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I just saw a kit to relocate the alternator on my 86 XJS V12 to the air pump bracket. The new alternator in 140 amps and you remove and discard the air pump. I've read that the air pump is useless anyway. Has anyone else done this? I keep having alternator issues, and as everyone knows...it's buried underneath. This seems like a good solution. Thoughts anyone?
I removed the air pump and stuff on all my V12's, basically day 1 of ownership.
No kits etc in those days, no Internet either.
The alternators were all upgraded to a 110amp Bosch unit from the later XJ40 6cyl cars, and left where they were.
I considered moving them up, for about 5 seconds, NAH, Bosch alternator, NEW wiring, what could possible go wrong?, and 20 years later, still doing what they do, no more intervention from me at all.
Clearly, the issue that is causing the fault needs sorting, and the most common on any V12 is bad engine earth, so extra, added earth straps, is a must in my opinion. That sorted all sorts of oddities on the PreHE Sedan.
Last edited by Grant Francis; 10-31-2017 at 04:59 AM.
I removed the air pump and stuff on all my V12's, basically day 1 of ownership.
No kits etc in those days, no Internet either.
The alternators were all upgraded to a 110amp Bosch unit from the later XJ40 6cyl cars, and left where they were.
I considered moving them up, for about 5 seconds, NAH, Bosch alternator, NEW wiring, what could possible go wrong?, and 20 years later, still doing what they do, no more intervention from me at all.
Clearly, the issue that is causing the fault needs sorting, and the most common on any V12 is bad engine earth, so extra, added earth straps, is a must in my opinion. That sorted all sorts of oddities on the PreHE Sedan.
Can I simply switch to the Bosch unit instead of the 75 amp Delco? Is it one wire? Also where is the earth/ground strap you mention? Here is the kit I'm considering.
Your up there, and things available a very different. Plus its been years, and XJ40's, even down here, in wrecking yards are thin at best. Back then, there were 2 or 3 in any yard anywhere.
All I did was aquired the alternator, and the long thru mounting bolt (10mm diam), and removed mine. The thru bolt on mine was 8mm, so the bracket came off, drilled the hole to suit the 10mm bolt, refitted, dropped the alternator in, fitted the original belt, and the adjuster. The wiring was simple, as it was the same as the old Lucas. I added an extra earth wire to the chassis bolt nearby, and a Power wire direct to the battery post on the firewall just under the brake booster (RHD).
The adjuster was sorted with a Jaguar OE idler arm and pulley, that I stole. You would probably have to make something these days, NOT hard, just think outside the box, simple. Toyota Landcruiser Diesel has a bracket and idler that looks close.
The earth strap/s of the V12 are hidden around the LH engine mount. 1st is engine to subframe, 2nd is subframe to chassis. They are crap, and always were. I use simple eye to eye battery cable, of whatever length I need, and fit 2 from the engine direct to the chassis. Usually engine mount bracket to subframe rear sandwich mount bolt, one on each side.
I do know most USA people use Delco stuff, coz it is as common as Bosch down here. I know ZIP about mounting Delco for obvious reasons.
The last 3 I did had the multi rib pulley on the "new" alternator, NO good, so replaced it with a V pulley from another Bosch alternator. GOOD thing here is that ALL Bosch alternators of those days had the same shaft diameter, very clever this Bosch mob.
Looking at the Hitachi alternator on my X300, I reckon that would make a sweet fit up to a V12, Pulley could be a challenge, but I dont have a V12 at the moment to go and experiment. Lots of alternatives out there, just gotta think outside that box a tad more.
Last edited by Grant Francis; 10-31-2017 at 08:26 AM.
Reason: spelling still sucks
Can I simply switch to the Bosch unit instead of the 75 amp Delco? Is it one wire? Also where is the earth/ground strap you mention? Here is the kit I'm considering.
could I bother you for a link to that alt? Google is burying me in close but wrong results.
could I bother you for a link to that alt? Google is burying me in close but wrong results.
You just ask for the 115 amp alt from the later v12 XJSs. The swap the grooved pulley (if it comes with one0 for the V belt pulley off the old one. Use a few washers if needed to align the pulley and the crankshaft pulley. As Grant mentioned, you need a long 10mm diameter bolt and to drill out the amp bracket that is easily unbolted from the engine to accept the wider bolt diameter. I have done this and it solves all problems.
You just ask for the 115 amp alt from the later v12 XJSs. The swap the grooved pulley (if it comes with one0 for the V belt pulley off the old one. Use a few washers if needed to align the pulley and the crankshaft pulley. As Grant mentioned, you need a long 10mm diameter bolt and to drill out the amp bracket that is easily unbolted from the engine to accept the wider bolt diameter. I have done this and it solves all problems.
I already have the 115A from later models, and had the proper pulley ( different shaft dia. ) fitted. But I would still like a link to this setup!
The earth strap/s of the V12 are hidden around the LH engine mount. 1st is engine to subframe, 2nd is subframe to chassis. They are crap, and always were. I use simple eye to eye battery cable, of whatever length I need, and fit 2 from the engine direct to the chassis. Usually engine mount bracket to subframe rear sandwich mount bolt, one on each side.
Redundant grounds: a "mod" everyone should very strongly consider.
Add redundant grounds to engine and instruments, methodically find and clean all other grounds......and you've preemptively solved about 80% of the much ballyhooed "Lucas, Prince of Darkness" mysteries.
I concur with Grant and Doug...ground ground ground! Clean the ground connections you can find, and add some more while your at it. Ground straps are cheap, and it's not hard to do.
I took my air pump off and hung a Sanden compressor on it, allowing me to get rid the the stock A/C compressor, which at the very least makes things a bit easier to work on, as well as improving the appearance of the engine compartment.
One thing you might consider (and I wish I had done it) is to remove the diodes from the new alternator and put them somewhere cooler, and put a small fan on them. Palm discusses this in his book. When I replaced my original alternator, I didn't bother with it thinking "that would never happen to me", but 6 months later I was removing my "new" alternator because of a bad diode. It would be a bit of work to do, but certainly no more than having to pull the alternator completely out. Just a thought.
very interested in removing the air pump and moving alternator to its location. Can anyone tell us there this kit is from? Does it include a tensionor? (I assume a tensioner takes the place of where the alternator was mounted?)
very interested in removing the air pump and moving alternator to its location. Can anyone tell us there this kit is from? Does it include a tensionor? (I assume a tensioner takes the place of where the alternator was mounted?)
Powermaster of California makes the kit. There was one on Ebay recently with a 140 amp alternator. Allegedly all you do is remove the air pump, fit the kit in its place, rewire a longer lead and snip the old alternator belt. I wouldn't personally do it...but who knows?
I'm surprised people seem like they haven't heard any kits for this before. Doesn't the guy that does the "quarterbreed conversions" also offer GM alternator kits?
I've had belts go out and both times its screwed with my voltage regulator. Otherwise the Lucas unit seems fine. PITA of a job though. I despise having to just change the alt belt because its the last one and the adjuster goes flat-by-flat
My car does not have the air pump but an idler pulley in its place which carries the AC belt. I would assume the air pump also carries the AC belt. So if you relocate the alternator to the airpump/idler location the AC belt would drive the alternator.
Also the one thing that kills alternator regulator/diodes is HEAT keep the alternator clean of oil which dust collects on and your alternator should last the rest of the life of the car. If you do relocate the diodes and regulator put them on a heat sink you do not need a fan to blow on them if heat sinked properly.
10-30-2017, 05:05 PM
Remove air pump and relocate alternator?
