REMOVAL & INSTALLATION
6-198 and 6-225 Engines
See Figures 1 and 2
- Remove the cylinder head, timing gear cover, camshaft sprocket, and timing chain.
- Remove the valve tappets, keeping them in order to ensure installation in their original locations.
- Remove the camshaft sprocket.
- Remove the distributor and oil pump.
- Remove the fuel pump.
- Install a long bolt into the front of the camshaft to facilitate its removal.
- Remove the camshaft, being careful not to damage the cam bearings with the cam lobes.
- Prior to installation, lubricate the camshaft lobes and bearing journals. It is recommended that 1 pt. of crankcase conditioner be added to the initial crankcase oil fill.
If replacing the camshaft, all of the tappet faces must be inspected for crown using a straightedge. If any negative crown (dishing) is observed, tappet must be replaced. The tappet must have a defined crown.
- Install the camshaft in the engine block.
- Reinstall the long bolt into the front of the camshaft.
- Install the fuel pump making sure you use a new gasket.
- Install the distributor and oil pump.
- Install the timing sprocket.
- Install the valve tappets, in their original locations. If installing a new camshaft, install new tappets.
- Install the cylinder head, using new gaskets, timing chain, and timing gear cover.
See Figure 3
- Remove the timing gear cover, the gasket and the front seal.
- Remove the idler pulley bracket.
- Align the timing marks.
- Using a puller, remove the camshaft drive gear.
- Remove the camshaft thrust plate.
- Remove the cylinder head.
- Using a magnet, remove the tappets, keeping them in order.
- Drain the cooling system and remove the radiator.
- If equipped with air conditioning, remove the condenser. See General Information & Maintenance .
- Carefully slide the camshaft from the block.
- Check the runout with a dial indicator. Support journals 1 and 4 on V-blocks and set the dial indicator on 2 and 3. Runout should be less than 0.0007 in. (0.0177mm). If runout exceeds 0.001 in. (0.05mm), replace the camshaft.
- Check the cam profile by measuring the cam long and short diameters with a micrometer. Inspect the cam profile for wear or damage. The long diameter should measure 1.816 in. (46.615mm); the short diameter should measure 1.552 in. (39.426mm). If the cam profile is worn or damaged, or the diameters differ from standard by 0.01 in. (0.5mm) or more, replace the camshaft.
- Check the camshaft journals for damage and wear. If excessively worn or damaged, the camshaft must be replaced.
- Check the journal ODs as given in the chart. Check the bearing IDs and figure the clearances. Clearances are given in the chart.
- Bearings are removed and installed with tool MH-061070.
- Be sure that the crankshaft is set with No. 1 cylinder at TDC. Torque the bolt to 25 ft. lbs. (34 Nm).
- Coat the camshaft with engine oil and carefully slide it into place. Don't damage the bearings.
- Install the tappets in their original order, if using original camshaft. If the camshaft was replaced, new tappets should be installed. When complete, assemble the cylinder head.
- Install the camshaft gear and the thrust plate on the camshaft. Be sure all the marks line up with the marks on the idler gear. Tighten the hold-down bolt to 12 ft. lbs. (16 Nm).
- Put the injection pump in position and mesh the pump drive gear with the idler gear so the marks on the drive gear match up properly with the marks on the idler gear. Be sure the pump mounting flange scale is set at the proper injection point.
- Install the mounting nuts on the timing gear case and tighten them.
- Connect the fuel feed line and the filter hoses to the pump.
- Operate the primer pump to bleed the air from the fuel system.
- Connect the injector pipes.
- Check the idler gear for end-play using a feeler gauge between the gear and the thrust plate. It should be 0.001-0.005 in. (0.05-0.15mm). If it exceeds 0.01 in. (0.35mm), replace the thrust plate.
- Check the gears for backlash by mounting a dial indicator so that lash is measured from the gear tooth profile at right angles to the gear shaft. When checking lash between the idler gear and injection pump drive gear, be sure that the stay bolt at the back of the pump is tight. Backlash should be 0.004-0.009 in. (0.11-0.24mm). If backlash exceeds 0.011 in. (0.30mm), replace the gear.
