REMOVAL & INSTALLATION
See Figures 1 through 10
Camshaft end-play (thrust clearance) must be checked before the cam is removed. Please refer to the Inspection section for details.
- Remove the valve cover.
- Drain the cooling system.
- Loosen the water pump pulley bolts.
- Remove the alternator belt.
- Raise the vehicle and safely support it on jackstands.
- Remove the power steering pivot bolt, if so equipped.
- Remove the bolt which goes through both the upper and lower timing belt covers.
- Lower the vehicle to the ground. Remove the power steering pump belt, if so equipped.
- Remove the water pump pulley.
- Disconnect the upper radiator hose at the engine water outlet.
- Label and disconnect vacuum hoses.
- Remove the upper timing belt cover and its gasket.
- At the distributor, label and disconnect the spark plug wires, the vacuum hoses and the electrical connections. Remove the distributor.
- Disconnect the hoses at the fuel pump and remove the fuel pump.
- Remove the distributor gear bolt.
- Remove the rocker arm assembly on 3A and 3A-C engines.
- Rotate the crankshaft clockwise and set the engine to TDC on the compression stroke for the No. 1 cylinder. Make sure the rockers for cylinder No. 1 are loose. If not, rotate the crankshaft one full turn.
- Matchmark and remove the timing belt from the camshaft pulley. Support the belt so that it doesn't change position on the crankshaft pulley.
- Loosen the camshaft bearing cap bolts a little at a time and in the correct sequence. After removal, label each cap.
- Remove the camshaft oil seal (at the pulley end) and then remove the camshaft by lifting it straight out of its bearings.
Although reasonable in weight, the cam is brittle in nature. Handle it gently and do not allow it to fall or hit objects. It may break into pieces.To install:
- When reinstalling, coat all the bearing journals with engine oil and place the camshaft in the cylinder head.
- Place the bearing caps on each journal with the arrows pointing towards the front of the engine.
- Apply multi-purpose grease to the inside of the oil seal. and apply liquid sealer on the outer circumference of the oil seal.
- Install the seal in position, being very careful to get it straight. Do not allow the seal to cock or move out of place during installation.
- Install the bearing cap for bearing No. 1 and apply silicone sealant to the lower ends of the of the seal.
- Tighten each bearing cap little at a time and in the correct sequence. Tighten the bolts to the figure listed in the component torque specifications chart in this section.
- Hold the camshaft with an adjustable wrench, then tighten the drive gear bolt to the figure listed in the component torque specifications chart in this section..
- Install the timing belt as previously outlined.
- Install the rocker arm assembly.
- Install the fuel pump with a new gasket and connect the hoses.
- Install the distributor and connect its vacuum hoses, electrical connections and the spark plug wires.
- Install the upper timing belt cover but don't install the bolt which holds both the upper and the lower covers yet.
- Connect the vacuum hoses.
- Connect the upper radiator hose to the water outlet.
- Install the water pump pulley.
- Install the power steering drive belt if so equipped.
- Elevate the vehicle and safely support it on jackstands.
- Install the bolt which connects the upper and lower timing belt covers.
- Install the power steering pump pivot bolt and the belt; adjust the belt tension.
- Lower the vehicle. Install the alternator belt and adjust it to the correct tension.
- Install the rocker arm (valve) cover with a new gasket.
- Refill the cooling system.
See Figures 11 through 15
The end-play or thrust clearance of the camshaft must be measured with the camshaft installed in the head. It must be checked before removal and after reinstallation. To check the end-play, mount a dial indicator accurate to 0.0001 (ten thousandths) of an inch on the end of the block, so that the tip bears on the end of the camshaft (the timing belt must be removed). Set the scale on the dial indicator to zero. Using a small prybar or similar tool, gently lever the camshaft back and forth in its mounts. Record the amount of deflection shown on the gauge and compare this number to the Camshaft Specifications Chart in this section.
Excessive end-play may indicate either a worn camshaft or a worn head; the worn cam is most likely and much cheaper to replace. Chances are good that if the cam is worn in this dimension (axial), substantial wear will show up in other measurements. A worn head must be replaced.
Mount the cam in V-blocks and set the dial indicator up on the round center journal. Zero the dial and rotate the camshaft. The circular runout should not exceed the following:
The cam must be replaced if runout is excessive.
Using a micrometer or caliper, measure the diameter of all the journals and the height of all the lobes. Record the readings and compare them to the Camshaft Specifications Chart in the beginning of this section. Any measurement beyond the stated limits indicates wear and the camshaft must be replaced.
Lobe wear is generally accompanied by scoring or visible metal damage on the lobes. Overhead camshaft engines are very sensitive to proper lubrication with clean, fresh oil. A worn cam may be your report card for poor maintenance intervals and late oil changes. If a new cam is required, order new rockers to accompany it so that there are two new surfaces in contact.
The clearance between the camshaft and its journals (bearings) must also be measured. Clean the camshaft, the journals and the bearing caps of any remaining oil and place the camshaft in position on the head. Lay a piece of compressible gauging material (Plastigage® or similar) on top of each journal on the cam.
Install the bearing caps in their correct order with the arrows pointing towards the front (pulley end) of the motor. Install the bearing cap bolts, then tighten them in three passes to the figure listed in the component torque specifications chart in this section.
Do not turn the camshaft with the gauging material installed.
Remove the bearing caps (in the correct order) and measure the gauging material at its widest point by comparing it to the scale provided with the package. Compare these measurements to the Camshaft Specifications Chart in this section. Any measurement beyond specifications indicates excessive wear. If you have already measured the cam (or replaced it) and determined it to be usable, excess bearing clearance indicates the need for a new head due to wear of the journals.
Remove the camshaft from the head and remove all traces of the gauging material. Check carefully for any small pieces clinging to contact faces.