Toyota 22R-E Service Manual page 37

EG1–3
ENGINE – ENGINE MECHANICAL
The 22R–E engine is in–line 4–cylinder engine with the cylinders numbered 1–2–3–4 from
the front. The crankshaft is supported by 5 bearings inside the crankcase. These bearing are
made of kelmet.
The crankshaft is integrated with 4 weights which are cast with it for balance. Oil holes are made
in the center of the crankshaft to supply oil to the connecting rods, bearing, pistons and other
components.
The firing order is 1–3–4–2. The cylinder head is made of aluminum alloy, with a cross flow
type intake and exhaust layout and with pent roof type combustion chambers. The spark plugs
are located to the left of the combustion chambers.
Coolant is introduced into the intake manifold, improving drivability during engine warm up.
Exhaust and intake valves are equipped with springs made, of special valve spring carbon steel
which are capable of following no matter what the engine speed.
The camshaft is driven by a timing chain. The cam journal is supported at 3 places, located at the
center and the front and rear of ends of each cylinder head. Lubrication of the cam journal gear
is accomplished by oil supplied through the oil passage in the cylinder head.
Adjustment of the valve clearance is done by means of an adjusting screw on the rocker arm for
easy adjustment.
The timing chain cover is made of aluminum alloy, with a water pump and oil pump on the outside.
Pistons are made of highly temperature–resistant aluminum alloy, and a depression is built into
the piston head to prevent interference with valves.
Piston pins are the full–floating type, with the pins fastened to neither the connecting rods nor
the piston boss, but with a snap ring fitted to both ends of each pin to prevent it from slipping out.
The No. 1 compression ring is made of stainless steel and the No. 2 compression ring is made of
cast iron. The oil ring is made of stainless steel. The outer diameter of each piston ring is slightly
larger than the diameter of the piston and the flexibility of the rings allows them to hug the
cylinder walls when they are mounted on the piston. No. 1 and No. 2 compression rings work to
prevent leakage of gas from the cylinder and the oil ring works to scrape oil off the cylinder walls
to prevent it from entering the combustion chambers.
The cylinder block is made of cast iron. It has 4 cylinders which are approximately 2 times the
length of the piston stroke. The top of each cylinder is closed off by the cylinder head and in the
lower end of the cylinders the crankshaft is installed, supported by 5 journals. In addition, the
cylinder block contains a water jacket, through which coolant is pumped to cool the cylinders.
The oil pan is bolted onto the bottom of the cylinder block. The oil pan is an oil reservoir made of
pressed steel sheet. A dividing plate is included inside the oil pan to keep sufficient oil in the
bottom of the pan even when the vehicle is tilted. The dividing plate prevents the intake of air and
allows oil circulation to be maintained even if the oil forms waves when the vehicle brakes
suddenly.