16-07-2012, 12:37 PM
Piston Failure Analysis
Piston ppt.ppt (Size: 1.73 MB / Downloads: 81)
Normal Pistons
Deposits vary from oil ash, brown, tan, to black/brown. Light color denotes higher cylinder temperatures.
Light scoring is normal, varnish from blow-by gas is normal
Heat Seizure
Excessive heat, over 1200F/650C EGT
Lean jetting or adjustments on carb
Incorrect loading on propeller allowing excessive RPM
Piston Fracture
Complete disassembly required to remove all material
Cause from excessive wear, excessive RPM with no load, excessive clearance fitting.
Outlet valve
An carbon relief arc (C-ARC)are used in it due to relief of urburnt carbon element.
This type of valve is made of bimetallic element upper tip is made of harder material.