Ok. These plugs are not like the plugs on the muscle cars I have rebuilt my whole life. Does anyone have a photo of how they should look with a proper gap? I have a 1919 T with a stock engine - hand crank.
These are Champion X plugs. That's what was originally used on Model T Fords. They have an advantage over more modern plugs you may find on a T: you can take them apart and clean them, so they are good for decades. The first two pictures show a version that can be completely disassembled. The terminal thread on top, I believe, is 6-40.
The third picture shows the type above with another type that has the cap crimped on at the top. The terminal is stuck in the insulator, but the bottom comes apart for cleaning. The terminal thread on these is 8-32.
Wow! Thanks! These photos are of great help. I am going out to the garage and start taking them apart right now.
I forgot to mention that the gap is on the SIDE of the post, not under it. The electrode angles up toward the post so gas or oil won't collect on the end of it. Gap is 1/32".
The electrode position was the missing question about the plugs. Thanks
Here you go, this is old time info....
Dan - Wondering what book you copied that piece about spark plugs is from? Well written, full of detail and great illustrations! Looks familier to me but I can't seem to find it in my "Model T library"!
Steve - Can't help but notice what beautiful close-up photos you take. Not only the spark plug photos on this thread but also close-up detail photos that you have shared with us in the past. Can't help but think it's a combination of a really good digital camera and lots of experience with it! EVERYBODY enjoys photos in this forum, and yours are right up there in quality with a few other "T" guys, including the beautiful carburetor photos that that ol' Montana auctioneer takes when he's not all involved in the Model T rear end Ruckstellification process!