I bought a box of these plugs at the Lau garage sale. They look just like regular Champion brass top X plugs but these say Champion 31 on them. Any one familiar with these?
Higher the number, hotter the plug, hotter plugs are good of a worn engine that is using a little oil.
I have only one of the 31 plugs. I wonder how a reasonably good T engine would run on a set of these?
I am running Champion 31 Made in Canada plugs, rebuilt engine, no problems first year since restoration.
Looks like the ground is at the tip of the electrode and I believe the X plugs are on the side. Jim