Hello people. This is my first post in this neck of the woods. I live in the UK, West Midlands area. I have been doing model engineering for many years, but am currently tackling my first petrol engine.
It's a Westbury designed 10cc twin side-valve job, castings from Hemingway Kits 1.
You can see my progress (not very up-to-date atm, sorry) here: 2.
The latest problem I have with the design is the cam profile. As designed, the tappets are too small in diameter for
the cams, inlet in particular. As shown by plugging the dimensions into this brilliant resource 3, for a brief part of the motion, the cam is in contact with the edge of the tappet face, which seems unlikely to be good for either, or for noise (quiet is one of my criteria of success). Design dimensions are the same as the 'Seal': Base circle radius: 11/64", flank radius: 9/16", lift: 5/64" opening angle: 120°. I probably can make the tappets bigger, but ... any advice?