During the initial delivery period up to 50 hours of engine use, what type of oil should be used?

During the initial delivery period up to 50 hours of engine use, what type of oil should be used?

• A. Aviation Grade Ashless Dispersant Oil
• B. Aviation Grade Straight Mineral Oil
• C. Aviation Grade Synthetic Oil
• D. Aviation Grade Multi-Grade Oil

Answer: (B)

During the first 50 hours, the engine is in a break-in period and needs oil that won’t interfere with the seating wear of the new or rebuilt parts. Aviation grade straight mineral oil has essentially no detergents or dispersants, so it allows piston rings and cylinder walls to wear in and establish a proper lubrication film without additives that could hinder the mating surfaces. After this initial period, you switch to the oil recommended for normal operation, which is typically an ashless dispersant oil that provides detergents to keep the engine clean and to suspend any contaminants. Oils with synthetic or multi-grade properties have different viscosity or additive chemistry that isn’t ideal for break-in and are used after the engine is considered run-in, per the POH.

During the first 50 hours, the engine is in a break-in period and needs oil that won’t interfere with the seating wear of the new or rebuilt parts. Aviation grade straight mineral oil has essentially no detergents or dispersants, so it allows piston rings and cylinder walls to wear in and establish a proper lubrication film without additives that could hinder the mating surfaces. After this initial period, you switch to the oil recommended for normal operation, which is typically an ashless dispersant oil that provides detergents to keep the engine clean and to suspend any contaminants. Oils with synthetic or multi-grade properties have different viscosity or additive chemistry that isn’t ideal for break-in and are used after the engine is considered run-in, per the POH.