Ford CMP Coil Bracket

[david moore]

Thanks Terry and Keith. The Canadian engine is a Mercury too. The bracket you show looks different from the one in the spares book and your diagrams do not show the extended air cleaner housing over top of the generator which I think would foul the arrangement shown - I need to check my truck today (cab 12). I'm sure I can rig something to fit. I have been using a "normal" cylindrical coil to date.

Another question - I assume that this proper Ford coil as shown in your diagrams needs the externally mounted ignition coil resistor in circuit? The modern 6V coils do not need that resistor.

Final question - which manuals have these good diagrams that you have reproduced?

[david moore]

Terry
Looking again at your photos - the bracket is as shown in my parts book (and is the arrangement that I need to copy) but the lighter gauge support bracket is not in my book. I'm wondering if the need for that support was found later to avoid too much vibration of the coil?

The arrangement shown by Keith is perhaps for a carrier?

[Paul Singleton]

Hello David,

I tried to post yesterday but I see that my post never appeared. Here is a picture of the coil mount in a Ford Pick up that my be easier to fabricate if you have the room under the hood.

[Grant Bowker]

Be cautious when relying on the illustrations in parts (or maintenance) manuals. I base this on the Chev manuals where I have seen some of the identical illistrations used in manuals published for civilian pattern vehicles before there were any CMPs. In other words, they did an earlier version of copy and paste or diagram recycling. Some are trustworthy, some are questionable and some are outright misleading, at least for Chevs and I wouldn't be surprised if the same happened at Ford given the pressures to get information out quickly, using the least manpower possible.

[david moore]

Hi Paul
What is the bracket actually attached to? Cant see in the picture.
Cheers

[Keith Webb]

Originally Posted by Grant Bowker

Be cautious when relying on the illustrations in parts (or maintenance) manuals. I base this on the Chev manuals where I have seen some of the identical illistrations used in manuals published for civilian pattern vehicles before there were any CMPs. In other words, they did an earlier version of copy and paste or diagram recycling. Some are trustworthy, some are questionable and some are outright misleading, at least for Chevs and I wouldn't be surprised if the same happened at Ford given the pressures to get information out quickly, using the least manpower possible.

Good point Grant, but in the case of the driver handbook the illustrations came from it is entirely accurate for a cab 13 Ford. The handbook it came from is the
F15-HB1. I have some NOS copies of this book available for $A50 each plus postage if anyone is interested. Many of the illustrations apply to most of the Ford cab 13 CMP range.
The other bracket with the original type coil is a pressed steel unit which is mounted using two bolts on the valley cover.
The ignition resistor is mounted next to the voltage regulator.

[Lynn Eades]

As nobody else has answered, Yes you need the external resistor with the Ford coil. The Ford coil is in fact a 4.5 volt coil in a 6 volt system, hence the need for the resistor. It might last a while on six volt, but will probably fail.
Tony Smith posted here some time back saying something to the effect that; The Ford coil is unreliable, even NOS ones are the same due to deterioration internally. You are better off with a modern replacement. (this is my recall)

[Keith Webb]

Originally Posted by Lynn Eades

As nobody else has answered, Yes you need the external resistor with the Ford coil. The Ford coil is in fact a 4.5 volt coil in a 6 volt system, hence the need for the resistor. It might last a while on six volt, but will probably fail.
Tony Smith posted here some time back saying something to the effect that; The Ford coil is unreliable, even NOS ones are the same due to deterioration internally. You are better off with a modern replacement. (this is my recall)

You are absolutely correct, the original Ford coils in my experience are unreliable due to age deterioration. I must admit though, the brown bakelite design is very neat.

[T Creighton]

David, Keith's first picture shows the same bracket as in the lead page of the engine section in MBF1 manual.
My parts manual shows a different one again. (picture)
The p/n is 21a-2257 which is a common prefix. Our local vintage Ford parts shop has them listed for $NZ 15.02
Can make inquiries if you want.
Cheers, Terry

[Keith Webb]

Originally Posted by T Creighton

David, Keith's first picture shows the same bracket as in the lead page of the engine section in MBF1 manual.
My parts manual shows a different one again. (picture)
The p/n is 21a-2257 which is a common prefix. Our local vintage Ford parts shop has them listed for $NZ 15.02
Can make inquiries if you want.
Cheers, Terry

I reckon this is the one for the cab 12 (as well as many other Ford models).

[david moore]

Terry
Thanks for bracket info - actually I managed to make a very neat job (I think) of attaching the coil to the support bracket for the air cleaner - mine is a cab 12 with a '42 engine so it has the extended "schnorkel" air cleaner supported on a strut in the "valley"

Lynn has answered another question that I had - why, when I switch on the ignition with the coil resistor in circuit does the latter get hot? I did notice that input to the resistor was 6.9V and output 4.9V which I thought was bad news until Lynn 's message said that's how it should be. Presumably not a good idea to leave the switch on without the engine running - though it should still get hot even them, shouldnt it? Same voltage and resistance? The mysteries of electrics!

I have noted that I should get a new resistor - or go back to the modern conventional cylinder type that does not need the external resistor.

[T Creighton]

Originally Posted by david moore

Lynn has answered another question that I had - why, when I switch on the ignition with the coil resistor in circuit does the latter get hot? I did notice that input to the resistor was 6.9V and output 4.9V which I thought was bad news until Lynn 's message said that's how it should be. Presumably not a good idea to leave the switch on without the engine running - though it should still get hot even them, shouldnt it? Same voltage and resistance? The mysteries of electrics!

David, Lynn or others may contradict me on this but as I understand it the wire type resistors heat up due to the current trying to overcome the resistance. As they heat up the resistance increases and voltage decreases until a balance is reached when 6v is reduced to 4v. Therefore more voltage is available for starting as the resistor is cold and passes nearly all the 6v as long as the key has not been left on for a while first and the points happen to be closed.
Some vehicles have a starting circuit which bypasses the resistor when the starter is engaged.
Some say put a cold wet rag on the carb or fuel line when a hot vehicle will not start. Maybe it should be put on the resistor and coil instead!!!
Regards, Terry