Ignition Light on After Distributor Rebuild

[Gordon Harrower]

I'm hoping there's a simple explanation for this. I had my 1963 3-Litre's distributor professionally rebuilt, and now the ignition light stays on all the time. I haven't had a chance to check all the earthing spots Phil enumerates elsewhere (to diagnose a glowing ignition light), but because this is the only change I've made, I'm wondering if it's related or a coincidence. Any quick thoughts?

Thanks,

Gordon.

[dmaxwell]

I would think it was a coincidence. Did you or the shop remove/replace the distributor? I think the ignition wire comes from the regulator and may have been knocked loose when the Distributor was removed or replaced.

David

[Ken Nelson]

Hi Gordon;
The ignition light doesn't really deal with the distributor and ignition. It goes on when you turn on the key, but indicates the charging system of the car, ie the generator and the voltage regulator's function. When the generator is making current and the regulator working to keep the battery up to charge, it goes out. So I would guess that you may have knocked another wire loose somewhere, or that the generator or voltage regulator are bad. Check the manual for ways to test these if need be.
Ken

[Phil Nottingham]

I agree - the wiring being already old and brittle can esaliy break as are the connections could have been damaged - its easy to test by using jumper cables from dynamo to rebulator (the D terminal does to the big dyn - F terminal goes to the little dyno one and also repair/replace. The warning light & charging ciruit relies on good earth at the regulator box as well - clean all.

DO NOT try to adjust the regulator box without instruments and following the WSM EXACTLY

[Gordon Harrower]

Gents,

After reading your posts and considering all this, I think you're on the right track. I'm only beginning to see both how brittle are some of the wires, and how little it takes to damage them or knock them askew accidentally. I'll do some testing and let you know how it goes.

Thanks,

Gordon.

[trymes]

I'm again offering advice on a subject with which I am unfamiliar, so my apologies if I am way off, but:

If the ignition light on your P5 is anything like those on my Riley or MG, then one side is connected to the generator and the other is connected to the battery (I'm generalizing here, and I'm no electrical engineer in case it isn't obvious...).

• When you turn on the key and the engine isn't running, current flows from the battery side and to the ground, lighting the light.
  
• When the engine is running, the generator/alternator provides equal voltage to the other side of the bulb, preventing any current from running through the bulb, turning it off.

As others have mentioned, if any of the wires under the bonnet that comprise that circuit got disconnected while the dizzy was being wrestled out of the engine, then only one side of the circuit will be sending current to the light, causing it to light all the time. If the battery side is disconnected, the light will not come on when the key is on and the engine stopped, but it will light when the engine is running. If the Generator side is unplugged, then the light will always be on.

I'd definitely start at the voltage regulator, as others have suggested.

Tom

[Gordon Harrower]

Gents,

Tested the dynamo output today and was getting just a volt or two, so it's off to be rebuilt. Thanks, as always, for your help and suggestions.

Gordon.

[Gordon Harrower]

Update. I took the generator to be rebuilt by a shop that's successfully rebuilt many components for me in the past. The guy told me today that my dynamo is "totally fried," with no salvageable inner parts.

Does anyone know what other cars used the same generator, or if it's possible to get the armature and field separately? The only complication is that I need to be able to attach the power-steering pump to it. One of the Rover guys here (U.S.) is trying to convince me to put in an alternator, but I'm resisting.

Thanks, Gordon.

[dmaxwell]

Gordon,

I've got the generator from my P5 that I don't need but it does not (and never has had) the pump on the back. Can it be used to fix yours?

David

[Gordon Harrower]

Hi David,

According to the parts manual, there was only one for the Mk II, so I guess so. The guy said he could put the plate with the PSP studs onto the back of another generator if I found one, the field coil and the armature being the critical parts.

Let's see what Phil and the gang say, and take it from there. I appreciate the offer.

Gordon.

