Drive Belt System Description
The drive belt system consists of the following components
- The drive belt
- The drive belt tensioner
- The drive belt idler pulley
- The crankshaft balancer pulley
- The accessory drive component mounting brackets
- The accessory drive components The power steering pump, if belt driven The generator The A/C compressor, if equipped The engine cooling fan, if belt driven The water pump, if belt driven The vacuum pump, if equipped The air compressor, if equipped
The drive belt system may use 1 belt or 2 belts. The drive belt is thin so that it can bend backwards and has several ribs to match the grooves in the pulleys. There also may be a V-belt style belt used to drive certain accessory drive components. The drive belts are made of different types of rubbers - chloroprene or EPDM - and have different layers or plys containing either fiber cloth or cords for reinforcement.
Both sides of the drive belt may be used to drive the different accessory drive components. When the back side of the drive belt is used to drive a pulley, the pulley is smooth.
The drive belt is pulled by the crankshaft balancer pulley across the accessory drive component pulleys. The spring loaded drive belt tensioner keeps constant tension on the drive belt to prevent the drive belt from slipping. The drive belt tensioner arm will move when loads are applied to the drive belt by the accessory drive components and the crankshaft.
The drive belt system may have an idler pulley, which is used to add wrap to the adjacent pulleys. Some systems use an idler pulley in place of an accessory drive component when the vehicle is not equipped with the accessory.
Lubrication Description
The lubrication system consists of an oil pan, oil pump screen, oil pump, oil filter and oil pressure regulator. This pressure-fed lubrication system supplies oil to the moving parts of the engine.
The oil pump picks up oil from the oil pan and feeds it under pressure to the various parts of the engine. An oil strainer is mounted before the inlet to the oil pump to remove impurities which could clog or damage the oil pump or other engine components. The oil pump itself is a trochoid gear type pump with internal drive and driven gears. When the drive rotates, the driven gear rotates in the same direction, but on a different center point. This causes the space between the gears to constantly open and narrow, pulling oil in from the oil pan when the space opens and pumping the oil out to the engine as it narrows.
The oil filter is a full flow type with a relief valve built into the paper filter element. Contaminants which can get into the oil during operation could cause accelerated engine wear or seizing if allowed into the engine. The oil filter, situated at the beginning of the oil passage circuit, removes these contaminants as the oil passes through it. The relief valve spring will open under the pressure of the oil and allow oil to bypass the filter and flow directly to the engine.
At high engine speeds, the oil pump supplies a much higher amount of oil than required for lubrication of the engine. The oil pressure regulator prevents too much oil from entering the engine lubrication passages. During normal oil supply, a coil spring and valve keeps the bypass closed, directing all oil pumped to the engine. When the amount of oil being pumped increases, the pressure becomes high enough to overcome the force of the spring, opening the valve and allowing excess oil to flow through the valve and drain back to the oil pan.
Oil is pumped from the oil pan by the oil pump. After it passes through the oil filter, it is fed through two paths to lubricate the cylinder block and cylinder head.
In one path, the oil is pumped through oil passages in the crankshaft to the connecting rods, then to the pistons and cylinders. It then drains back to the oil pan.
In the second path, the oil is pumped through passages to the camshaft. The oil passes through internal passageways in the camshafts to lubricate the valve assemblies before draining back to the oil pan.