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A year ago, my 4A occasionally would not start. No whirring, clicking etc, just nothing. Had a few Push starts to get me going when it happened, but one of our group noticed my Battery earth lead wasn't very tight on the bulkhead. (I'd already checked all the connections on the positive side) That seemed to cure it.

However, some of our group went on a trip to Northumberland a couple of weeks ago, me included. The car ran well, started everytime I needed it to.....  until the Angel of the North, where it wouldnt start at all. A bump start sorted it, and then again everytime we stopped somewhere. (The Cov lads are very fit now...)

Symptoms diiferent, I could hear the starter motor spinning, but it wasn't engaging. I tried each day but no success. so lots of bump starts on the way home. General consensus was the starter motor. Mine was the original (at least, it was the same one on the car in 1975 when I bought it). I ordered a High Torq SM, then went to my garage to take a look and start stripping it. Thought I would try to start it, and it fired first time....

Anyway, changed the old SM to Hi Torq, (Joining power leads on the same post of the original solenoid, so bypassing it) and thought all was good as it started the car every time... until today. I took it a 20 minute run, then stopped to get some fuel, and after filling up, it wouldnt start again. SM whirring (albeit at a higher pitch than my old one)

So, new SM, New battery leads to solenoid and SM (good for 300A), New ignition switch, Battery is showing 12.8V (can't check CCA as it wont turn over) and about 12.5V at the SM connection, all leads tight, earth from battery good and tight, Old solenoid bypassed....

My plan is to swap battery from my daily driver to rule that in or out, but anything else anyone can think of?

Thanks

John

I think I'm about the only old thing in/on the car now...  :D

 

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If you can hear the starter motor whirring there is nothing wrong with the electrics John.  I think this can only be a failure of the motor to engage with the ring gear.  That means something is badly worn, or maybe loose or broken?, and since this has happened with two different starter motors it is probably the ring gear.  Your new Hi Torque motor worked because the starter pinion was new and just made contact.  Now maybe it has worn down a bit so it no longer engages. Or it could be broken teeth on the ring gear and if the engine stops in that particular position there is nothing for the starter to engage.

 

 

Edited by RobH
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Posted (edited)
9 minutes ago, RobH said:

If you can hear the starter motor whirring there is nothing wrong with the electrics John.  I think this can only be a failure of the motor to engage with the ring gear.  That means something is badly worn, or maybe loose?, and since this has happened with two different starter motors it is probably the ring gear.  Your new Hi Torque motor worked because the starter pinion was new and just made contact.  Now maybe it has worn down a bit so it no longer engages.

 

 

That is my worse case scenario, although the new SM has only been on a week, so shouldn’t be any wear. Only started it between 6 or 10 times, before today. Could be wear in certain places on the ring gear, and the SM keeps finding them….

 

although, forgot to mention, now it’s not whirring, it’s not doing anything on turn of the key, except the ammeter going well into negative.

Edited by johnwill
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3 minutes ago, johnwill said:

although, forgot to mention, now it’s not whirring, it’s not doing anything on turn of the key, except the ammeter going well into negative.

Possibly starter motor jammed then.  Some Hi torque motor solenoids can take 40 amps which would account for that current, as they have to shift the pinion mechanism (they should be connected via a relay rather than direct from the ignition switch) .  The solenoid has contacts which turn on the motor when the gears are in mesh so perhaps it isn't managing to move that far. If it was making contact the motor current would be very high and things would get rather hot if the motor was stalled.  I don't think those starters have the shaft end accessible to turn with a spanner -  have you tried turning the engine by hand to try to free it? 

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9 minutes ago, RobH said:

Possibly starter motor jammed then.  Some Hi torque motor solenoids can take 40 amps which would account for that current, as they have to shift the pinion mechanism (they should be connected via a relay rather than direct from the ignition switch) .  The solenoid has contacts which turn on the motor when the gears are in mesh so perhaps it isn't managing to move that far. If it was making contact the motor current would be very high and things would get rather hot if the motor was stalled.  I don't think those starters have the shaft end accessible to turn with a spanner -  have you tried turning the engine by hand to try to free it? 

