Cutting corners on automotive engines 9

[enginesrus]

Like the crankshaft snout that has no keyway cut into it, and requires a nice tight bolt to push on the harmonic balancer to keep the timing gear from rotating and throwing the valve actuating system out of time.
And best of all the bolt has a right hand thread (clock wise to tighten) and that end of the crankshaft turns the same direction, so you have not only dynamic movement from engine and firing pulses, but also any belt driven accessories like alternator, power steering pump and what ever else is belt driven tending to loosen that bolt. I personally don't think you would ever find such idiocy on an aircraft.

 

[Lou Scannon]

Valve pockets may not be avoidable in all cases, but a downside in SI engines is hotspots that can adversely affect the combustion recipe. In both SI and CI engines, the hotspots anyway can be a limiting factor on the engine's thermal limit (meaning maximum power capability, with reliability, not to be confused with maximum power capability without reliability). Also for both SI and CI engines, the valve pockets could constitute charge motion disrupters that again, adversely affect the combustion recipe.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz