MTFCA Forum

We have a 1926 New and Improved touring and it had an occasional skip. I thought it was time to clean the plugs and timer. Removing the plugs there was a carbon build up. I cleaned off the carbon with acid thinking it would come out cleaner than any other way. Completed the cleaning and installed the plugs. The car would not start. Charged the battery and tried again. No luck. I took all the plugs out and reattached the plug wires with the plugs resting on the head. One plug occasionally had a spark. They were grounded out and even cleaning again with brake cleaner would not let the insulators work. Who new the acid would disable the plugs. Replaced the plugs and the car was back running well.

While feeling good about this discovery, we noticed the spark plug wires were occasionally sending a spark, at the coil box end over to the 6 volt wires on the box. Repositioned the high tension wires away from the 6 volt wires and it stopped the random sparking and the skipping that started this maintenance, has stopped.

Always a learning experience and a car show where ever you stop.

Nick

Better way to clean is to scrape off the electrodes and or sandblast the insulators. That acid, must have either opened some connection or caused an internal short which would cause no spark. The old spark plug cleaners were small sandblasters.
Norm

acid is very good conductor and so are its salts. your plugs are shorted. most salts are water soluble so you might save them by a long soak I water.

Of course there are acids and there are acids. What acid did you use for your cleaning? A search of the internet suggest muriatic (hydrochloic) acid of a weak percentage. Or as suggested from a period publication Acetic (Vinegar) Acid.

Of course I believe the suggestion id for the top of the sparking plug and not the electrodes. Best a wire brush or grit blast.

An old trick on your mechanic friend. Dip a rag in battery acid. Wipe the outside of each sparkplug with the rag. The car will not start and it probably will take your friend to find the issue.
Art Mirtes

Norman Kling wrote: ↑

Sun Jul 25, 2021 7:10 pm

Better way to clean is to scrape off the electrodes and or sandblast the insulators. That acid, must have either opened some connection or caused an internal short which would cause no spark. The old spark plug cleaners were small sandblasters.
Norm

I have one of those that my grandfather bought prior to WW2.

I knew it existed because I remember him using it when I was a kid and I knew it was in my dad's stash of misc stuff. My dad found it a few weeks ago and gave it to me.

Can't wait to dust it off and use it on my plugs.