Like a rev limiter?

[Griff]

Had a better look today. The cam on the inlet valve side is ok, but the valve seat has broken up due to the hammering caused by the valve slamming shut. The aluminium under the valve spring also looks like the hammering has started to wear it away. The lobe on the exhaust side of the cam-shaft looks pretty worn due to a poor surface finish or low oil in the past maybe?
I had a spare rocker arm from another engine so I lashed the engine back together and it actually ran! I think I'll just run it until it dies again and then look at swapping the engine over, or getting something less delicate.

[MJH]

Ouch…the valve clearance is set at TDC on the compression stroke, .07 on the inlet is correct but the exhaust should be at 0.10-0.12 they are different.