In a four-year test, Enstrom Helicopters powered by Lycoming engines were flown in year-round conditions for Chicago's WGN Radio's traffic reports. One 12oz. can of AVBLEND was added to the engine oil at each 50 hour change interval up to the engine's TBO.

FAA inspectors performed two consecutive engine disassembly inspections. Both inspections (1,000 hours and 1,100 respectively) produced impressive results. Less than .001 of an inch total wear between the critical exhaust valve stem-guide dimension was observed at both teardown inspection periods. Exhaust and intake valve, guides and seats showed minimal, if any carbon and deposit build-up. Pistons, rings, ring lands and combustion chambers also showed minimal carbon/deposit build-up and were in excellent condition. All four cylinders still consisted of the original nitride-steel barrels and were used for five complete overhaul cycles over a 10-year period, with no chroming or oversizing processes during engine service time.