DF Sales&Marketing
Oil Tech Moderator
Question: my engine burned a piston. What does that mean? - and why did it happen?
Answer: it means the piston failed due to excessive heat in the combustion chamber. A burned piston will typically have a melted appearance, or a hole burned completely through the top of the piston. Aluminum can only withstand so much heat, and when it gets too hot, it melts. The underlying cause is usually detonation and/or pre-ignition.
Detonation occurs when the temperature and pressure inside a cylinder exceed the fuel’s octane rating. Instead of igniting when the spark plug fires, the air/fuel ignites spontaneously much like a diesel engine. This creates multiple flame fronts within the combustion chamber that collide and hammer the top of the piston, producing a metallic knocking noise called “spark knock.”
common causes of pre-ignition detonation include a buildup of carbon deposits in the combustion chamber and on the top of the piston that increase compression, no egr (exhaust gas recirculation), over-advanced ignition timing, a bad knock sensor, a lean fuel mixture, low quality gasoline that does not meet minimum octane requirements, or any cooling problems that causes the engine to run hotter than normal (coolant leak, low coolant level, bad water pump, stuck thermostat, restricted radiator, defective cooling fan, even exhaust restrictions that back up heat into the engine.)
pre-ignition occurs if a hot spot develops in the combustion chamber that ignites the air/fuel mixture before the spark plug fires. The hot spot May be the spark plug itself, an overheated exhaust valve, carbon deposits in the combustion chamber, or a sharp edge in the combustion chamber.
Common causes of pre-ignition include the wrong heat range spark plugs (too hot for the application), carbon deposits in the combustion chamber and on the tops of the pistons, a lean fuel mixture, detonation or anything that makes the engine run hotter than normal.
On engines that are turbocharged or supercharged, too much boost pressure and/or not enough fuel can burn a piston very quickly. Check the operation of the wastegate and boost control system. If the turbo system has been tweaked to deliver higher than stock boost pressure for more power, the turbo May be pushing more air into the engine than the stock injectors can handle, causing the fuel mixture to lean out and burn the piston.
An often overlooked cause of piston burning is a weak or dirty fuel injector. If an injector is not spraying enough fuel into the combustion chamber, the air/fuel mixture in that cylinder May become too lean increasing the risk of detonation, pre-ignition and piston damage.
Editor’s note: a lot of the fuel available today is a little less than ideal in many areas, especially in the detergency aspect. A dirty fuel system causes poor fuel economy, poor performance and increased maintenance costs. Swepco 503 eliminates these problems by keeping fuel injectors, pumps and other close tolerance components clean. Special chemistry dissolves and removes harmful gum, varnish & carbon deposits in fuel systems and upper cylinder areas.
Swepco 503 is a unique blend of specialized high-temperature resistant solvents and highly effective rust and corrosion inhibitors. The carefully balanced solvent portion is extremely effective for removal of all forms of harmful engine deposits as well as prevention of their formation, including gum and residues which tend to form in fuel injectors, fuel tanks, fuel filters and fuel lines, inhibiting proper fuel delivery and robbing power. It will not overheat, warp or burn exhaust valves. A 12 oz bottle of 503 will treat 30 gallons of gasoline.
Question: what is a “scuffed” piston?
Answer: a scuffed piston is one that has been damaged by rubbing against the cylinder wall. The metal-to-metal contact smears the metal on the skirt of the piston and damages the piston.
Scuffed pistons can be caused by too much heat in the combustion chamber, engine overheating or inadequate lubrication. The piston-to-cylinder clearances in most late model engines is much less than it used to be to reduce piston rock and noise. Consequently, if the piston or cylinder gets too hot, the clearance goes away and you get metal-to-metal contact.
In instances where piston scuffing occurred due to a loss of lubrication, the underlying cause May be a low oil level in the crankcase (due to a lack of maintenance or an oil leak), low oil pressure (a worn oil pump), poor oil quality, or oil breakdown (not changing the oil often enough).
When diagnosing a scuffed piston, note where the piston is scuffed. If the cause is overheating, the scuffing will mostly be on the upper ring lands and on the sides near the wrist pins.
There May also be oil carbon and lacquer burned onto the underside of the piston indicating it got too hot. Scuff marks on the lower skirt area often indicates a lack of lubrication (check the oil pump and pickup screen). Scuff marks on the edges or corners of the thrust sides of the piston May be the result of bore distortion. Scuffing on both thrust sides would indicate binding in the writst pin.
Editor’s note: swepco engine oils use the proprietary additive “dimonyl” which acts as a synergist to enchance the performance of base stocks and additives. It forms a protective film eliminating premature wear and friction and helps improve fuel economy by reducing friction & drag. It also helps build the film strength required to withstand extreme pressures.
