So ok I've got it all wrong and that's just not me. So recently we had to change 6 cly on 210 where the operator was experimenting with lop. Fuel flow px where check on cal gauges as per m/m. Mags check no further defect where found but we still has 6 dead cly. May be my imagination. Any way operator was ok about it. Yo see wasn't his areoane he just operated the owner had to put the bill for the cly and that with the aircraft out of service we'll mmmm $$$$$$. We used to do top o/h here and then get an extension on engine tbo but casa stop that. One place I worked had a system of maintenance that gave an enormous life extension to there tsio 540s with tops done same as hazeltons airlines. Now with all of this have a look what's in front of you. The weakest part is the exhaust valve. M/M states nil leakage past the valve on a leak rate test. Now if I'm wrong what causes 6 cly to all be u/s at the same time. Maybe I should give it all away and do some thing else.
Now still anyone tell me what the first indication is of a blocked injector is.