View Full Version : TR4/4A Alternator Conversion - TR4A

Mickey Richaud
01-16-2010, 06:15 PM
Anyone done one of these? Fellow club member asked me about it today. Info?


01-16-2010, 08:32 PM
What do you need to know, Mickey? I've done several TR3As, shouldn't be any different for a 4A except you won't need to convert to negative ground.

In fact I just picked up an alternator today to put in TS13571L. Didn't get quite the same model shown here


but it's similar.

As I've done before, I'll probably replace the lower mounts with a single long bolt & some suitable spacers (making sure one of the alternator legs can float on it's sleeve). The bracket with the slot for adjustment can be bent to fit. And I'll just bore an original pulley (if necessary) to fit on the alternator shaft, so I can continue to use a wide belt.

This is a "4 wire" alternator, I'm not sure offhand what the 4th wire is for. I'll join the big output terminal together with the brown/white and brown/blue wires at the original control box location. The 'sense' input gets a new wire to the starter solenoid; and the 'lamp' output connects to the small brown/yellow wire that was on the 'D' terminal of the control box (which runs to the warning light on the dash).

The 4th terminal <span style="font-weight: bold">may</span> be supposed to get ignition voltage, in which case I'll run a wire to the fuse block. Got the information around here somewhere, just not handy at the moment.

Mickey Richaud
01-16-2010, 08:53 PM
Thanks, Randall - that's helpful. I think his main question was regarding the pulley/belt issue. I'll email him your post and see if that helps.


01-16-2010, 09:11 PM

There are a couple of old threads lurking on this as well - for a 4a a cheap solution is to get a Delco 10si alternator, around $50-$60. Also, there is a pulley available that will fit the Delco and allow you to keep the wide belt. That's what I currently have in my TR4, its been good for a couple years now.


01-16-2010, 10:21 PM
I had saved this pulley info.


Mickey Richaud
01-17-2010, 07:33 AM
Thanks, guys - Will pass this on as well.