April, 2006

2100 Walnut Street

Kansas City, MO 64108

Local Chapter of MAFCA and MARC

NEWS

‘A’

LETTER

Heart of America Model A Ford Club

“

Certificate of Merit” 2004

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Best Newsletter

Honorable Mention” 2004

1

A HIGH VOLTAGE CONVERSATION

Several weeks ago, several members of our club met for an evening meal at a trendy restaurant in North Kansas City. We

sat around a large round table right next to a large fireplace and bar. At first, the conversation was lighthearted, and it

was shaping to be a wonderful dinning and fellowship experience. However, storm clouds were about to gather.

Somehow, the topic of ignition coils came from the sideline to a center stage position. The point of discussion centered

on the question of, does reversing the polarity of the two wires on either side of the distributor wire reduce the voltage

produced by the coil? The gentleman seated to my immediate left made a case that reversing the wires did indeed, result

in a drop of voltage. The gentleman seated to my immediate right favored the theory that reversing the wires did not

make any appreciable difference in voltage. I think it is important to add at this point that both gentlemen have a formal

education in the field of electricity and electronics. The conversation was stimulating and informative, at first. Then I

noticed it was beginning to take on something of an intellectual contest. The jaw muscles began to tighten on the gentle-

man to my right. At the same time, the gentleman seated on my left began to bow his back.

This posturing went on and then escalated to the point where there might be physical contact. I thought this might be fun

since it had been years since I was in a good barroom brawl. Besides, if there was any damage our treasurer was there to

pay any damages so we could all attend our after dinner meeting. Luck was not on my side and I was destined to disap-

pointment because such a fight never erupted and the dispute was not settled on the manly court of honor. Therefore, the

original question was still unanswered.

Answering the riddle of polarity was an intriguing challenge that demanded a response from a non-bias individual. So, I

took it upon myself to investigate.

It seems there were two styles of coils used in the Model A. One was marked with a plus (+) and minus (-) because this

coil was polarity sensitive. Reversing the wires could indeed produce a lower output voltage from the coil to the distribu-

tor. The other coil used by Ford was not marked. In this instance, it didn’t matter which wire went where. Most of you

have probably heard about the pencil test to check for polarity and voltage. When I interviewed several people about this

test what surfaced was a minefield of information or disinformation depending on the person’s perspective. A very ex-

perienced senior member of our club came to the rescue by giving some excellent advice to check for proper polarity.

Secure an analogue voltage meter and disconnect the coil to distributor high voltage wire. Connect the meter to the dis-

tributor end of the coil wire and crank the engine. Notice the voltage spike on the meter. Now, reverse the smaller wires

and do the test. If the spike is less or more, you have your answer. An alternative would be to stand in a bucket of water

and grab onto the engine block with one hand and the coil wire with the other. Appoint someone to crank the engine and

measure how high your hair stands on end. The higher your hair goes, the more the voltage. Caution: This test will not

work for folic challenged people.

I hope to see you at our April membership meeting at our regular meeting place.

President Chris Launer