Engine problem

Lack of compression in that cylinder indicates a mechanical problem. Most likely a valve train problem, do the rockers appear tp be broken (compare to others)? Have you timed your engine before? Place the engine at top dead center cylinder number one firing, both valves should be loose, you can measure the clearance with a feeler guage, the measurement for clearance I think is .008, you can google that to be sure. if the measurement is too loose (wide) check the adjustment screw see if it is stripped out, you may need to replace the adjusting assembly. If the adjustment is correct and you have a compression leak from the valve it is probably burned and nothing short of cylinder head removal will fix it. I hope this helps you, good luck!