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Electrical Fault

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tjr567 Avatar
tjr567 Tim J
Nowra, NSW, Australia   AUS
1949 Morris Minor MM Tourer "Olive"
1957 Morris Minor 1000 "Elsie"
Good afternoon,
So after a couple of weeks rebuilding the brakes on my 49 Tourer its time to tackle the next issue.
My 1000 has developed an electrical issue and just wondering if anyone may have some pointers before I start disconnecting and isolating.
The car is standard (as in a generator) and has been made negative earth. The only modification to the electrical is the inclusion of LED indicators front and back.
So when I start the car, as the revs pick up the generator lamp on the speedometer fades out as usual, Then as the revs increase the lamp comes back on and the illumination lamps in the speedo light up, then keep increasing the revs and I hear a click (I presume in the regulator) and everything goes back to normal. I'm wondering if I cam getting voltage leakage onto the negative rail or something. Anyone come across something like this before? Basically I want to know if its likely to be a regulator issue or if I need to delve into the wiring and start isolating portions.

Cheers
Tim

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emjay Jim English
Marietta, PA, USA   USA
Having the back light bulbs lit indicates a grounding issue, but the regulator is probably the problem. Take the cover of the regulator and follow the regulator adjusting procedure in the workshop manuals. Simply, the cut-out should be open when not running and once the generator puts out enough, the cut out closes and should stay closed. The other coil should be closed until the voltage gets too high. Confirming the wires to the regulator are correct and in the right spot should be done first. Had the car been behaving? Is it a new regulator or an original?

0123 Mike D
Biddulp, Staffs, UK   GBR
In reply to # 26288 by tjr567 Good afternoon,
So after a couple of weeks rebuilding the brakes on my 49 Tourer its time to tackle the next issue.
My 1000 has developed an electrical issue and just wondering if anyone may have some pointers before I start disconnecting and isolating.
The car is standard (as in a generator) and has been made negative earth. The only modification to the electrical is the inclusion of LED indicators front and back.
So when I start the car, as the revs pick up the generator lamp on the speedometer fades out as usual, Then as the revs increase the lamp comes back on and the illumination lamps in the speedo light up Zummat wrong there Matey
sad smiley
, then keep increasing the revs and I hear a click (I presume in the regulator) and everything goes back to normal. I'm wondering if I cam getting voltage leakage onto the negative rail or something. Anyone come across something like this before? Basically I want to know if its likely to be a regulator issue
Not likely
or if I need to delve into the wiring and start isolating portions thumbs up
Arh, start wi' they speedo lights..

Cheers
Tim

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tjr567 Avatar
tjr567 Tim J
Nowra, NSW, Australia   AUS
1949 Morris Minor MM Tourer "Olive"
1957 Morris Minor 1000 "Elsie"
Thanks Jim,
Its an original regulator.
It was doing it this afternoon so I took the cover off the regulator and flicked the contacts a few times. It seemed to settle it down for a short period so maybe the issue is something sticking in the regulator and letting the voltage get too high before it pulls the contact in.
The car was running fine. The only thing I have done lately to the electrical is pull the indicator switch out an clean the contacts as it was failing on the left hand switch.
Will do some more isolating with a multi-meter over the weekend and see if I can isolate it.

Tim

0123 Mike D
Biddulp, Staffs, UK   GBR
You a purist Tim?

nudenut Avatar
nudenut Silver Member Reg K
Perth, Perth Western Australia, Australia   AUS
As Jim suggests it is most likely points sticking in regulator, has the car been stationary for a long time ?

Cheers

tjr567 Avatar
tjr567 Tim J
Nowra, NSW, Australia   AUS
1949 Morris Minor MM Tourer "Olive"
1957 Morris Minor 1000 "Elsie"
Thanks Reg
Until six weeks ago it was stationary for 38 years!
I've just finished a ground up rebuild. I haven't done the final update on my blog but if you go to www.tjr567.wordpress.com you can check it out.
I have just cleaned the points on the regulator but didn't resolve. The issue is still there with both fuses out so that narrows it down a bit. I'm still inclined to think its in the regulator. I'll drag out the circuit diagram on the weekend and see if I can isolate a few things. A replacement regulator might be in order. Was working fine for the first six weeks though !
Trials and tribulations!

Cheers
Tim

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tjr567 Avatar
tjr567 Tim J
Nowra, NSW, Australia   AUS
1949 Morris Minor MM Tourer "Olive"
1957 Morris Minor 1000 "Elsie"
Hi Mike,
By purist do you mean would I consider changing over to an alternator?
At this point I'd rather keep it stock standard, although I never say never.
I used to be a radio mechanic in a former life so I see this as a bit of a challenge .....

Cheers
Tim

0123 Mike D
Biddulp, Staffs, UK   GBR
An alternator is your best solution Tim.thumbs up

Mainly because one will get you decent headlights.
Additionally, you will be able to use LED / COB bulbs.

Some interesting reading here thumbs up
http://www.dynamoregulatorconversions.com/lucas-mechanical-cvcs.php

Purists keep their cars pure.
Ie, the way they came out the factory.

