Starter not running

[BurArrow]

Hi all,

Having an issue in my restoration currently, when I turn the key I get the click of the solenoid but no starter activity.

I've checked the voltage past the solenoid and to the terminal on the starter and it seemed okay. Whipped the starter out and disassembled, cleaned up the commutator (which looks like its had a rough re cutting in the past). Didn't seem to be any shorts. I managed to confirm the starter was working by jumping it straight to the cars battery on the bench.

And of course when it's back in the car no sign of life. I'm a little stumped, what can I look at next?

[Rutty]

Bad or no earth. Assuming the battery is earthed to the body then the engine will need an earth to the body as well. 

[BurArrow]

Hi Rutty cheers for the speedy reply, battery negative is straight to the bell housing and I've checked the resistance from battery terminal to the body of the starter which was nice and low.

 

[Clive]

Indeed, but could be a poor positive connection too.  Check the solenoid itself by jumping that with a big screwdriver/spanner or whatever. 

But earths are the most commosn issue. I run an earth from the battery to one of the gearbox/block bolts. Using a jump lead can confirm one way or another

[BurArrow]

Thanks both! I'll check those out next.

[glang]

1 hour ago, BurArrow said:

I've checked the resistance from battery terminal to the body of the starter which was nice and low.

Im afraid its not as simple as checking resistance of this circuit unless you have some pretty specialised gear. As the current is so high, in excess of 300amp for example, a resistance of just 3 milli ohms will give a drop of almost 1v plus generate around 300w of heat so the resistance increases rapidly etc. 

[shenderson]

It's worth checking/cleaning the contacts in the solenoid - if you can dismantle it.

[glang]

The starter solenoid can indeed be dismantled but is not intended to be as mine was rivetted together. Most people just replace them as not expensive but I took mine apart and flipped over the copper contact bar inside so that the burnt areas were replaced by virgin material. I then reassembled it using small nuts and bolts and its worked well ever since.

However as I said in my previous post anywhere with high resistance will generate heat on trying to start so its worth touching each component and connection to feel for this...

[BurArrow]

Took the starter out again and cleaned up the face to the bell housing on both sides. Cleaned up the terminals on the cables all around. Gave the motor another go on the bench using the positive terminal cable and the body of the motor and that sparked into life. Still no dice when back in the car, even when bridging the solenoid, no sparks or sign of life.

The only cable I couldn't clean up was the negative from the bell housing as that bolt needs freeing, so that looks like the culprit. Enough juice for lights and gauges, not enough to crank it.

[glang]

Its a real pity you cant get hold of a set of jump leads as these would help you identify the problem much quicker. Remember the high resistance connection could be anywhere in the whole starter circuit which also includes: battery terminals +ve and -ve, earth cable from battery to body connection, both ends of the chassis to engine earth cable (this is usually at the front of the engine).

You may think that all of these are ok because other smaller electrical loads like lights and things are working but thats not the case because of the high current the starter draws... 

[standardthread]

It could be broken strands in your present earth not giving enough current?

New earth cables complete aren't expensive. The previous owner of my Dolomite had an issue and added one running the full length of the engine, it caused servicing problems so I replaced it with a new one from battery to the front of the block.

You can't have too many earths. Problem sorted.

[BurArrow]

Progress with some jump leads! I bridged from the solenoid +ve to starter terminal, and battery -ve to the -ve terminal floating and it turned over. As that is basically the complete circuit minus the solenoid I connected back up and then strangely the ignition turned over and I almost had it started, but after a couple of tries back to nothing.

So even though I used all the cables in the test I'll make up some new cables anyway.

But I found that the ignition coil was getting hot, not something I expected - do they get hot to the touch when running? Its not too hot to touch but at least 40C

[glang]

Dont completely follow what youve done with the jump leads but I would do +ve and -ve separately starting with system as normal and not working. Then put jump lead from +ve battery terminal (try to get it onto the actual battery terminal not just the lead terminal) onto the starter motor terminal (again the actual threaded stud). If the engine turns well all the -ve side is proved good but if not repeat the procedure with just one lead but on the -ve side...

Coil temperature normal but make sure its connected the right way round: -ve to points/electronic ignition.

[BurArrow]

So I attached my jump leads from the starter +ve directly to the battery without sign of life. So after completely refreshing all the leads with new 300A I came to the conclusion it was the starter itself.

Replaced that and hey presto it turns over, doesn't start yet but that's for another day 🙂

Thanks all!