John Builds Kerzel Hit & Miss

[Steamchick]

NOTE: The piston pin end-caps need to be DOMED the same radius as half the bore diameter. - It was common practice 60 or more years ago with racing 2-strokes (Villiers engines, BSA Bantam engines, etc.) - to eliminate circlip breakage (By eliminating the circlips).
K

 

[doc1955]

Hi doc1955: Just curiosity.... (I worked on engine design for a car manufacturer) what plug-gap are you working with? - What compression ratio is there on your engine? - Of course, I was thinking of typically 10:1 compression with plug gaps of 0.025 ~ 0.040 inch. But maybe you simply don't have that much compression on the models, nor full sized plugs with such large gaps?
Hence you'll manage with lower voltages and the current will be lower as well. - My smallest engine experience is with 50cc Honda engines at around 9:1. Using 0.5mm spark plug gap.
Cheers!
Ken

Motors have pretty decent compression never checked any or know what they are I run a .020 plug gap on a home made plug and also have run the same on I think a cm-6.