A hot coil, a hot horn, and hot backup lights

Posted Feb 16, 2012 By Bill Sherk

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The Car Detective poses with his 1947 Mercury convertible with the horn that overheated.

The Car Detective poses with his 1947 Mercury convertible with the horn that overheated.

EMC Lifestyle - An email arrived from Nigel Creasy of Kemptville, Ont., reads: "Dear Bill, I always read your interesting stories in the EMC newspaper, and yesterday's issue was no exception. You talked about a 1940 Buick Special which failed repeatedly on a trip to a wedding with the happy couple on board. I had a parallel experience with a car of similar vintage in Central Africa in the 1950s.

"The Buick kept on conking out for no obvious reason on a journey from Harare, Zimbabwe, to a village on the Zambesi River. The only thing obviously abnormal was an overheating ignition coil. This had nothing to do with the coil itself but with the ignition points, which had closed up from normal wear of the cam follower inside the distributor, causing the coil to be energized continuously instead of intermittently. This duty, for which it was never designed, produces no spark but an overheated coil instead.

"The cure is obvious: using an ordinary screwdriver, unscrew the fixed contact locking screw and slide the fixed contact to give an eyeballed estimate of the correct contact opening of about .025". Restore the distributor cap after tightening the screw. A small dab of engine oil from your dipstick gives the ignition system a new lease on life."

Well, Nigel, I had a similar experience, not with a coil but with the "ah-OO-gah" horn on my street rodded 1947 Mercury convertible. We were invited to lead the parade through Leamington, Ont., during our annual Tomato Festival. The street was lined with hundreds of spectators, including lots of children. As soon as I gave them the first blast on my horn, the kids yelled: "Blow it again, Mister!" Not wishing to disappoint them, I kept blowing it until we reached the centre of town, where it was reduced to a peep, then stopped altogether.

Thinking I had burned it out, I drove on hornless but waved at everyone. Near the end of the parade, I tried it again and it was as loud as ever! It had overheated from constant blowing and needed a few minutes to cool down.

Murray Woolner is a retired school principal and real estate agent in this same town. Back around 1960, he owned a Vauxhall (a little 4-passenger English car sold through Pontiac-Buick dealerships). The car had back-up lights but you had to move a lever to turn them on and off. He forgot to turn them off one day while driving home, and by the time he turned into his driveway, the plastic lenses had melted! They were not designed to withstand prolonged exposure to heat.

If the story of your car is published in this column, you will receive a copy of Bill Sherk's latest book "Old Car Detective Favourite Stories, 1925 to 1965." To share your stories, email billtsherk@sympatico.ca or write Bill Sherk, 25 John Street, P.O. Box 255, Leamington, ON N8H 3W2.