While I have the Mk10 engine bay empty and waiting on the machine shop for engine work, I’m repairing and upgrading. I’d like to replace the existing Lucas alternator with a new unit, but have been frustrated in trying to find something off the shelf that fits without building a new bracket. I have built brackets for the alternator conversions on my Mk2 and 120, but they won’t work with the ac unit on the Mk10. I’ve seen the Universal Lucas mentioned several times (see photo), but I don’t see how it could bolt up to the original bracket (below). Am I looking at the right alternator? My local flaps was not able to find a GM alternator that has both the right pulley spacing and a workable flange. Anybody know of something that will work?
Thanks, Ron
I may have had to change the mounting bracket to the block as well, to an XJ item, cant remember, I will post up a pic soon,
It was a real tight fit, I needed a curved adjuster, although possibly the threaded later XJ adjuster would work
and a non-standard belt
It does do away with all the external regulation parts, and has given me no trouble in the 5 or so years I have had it fitted
I do not think the original 43Amp AC11 is sufficient for an A/C vehicle
You can use MANY GM alts, one wire or 3 but you have to shim the space in the cradle or bracket.
Once its done,you will never look back and after 200,000miles you might need a new one 
gtjoey1314
Since the Lucas Universal is not a bolt-in, I will use a GM alternator, as I have done in the past. The reliability is not what you say, though, as I just replaced the 3 wire GM unit on my Mk2 that has been there only 2K miles - the huge advantage over the original is getting one off the shelf from the local parts store for $50. For the Mk10, it will require making one of the two brackets, as none of the numerous alternators I’ve looked at will accommodate both the pulley offset and the lateral mount hole for the original bracket. Not a a huge deal, but I’ll temporarily put the Lucas back on when the car is recommissioned with it’s new engine and transmission, leave the upgrade for the near future. The alternator is easy enough to change out, and I’ll not be putting the ac system back in for awhile.
I will also be replacing the existing ammeter with a voltmeter, as it is my understanding that the oem meter is not rated for a 70 amp alternator, plus not even the original was a good idea. I can transplant the guts of an xj6 into the ammeter case as I’ve done before, but I think I’ll just buy the Nissonger one for 105$ - so far behind on this car!
I appreciate the insights.
Ron, Anytime, yes rebuilts are spotty but for that money you could buy one for every day of the week
Get a powermaster or gm NEW unit…
Then your done.
Good luck
gtjoey1314
A Smiths XJ voltmeter looks correct