- Install a new front seal (using a new gasket), the timing gear cover and the crankshaft drive pulley.
- Check the oil seal and cone surfaces. Runout should not exceed 0.001 in. (0.5mm). If it does, or if any contact surface is damaged, replace the pulley.
- Install the radiator and condenser.
- Fill the cooling system and crankcase.
- Drain the cooling system.
- Remove the radiator.
- Remove the fan.
- Remove the timing chain cover.
- Rotate the crankshaft until the timing marks are aligned.
- Remove the camshaft sprocket bolt.
- Remove the valve covers.
- Lift the tappets out by hand and hold them in position using spring-type clothes pins and blocks.
- At this point, measure the camshaft end-play. If end-play exceeds 0.006 in. (0.15 mm), replace the thrust plate.
- Slide the sprocket and chain off of the camshaft.
- Slide the camshaft from the block.
- Coat the new camshaft with clean engine oil and carefully slide it into place without nicking the bearings.
- Align the timing marks, then install the camshaft sprocket and timing chain.
- Torque the sprocket bolt to 20 ft. lbs. (27 Nm). If a new thrust plate is being installed, torque the bolts to 35 ft. lbs. (47 Nm).
- Install the timing chain cover, fan and radiator.
- Fill the cooling system.
See Figures 4 through 10
- Remove the intake manifold, cylinder head covers, rocker arm assemblies, pushrods, and valve tappets, keeping them in order to insure the installation in their original locations.
- Remove the timing gear cover, the camshaft and the crankshaft sprockets, along with the timing chain.
- Remove the distributor, then lift out the oil pump and distributor driveshaft. On 400 and 440 cu. in. engines, remove the fuel pump to allow the pushrod to drop away from the cam eccentric.
- Remove the camshaft thrust plate (on the 7, 318 and 360). Note the location of the oil tab.
- Install a long bolt into the front of the camshaft and remove the camshaft, being careful not to damage the cam bearings with the cam lobes.
- Prior to installation, lubricate the camshaft lobes and bearings journals. It is recommended that 1 pt. of Crankcase Conditioner be added to the initial crankcase oil fill. Insert the camshaft into the engine block within 2 in. (50.8mm) of its final position in the block.
- Have an assistant support the camshaft with a suitable tool to prevent the camshaft from contacting the welch plug in the rear of the engine block. Position the suitable tool against the rear side of the cam gear and be careful not to damage the cam lobes.
This tool should remain intact until the camshaft and crankshaft sprockets and timing chain have been installed.
- Replace the camshaft thrust plate. If camshaft end-play exceeds 0.010 in. (0.25mm), install a new thrust plate. It should be 0.002-0.006 in. (0.05-0.15mm) with the new plate.
- Install the timing chain and sprockets, timing gear cover, and pulley.
- Install the tappets, pushrods, rocker arms, and cylinder head covers. Install fuel pump, if removed.
- Install the oil pump driveshaft, followed by the distributor.
- After starting the engine, adjust the ignition timing.
The camshaft has an integral oil pump, distributor drive gear and fuel pump eccentric.
Rearward camshaft thrust is taken by rear face of the cast iron camshaft gear hub, bearing directly on the front of the cylinder block, eliminating the need for a thrust plate. The helical oil pump and distributor drive gear and the camshaft lobe taper both tend to produce only a rearward thrust.
- With tappets and timing gears removed, withdraw the distributor and governor assembly.
- Lift out oil pump distributor driveshaft.
- Remove fuel pump to allow pushrod to drop away from cam eccentric.
- Remove camshaft, being careful not to damage cam bearings with cam lobes.
- Lubricate camshaft lobes and camshaft bearing journals.
- Insert camshaft to within 2 in. (51mm) of its final position in cylinder block.
- Modify Tool C-3509 by grinding off index lug holding upper arm on tool and rotate arm 180°.
- Install Tool C-3509 in place of distributor drive gear and shaft.
