Hi there,

I'm trying to help my uncle rewiring his XK150 early. It was in a very poor state and quite incomplete, but the rebuilding is going quite well. We've got a nice new good quality wiring loom, but it's made for the original setup. (+ground & generator)

There is an rebuild motor in it, with an alternator instead of the old generator. This requires changing the car to neg. ground. No problem so far. (swap coil wires, amp.meter and diode of the fuelpump)

But wiring the new alternator (2 wire connections on alternator, yellow (charge) & yellow-green (field) into the car the right way seems to me like a bit of a problem. I want to make it look all the way original. So I was thinking of using the old voltage regulator and wire everything inside that the right way. The yellow alternator wire seems to me quite thin too.

Has anybody done this before? All info is welcome, explaned with wiring diagrams would be great!

 

Yes I replaced the Generator with a alternator in my XK150.
The old regulator is just there for the looks, and cant be used for the alternator.
And you should NOT be connect it anymore, ( I removed all the internals )
I used a alternator with build in regulator, so 2 wires, just like yours
The Yellow wire is for the light on the Dash.
The other wire Brown/white should be used for Charge.
Regards, Peter Jan ( Xk150fhc )

 

Hello peter jan, sorry for my late reply, but thanks for yours! i've been away for a while.
Info specific for the xk150 on this subject is hard to find.
Do maybe have a picture of the fuse box wiring and one from how you've wired the charging wires to the old regulator? I will also use it for the looks and remove al the internals....
I have a big yellow wire and a thinner yellow-green wire coming from the alternator and from the dash and fusebox some brown and white ones. I really would like to see how you've done that.
Hope you can help me out!

 

Hello,

I made a modified wire schematic, attached to this reply.
I also have the new wiring loom for the old generator.
buts it's easy to modify.
The old voltage regulator internals are removed.
Have put 2 relay's in there, but you can't see that.( fog lights and Horns )
You can't actually see the connections of the regulator, as the cover for the fusebox is in front of it.

 

Hello,

This comes a bit late, but if you are still interested in this issue . . . .

I just completed restoration of and early XK150 fhc. My goal was to produce as modern a driver as possible but to make sure that all upgrades were sympathetic, of which there many--5-speed transmission, upgraded cooling system with electric fan, upgraded starter, street performance cams, boosted compression, enlarged valves, tappet retainers, lighter vibration damper, slightly wider wire wheels with radial tires, sound system, conversion to negative ground and alternator (see below as this is what pertains to your thread), and electronic ignition.

The only departure was replacement of the 2 SU carburetors with 3-45 DCOE Weber (accompanied by a more adequate fuel pump). No particular reason. It's just something I have always wanted. It wasn't easy because most Weber setups for XK's are made for the straight port head and I had the earlier B-type head. However, I eventually found a manifold that was made for the application.

The car is an absolute thrill to drive and turns a lot of heads. People stop me and ask to take photos.

To return to your subject, you have probably already sorted out the wiring issues and come up with your own solution regarding the voltage regulator. I just went "around" the regulator, butted the armature wire (large yellow) to the charge wire (large brown) and the field wire (small yellow) to the generator light (small yellow/white) and tucked them below the regulator, behind the fuse box, out of site. The voltage regulator is now just for looks.

What I have to add that might interest you is the alternator, itself. Since you were going to so much trouble to retain an original look in connection with the voltage regulator, you might be troubled by the look of the alternator. It is a dead give-away of a non-original car, but a necessity for most owners who want to actually drive their cars. Don Allen in Florence, Oregon makes what he calls a "Gener-Nator" (www.gener-nator.com). Send him your old generator, and he will build an alternator into it. Or, if you don't have your old generator or don't want to give it up, he will provide you with one at a little extra cost. Voila! You have preserved the original look of the car but with a modern, negative ground alternator.

Don is also very helpful. He furnished wiring instructions and is available by phone for technical assistance (541-902-2255).

Hope you are enjoying your 150. Yes, the 120's are the purest's XK, but the 150's are practical drivers 55 years later. It took me 7 years but was worth it.