Ash content corrolations to Pre-Ignition

[vex]

Originally Posted by joff

Very interesting thread.

Any speculation as to why oil ash content causes higher preignition? Is it because of the ash in the exhaust->intake carry-over volume due to the burning oil in the expansion/exhuast strokes?




Preignition within 8 cycles??!! I doubt many people have paid that much attention to oil ash content in the past -- how can there not be more blown motors because of this?

8 cycles on a single rotor test bed. Just because you have a pre-ignition event does not mean you'd have a catastrophic pre-ignition event.

As for speculation on why the ash causes pre-ignition events it's nothing more than a few ideas being passed around. As it stands right now the Pre-ignition is a direct result of ash because of carbon build up on the combustion surfaces. The carbon build up carries over heat causing the pre-ignition event where the gas reaches its flash point with contact to the surface. But that's just a theory.