Valve lift at TDC, piston-valve clearance

[rcfanatic]

Two questions.

1. Got an 885 head with stock cam..When the hash mark on the cam sprocket is aligned with the mark on the cylinder head, this should indicate TDC correct? When the mark is aligned the valves are completely closed. I found this graph for M20 valve lift that indicates about 1mm of lift at TDC. So what am I doing wrong?

2. Which angle (relative to the cam sprocket) do the valves make their closest approach to piston #1? I'm checking the valve clearance with a dial indicator.

Closing in on the end of this project.. just need to get the clearances figured out. Thanks

[jlevie]

The hash marks on the flywheel and camshaft sprocket mark TDC on firing stroke for cylinder 1, at which point both valves are closed. Valve overlap occurs at TDC between the exhaust and intake stroke.The closest approach of the valves to the pistons occurs about 115deg on either side of that point.

[rcfanatic]

The hash marks on the flywheel and camshaft sprocket mark TDC on firing stroke for cylinder 1, at which point both valves are closed. Valve overlap occurs at TDC between the exhaust and intake stroke.The closest approach of the valves to the pistons occurs about 115deg on either side of that point.

Perfect.. thanks very much, Jim