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alastairq



Joined: 14 Oct 2016
Posts: 1510
Location: East Yorkshire

PostPosted: Sun Nov 01, 2020 8:18 pm    Post subject: Reply with quote

Daft I know..but is the coil wired up the right way for the earth polarity?
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Dellow Mk2, 1951 built, reg 1952.
Ford Mustang coupe, 1967, 6 cylinder auto.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces.
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peter scott



Joined: 18 Dec 2007
Posts: 6543
Location: Edinburgh

PostPosted: Sun Nov 01, 2020 10:33 pm    Post subject: Reply with quote

alastairq wrote:
Daft I know..but is the coil wired up the right way for the earth polarity?


I know it affects how the plug electrodes erode but I'm not aware of it being critical to engine starting.

Peter
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1939 SS Jaguar 2Ĺ litre saloon
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alastairq



Joined: 14 Oct 2016
Posts: 1510
Location: East Yorkshire

PostPosted: Mon Nov 02, 2020 12:27 am    Post subject: Reply with quote

peter scott wrote:
alastairq wrote:
Daft I know..but is the coil wired up the right way for the earth polarity?


I know it affects how the plug electrodes erode but I'm not aware of it being critical to engine starting.

Peter


It can result in a reduced spark.
_________________
Dellow Mk2, 1951 built, reg 1952.
Ford Mustang coupe, 1967, 6 cylinder auto.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces.
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Rootes75



Joined: 30 Apr 2013
Posts: 3117
Location: The Somerset Levels

PostPosted: Mon Nov 02, 2020 8:04 am    Post subject: Reply with quote

Yes, connected either way the coil will still produce a spark. The difference being that the incorrect way will produce a much weaker spark.

We were wondering if the starter would be sapping all the battery power and that may be the issue?
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1937 Ford 7w
1937 Hillman 80
1946 ERF C.I.5
1947 Hillman Minx
1955 Hillman Minx Mk8
1950 Commer R541
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alastairq



Joined: 14 Oct 2016
Posts: 1510
Location: East Yorkshire

PostPosted: Mon Nov 02, 2020 11:03 am    Post subject: Reply with quote

Quote:
We were wondering if the starter would be sapping all the battery power and that may be the issue?


You could try disconnecting the starter from the vehicle supply, and operating it from an independant battery?
_________________
Dellow Mk2, 1951 built, reg 1952.
Ford Mustang coupe, 1967, 6 cylinder auto.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces.
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Peter_L



Joined: 10 Apr 2008
Posts: 2597
Location: New Brunswick. Canada.

PostPosted: Mon Nov 02, 2020 1:26 pm    Post subject: Reply with quote

alastairq wrote:
peter scott wrote:
alastairq wrote:
Daft I know..but is the coil wired up the right way for the earth polarity?


I know it affects how the plug electrodes erode but I'm not aware of it being critical to engine starting.

Peter


It can result in a reduced spark.


Full Link to subject: https://mgaguru.com/mgtech/ignition/ig104.htm

Quote from above article..."Why then do we worry about coil polarity? Because the spark plugs do care which way the electrons are flowing in the high tension circuit. The spark plug has a thermally insulated center electrode (surrounded by ceramic). With engine running the center electrode runs substantially hotter than the exposed end electrode. Design of the ceramic insulator determines how hot the center electrode will run, leading to the designation of hotter or colder spark plugs. As electrons go, they love to jump away from a hot surface and fly toward a colder surface, so it is easier to drive them from hot to cold rather than from cold to hot. End result is a difference of 15 to 30 percent in voltage required to make spark "initially" jump the gap on the plug depending on which way it is going. So the spark plug prefers to see a voltage potential that is negative on the center electrode and positive on the end electrode for the very first hop of the spark. Oddly enough, this has nothing to do with polarity of the vehicle electrical system, but it is influenced by the common connection inside the ignition coil. End Quote.
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ukdave2002



Joined: 23 Nov 2007
Posts: 3653
Location: South Cheshire

PostPosted: Mon Nov 02, 2020 4:00 pm    Post subject: Reply with quote

If everything else was ok , the coil being fitted the wrong way round won't prevent an engine from starting, unless the spark is so marginal (for other reasons) that its the straw to break the camels back.

