Is the trend now to go with lighter viscosity oils in equipment.

[sixdogs]

Honda has a failed philosophy in their continued use of timing belts on their engines. Having to break into the engine to replace timing belts so early in an engines life is poor engineering practice.

Agreed. I have no problem with a timing belt but a four hour wait in a dealer's shop and an outrageous labor cost to replace one at 70,000 (?) miles is a designed ripoff I want no part of. I actually stopped buying Toyota trucks that had timing belts on them until they went to chains. I don't mind engineers designing whatever the company wants but I don't have to buy it.

 

[Grumpycat]

The 3 cyl Ford 1.0 ecoboost had an interesting solution of running the belt in oil, lowered friction even further and extended service life, supposedly good for the life of the engine.

On almost all aircraft engines the accessories are gear driven, no belts or chains (a few older, very simple designs have a belt driven generator or alternator though). Weight is orders of magnitude more important on an aircraft than a car, yet they went with gears instead of belts. Durability and reliability are obviously high priority on aircraft powerplants. The reason for belts/chains is a cost one (and overhead cam as mentioned, but I'm not sure how many models of 'equipment' employ that)

The 160cc Honda OHC utility engines have belt in oil. Expect all OHC utility engines have belts in oil.

Reliability trumps weight on aircraft. The point about lowered weight in automotive applications is that less mass in the valve train allows engine to change speeds quicker. Requires less power to accelerate the valve mass.

Nobody mentioned Ducati Desmodromic engines. No springs on the valves.