Just out of curiosity really and to broaden my knowledge, what are inconel valves? Also why can't you have stainless with iron, seizing issues?
Just ran a magnet over it. The valve seats and stem guides are magnetic. Don't ask what specific material!
I've seen inconel in the exhaust heat shielding for Colin McRae's focus..
http://www.darchem.co.uk/products/insulation/automotive.stm
if this is all for a n/a engine then sodium filled valves are overkill, just go for ss valves and phos bronze guides
You can get the existing valve guides sleeved with phosphor bronze, pretty cheap and extremely reliable.
Pete
with respect to the alfa engineer he might be right, BUT i am speaking from exsperience and on my 1310 turbo project i use steel guides and road quality velves with no problems, the only backdraw of not using ss is that the valves need lapping a bit more often, i know people with 280 brake only using phos bronze guides and ss valves, oh ye another down fall of sodium filled valves are they are two peice so can come apart, most 214ss valves are 1 piece
It's -- arguably -- overkill, but not by too much if at all. Even the 105 bhp Uno Turbo used sodium filled stainless exhaust valves (and IIRC, water injection).
Of course, the idea is to get the heat out of the valves as quickly as possible to help keep detonation at bay.
if the japs didnt think sodium filled valves wernt needed then i would go with it there not stupid, better then most of us at r and d