Piston speed effect on wear

[boscoe99]

How much will the speed of a piston effect wear on the rings and cylinder walls, all else being equal?

Let's say that at 6K a piston will travel up and down at twice the speed that it will at 3K RPM. If one motor is run at 6K for one hour and another motor is run at 3K for two hours (so that both pistons travel the same total up and down distance) how much more wear would one expect on the faster moving engine? Or, would there be any difference?

Inquiring minds need to know. And, this is not a trick question.

[robert graham]

It's a good question, and normal common sense would say increases in RPM's would increase wear....but you'd probably need an engine laboratory to prove it conclusively....and I've really never known of an outboard to die due to cylinder/piston wear....maybe you guys have?...

[rodbolt17]

in 30 yrs of working on two strokes I have only seen TWO wear a ridge in a cyl.
both were 70 evinrudes and both were used to crab,net and oyster for about 15 yrs.
go play, enjoy your rig.

[rodbolt17]

overproping is the biggest killer, other than overheat, of outboards.

that piston goes from a dead stop,NO motion, accelerates to full speed and THEN dead stops again.

that's a fair load on the wristpins just dealing with piston weight.

add the extra load of lugging the motor(over propped = excessive combustion pressure) and the wrist pins fail.

to much overpropped and detonation eats the piston crowns at the lands long before the wristpin can fail.