[Phil Nottingham]

The Lucas dynamo was a modified standard C45 with different end cap for the pump fixing lugs and an extended armature with a slot to drive the pump it was only used on Mk2 and Mk3's with power steering - some Mk2 saloons had manual.

I recall the same pump/dynamo was used on BMC Austin Westminster A110 Farina of the 1960's

An alternator conversion would be interesting as the pump would have to be resited somewhere and I cannot see where room exists unless a remote electric can be sourced

[Gordon Harrower]

Phil,

I'm confused because the parts catalog says it's a C42, that the Mk I has a C45. In any case, I think I have a lead on a used one here. It appears that the XKE uses a C42 as well, but might not have the modifications you mention. I'm going to stop by Moss Motors just to increase my frustration level.

Gordon.

[dmaxwell]

If the 3.8 E Type uses the same generator, I'll have two spares as I converted my '62 E Type to negative ground many years ago and being a good pack rat (genes from both parents) am sure I still have it plus the one from the '65 MkIIc.
David

[Gordon Harrower]

Hi David,

This is one of those arcane Rover situations. From what I can gather, while other cars, such as Jaguar and the 2.6 Land Rover, share the base-model dynamo, the one with power steering was made only for the Rover 3 Litre with PS.

The guy at the electrical shop said he hasn't even found a reference to the armature and field coil among all his resources. He showed me the old ones and they were, indeed, fried. He guesses that the voltage regulator went bad, causing this damage.

So, thanks very much, but it appears I need an exact replacement. Dirk Burrowes thinks he might have one, so that's my latest hope.

Gordon.

[Phil Nottingham]

Surely both field coils and armature can be rewound locally?

[Gordon Harrower]

Perhaps it's a lost art around here, but this guy said the old ones are too damaged, as if it had actually burned for quite some time. Dirk said he's got one he'll send me, so that's a great start. I'd better replace the regulator, too.

Gordon.

[dmaxwell]

If you can get the right one, it will probably be better than trying to cobble one together.

David

[Phil Nottingham]

The Lucas RB340 regulator was commonly used on larger UK cars includin Fords/Vauaxhalls and BMC's in the 1960's - however there are are 2 models 22A and 30A plus a lot of minor variations which do not matter much.

Using the very common and cheap 22A version is OK if electric load is kept low (which is not the case in a UK winter at night, in the rain with wipers/heater and lights full on) and not much idling is done. The 30A one is much rarer and commands a huge premium.

Many dynamos are ruined by a faulty regualtor or wiring to it but mine was damaged when the pump seized and mangled the end of the commutator shaft despite the nylon? bush that is supposed to stop this happening.

The special endplate bracket can also fracture so it worth getting a duff dynamo for spares if you can

[Gordon Harrower]

Thanks Phil, Dave, and others for this thread. As annoying as my constant P5 problems are, I learn a great deal from you guys in the process.

Gordon.

[trymes]

I would also imagine that your Generator/Dynamo ought to be rebuildable. I would seek a second opinion if I were you. Cost would be the limiting factor here, as I remember having a discussion that involved custom windings, etc.

I can refer you to the fellow near me that rebuilt my Riley's Generator last year, though success is not assured, as that generator is much more common, being shared with the MGA, etc.

Tom

PS: I have gathered from this thread that all Mk III cars are negative ground, but fitted with a dynamo, not an alternator? Interesting.

[Ken Nelson]

I rebuilt a 1966 3.8 litre Jag Model S that had the same power steering pump assembly bolted to the back like the Rover. I would think it must be the identical unit-you might check with Jag suppliers also. Ken

[Phil Nottingham]

Mk3's had improved electrics and in readiness for alternators were made -ve earth.

Note I saw a diesel alternator which had the servo vac exahsuter bolted on the end so speace allowing something like this cound be used - this one was off a van and was a little bulky - AC Delco I think

[Warwick]

Diesel Landcruisers used to have the vac pump driven off the back of the alternator too.

[rcoups]

I have heard Pajero's have alternators with a pump drive fitted to the back of them