Very cool, Andy. What prop difference are you seeing without liquid torque? Did you have to experiment much with head buttons?
Same L.E. pitch Tim. Much less cup and a little less blade area. The methanol does not NEED the load like nitro does.
I made ONE head. Did not even calculate the C.R. I just made the volume much smaller than what we use for 60% nitro.
I simply cut until it LOOKED ABOUT RIGHT. LOL
I guesstimate C.R. to be about 17/1. Maybe a little more. It takes a GOOD starter to fire off this engine!.. I mean to turn it over!
Started with .022" clearance and worked my way down. Stopped when I got to .005" which is where it worked best.
Carb bore, spraybar bore and stinger are all important just like nitro but the best dimensions are not the same. However, I have not had time to get that part
totally worked out yet.... Just roughed out. Generally, the spray bar bore must be much smaller or the card bore much bigger or the stinger much bigger. Some carbs would actually work without pipe pressure.
Used an O'Donnell 99 Turbo plug...have not burned or broke the element....still shiny.