18ACR alternator

[John L]

Following on from the thread about batteries, I'm toying with fitting an 18ACR alternator, as I'm no real electrician, what/how do I take out the wing mounted regulator and wire in the new 18ACR, I know I will need the plug kit, but sure how the wiring should then go, would a kind member draw up a wiring diagram, for before and after please?

John

[Andy Moltu]

If it's a 6 the regulator is part of the alternator and should be a straight swap.

[John L]

Its a CP 15AC and not R, with a separate control unit on the left hand wing.

[Mike C]

Good man  Vitessesteve, - have a look at page 36 of this from his website :

https://app.box.com/s/1grrnsn3ez49a2rlej9h4d5zj87bh1s3

 

[RobH]

The wiring is really simple John. After disconnecting your old control box you will have four wires.

Remove the Brown/Red wire and the Brown/Green wire,  as these are no longer necessary. (The B/R is connected to the starter solenoid so is live. Best to disconnect both ends and tape them up if you can't remove it completely)

The Brown/Yellow wires will be needed but should be joined and sleeved where they were both connected to the regulator if necessary, as you need this to reach the alternator. 

Your old alternator will have a black earth wire - this is not needed. 

 

 The new alternator will have a single three-way socket connection.

The small spade connection goes to the ignition lamp which is the old Brown/Yellow wire. 

The two large spade connections are both alternator output and one should be connected to the old thick Brown/White wire (which runs from the alternator to the ammeter). You may want to beef up that wire though because of the extra current available from the alternator. You could replace it with a thicker single wire or run a new one in parallel and connect to the second large alternator terminal.

That's it. Good luck.  

Edited June 27, 2020 by RobH

[John L]

Thanks Rob,  I'm sure I should be able to follow that, its great!

John

[Andy Moltu]

Forgot that a few CPs came out with a regulator.

[stuart]

11 hours ago, Andy Moltu said:

Forgot that a few CPs came out with a regulator.

All early cars up to end of 1970.

Stuart.

[Andy Moltu]

Not all early cars.

Mine is a 69 and it never had a regulator. I t was still on the original loom 33 years ago when I got it which had no signs of having been altered. I knew the car for 7 years before that.

I suppose it may have had an entire loom and had the regulator removed in the first 10 years of its life.

[astontr6]

17 hours ago, Andy Moltu said:

Not all early cars.

Mine is a 69 and it never had a regulator. I t was still on the original loom 33 years ago when I got it which had no signs of having been altered. I knew the car for 7 years before that.

I suppose it may have had an entire loom and had the regulator removed in the first 10 years of its life.

On the early 15ACR's with integral regulators this was a weak point as I had a 1970 TR with one. The Alternator regulator failed a number of times and I used to go to a main Lucas dealer who would change the whole unit without question as Lucas had problems with these and tried to get away with using cheap components. In the end he told me to use an 18 ACR as it was ruggedized and was a straight bolt on job.  I only had to pay the difference, never had anymore trouble. But I did notice the difference in electrical performance straight away.

Bruce.