Answer: it means the piston failed due to excessive heat in the combustion chamber. A burned piston will typically have a melted appearance, or a hole burned completely through the top of the piston. Aluminum can only withstand so much heat, and when it gets too hot, it melts. The underlying cause is usually detonation and/or pre-ignition.
Detonation occurs when the temperature and pressure inside a cylinder exceed the fuel’s octane rating. Instead of igniting when the spark plug fires, the air/fuel ignites spontaneously much like a diesel engine. This creates multiple flame fronts within the combustion chamber that collide and hammer the top of the piston, producing a metallic knocking noise called “spark knock.”
common causes of pre-ignition detonation include a buildup of carbon deposits in the combustion chamber and on the top of the piston that increase compression, no egr (exhaust gas recirculation), over-advanced ignition timing, a bad knock sensor, a lean fuel mixture, low quality gasoline that does not meet minimum octane requirements, or any cooling problems that causes the engine to run hotter than normal (coolant leak, low coolant level, bad water pump, stuck thermostat, restricted radiator, defective cooling fan, even exhaust restrictions that back up heat into the engine.)
pre-ignition occurs if a hot spot develops in the combustion chamber that ignites the air/fuel mixture before the spark plug fires. The hot spot May be the spark plug itself, an overheated exhaust valve, carbon deposits in the combustion chamber, or a sharp edge in the combustion chamber.
Common causes of pre-ignition include the wrong heat range spark plugs (too hot for the application), carbon deposits in the combustion chamber and on the tops of the pistons, a lean fuel mixture, detonation or anything that makes the engine run hotter than normal.
On engines that are turbocharged or supercharged, too much boost pressure and/or not enough fuel can burn a piston very quickly. Check the operation of the wastegate and boost control system. If the turbo system has been tweaked to deliver higher than stock boost pressure for more power, the turbo May be pushing more air into the engine than the stock injectors can handle, causing the fuel mixture to lean out and burn the piston.
An often overlooked cause of piston burning is a weak or dirty fuel injector. If an injector is not spraying enough fuel into the combustion chamber, the air/fuel mixture in that cylinder May become too lean increasing the risk of detonation, pre-ignition and piston damage.
Editor’s note: a lot of the fuel available today is a little less than ideal in many areas, especially in the detergency aspect. A dirty fuel system causes poor fuel economy, poor performance and increased maintenance costs. Swepco 503 eliminates these problems by keeping fuel injectors, pumps and other close tolerance components clean. Special chemistry dissolves and removes harmful gum, varnish & carbon deposits in fuel systems and upper cylinder areas.
Swepco 503 is a unique blend of specialized high-temperature resistant solvents and highly effective rust and corrosion inhibitors. The carefully balanced solvent portion is extremely effective for removal of all forms of harmful engine deposits as well as prevention of their formation, including gum and residues which tend to form in fuel injectors, fuel tanks, fuel filters and fuel lines, inhibiting proper fuel delivery and robbing power. It will not overheat, warp or burn exhaust valves. A 12 oz bottle of 503 will treat 30 gallons of gasoline.
Question: what is a “scuffed” piston?
Answer: a scuffed piston is one that has been damaged by rubbing against the cylinder wall. The metal-to-metal contact smears the metal on the skirt of the piston and damages the piston.
Scuffed pistons can be caused by too much heat in the combustion chamber, engine overheating or inadequate lubrication. The piston-to-cylinder clearances in most late model engines is much less than it used to be to reduce piston rock and noise. Consequently, if the piston or cylinder gets too hot, the clearance goes away and you get metal-to-metal contact.
In instances where piston scuffing occurred due to a loss of lubrication, the underlying cause May be a low oil level in the crankcase (due to a lack of maintenance or an oil leak), low oil pressure (a worn oil pump), poor oil quality, or oil breakdown (not changing the oil often enough).
When diagnosing a scuffed piston, note where the piston is scuffed. If the cause is overheating, the scuffing will mostly be on the upper ring lands and on the sides near the wrist pins.
There May also be oil carbon and lacquer burned onto the underside of the piston indicating it got too hot. Scuff marks on the lower skirt area often indicates a lack of lubrication (check the oil pump and pickup screen). Scuff marks on the edges or corners of the thrust sides of the piston May be the result of bore distortion. Scuffing on both thrust sides would indicate binding in the writst pin.
Editor’s note: swepco engine oils use the proprietary additive “dimonyl” which acts as a synergist to enchance the performance of base stocks and additives. It forms a protective film eliminating premature wear and friction and helps improve fuel economy by reducing friction & drag. It also helps build the film strength required to withstand extreme pressures.