so Jabiru decided to dumb the engine down by fitting hydraulic lifters. The mass of the solid lifter is tiny in comparison. Ergo large mass smashing back and fort
I don't believe reducing unnecessary maintence and the potential for inducing oil leaks every 25 hours is 'dumbing down'. I for one encouraged Rod to fit hydraulic lifters every time I saw him. Even my old 55 Vauxhall had hydraulic lifters. People who like adjusting tappets need to get a life.
I don't think mass had much to do with hydraulic valve problems. I think it was more a cam shape problem. It allowed the valves to shut too quickly or open too slowly or something like that. Forgive me but it was a while ago that I heard the explanation.
I fully agree about the need to control cooling and the need for accurate gauges.