I posted this in the sc board as well...
I have some questions for anyone familiar with Engines.
Are the valves in the sc400, 1992 hydraulic?
Thus self adjusting?
I went to a mechanic to ask about getting my valve lash adjusted, I guess that's when youy measure/replace the plates correct? Because it's noisy and it's been ticking since last year (it starts when the engine warms up) He said that's definately the noise but if it's Hydraulic it's due to build up and gunk from thick oil (high mileage) between the valve and the plate or whatever it's called and running the engine with thin oil for a few minutes would take care of it to clear it out.

Can anyone agree with this? He said he can do this when he replaces my timing belt in 2 weeks.