will be at a reasonably high rpm, so you’d need to check the output curves of both to see if you get any benefit at idle.

The risk is if you have a battery internal fault that causes a big draw, the new alternator can supply more current, which may cook the wiring, whereas the old one could have been ok.
 

GRTV8

Well-Known Member
#3
Thanks for your reply Tom W
Now my dilemma unfolds. The instruction sheet is written by a moron.
My old Alt had two terminals .yellow/black wire and solid black wire.
The new Alt has three terminals. Im thinking "W" on the edge is an earth , Im sure the solid black wire goes on B+ terminal at bottom of picture , but where does the Yellow /Brown wire go. Is it on the "?" terminal or the "W" terminal
Just checking before I blow the ghost of Lord Lucas to hell.
 

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Last edited:

roverp480

Active Member
#4
Cannot you ask Repco what the termination is ? . Found this on the web https://www.qxcomponents.co.uk/tech.pdf. It looks as though its the two terminals inside the black plastic area that are used. (LUCAS A127 stud termination)
The wires on your loom should be brown ( Thick) output lead and Brown with Yellow trace ( thin) warning light , I assume the brown had turned black with age
 

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Tom W

Active Member
#5
The W terminal is to get a tacho to work on a diesel. You don’t need that, don’t connect anything to it.

Your original alternator isn’t original, being Bosch, but they should both connect the same. B+ is the main battery terminal, the other is the one connected to the warning light.
 

GRTV8

Well-Known Member
#6
Cannot you ask Repco what the termination is ? . Found this on the web https://www.qxcomponents.co.uk/tech.pdf. It looks as though its the two terminals inside the black plastic area that are used. (LUCAS A127 stud termination)
The wires on your loom should be brown ( Thick) output lead and Brown with Yellow trace ( thin) warning light , I assume the brown had turned black with age
Thanks roverp480
Very helpful - makes total sense
You should have written the instruction sheet
 

GRTV8

Well-Known Member
#7
The W terminal is to get a tacho to work on a diesel. You don’t need that, don’t connect anything to it.

Your original alternator isn’t original, being Bosch, but they should both connect the same. B+ is the main battery terminal, the other is the one connected to the warning light.
Thanks Tom W
Yes my old knackered alternator is a replacement for the original Lucas.
You and roverp480 have made sense of the terminals.
Im not happy the "W" post will be live when operating. I'll insulate that one.
The new OEX alternator is about half the price of a Bosch replacement. I did a quick google search and the OEX seems to check out in the reviews. They just need to sort their instruction sheet.
part # for the "OEX" is LXA119 - for anyone else needing to sort an alternative alternator.
cheers mate
Gerald
 
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