The cylinder head assembly has one inlet valve and one exhaust valve for each cylinder. Each valve has a single valve spring and a valve seal. The valve and the valve spring are held in position by a valve spring retainer and two collets. The valve seal fits over the top of the valve guide. The valve guides can be replaced.
The ports for the inlet and for the exhaust valves are on the left side of the cylinder head.
The cylinder block does not have cylinder liners. The cylinder walls are honed.
The valve mechanism cover is made from aluminum. The cover contains the following components:
- A closed breather assembly
- An oil filler cap
- A seal for the face toward the cylinder head
- Holes for four cap nuts
- Holes for two bolts
- An air inlet manifold
The cap nuts are threaded onto studs. The steel studs are threaded into the cylinder head.
The bolts are threaded onto the cover for the rocker shaft assembly.
The valve mechanism cover contains a closed breather assembly. The gases in the valve cover, which are caused by blowby, pass from the crankcase to the inlet manifold.
The pistons of the engine have a combustion chamber in the crown of the piston in order to provide an efficient mix of the fuel and the air.
The piston pin is off-center in order to reduce the noise level.
The pistons have two compression rings and an oil control ring.
The correct piston height is important in order to ensure that the piston does not contact the cylinder head. The correct piston height also ensures the efficient combustion of fuel which is necessary in order to conform to requirements for emissions. The piston must not be machined in order to obtain the correct piston height.
A piston and connecting rod are matched to each cylinder.
One height of piston is available. The inside of the piston is marked "Shibaura". This reference mark faces the right side of the engine. Refer to Testing and Adjusting, "Piston Height - Inspect" for procedures to measure the piston height.
Identification marks on the connecting rod and the connecting rod cap must align. The identification marks face the right side of the engine.
The main bearing caps have a chamfered edge on one side. The chamfer faces the front of the engine.
The timing gear case contains the following components:
- Front oil seal for the crankshaft pulley
- The bolt for the adjustment of engine smoke.
- Engine oil pump
- Adjustment screw for setting the maximum fuel position
- Adjustment screw for setting the maximum speed position
- Idle set bolt
- Linkage for the fuel injection pump
- Fuel Control lever for the governor
- Throttle
The crankshaft for the C0.5 engine has two main journal bearings. The crankshaft for the C0.7, C1.1 and C1.5 engines have four main journal bearings. The crankshaft for the C1.6 and the C2.2 NA and Turbocharged engines have five main journal bearings. The crankshaft has a front bearing that is pressed in the cylinder block.
The thrust washers are hemispherical in shape. The C1.1 and C1.5 engines have two thrust washers that are located on both sides of the bottom half of holder for the rear main bearing. The C2.2 NA and Turbocharged engines have a third thrust washer that is located on the rear side of the upper half of the holder for the rear main bearing.
Note: The thrust washers on the C0.05, C0.07, C1.1 and C1.5 engines are machined into the aluminum holder for the rear main bearing.
The crankshaft has a front oil seal and a rear oil seal.
The timing case is made of aluminum. The timing gears are stamped with timing marks in order to ensure the correct assembly of the gears.
The number one piston is at the top center position on the compression stroke when the following timing marks are aligned:
- Idler gear
- Crankshaft gear
- Camshaft gear
- Crankshaft pulley
- Timing case
The crankshaft gear turns the idler gear which then turns the camshaft gear.
The idler gear contains the oil pump. The idler gear turns the gear for the tachometer.
The crankshaft pulley drives the pulley on the water pump and the pulley which drives the alternator.