For only 500 notes,
you could get an alternator
that looks like a Lucas dynamo confused smiley

https://minispares.com/product/classic/GXE1006.aspx

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tjr567 Avatar
tjr567 Tim J
Nowra, NSW, Australia   AUS
1949 Morris Minor MM Tourer "Olive"
1957 Morris Minor 1000 "Elsie"
Hi all,
I spent the day resolving this issue.
I did some tracing on the diagram and realised that for the ignition warning light to be coming back on then there had to be a potential difference between the battery positive and the input of the generator at the regulator. I did some ohms testing and discovered that I was getting 8 Ohms between the earth of the regulator and the negative terminal of the battery. As Jim suggested an earth fault. As far as I can gather the resistance on the earth was acting as some sort of shunt on the incoming from the generator dragging it back down to ground. This was causing the regulator to hold in longer than normal then chatter.
So I chased the earths and found a high resistance on the main earth from the loom where it sits under the bolt for the accelerator shield at the firewall. Got the Dremel out and took it back to nice clean metal then bolted it al back together. Issue gone!
Now during all this, when I had first taken the indicator switch apart and reassembled, there had been an initial issue with the horn not working. This was before I noticed the regulator issue.. At that point I had disconnected the horn. Now I reconnected the horn ....and the right hand indicator came on. Pulled the switch back off and found that bolting the plastic cover to the bottom of the switch had sandwiched the right hand indicator wire onto the positive contact for the horn. Easy fix.
So as it turns out, the entire system was getting its earth through the indicator switch some hows, thus disguising the poor earth at the firewall. When I had removed the indicator switch to repair it and then created the short putting it back together, that disrupted that earth so it had to rely on the proper earth which was dodgy.
Anyway, all systems go. Thanks for the advice. As usual, its great to tap into the wisdom of the big broad Morris Minor community.

Cheers
Tim

0123 Mike D
Biddulp, Staffs, UK   GBR
Tim the ifn warning light bulb
gets power from the ign switch
when you switch the ign on.

The ign light earths
through the dynamo.

When the dynamo starts charging
it bungs 12+ volts at the bulb
from the other end.

The ign light out because
it's getting 14+v from both ends.

Dynamos should be regulated to 14.5+ volts.

If you connect a lead light
between battery live terminal
and dynamo field coil
the light will light
when the dynamo
is not charging..

It goes out when the
dynamo starts charging.

The ignition light work the same way as that lead light.

emjay Jim English
Marietta, PA, USA   USA
Great work. The electrical system is actually quite good and simple. If there is a weakness,it would be the insulation in spots is weak. I think the reason Lucas gets such a bad rap is after owners "fix" theirs by adding extra wires. It might be different on other British cars, but for Minors I find if you get it back to the original design, it works just fine.

0123 Mike D
Biddulp, Staffs, UK   GBR
Lucas stuff was wasn't good enough, off the shelf..

According to Haynes,
the maximum output voltage is only 13.5 sad smiley
If you drove for a month of Sundays
to get the battery to 80% full.

Max output at 19 amps leaves sweet fa
to charge the battery if you are running
your heater, your wipers and headlights.

The regulator soon went off kilter.
If it hiked the voltage the dynamo failed.
If it dropped the voltage, the battery failed.

On the plus side, I made a lot of money
jump starting plonkers' cars thanks to

Roll of drums please smiling smiley

Jo Lucas,
Prince of Darkness

smileys with beer

John in Eugene Avatar
John in Eugene Gold Member John Quilter
Eugene, Oregon, USA   USA
All's well when you can fix an electrical issue with no lost of smoke from the wiring. smileys with beer


John F. Quilter
Eugene, Oregon USA

In reply to # 26419 by tjr567 Hi all,
I spent the day resolving this issue.
I did some tracing on the diagram and realised that for the ignition warning light to be coming back on then there had to be a potential difference between the battery positive and the input of the generator at the regulator. I did some ohms testing and discovered that I was getting 8 Ohms between the earth of the regulator and the negative terminal of the battery. As Jim suggested an earth fault. As far as I can gather the resistance on the earth was acting as some sort of shunt on the incoming from the generator dragging it back down to ground. This was causing the regulator to hold in longer than normal then chatter.
So I chased the earths and found a high resistance on the main earth from the loom where it sits under the bolt for the accelerator shield at the firewall. Got the Dremel out and took it back to nice clean metal then bolted it al back together. Issue gone!
Now during all this, when I had first taken the indicator switch apart and reassembled, there had been an initial issue with the horn not working. This was before I noticed the regulator issue.. At that point I had disconnected the horn. Now I reconnected the horn ....and the right hand indicator came on. Pulled the switch back off and found that bolting the plastic cover to the bottom of the switch had sandwiched the right hand indicator wire onto the positive contact for the horn. Easy fix.
So as it turns out, the entire system was getting its earth through the indicator switch some hows, thus disguising the poor earth at the firewall. When I had removed the indicator switch to repair it and then created the short putting it back together, that disrupted that earth so it had to rely on the proper earth which was dodgy.
Anyway, all systems go. Thanks for the advice. As usual, its great to tap into the wisdom of the big broad Morris Minor community.

Cheers
Tim

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