Charging System/Javelin speedometer

[KenR]

Hello all,
I am trying to make some progress with getting my Javelin into shape for the coming season - its last outing was to the Peebles Rally
(we left for our annual six-month trip to the USA just after this). It ran very well to and from the Borders, but on our return to the
UK in November, I found that the charging system was playing up once again. The dynamo is functioning correctly (I checked the output with an AVO meter) but the ignition light
wont go out and the ammeter doesn't show a charge whatever the revs. A PO has helpfully fitted an electronic voltage regulator inside the
Lucas control box and I am unsure how to check this out - any advice would be welcome. If it turns out that the regulator is faulty, then I may as well fit
a dynamator replacement and do away with it.
While checking the charging system wiring, I took the speedometer out, partly because the trip odometer reset shaft is broken (it is on its way to Drummond Black,
who will try and fabricate a replacement - thanks in advance Drummond), but also because the ignition bulb doesn't illuminate the ign warning lens (the red 'jewel' is missing completely)
and only shines through the bottom of the odometer. I suspect a part is missing here - has anyone who has examined a Javelin Deluxe speedo tell me if this is the case?
This is fairly minor stuff, I know, and thanks to Drummond, Eddie and Jack for their valuable inspection and advice regarding my Javelin, I have plenty else to be getting on with.
However, I would like to sort these issues out if at all possible.

[Keith Clements]

Ken,
I hope you have studied the Lucas Fault finding notes in the Gallery and TOPIC how it works to see how it is supposed to work. Obviously does not say how an electronic system should be checked out.
Was it previously working? If so, then it has either blown up or a connection has failed. The PO (Previous Owner) may have thought it was a more reliable solution, but you can fix the Lucas box even after 50 years of neglect.

I have not yet fitted the Dynamator to my car although it is due to go on, but the car has been running on alternator for over 25 years. You do have to be careful that the battery is well connected when the engine is running .

From memory there is a red plastic cylinder in the speedo that transmits the light. I have just converted all mine on the Jup to LED in various colours white for illumination, red for ignition, blue for main beam, green for turn and orange for wiper.

[KenR]

Many thanks for your input, Keith. These are useful documents for explaining how the charging system should work. I have already determined that the dynamo and wiring up to the voltage regulator is OK.
What I cannot work out is how to isolate the battery from the dynamo for further testing - no electro-mechanical contacts to slip a piece of card between! I have cleaned and remade all the contacts at the regulator
and will follow this through the ammeter, ignition switch, solenoid and back to the battery. If no fault presents itself, I will have to assume that the electronic regulator has failed
(I should have mentioned that I had to replace a burnt out 25A fuse inside the regulator...so perhaps it was unable to protect the components).
I have a red plastic 'jewel' that could be fitted to the speedo dial....just a matter of finding some way of guiding the light from the bulbholder. On the other hand, if I go down the route of the dynamator
(which is not much more expensive than I replacement electronic regulator) then I will need to upgrade some wiring anyway, so might also try the LEDs while I am at it.

[Keith Clements]

Fusing of circuits is a bit more complex than most people think ( and most people do not even think about such things!)
Generally it is there in automotive circuits to protect the wiring from catching on fire. In many cases the fusing is chosen (wrongly) to detect a fault condition by choosing a fuse of capacity just above the current when all components are on. So if you have 4 circuits (protected by a single fuse) going to each corner of the car each carrying 5 amps you put in a fuse greater than 20A, say 25 A. But this means you would need 30A capacity wiring throughout the car to be safe.

The second issue is the speed at which the fuse blows. Slow blow fuses will allow a higher than normal current to flow for a short time and this is required for motors that take a high switch on current. The wiring can stand this as it will take some time to heat up but silicon technology may not survive. Many modern electronic circuits are protected using fast acting semiconductors but your box may not have had these.

