.... in my Model Ts. Just removed one with about 400 miles of wear. The interior electrode was needle thin. My magnetometer reveals I'm producing 30 volts at about 20 MPH. Are these plugs only made for 12 V D.C. Gèrman cars? Interested in hearing other's experiences.
A quick internet search brings this up, I'm pretty sure that the plug can handle it. Modern coils on cars are about 100-150:1 so they boost that 12vdc way up.
You may check to see if your gap was too wide or not wide enough.
I think a lot of those plugs have needle thin electrodes to begin with.
It doesn't matter so much how much voltage you put into the coil as it does how much you get out. As Jeffery states, a T coil will never get anywhere close to the output of a modern ignition, which these plugs are made for.
Thanks Jeffrey and Jerry, good advice indeed. I had no idea that modern coils put out that much voltage. This is about my only detraction from originality because of replacement availability on a tour. For the price of a Champion X the wife and I can have a steak dinner and the F 11s and A 25s aren't in most local parts stores. Actually, the set of 9mm Bosch I bought today won't be going on a tour. They're for my '22 Fordson F. Thanks guys !
9mm? The smallest plugs I've seen in a car were 10mm, used on Packards in the 30's/40's and Volvo's in the 40's/50's. The modern plugs used in T's are usually 14mm.