- Hold tool in position with distributor lock plate screw. This tool will restrict camshaft from being pushed in too far and prevent knocking out the welch plug in rear of the cylinder block. The tool should remain installed until camshaft and crankshaft gear have been installed.
Camshaft Lobe Lift
Check the lift of each lobe in consecutive order and make a note of the reading.
- Remove the fresh air inlet tube and the air cleaner. Remove the heater hose and crankcase ventilation hoses. Remove valve rocker arm cover(s).
- Remove the rocker arm stud nut or fulcrum bolts, fulcrum seat and rocker arm.
- Make sure the pushrod is in the valve tappet socket. Install a dial indicator so that the actuating point of the indicator is in the pushrod socket (or the indicator ball socket adaptor is on the end of the pushrod) and in the same plane as the pushrod movement.
- Disconnect the I (ignition) terminal, and the S (starter) terminal at the starter relay. Install an auxiliary starter switch between the battery and S terminals of the start relay. Crank the engine with the ignition switch OFF . Turn the crankshaft over until the tappet is on the base circle of the camshaft lobe. At this position, the pushrod will be in its lowest position.
- Zero the dial indicator. Continue to rotate the crankshaft slowly until the pushrod is in the fully raised position.
- Compare the total lift recorded on the dial indicator with the specification shown on the Camshaft Specification chart.
To check the accuracy of the original indicator reading, continue to rotate the crankshaft until the indicator reads zero. If the lift on any lobe is below specified wear limits listed, the camshaft and the valve tappets must be replaced.
- Install the dial indicator and auxiliary starter switch.
- Install the rocker arm, fulcrum seat and stud nut or fulcrum bolts. Check the valve clearance. Adjust if required (refer to procedure in this section).
- Install the valve rocker arm cover(s) and the air cleaner.
On all gasoline V8 engines, prying against the aluminum-nylon camshaft sprocket, with the valve train load on the camshaft, can break or damage the sprocket. Therefore, the rocker arm adjusting nuts must be backed off, or the rocker arm and shaft assembly must be loosened sufficiently to free the camshaft. After checking the camshaft end-play, check the valve clearance. Adjust if required.
- Push the camshaft toward the rear of the engine. Install a dial indicator so that the indicator point is on the camshaft sprocket attaching screw.
- Zero the dial indicator. Position a pry tool between the camshaft gear and the block. Pull the camshaft forward and release it. Compare the dial indicator reading with the specifications.
- If the end-play is excessive, check the spacer for correct installation before it is removed. If the spacer is correctly installed, replace the thrust plate.
- Remove the dial indicator.
CAMSHAFT BEARING REPLACEMENT
See Figures 11, 12 and 13
- Remove the engine following the procedures in this section and install it on a work stand.
- Remove the camshaft, flywheel and crankshaft, following the appropriate procedures. Push the pistons to the top of the cylinder.
- Remove the camshaft rear bearing bore plug. Remove the camshaft bearings with a bearing removal tool.
- Select the proper size expanding collect and back-up nut, then assemble on the mandrel. With the expanding collect collapsed, install the collect assembly in the camshaft bearing and tighten the back-up nut on the expanding mandrel until the collect fits the camshaft bearing.
- Convoke the puller screw and extension (if necessary) and install on the expanding mandrel. Wrap a cloth around the threads of the puller screw to protect the front bearing or journal. Tighten the pulling nut against the thrust bearing and pulling plate to remove the camshaft bearing. Be sure to hold a wrench on the end of the puller screw to prevent it from turning.
- To remove the front bearing, install the puller from the rear of the cylinder block.
- Position the new bearings at the bearing bores, and press them in place. Be sure to center the pulling plate and puller screw to avoid damage to the bearing. Failure to use the correct expanding collect can cause severe bearing damage. Align the oil holes in the bearings with the oil holes in the cylinder block before pressing bearings into place.
- Install the camshaft rear bearing bore plug.
- Install the camshaft, crankshaft, flywheel and related parts, following the appropriate procedures.
- Install the engine in the truck, following procedures described earlier in this section.