REMOVAL & INSTALLATION
230 and 250 cid Engines
See Figures 1 through 5
- Drain the cooling system and remove the air cleaner. Disconnect the PCV hose.
- Disconnect the accelerator pedal rod at the bell crank on the manifold, and the fuel and vacuum lines at the carburetor.
- Disconnect the exhaust pipe at the manifold flange, then remove the manifold bolts and clamps and remove the manifolds and carburetor as an assembly. There is a ring gasket at the exhaust manifold flange, and a gasket for each of the manifolds at the head. These will have to be replaced. On 1977 and later models with an integral intake manifold, remove the carburetor at the intake manifold, and remove the exhaust manifold.
- Remove the fuel and vacuum line retaining clip from the water outlet. Then, disconnect the wire harness from the heat sending unit and coil, leaving the harness clear of the clips on the rocker arm cover.
- Disconnect the radiator hose at the water outlet housing and the battery ground strap at the cylinder head.
- Number the spark plug wires, then remove the wires and spark plugs. Disconnect the coil-to-distributor primary wire lead at the coil and remove the coil (except integral coil HEI).
- Remove the rocker arm cover. Back off the rocker arm nuts, pivot the rocker arms to clear the pushrods and remove the pushrods. Be certain to keep the pushrods in the order in which they came out. They must be returned to their original positions.
1977 and later model sixes do not use a rocker arm cover gasket. RTV sealer is used in its place.
- Remove the cylinder head bolts, cylinder head and gasket.
- Clean the mating surfaces of the cylinder head and block. Check the cylinder head and block for warpage with a straightedge and feeler gauge. Warpage must not exceed 0.006 in. over a six inch span. If this limit is exceeded, the head or block should be milled flat.
- Clean the head bolts and the threads in the cylinder block, since dirt will affect torque readings.
- Install a new head gasket over the dowel pins. Do not use sealer on combination steel/asbestos gaskets.
- Guide and lower the cylinder head into place over dowels and gasket.
- Oil the cylinder head bolts, install and run them down snug.
- Tighten the cylinder head bolts a little at a time with a torque wrench in the correct sequence. Final torque should be 90-95 ft. lbs. except for the left front head bolt, which should be torqued to 85 ft. lbs.
- Install the valve pushrods down through the cylinder head openings and seat them in their lifter sockets.
- Install the rocker arms, balls and nuts, then tighten the rocker arm nuts until all pushrod play is taken up.
- Install the thermostat, thermostat housing and water outlet using new gaskets. Then, connect the radiator hose.
- Install the heat sending switch and tighten to 15-20 ft. lbs.
- Clean the spark plugs or install new ones.
- Install the coil, then connect the heat sending unit and the coil primary wires. Connect the battery ground cable at the cylinder head.
- Clean the surfaces of the manifold(s) and install a new gasket or gaskets over the manifold studs. Install the manifold(s). Clean and oil the bolts, then install and tighten them in sequence to the specified values. Connect the exhaust pipe to the manifold, using a new ring gasket.
- Install the carburetor, if it was removed, and reconnect the carburetor linkage.
- Connect the PCV, fuel and vacuum lines, then secure the lines in the clip at water outlet.
- Fill the cooling system and check for leaks.
- Adjust the valve lash.
- Install the rocker arm cover and position the wiring harness in the clips.
- Clean and install the air cleaner
Except 230, 231 and 250 cid Engines
See Figures 6 through 10
- Drain the coolant. Remove the air cleaner.
- Radiator and heater hose from manifold
- Throttle linkage
- Fuel line
- Coil wires
- Temperature sending unit
- Power brake hose, distributor vacuum hose, and crankcase vent hoses.
- Distributor, marking position
- Alternator upper bracket
- Coil and its bracket (where so equipped)
On 1977 and later engines, remove all of the following with which the engine is equipped:
- Air cleaner bracket
- Air pump bracket
- Accelerator return spring and bracket
- Accelerator bellcrank
- Remove all manifold attaching bolts, and remove the intake manifold.
