I'm sorry for reviving an old topic, but I've got something to ask.
So there is ABSOLUTELY no need to use sodium-filled exhaust valves if an engine doesn't feature forced induction and I want it to be pretty durable, right?
I'm building a russian engine in 4AGE style, changing all the valves to light 6 mm stem ones. I've got a set of Subaru WRX STi sodium filled exhaust valves, but they would require larger clearences than solid ones, would they? So if I'm likely to build the engine in Toyota durability style, I'm better to switch to solid valves and tighter clearences.
The engine is quite known for burning exhaust valves, that's why I've chosen the WRX STi sodium-filled exhaust valves. (They are almost completely identical, only +0.5 mm in height)
