1996 C-220 4-cyl dead #2 cyl

[Brickyard400]

1996 C220 with 240k 4-cyl has dead #2 cyl. Good spark, injector ok, zero compression. Engine would start and run missing on #2, with no ticking or noise. Pressurized thru the #2 sparkplug hole and air is exiting thru exhaust, even when the cam has the exh valves closed. Suspected broken valvespring, pulled valve cover, all looks good. Lifters are tight against the cam. I can pry the lifter away from the cam and it springs right back, suggesting the valve stem is not stuck in the guide. Now suspecting a pumped up (stuck with dirt) lifter or burned valve. Oil was very dirty, indicating previous owner performed poor or no maint. Tonight I plan to pull the exh cam and get the lifters out for inspection. Next step is pull the head, which I want to avoid if possible. Question is, are these engines known for lifter problems or burned valves? Looks like it has not jumped time, chain was tight and other cyls are good. thanks for any comments! -Don in Indy