I'm getting close to firing up my Speedster for the first time, but before I do, I'd like to gain some advice on the right/best spark plugs for the Waukesha Ricardo head. It has .062" removed from the surface and presently its fitted up with good, used Champion C4 plugs.
Because they're bigger than the plugs used in Model T heads, I'm flying blind. So any advice would be welcome.
Thanks in advance,
Howdy Rob, I run a Waukesha Ricardo head on my '19 centerdoor and it's the preppiest T in my stable. I just use the F11s.....
I run original (NOS) Champion X's in both of mine - no worries !
Any plug is good
Just put it in the hole and beat it in with a hammer
The Waukesha heads used to have the same 1/2" tapered thread plugs as the T head, but maybe someone drilled and threaded your head for larger thread plugs? Try measure the thread and source adapters or try find fitting plugs among swap meet sellers or online.
Model A Fords have 7/8"x18 spark plug threads, maybe that's what you've got?
I think you're correct in this. This head had 7/8" Champion C-4 plugs fitted when I imported it and Champion X's just drop into the hole.
Since these heads were used on Fordsons as well as T's and were produced well after production of the T stopped, could it have been made this way, rather than having been modified?
I also have here a set of NOS Leonard 4-HD plugs which also screw into the thing. The Spark Plug collectors club tell me that on a heat range scale of 1-10, the C-4's are around a 7 while the 4-HD's are about 3.
I guess I should be asking this of a Model A forum, but can anyone suggest a middle of the range plug? What about the Champion 3X ?
Thanks again and cheers,
I would consider retapping the holes for threaded inserts. I saved a no Made in USA head that way. Hard to beat Champion X plugs in a T.