Inclined Panel Deposit Test
15W-50 Semi-synthetic oil
With and Without CamGuard
540ºF – 2 hours
With CamGuard |
Without CamGuard |
540ºF – 4 hours
With CamGuard |
Without CamGuard |
The Inclined Panel Deposit test is used to determine how well a lubricant resists oxidation and deposit formation due to thermal breakdown. The stainless steel panels are held at an incline at a temperature of 540 degrees F. Oil is dripped continuously along the centerline of the panel one quarter of the way down marked by the two lines. The oil flows toward the pointed end of the panel where it drips off to be collected and reapplied to the hot panel. This accelerated test is designed to emulate the deposit forming tendencies of oils.
Aircraft engines are designed to run with large clearances. The reasons for this include the age of their design, the materials used, and most importantly the fact that they are air-cooled. Large clearances between pistons and cylinders lead to large amounts of blow-by, the gas that leaks by the piston rings during the high-pressure combustion events. Blow-by gas is made up of combustion by-products such as carbon dioxide, water and lead oxides, it also contains large amounts of air, partially combusted fuel (very reactive) and raw fuel. An engine that uses 15 gallons of fuel per hour may put 0.5 gallons of partially combusted and raw fuel into the crankcase per hour. Most of these fuel components are volatile and the vapors exit the engine through the crankcase breather. Other components are less volatile and remain in the engine diluting the oil. It is the blow-by gas that contaminates the oil and gives it that characteristic smell after only a few hours. It is the blow-by components that remain in the oil that are real troublemakers. They not only dilute the oil and additives but they are extremely reactive. In the upper ring zone they overwhelm the dispersant and antioxidants leading to carbon and lead deposits. Analysis of deposits found in the upper piston ring groove show them to contain over 2% lead and therefore fuel derived. Oil companies only put enough antioxidant to protect the bulk oil from oxidizing. This however is not the problem. CamGuard uses multiple high molecular weight antioxidants to address this “blow-by fuel dilution” unique to aircraft engines. The result is fewer deposits, which dramatically reduces the chance of sticking piston rings or valve guide “morning sickness”.
We tested a popular 15W-50 semi-synthetic oil with and without the addition of 5% CamGuard. The results on both the 2 and 4 hour tests show a dramatic reduction in the total amount of deposit formed with the use of CamGuard.