Dave
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Rootes75



Joined: 30 Apr 2013
Posts: 3117
Location: The Somerset Levels

PostPosted: Sun Nov 08, 2020 6:18 pm    Post subject: Reply with quote

Well, finally we have the Commer engine running!

We have literally tried everything so thanks for all sugestions. In the end we removed the starter motor as we thought it may be taking too much power resulting in a poor feed to the coil.

But, when we bench tested it we found that although she spins up the engaging dog didnt travel far enough, so cleaned and oiled etc and we got the right amount of travel. We refitted it but firstly checked the ring gear for tooth wear, it was fine.

Next we connected everything back up and now she was turning over at a really good speed but still not even firing. So we checked the spark at the plugs and it was very weak, then at the contacts and this was good. So, we took a look at the sprung graphite in the cap and we found its movement very small. So, I had a dizzy from one of Hillmans on the bench and we changed the graphite over. This time with everything reconnected she fired straight away on full choke, not only fired but stayed running. Lots of relief and plenty of smiles!

We have to now fit a new downpipe gasket and replace the brass nuts and then hopefully she will run with no choke, at present you can hear her sucking air in so obviously messing up the mixture.
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1937 Ford 7w
1937 Hillman 80
1946 ERF C.I.5
1947 Hillman Minx
1955 Hillman Minx Mk8
1950 Commer R541
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alastairq



Joined: 14 Oct 2016
Posts: 1510
Location: East Yorkshire

PostPosted: Sun Nov 08, 2020 7:08 pm    Post subject: Reply with quote

Splendid. Onwards and upwards??
_________________
Dellow Mk2, 1951 built, reg 1952.
Ford Mustang coupe, 1967, 6 cylinder auto.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
----------------------------------------------
Ford Pop chassis, Ashley 1172 bodyshell, in pieces.
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kevin2306



Joined: 01 Jul 2013
Posts: 1351
Location: nr Llangollen, north wales

PostPosted: Sun Nov 08, 2020 7:51 pm    Post subject: Reply with quote

Thatís great news indeed.

Kev
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peter scott



Joined: 18 Dec 2007
Posts: 6543
Location: Edinburgh

PostPosted: Sun Nov 08, 2020 10:30 pm    Post subject: Reply with quote

kevin2306 wrote:
Thatís great news indeed.

Kev


+1

Peter
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http://www.nostalgiatech.co.uk
1939 SS Jaguar 2Ĺ litre saloon
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old iron



Joined: 22 Mar 2016
Posts: 125

PostPosted: Sun Nov 08, 2020 11:21 pm    Post subject: Reply with quote

Pleased to hear that you have now resolved the mystery
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Rootes75



Joined: 30 Apr 2013
Posts: 3117
Location: The Somerset Levels

PostPosted: Sun Nov 08, 2020 11:25 pm    Post subject: Reply with quote

Its funny but we've all been at this restoring/tinkering business for a long time but there is always something new with each vehicle that can stump you or have you running round in circles!
_________________
1937 Ford 7w
1937 Hillman 80
1946 ERF C.I.5
1947 Hillman Minx
1955 Hillman Minx Mk8
1950 Commer R541
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badhuis



Joined: 20 Aug 2008
Posts: 1191
Location: Netherlands

PostPosted: Mon Nov 09, 2020 10:01 am    Post subject: Reply with quote

Excellent news!
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Rootes75



Joined: 30 Apr 2013
Posts: 3117
Location: The Somerset Levels

PostPosted: Sun Nov 15, 2020 1:49 pm    Post subject: Reply with quote

Another morning tinkering, she was still only running on full choke so we have stripped and cleaned the jets etc and not she starts and ticks over without any choke!!

She is still sucking in plenty of air as I am waiting for a downpipe gasket. Again, as so many times before Speedy Spares have found one for me. Can't recommend them highly enough.
_________________
1937 Ford 7w
1937 Hillman 80
1946 ERF C.I.5
1947 Hillman Minx
1955 Hillman Minx Mk8
1950 Commer R541
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View user's profile Send private message
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