Hi all,

More little niggles with my 76 S2.

I am not sure what manufacturer my alternator is, the only markings I can see are on the attached regulator, HUCO 130670

For the last couple of weeks the alternator has not started charging properly in the mornings. The gauge has sat over at 12V and the ign light has been on faintly. for the first week if I revved the car to around 3,000rpm the light would go out and the alternator would charge to a little over 13V. When driving home in the afternoon after sitting in the sun the car would generally start charging properly when I started it up.

For the last couple of days even after I have revved the engine up to get the light out the alternator has then failed again within the first 10 minutes of driving, although after 10min or so it will stay charging.

As recommended I cleaned the small trigger (I assume) connection on the alternator with emmery paper and contact cleaner and made sure the connection was nice and tight but this has made no difference. My best guesses are as follows:

damage to trigger wire

poor connection at other end of trigger wire (where does it go?)

short in regulator

worn brushes (I add this one only because the previous owner used to replace the brushes quite regularly)

Any suggestions? I'm going away on a big trip in 3 days and don't want to have to worry about this.

 

originally it must have been a Lucas alt. I would get a replacement alternator, the car deserves it and so do you. (have it bench-tested and/or rebuilt).

 

Seems quite likely. The car is not playing nice at the moment. While looking at the alternator I spotted a leak in the short hose on the top left side of the radiator. In replacing that I managed to short out one of the aftermarket relays fitted for the headlights, destroying the relay. I also had to cut a replacement section of hose for the short connector from one of the hoses that goes to the cap on top of the engine as it was after hours and I had no spare in the right size. After doing this and driving home before it got dark enough to use my now non-existent headlights I discovered when I parked at home there is now a slight hiss of pressure coming from either the cap on the engine head or the hose I shortened to it

I am leaving Saturday morning for a 900km drive up the coast and really want to take this car but it really doesn't seem to want to go!

 

Speaking solely on my experience with another Lucas automotive circuit set in an MG B -- get it replaced with a GM based equivalent. I think you can get them at 'broken kitty'.

Oh: and clean every connection you see when you get into a project like this. Just out of good habit.

 

IMHO there is nothing fundamentally wrong with Lucas alternators. In my experience they are as long lasting and reliable as any other.

Until they are rebuilt, that is.

Once an alternator of *any* brand is rebuilt all bets are off. Future perormance and reliability is much more dependant on the quality of the rebuild than the name brand of the component.

Great idea to clean any and all electrical connections as you go. Getting into this habit will pre-emptively solve the majority of the dreaded and ballyhooed Lucas nightmares! :-)

Cheers
DD

 

I replaced my original Lucas alt with the GMalt kit and new alternator from broken kitty. I don't know if the alternator I got was bad but it does not perform as good as the Lucas in that the GM alt does not reach the 13V mark in the gauge, especially with the a/c running, or with headlights on; in fact the gauge goes down (left) as you turn accessories on, compared to the Lucas which always remained steady at 13V no matter what load you threw at it. Fortunately, I saved the original Lucas which had nothing wrong with it, I just fell for the "more amps is better" pitch. I keep saying I'm going to replace the GM alt with the original Lucas alt but the job is such a pita I keep postponing it. But I promise here and now, I'm going back to the Lucas. (observe I did not say WHEN).

 

Jose:

You may well have a Lucas unit in better condition than the Delco. Or, it may be a matter of pulley ratio. As Doug says, rebuilds vary widely in quality. I was in a shop that did that type of work. reminded me that if one enjpoys sausage, never go into a sausage factory!!!

And, I really don't have much confidnce in the fascia guage other than as an indicator, certainly not a measurement device of much accuracy.


I made a patch cord that connects at the cigar receptacle to my digital VOM. Then, I can read in real time under various conditions.

Devilish:

After market headlamp relays? Oh, me. Perhaps properly installed, OK. But, is the original big Hella still in the circuit. Yay, a relay triggering relays??? Or was it abandoned in favor of theafter markets?

The exciter wire goes to the lamp in the dash. Open and check for continuity, voltage and resistance.

I'd go on the trip. Just take a spare fully charged battery. In emergency, it will get yopu home. And, of course, the rule. If you have it you will not need it. Naturally, the onverse is equally valid.

Go for it and enjoy

PS download the lamp schematic for your car. Captainjaguarscathouse.com, I think, google for it, if not, an Aus place.

Or failing thst PM me and I'll scan the page from my S57 book.

 

Another thing that may cause the same symptoms is a failing battery, Easy to get checked. At least hat would rule that out.

 

JagCad, I confirmed the GM alt pulley size is the same as the Lucas, must be the alternator or the way the GM alternator runs; The alt I purchased from John's Cars was new, not rebuilt. I don't know, may be the Lucas alt is rigged so it makes the gauge "read" a constant 13V, and it may be the GM is reading the actual voltage under different loads. Overall, I don't think the gauge indicator should go down according to the amount of load, remember, the Lucas didn't do that. The only way to eliminate any doubt is to reinstall the Lucas. Talk about reliable, my '65 S type still has the original Lucas Generator, dated 9/64, and it keeps going. Only trouble is it can't keep up with my 100 watt each spot lamps!

 

Thanks,

Yes I believe the relays were put in when the 100W high beams were fitted, so as far as I can tell the original big relay is still there but there are some newer higher amp relays run next to it,from the looks relay-triggering-relay :P

 

Had a tame auto elec take a 5sec look and he was pretty certain of alternator rather than battery failing. Have had no starting issues battery power wise

 

Well I did the trip. All the way up the alternator played up, getting worse and worse, I tried playing with the black thin wire assuming it was the trigger, cut the connection and crimped a new one on the side of the road but to no avail.

When I got up there I removed the regulator from the back of the alternator (a Huco unit which screws to the back), and a small black capacitor with a dodgy looking wire. cleaned up the capacitor and refitted, tightened the connections of the regulator and screwed the regulator back on and it worked like it had when I bought it, charged nicely for the rest of the trip and all the way home.

Today I head back to work and it's playing up all over again....

 

Had a similar problem with my S2 XJ6 . Removed the alternator and took it to auto electrician. He took it apart and found a screw with stripped thread holding a diode?,inside rear cover. That was 35 years ago, so details are sketchy.

 

fingers crossed it is something like that. Would love to know what the external capacitor is for? Alternator is behaving in the last few days again so I am very confused.

 

External capacitor is to stop interference with radio; can be removed.

 

That's what the local parts store said when I mentioned it, was just curious. What does it plug in to?