Ford alternator-how to needed

[Roy Fellingham]

Hi, can someone email me the idiots guide to replacing the original P5b alternator with a modern one and losing the original boxes? Wiring diagram preferably included please along with suitable alternator model(s) that can be used. I know it was in one of the old issues of the magazine but unfortunately my magazines are spread out all over the place in various boxes etc...
rov3r at ntlworld dot com
Many thanks

[Smallfry]

You really need to stick to a Lucas alternator as all the mountings are the same. Then you have the choice of either a battery sensed, or a machine sensed unit. You can fit either, but the machine sensed type is simpler............

The biggest problem with this is getting the belt alignment correct.

I would suggest an A127 which is 45 amps. You dont really need more, but if you insist get an A133 which varies around 70 amps

DONT buy an old ACR series unit. They are low output, unreliable, and wear out their brushes in a strange way.

Wiring is no problem. I can help with that once you tell me what you have.

[Roy of the Rovers]

Thanks smallfry, what sort of cost are we looking at for these? As an aside to this, I also have a mid eighties 3.5 range rover one in the garage. Would this do the same job? Mind you if the price is reasonable on the others I may as well get new..

[Roy of the Rovers]

Smallfry, can you give me a generic how to, I'm not going to get round to this for a while and I can print it off ready for the time. There must be a standard way of wiring a modern alternator to bypass the old wiring, I'd imagine its the same for all modern ones.
Thanks
Roy

[Deleted]

The wiring is very simple on modern machine sensed types - the Field connections are merely disconnected at the Regulator box 4TR (Square red or black on the bulkhead) and the warning light 3AW can unplugged and bridge the two cables of the three in the plug which are not earthed (black is earth but the other two which are blue/brown and brown yellow but on old fabric covered cable they may have gone black as well).

Its also better to disconnect the 6RA relay as well - tape up all loose Lucars including the redundant filed connections + and - at the alternator end.

The effect of this will be to leave the heavy battery cable and the Yellow/Brown warning light cable at the Alternator end. You should buy a new plug to suit the alternator and properly crimp the terminals on. If the main alternator terminal crimps are poor and loose they will easily overheat with the load. The cable should be heavy enough.

[Smallfry]

Basically Roy, what you are trying to achieve is......

The main output wire(s) from the alternator should go direct to the main battery side of the starter solenoid.

The small warning lamp wire should go directly to the warning lamp, bypassing the control unit (the one that looks like a flasher unit)

Most modern units will have a "bolt on" main terminal intead of the older Lucas plug in type, which is called an "AMP" terminal. As Mr T-Bar said, always make the best joints you can, and make sure any cable you use is up to the job. If you use the RR alternator, I would have concerns about using the original output cable from the old 11AC unit which only had to handle 45 amps max, whereas the RR one will put out either 70 or 100 amps. I know it doesnt put out that much all the time, but its better to be safe than sorry !

[Roy of the Rovers]

Much appreciated thanks