Oil and Oil Systems

Purpose of Oil• The purpose of oil is to…

reduce friction.– Friction: is the resistance to motion created

by 2 metallic objects rubbing against each other resulting wear on the materials and producing heat as a by product.

– Example: the brakes on a car when you press the brake pedal you are causing the brake pads to rub against the rotor causing friction and slowing the car down.

Types of Oil• There are several different types of oil but in

typically small engines use either synthetic or conventional oil.– Synthetic- has chemical additives to improve the

composition, results more expensive, yet more efficient

– Conventional- petroleum based (pumped from oil wells) no additives involved is cheaper

Oil Ratings• Oil is rated by its viscosity• Viscosity: is thickness or thinness of a liquid.

– Example: Water has a low viscosity, maple syrup has a high viscosity.

• Engine oil must be thin enough during cold temperatures yet thick enough with high heat conditions.– Two ratings:

• SAE 5W-30 Rating at 212 F (high temp. rating)• SAE 5W-30 Rating at 0 F (low temp. rating)

What does this mean?

What does each API rating mean?

1 2 3

4 5 6

Thick Oil vs. Thin Oil

• Thick oil is used to protect against extreme temperature, reduces fuel economy.

• Thin oil is used because it aids in cold engine starting, improves fuel economy.

Your Assignment• Define the following oil systems

– Splash lubrication– Barrel pump pressure lubrication– Full pressure lubrication

• Draw a picture and label the parts of all three systems.

• Next in a short paragraph describe how EACH of the three systems work.