1942 - 1947 Chevrolet Shop Manual



	6-24

	Valve spring cap covers, of an umbrella type are used on all intake valve stem ends. The cap covers are designed to carry the oil which flows down the rocker arms to lubricate the valve end of the arms, out over the intake valve spring. This reduces the amount of oil reaching the intake valve stems for guide lubrication to only that amount required for proper lubrication, thus controlling oil consumption and smoking when the engine is idling. VALVE LIFTERS AND PUSH RODS Chevrolet valve lifters are made in two parts. The lower part is machined from a casting, the bottom of which is chilled during the casting operation to produce a hard wearing surface. The Upper part, incorporating the push rod seat, is machined and hardened to produce a smooth, long-wearing seat. The lifter unit is completed by brazing the steel seat into the cast part of the lifter. Fig. 51 shows the construction of the lifter in cross-section.	ROCKER ARMS AND SHAFTS The valve rocker arms are made of a newly developed metal known as Armasteel which reduces wear of these parts to a minimum. The ends contacting the valve stems are especially hardened. The rocker arms are diamond bored and bear directly on the rocker arm shafts. After boring each arm is given a wear resisting coating for protection against scuffing or scoring during the break-in period. Due to the combustion chamber design and valve positions, all rocker arms are offset at an angle. There are four different types of rocker arms used; right and left hand angle intake arms, and right and left hand angle exhaust. None of these rocker arms are interchangeable, one with the other nor with previous models other than 1941, and care must be used when assembling the rocker arms to the rocker arm shaft to place each arm in its correct position to line up with the valve it is to operate.


		Fig. 52—Valve Rocker Arm Identification Each type rocker arm carries a different part number and for identification purposes a number (I, 2, 5 or 6) is cast on the side of each arm, Fig. 52. The following chart shows rocker arm identification numbers as well as the type, where used and the part number. Number on Type Part Rocker Arm Rocker Arm For Cylinder Number 1 L. H. Exhaust 1-3-5 Exhaust 839459 2 R. H. Exhaust 2-4-6 Exhaust 839460 5 L. H. Intake 2-4-6 Intake 839463 6 R. H. Intake 1-3-5 Intake 839464 The rocker arms, springs and shaft supports are assembled to the rocker arms shafts and locked in place with hair pin springs, in the order shown in Fig. 53. Fig. 54 shows the rocker arm and shaft assemblies correctly installed on the head. The rocker arm shafts are hollow and have holes drilled in them to allow oil to pass into the rocker arms where they bear on the shafts.
	Fig. 51-Valve Lifters When assembling the valve lifter to the engine, it should be a free fit, and the end that contacts the camshaft should be smooth. If this surface shows signs of wear or roughness it is good practice to replace the lifter. The push rods arc made from a solid piece of steel with the two ends forged to form the contacts with the lifter and rocker arm adjusting screw. These ends are carefully machined and hardened to produce a smooth hard surface that will give thousands of miles of service with the minimum amount of wear.