Started work on my VCH

[david.anderson]

Brian
5/8 advance is too much for your compression ratio. It could result in pinking and a cracked piston The HS all alloy engines are specified ½” advance at 9 to 1. I am using 7/16” advance at 10 to 1 although my piston does incorporate some squish. Generally, as you increase compression you must also retard a little. In your case i would set 1/2"
Once on the road and running you should always be at or near full advance (only ever full advance from 3000rpm +) and only retard to come back to idle. The use of the valve lifter to stop the engine is normal. Likewise to fully retard on a hill will kill the engine power.
David

[Brian_Walker]

Thanks David, I think I'm having to run the 5/8" spark advance because the cam may be one tooth out. Re-checking my cams now, my 51 service notes say 5/8" for fast runs. I did a bit of digging and it appears even though the serial number is TR (1952) it was built in Sept 1951 and was #17 of the line but not shipped to Australia till Jan 1952. I read a piece that said GB boxes and single lobe cams were not changed until TR122.
Once I have checked cams I will re-time to 1/2" and see how it goes.
The trick with the retard on the hill was to take it back to 1/2" advance and see if it speeds up.
Brian