BOLT 6L3670 - Caterpillar

Cylinder Head and Block
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:
An oil filler cap
A seal for the face toward the cylinder head
Holes for four cap nuts
Holes for two boltsThe 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.Pistons and Connecting Rods
The pistons of the engine have a combustion chamber in the crown of the piston to provide an efficient mix of the fuel and the air.The piston pin is off-center to reduce the noise level.The pistons have two compression rings and an oil control ring.The correct piston height is important 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 to conform to requirements for emissions. The piston must not be machined to obtain the correct piston height.A piston and connecting rod are matched to each cylinder.One height of piston is available. Inside the piston is marked "Shibaura". This reference mark faces the right side of the engine. Refer to Systems Operation 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.Timing Gear Case and Gears
The timing gear case contains the following components:
Front oil seal for the crankshaft pulley
Engine oil pumpThe crankshaft has 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 engine has three thrust washers. Two of the thrust washers are on both sides of the bottom half of holder for the rear main bearing. The third thrust washer is on the rear side of the upper half of the 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 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
Fuel injection pump gear
Crankshaft pulley
Timing caseThe crankshaft gear turns the idler gear which then turns the camshaft gear.The