One click and it’s dead! Help!

[Oldmogman]

Wonder if anyone can help me diagnose this puzzler?

Sometimes when I try to start the engine there’s just a click (from the solenoid?), the ignition light goes out and everything is dead: no starter, no ignition, no lights, no nothing.

I can ‘re-set’ things by disconnecting and reconnecting the battery, but the same thing happens again.

The ring gear and starter pinion are not jamming, the battery cables and earth leads are secure, the solenoid is fine as are all the fuses.

However, other times the car starts normally.

Oddly, this started happening since I fitted a new battery. It’s a 45 amp/hour battery like the old one. Could it be that the new battery has more power that the regulator can handle? Could the voltage regulator be faulty? Or something else?

I would guess the regulator is about 20 years old now.

Thanks all.

[simmitc]

Unlikely to be to do with the regulator, this is going to be (a) poor connections, (b) faulty battery, (c) faulty solenoid (d) faulty starter motor. It sounds as though when the solenoid is operated, it simply takes all the available power from the battery, hence losing the ignition light. This could be due to the starter motor being jammed (not the same as being stuck in the ring gear). However, as the problem started after fitting a new battery, my first choice would be to double check all connections, and then change the battery for a known good one.

However, why did you change the battery? If the old one was not charging, then you could have a dynamo or control box fault, which is imply still evident. When you get the current problem, do you have to charge the battery, or does the car start OK a few minutes later? If you rev the engine, do the headlamps get brighter? Happy hunting.

[MarkyB]

If you have the cap type battery connectors chuck them away and get the clamp type.
Also make sure there is a well connected earth strap that bridges the rubber engine mounts.
You can use a jumper lead to do this for test purposes.

[bmcecosse]

As above - it's a 'bad'connection. Either within the battery - or at the connectors.....

[moggiethouable]

I have to concur, I had this exactly on a previous motor and it turned out to be the earth strap from the battery, not making contact to the chassis sufficiently. Emery the metal on the chassis where the strap is bolted to, it worked for me and make sure it is a tight fit on the battery. Good luck

[Oldmogman]

Thanks guys

I’ve re-checked all the connections, including the earth strap from the gearbox to the crossmember, and all are sound. But I will try the suggestion of cleaning up the cable contacts with emery.

Simmitc - Your point about the starter motor is interesting. Sometimes the starter winces and almost stops when trying to turn over the engine before springing into life again turning it properly – rather like what happens when you try to start an engine with the timing too far advanced, apparently (the timing on my engine is correct).

This has been happening sporadically for a while, and well before the new battery was fitted.

I checked the starter today and found there was a fair amount of side-to-side movement at the end of the shaft (the terminal end with the square lug), perhaps as much as a half a millimetre or more and certainly enough to make a tapping sound when waggled. Is this normal? Could this cause the starter to jam?

If I were to strip down the starter motor, what faults should I be looking for?

And in answer to your question, the battery was replaced because it wasn’t holding a charge when left idle for a few days – confirmed by a test at my local battery/tyre/exhaust centre.

[simmitc]

You can strip a starter motor, but if the bearings have gone and the contacts started to wear, it's much easier to buy a new unit - they are available from all the usual suppliers, not terribly expensive, and you don't need an exchange unit. Not too expensive, although they won't last as long as the old one, it's a simple swap.

You could test the solenoid: Next time the problem occurs, take a jump lead (must be heavy cable, not a thin one). On the solenoid, clip one end of the cable to the large terminal that goes to the starter motor, and then touch the other end of the cable to the other large terminal. Be prepared for sparks. If the motor now works, then the solenoid is at fault. If the starter does not turn, then it is the starter that is at fault. Good luck.

[Oldmogman]

Thanks Simmitc

I tested the solenoid by bridging contacts with a screwdriver when the last 'blackout' occurred - nothing happened because there was power so no sparks!

As for the starter motor, does the amount of movement I described suggest the bearings have gone? (I wasn't looking to recondition it myself so much as establish whether it really was at fault before I spent out on a new one!)

The starter works fine most of the time - except for the occasional 'wincing' when it seems to struggle to turn over the engine, as above.

[bmcecosse]

The timing on your engine is obviously NOT correct - it is indeed kicking against the starter.

[Oldmogman]

The timing is spot-on - it's been set up with a strobe, taking into account the advance curve advised by BBC, and tested throughout the rev range.

[Oldmogman]

Forgot to add, there's no pinking under load, either!

[bmcecosse]

The timing is 'spot on' to what????? Any suggestions made by BMC 50 years ago are well wrong today! The fuel we use now is completely different. Advance the dizzy till you DO get some pinking - then take it back slightly until it's not quite pinking. Best you can do. And, sell the strobe on ebay..........

[whyperion]

Assuming timing ok , it probably is the starter. Remove starter and test it with a direct wired connection to a battery to check. It might just need the rear plate removing and the brushes replacing , the little springs could be jamming up against the ?commutator? part.