- Disconnect the air manifold and tubes, and spark plug wires, remove the air cleaner preheater and spark plug heat shields, loosen and remove the exhaust manifold flange nuts, then lower the exhaust pipe assembly and hang it from the frame with wire.
- Remove the manifold end bolts, then the center ones and remove the manifold from the engine.
- Remove rocker arm cover(s). Loosen the rocker nuts and pivot rockers 90º to permit removal of the pushrods. Remove the pushrods, marking the location of each.
- Remove the cylinder head bolts, cylinder head, and gasket.
- Inspect the gasket surfaces on the head(s). All surface must be clean and free of nicks and burrs. The threads on bolts and inside the bolt holes in the block must be clean. Inspect the head for warpage as described later in the engine rebuilding section.
Install, reversing the removal procedures, keeping the following important points in mind:
- Tighten the head bolts in several stages, going in the pattern specified in the illustration.
- Coat new gaskets (both sides) and head bolts with sealer, unless a combination steel-asbestos gasket is used; in that case, put sealer on the head bolts only, and let the gasket dry.
- Make sure to relocate pushrods according to their markings. Adjust the valves before running the engine. Then, readjust the valves with the engine hot and running.
- Coat [cf2]new rocker cover gaskets with sealer, and tighten the cover bolts to the specified torque evenly in several stages.
See Figure 11
On vehicles equipped with AIR, disconnect the rubber hose at the injection tubing check valve. This way the tubing will not have to be removed from the exhaust manifold.
- Remove the intake manifold, as detailed later in this section.
When removing the right cylinder head:
- Loosen and remove all drive belts.
- Tag and disconnect the wires leading from the rear of the alternator.
- Remove the air conditioning compressor (if so equipped) and position it out of the way with all the hoses still connected.
- Remove the alternator and its mounting bracket.
When removing the left cylinder head:
- Remove the oil gauge rod.
- Remove the power steering pump (if so equipped) and its bracket, then position it out of the way with the hoses still attached.
- Tag and disconnect the spark plug wires and remove the spark plug wire clips from the cylinder head cover studs.
- Remove the exhaust manifold mounting bolts from the head which is being removed, then pull the manifold away from the head.
- Use an air hose, if available, or a bunch of clean rags to clean the dirt off the head and surrounding areas thoroughly. It is extremely important to avoid getting dirt into the hydraulic valve lifters.
- Remove the cylinder head cover from the top of the head that you wish to remove.
- Remove the rocker arm and shaft assembly from the cylinder head, then remove the pushrods.
If the valve lifters are to be serviced, remove them at this time. Otherwise, protect the lifters and the camshaft from dust and dirt by covering the entire area with a clean cloth. Whenever the lifters or the pushrods are removed from the head it is always a good idea to place them in a wooden block with numbered holes to keep them identified as to their position in the engine.
- Loosen and remove all the cylinder head bolts and lift off the head.
- Clean the engine block gasket surface thoroughly. Make sure that no foreign material has fallen into the cylinder bores, the bolt holes or into the valve lifter area. It is always a good idea to clean out the bolt holes with an air hose if one is available.
- Install a new head gasket with the bead facing down toward the cylinder block. The dowels in the block will hold the gasket in place.
- Clean the gasket surface of the cylinder head and carefully set it into place on the dowels in the cylinder block.
- Use a heavy body thread sealer on all of the head bolts since the bolt holes go all the way through into the coolant.
- Install the head bolts. Tighten the bolts a little at a time in three even steps in the sequence shown in the illustration. Tighten the bolts to a final torque equal to that given in the "Torque Specifications" chart.
- Installation of the remaining components is in the reverse order of removal.
Valve guides are integral with the cylinder head on all engines. Valve guide bores may be reamed to accommodate oversize valves. If wear permits, valve guides can be knurled to allow the retention of standard valves. Maximum allowable valve stem-to-guide bore clearances are listed under valve specifications.