Since the subject pops up every now and then, here is the info I have available:
1. DETs do have sodium-filled exhaust valves.
2. DEs MAY have sodium-filled exhaust valves.
3. There are 2 ways you can actually recognize them.
A. By checking the valve head (side looking in teh combustion chamber)
B. By checking the diameter of teh valve stem.
Consult the following images for identifying exhuast valves (they are from the N14 FSM, circa 1991):
General SR20DE(T) valve identification
Sodium Valve Head Marking
SDS sheet for valves
Note in this last one the difference in the Valve Stem Diameter.
There are also threads in the forum that point to the fact that similar stem-diameter valves find habitate in K-series engines so look for them (especially since the valve guides for the K can accomodate the large stem diamaters for sodium filled valves).
Chris
