REMOVAL & INSTALLATION
6-144 (2.4L), 6-170 (2.8L) and 6-200 (3.3L)
- Remove the front cover, align the timing marks, and remove the timing chain and related parts as stated before.
- Remove the cylinder head as previously outlined.
- Disconnect the distributor primary wire at the ignition coil. Loosen the distributor lock-bolt and remove the distributor.
- Disconnect and plug the fuel inlet line at the fuel pump. Remove the fuel pump and gasket.
- Remove the valve tappets with a magnet. Note that the tappets must be replaced in the same positions from which they are removed.
- Remove the oil level dipstick.
- Remove the headlight doors and disconnect the light ground wires and the screws. Disconnect the headlights and parking lights.
- Remove the grille and hood lock as an assembly.
- Carefully withdraw the camshaft from the engine.
- In preparation for installing the camshaft, clean the passage that feeds the rocker arm shaft by blowing compressed air into the opening in the block. Oil the camshaft journals and apply Lubriplate® to all of the camshaft lobes. If a new camshaft is being installed, the spacer and dowel from the old camshaft must be used. Carefully slide the camshaft through the bearings.
- Assemble the engine in the reverse order of disassembly.
- Remove the grille, radiator, air conditioner condenser, and timing cover.
- Remove the distributor, fuel pump, oil pan and oil pump.
- Align the timing marks. Unbolt the camshaft thrust plate, working through the holes in the camshaft gear.
- Loosen the rocker arms, remove the pushrods, take off the side cover and remove the valve lifter with a magnet.
- Remove the camshaft very carefully to prevent nicking the bearings.
- Oil the camshaft bearing journals and use Lubriplate® or something similar on the lobes. Install the camshaft, gear, and thrust plate, aligning the gear marks. Tighten down the thrust plate. Make sure that the camshaft end-play is not excessive.
- The last item to be replaced is the distributor. The rotor should be at the firing position for No. 1 cylinder, with the timing gear marks aligned.
- Remove the intake manifold and valley pan, if so equipped.
- Remove the rocker covers, and either remove the rocker arm shafts or loosen the rockers on their pivots and remove the pushrods. The pushrods must be reinstalled in their original positions.
- Remove the valve lifters in sequence with a magnet. They must be replaced in their original positions.
- Remove the timing gear cover and timing chain (timing gear on 8-cylinder diesel) and sprockets.
- In addition to the radiator and air conditioning condenser, if so equipped, it may be necessary to remove the front grille assembly and the hook lock assembly to gain the necessary clearance to code the camshaft out of the front of the engine.
- Coat the camshaft with engine oil liberally before installing it. Slide the camshaft into the engine very carefully so as not to scratch the bearing bores with the camshaft lobes. Install the camshaft thrust plate and tighten the attaching screws to 9-12 ft. lbs. (12-16 Nm). Measure the camshaft end-play. If the end-play is more than 0.009 in. (0.228mm), replace the thrust plate. Assemble the remaining components in the reverse order of removal.
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 D78P-4201-B or equivalent. so that the actuating point of the indicator is in the push rod socket (or the indicator ball socket adaptor tool 6565-AB is on the end of the push rod) and in the same plane as the push rod movement.
- Disconnect the I terminal and the S 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 push rod will be in its lowest position.
- Zero the dial indicator. Continue to rotate the crankshaft slowly until the push rod 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 left on any lobe is below specified wear limits listed, the camshaft and the valve tappet operating on the worn lobe(s) 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.
- Push the camshaft toward the rear of the engine. Install a dial indicator (Tool D78P-4201-F, -G or equivalent so that the indicator point is on the camshaft sprocket attaching screw.
- Zero the dial indicator. Position a prybar 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
- 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 Tool T65L-6250-A or equivalent.
- Select the proper size expanding collet and back-up nut and assemble on the mandrel. With the expanding collet collapsed, install the collet assembly in the camshaft bearing and tighten the back-up nut on the expanding mandrel until the collet fits the camshaft bearing.
- Assemble 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 with tool T65L-6250-A or equivalent. Be sure to center the pulling plate and puller screw to avoid damage to the bearing. Failure to use the correct expanding collet 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 van, following procedures described earlier in this Section.