[Johnno]

Just had another look at the video, looks like a shim spacer is added to the front of the rachet

[Wingerdave]

So, earlier someone said the engine was of the "interference" persuasion. If that is the limit of the damage them i withdraw my earlier comments on replacing the engine.

But..... I'd be loath to call this an interference engine, more like a sort of hybrid design where the valves Kiss the pistons in an almost pseudo-erotic, SM manner. A true old school interference engine will demolish itself.

 

[Phil №❶]

valve kissing pseudo-erotic, SM manner engines, seem to fit this forum quite well. 

[Wingerdave]

That would seem to be the case, yes.