The old fusing system on the Jowett was very basic and indeed was bypassed by some components such as the clock directly to battery, the regulator via ammeter, the ignition switch and lights via the A1 terminal. It is advisable to upgrade if you want to protect your car from fire.

On a Jup a 35A fuse 'protected' the ignition on circuit and a 35A fuse 'protected' the horn circuit.

If you fit an alternator or Dynamator you should add many more fuses as they can deliver 60 amps very quickly.

See the wiring diagram here of the system that has been on my Jup for 26 years and has just been upgraded with a new fuse box and relay system (details later in Josephine rebuild topic))

Note the designed for current requirements which determined the wire size and thus fuse size for each circuit.

[Mike Allfrey]

I am currently working on the 'restoration' of my complete set of Lucas Overseas Technical Correspondence Course and will be sending the completed books to Keith once finished.

In the meantime, the Lucas generators and control boxes sections have been done. What is interesting is the frequent reminders, throughout the course, of the requirement for sound earth connections all the way to the battery connection. That has brought back some tractor memories, when we were called out to a 'tractor will not start', usually in winter up on the Mendip Hills. If it turned out to be a bad connection at a battery terminal, we tied a label to the steering wheel which read, "Next Time Try Domestic Science", with an explanation to maintain sound, clean, connections at the battery terminals.

The Lucas training material advises strongly that the generator (dynamo) and control box in a vehicle are very carefully matched, even to the extent of the various lamp bulb filaments, horns, trafficators etc. are all a part of the dynamo and control box setup.

How many of us regularly lubricate the rear dynamo bush? How often do we check the condition of the commutator and the brushes? All of this falls into 'normal' maintenance and, with our cars sitting idle for lengthy periods, 'settling' at the dynamo could cause charging problems.

Another point we need to watch out for is the state of the fan belt and its drive pulleys etc.

In my working life, I never had any need to make adjustments at Lucas control boxes, to get a dynamo to properly charge again, it was usually in the dynamo itself; or a poor quality earth from the engine to chassis/body frame - mostly.!

Mention of the Mendip Hills reminds me that one farmer up there, in the later 1950s, had a Riley Blue Streak Kestrel firmly stored in a shed. I ached after that car for a while, but he would not sell. Then I obtained my Jupiter and we all know what they do to us!

All the best,

Mike A.

[KenR]

AC12623E-1D63-415F-9BAB-72D03579CB1D.jpeg

Thanks for all the above helpful information. I am working my way through the charging/starting system and am in the process of replacing the battery leads, battery isolator to solenoid and solenoid to starter leads. The engine earth lead has been replaced at some stage but I will add another anyway. I’ve also ordered a larger (62Ah) battery, as the 35Ah battery currently fitted, although only 4 years old, is a bit underpowered I feel. I had a look at the switch panel wiring today and will clean up and tin some of the bare wire connections to the ignition switch and starter button. I was a little surprised to see the loose yellow wire and black earth shown in the attached photo...but I suspect these are the (missing) connections for the cigar lighter, which I have now removed for cleaning/testing. I should be able to check this with my AVO meter, once I have recharged my LED inspection light!...lack of light, faded wire colours and less than 20/20 vision - not to mention the contortions necessary to inspect the rear of the dash - make the whole task quite challenging....
PS...apologies for photo but had great difficulty making it small enough to fit!

[Keith Clements]

When you say tin wires does that mean solder? Solder makes copper brittle and I would not recommend. The recommended way these days is to use sleeves that hold wires together in screw down terminals or crimp connectors.

[Mike Allfrey]

Hello Ken and Keith,

To date, since 1956, I have not experienced a failure of a soldered cable wire joint, be it wire to wire, or eye-terminal to cable wire types of joints. I appreciate the modern crimping methods, but they do look awful on vintage to classic vehicles, as does an assortment of modern plastic multi-coloured cables, and those awful blue plug leads with yellow connections that show up every oily finger print. But those are other matters!

