Detection of Piston Overheating

Shatter Cooling Effect (less at slow speed) - piston go up, more pipe length, less pressure Piston come down, more pressure Crown damage Thermal stress, mechanical loading Direct oxidation Catalytic oxidation Wet corrosion, water in fuel Piston Overheat due to: Overloading - excessive fuel Poor lubrication - friction more, heat up, water in fuel Poor coolant and faulty circulation - pressure and volume, deposits, scale and carbon for oil cooled, engine running slow, no full flow of coolant. Faulty injector - impingement - localized burning, star crack. Peel off layer, crazy crack Leaky after burning - loop scavenging hot gas return to crown Distorted liner or oversized piston - touch and friction, misaligned piston Faulty piston ring - blow by of gas Insufficient air from turbocharger for cooling Detection of Piston Overheating Occur at slow speed due to coolant not agitated and effectiveness reduced. Rise in cooling water return temperature Noise in cooling system due to vapor lock Crank mist for trunk piston using splash lubrication Dry patches and discolorization Smoke and smell   Aluminum piston Lose shine if overheated White powder oxidized or ash from fuel Worn groove can be deposited by argon arc method, but cannot do too many times due to weakening of material Piston Ring Material Made slightly harder than piston Ring speed faster, area of contact less Copper ring Loop scavenging for long piston skirt to avoid micro seizure due to piston touching liner Ring breakage Worn piston ring grooves, not straight, blow past Worn cylinder liners blow past Deposits in ring grooves, blow past Sticking rings blow past Combustion knock. Improper timing. Inadequate cetane no. Of fuel Local blow by of ring - blocked ring groove, chamfered too much, ring twisted Excessive piston clearance - piston slap (move sideways) Ring flutter Oil of inadequate quality Incorrect design of scavenging and exhaust ports, chamfer not proper. (Make narrow so that less length of ring unsupported) Incorrect shape of rings - chamfer, no allowance for expansion outwards Deposits on Piston Rings and Piston due to: Improper air filtration Improper fuel filtration (gas engine) Wet or corrosive gas Improper combustion High cylinder oil feed rate Worn or weak rings Incorrect jacket water temperature Continuous overload operation Blow by of piston ring High crankcase vacuum (trunk piston engine) High crankcase oil level (trunk piston engine)

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