No. I rocked it a bit, and then gave up for the night :) will do that tomorrow 

thanks for your response

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Hi John

I agree with Rob seems your ring gear is worn it will only be worn in a couple of areas so it you can slightly turn the engine you may find the starter will engage (but will return to worn spots when you switch off) if you are using a high torque starter your switch circuit should go through a relay and I would also fit an additional earth from battery to engine

Chris   

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1 hour ago, trchris said:

Hi John

I agree with Rob seems your ring gear is worn it will only be worn in a couple of areas so it you can slightly turn the engine you may find the starter will engage (but will return to worn spots when you switch off) if you are using a high torque starter your switch circuit should go through a relay and I would also fit an additional earth from battery to engine

Chris   

I’ve fitted an additional earth already so all good there. What relay would you suggest?

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You have already got one - use the original starter solenoid as a relay, that's what I have done.

Bob.

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Posted (edited)
4 minutes ago, Lebro said:

You have already got one - use the original starter solenoid as a relay, that's what I have done.

Bob.

A question Bob, the red/white wire. Should it go on the small connector or the main terminal on the opposite side of the solenoid to the battery lead? Eg the terminal the old lead from the old SM used to be on

Edited by johnwill
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Join both the heavy cables on one terminal of the original solenoid, together with any brown wires. connect the red/white wire from the starter switch to the small terminal (as it was originaly), add a new thin wire from the unused large terminal on the original solenoid down to the small terminal on the starter motor. do not link the small & large terminals on the starter.

Bob.

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There needs to be a very good return electrical path from engine to chassis for the starter motor to do its job.

It is a substantial flexible, unsheathed cable, low down at front left of the engine - Part 131116 (can't find any picture).

If this cable is loose, frayed or making a bad connection, it will cause the problem you have described.

Ian Cornish

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1 hour ago, trchris said:

You can do as Bob suggests  but make sure the wire feeding the starter solenoid is rated at 40/50amps 

Chris 

Ah, now that I’m not sure of. I used some wire I had in my garage, but no idea what it’s rated as. I assume that wouldn’t cause the not starting issue I have?

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50 minutes ago, ianc said:

There needs to be a very good return electrical path from engine to chassis for the starter motor to do its job.

It is a substantial flexible, unsheathed cable, low down at front left of the engine - Part 131116 (can't find any picture).

If this cable is loose, frayed or making a bad connection, it will cause the problem you have described.

Ian Cornish

Ian, the cable you mention is good and connected solidly, I also have a 2nd cable from bulkhead to engine

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30 minutes ago, johnwill said:

Ah, now that I’m not sure of. I used some wire I had in my garage, but no idea what it’s rated as. I assume that wouldn’t cause the not starting issue I have?

No. If the wire is under-rated it will get hot but it won't stop the starter from working. There must be a connection else you wouldn't see all that current on the ammeter.  You need to change the feed to include the relay as Bob has described though, because as it is you risk damaging the ignition switch.  You can beef up the wire at the same time if that is necessary.

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21 hours ago, trchris said:

Hi John

I agree with Rob seems your ring gear is worn it will only be worn in a couple of areas so it you can slightly turn the engine you may find the starter will engage (but will return to worn spots when you switch off) if you are using a high torque starter your switch circuit should go through a relay and I would also fit an additional earth from battery to engine

Chris  

+1, pushing the car forward afew inches in 3gear will do the trick. Peter

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Update on this issue

I had tested the battery with my multimeter, and it was showing 12.8V. I also charged up a booster I had bought a couple of years ago (Not much bigger than a laptop power block..) and used that to see if that made a difference, hoping the extra power it offered would rule the battery in or out. It made no difference.

Decided Saturday to put my old Machine Mart booster back on charge (it is charged regularly, but never gets full power, hence the new one). Tried that on my car today and it turned over...

Took Battery to local supplier, and found one of the cells was not great, and although It still registered around 12.7V under no load, it failed miserably under load. Bought new battery, fitted, and she's back to starting every time.

I'm keeping my fingers crossed (once bitten etc) but hopefully this has solved the problem.

Bad luck the "new" booster failed to work, as it would have pointed to the likely issue a lot earlier.

Thanks for all the advice

John

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  • 2 weeks later...
On 7/10/2021 at 10:42 AM, RobH said:

No. If the wire is under-rated it will get hot but it won't stop the starter from working. There must be a connection else you wouldn't see all that current on the ammeter.  You need to change the feed to include the relay as Bob has described though, because as it is you risk damaging the ignition switch.  You can beef up the wire at the same time if that is necessary.

Followed your advice on this too. Thanks

John

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