However, my lecturer at Bristol Technical College (to become Bristol College of Science & Technology, and whatever since), instructed us to hols a cable vertical while being tinned. The idea was to have the solder flow down into the insulated portion, to support the soldered joint. Maybe Mr Conway was right? This was before the time saving crimp technique came into vogue.

I still have a firm belief that a soldered joint is best, and looks correct. But then, I am (thankfully) rather old fashioned!

All the best,

Mike A.

[Srenner]

I used to work for a professional race team supported by Mazda, building in the shop and traveling to the races as part of the pit crew. Many lessons and improvements came from my time building cars for them. Among the tools was a $300 pair of crimping pliers generally used in the building and repair of aircraft. The wiring of the race cars followed the best practices as required by the FAA (Federal Aviation Administration) so as to lessen the possibility of losing a race due to a wire connection failing. Nothing was soldered. How to fasten clamps, positions of terminals, types of clamps, bending radii, ad naseum.

Solder works, but one needs to be careful about the flow and heat. Best to use shrink tube to insulate and help support the area. And shrink tube colors help identify those faded Lucas wires. It is a good idea to tin the exposed ends of wires as the copper develops oxides that impact conductivity. We have all seen the powdery green on those old wires.

People would ask, "What does Sebring look like" or " Texas International Speedway", my answer was "Just like the engine bay of a Mazda 3." The wiring never failed, but don't get me started on cam sensors.

[Mike Allfrey]

Hello Ken,

At the control box, have you checked the earth terminal for continuity?

Also, at the dynamo, are the brushes free?

The Lucas Test Routine
And finally, to summarise the whole business, here is a list of the operations which should be carried out in the order shown.
CHECKING THE CHARGING SYSTEM
Battery:
1. Hydrometer Test
2. Heavy Discharge Test
Dynamo:
3. Drive Belt
4. Dynamo Bearings
5. Brushes and Commutator
6. Armature Circuit
7. Field Circuit
8. Cables and Connections
Control Box
9. Open Circuit Settings
10. Cables and Connections
12. Cutout Operation

The above list is from the Lucas Training Course.

A lot of that is for an auto-electrician, but they are the logical steps to take. Remember that the 'Field' circuit provides voltage TO the dynamo to energise the field coils to electro-magnetise the dynamo's north and south poles.

All the best,

Mike A.

[KenR]

Well, you learn something new every day! I have always cleaned and tinned corroded or otherwise poor quality bare wire ends...and for that matter, tinned and soldered spade connectors where the crimping was of dubious quality. I did not realise that this could weaken the copper wire. It is quite apparent that our classic car wiring often leaves a lot to be desired, with corrosion in bare wires often extending well back into the insulation...and the insulation itself having hardened to the point of losing any flexibility. On top of this, I have come across a couple of wires on my Javelin where the outer fabric and insulation looks partly melted - perhaps through a bad connection causing overheating? Moreover, as previous owners might well have cut away corroded wires to remake a clean connection, it is apparent that some wires are only just long enough to reach their intended connector. No doubt the safest solution to all this would be to replace the loom with a new one, but for those of us trying to do a ‘running restoration’ this is probably a step too far. (If I get around to a strip down and full respray, then a new loom may be in order...).
I like the idea of the bare wire end sleeves - are these what is are also referred to as ‘bootlace ferrules’? I think I’ll try those on the connections to the voltage regulator and (if I fit a dynamator) on any wiring upgrades/additional fuses.
Meanwhile, I have a new battery and cables to fit. I have also been in touch with Scott Mitchell at Classic Spares, in South Lanarkshire, who handles instrument repairs and can supply the missing items for my speedometer. Drummond has done a great job in turning a replacement reset shaft for the trip odometer, so that is another job completed. I should have the petrol tank out by this weekend ready to go to East End Radiators here in Glasgow for refurbishing.
I’d like to have it running again by the end of next month...but we shall see!