REMOVAL & INSTALLATION
See Figures 1 through 12
- Disconnect the battery cables at the battery.
- Drain the engine block of coolant by removing the drain plugs located on the engine block above the top of the oil pan.
- Remove the intake manifold as described. Remove the alternator lower mounting bolt, and lay the unit aside.
- Remove the exhaust manifolds. If the vehicle has A/C, dismount the compressor and position it out of the way. Do not disconnect the refrigerant lines.
- Back off the rocker arm nuts and pivot the rocker arms out of the way so that the pushrods can be removed. Identify the pushrods so that they can be reinstalled in their original locations.
- Remove the cylinder head bolts and cylinder heads.
- Install using new gaskets. The head gasket is installed with the bead up.
Coat a steel gasket, thinly and evenly, on both sides with sealer. If a steel asbestos gasket is used, do not apply sealer. Clean the bolt threads, apply sealing compound and install the bolts finger-tight.
- Tighten the head bolts a little at a time in the sequence illustrated to the specified torque.
- Install the exhaust and intake manifolds.
- Adjust the valves.
See Figures 13 through 23
- With cylinder head removed, remove valve rocker arm nuts, balls and rocker arms (if not previously done).
- Using Tool J-15062, or equivalent, compress the valve springs and remove stem keys. Release the compressor tool and remove rotators or spring caps, oil shedders, springs and damper assembly, then remove oil seals and valve spring shims.
- Remove valves from cylinder head and place them in a rack in their proper sequence so that they can be assembled in their original positions. Discard any bent or damaged valves.
- Clean all carbon from combustion chambers and valve ports using a wire brush.
- Thoroughly clean the valve guides using a suitable wire bore brush.
- Clean all carbon and sludge from pushrods, rocker arms and pushrod guides. Discard bent pushrods.
- Clean valve stems and heads on a buffing wheel.
- Clean carbon deposits from head gasket mating surface. Be careful not to score the machined gasket surface while cleaning.
- Inspect the cylinder head for cracks in the exhaust ports, combustion chambers, or external cracks to the water chamber.
- Inspect the valves for burned heads, cracked faces or damaged stems.
Excessive valve stem to bore clearance will cause excessive oil consumption and may cause valve breakage. Insufficient clearance will result in noisy and sticky functioning of the valve and disturb engine smoothness.
Measure valve stem clearance as follows:
- Clamp a dial indicator on one side of the cylinder head rocker arm cover gasket rail.
- Locate the indicator so that movement of the valve stem from side to side (crosswise to the head) will cause a direct movement of the indicator stem. The indicator stem must contact the side of the valve stem just above the valve guide.
- Drop the valve head about 1 / 16 in. off the valve seat.
- Move the stem of the valve from side to side using light pressure to obtain a clearance reading. If clearance exceeds specifications, it will be necessary to ream valve guides for oversize valves.
See "Valve Guide and Seat Service" for detailed overhaul procedures.
- Check valve spring tension with a suitable spring tester. Springs should be compressed to the specified height and checked against the specifications chart. Springs should be replaced if not within 10 lbs. (44N) of the specified load (without dampers).
- Inspect rocker arm studs for wear or damage.
- Check the cylinder head for warpage with a straightedge. If warpage exceeds .003 in. in a 6 in. span, or .006 in. over the total length, the cylinder head must be resurfaced (which is akin to planing a piece of wood). Resurfacing can be performed at most machine shops.
When resurfacing the cylinder heads(s) of V8 engines, the intake manifold mounting position is altered, and must be corrected by machining a proportionate amount from the intake manifold flange.
- Insert a valve in the proper port.
Assemble the valve spring and related parts as follows:
- Set the valve spring shim, valve spring, damper assembly, oil shedder and valve cap or rotator in place.
- Compress the spring with Tool J-8062, or equivalent.
- Install oil seal in the lower groove of the stem, making sure that the seal is flat and not twisted.
- Install the valve and release the compressor tool making sure that the valve stems seat properly in the upper groove of the valve stem. Grease may be used to hold the locks in place while releasing the compressor tool.
- Install the remaining valves, repeating assembly sequence.
- Check each valve stem oil seal by placing a Leak Detector Tool J-23994, or equivalent, over the end of the valve stem and against the cap (or rotator). Operate the vacuum pump and make sure no air leaks past the seal.
- Check the installed height of the valve springs, using a narrow thin scale. A cutaway scale will help. Measure from the top of the shim or the spring seat to the top of the oil shedder. If this is found to exceed the specified height, install a valve spring seat shim approximately 1 / 16 in. (1.6mm) thick. At no time should the spring be shimmed to give an installed height under the minimum specified.