While the rest of the world is in Wendover –
After quite a bit of back and forth between Fordboy, Dema Elgin and myself, we have settled on a grind that will fit the rather tight confines of the combustion chamber of the Midget. There are a quintabazillion grinds for the A-series, and none of the readily available stock grinds would give me the lift and acceleration/deceleration rates I needed to have without crashing the valves. After reams of documentation, notes, graphs and charts, much of which I’m just starting to have a better, if not complete understanding of, Dema came up with a lobe pattern that will work with my rather small lifters and still get me better than .500 lift rather quickly.
Fordboy, I am in your debt for the hours of slide rule work you put into this.
The lobe is a .350 lift, 252 duration at .050, ground on a 108 LCAs. For a comparison, the cam that was in it was .340 lift, 264 duration @ .050 on 105.5 and 102.5 advertised centerlines (scatter pattern).
I’ve ditched the scatter pattern principal this time, not because it’s not a good idea, but because the clearances are very tight at and around TDC. Additionally, to have to deal with two differing cam lobe center angles left reduced margins for error or adjustment. This grind is in keeping with the general comment from David Vizard as to what he thought the engine probably needed, and verified by what Fordboy’s research lead to.
On, Wisconsin - Go Marty, Go Stan.