REMOVAL & INSTALLATION
- Remove the camshafts as described in the camshaft section.
- With the camshafts removed, remove the rocker arms and the pushrods.
- Use a suitable valve lifter removal tool and remove the hydraulic tappet (lifter) from the cylinder head hydraulic tappet mounting hole.
Use the following steps to inspect the hydraulic tappet (lifter).
- Inspect the hydraulic tappet for wear or damage or for a clogged oil hole.
- Measure the free length of each hydraulic tappet by attaching the hydraulic tappet bleeder to the tappet. Then push and release the bleeder slowly while in a container filled with 10W-30W engine oil. Be sure to keep the hydraulic tappet upright and below the surface of the oil while pushing and release the bleeder.
- Continue operating the bleeder until there are no air bubbles left in the hydraulic tappet.
- Remove the hydraulic tappet and try to compress it quickly by hand. Measure the compression stroke with a dial indicator on a surface plate. The standard compression stroke measurement should be 0.0004-0.003 in. (0.01-0.08mm).
- Pour engine oil into the cylinder head hydraulic tappet mounting hole, up to the level of the oil path.
- Install the hydraulic tappet into the cylinder head. Do not rotate the hydraulic tappet while inserting it into the head.
- Pour engine oil into the oil fillers on the cylinder head.
- Install the pushrods and rocker arms. Be sure to install each part in its original position. Loosen the rocker arm adjusting screws and locknuts before installation.
- Install the camshafts and camshaft oil seals. Be sure to take note of the locations of the camshafts; the front camshaft has a groove for driving the distributor. Adjust the exhaust valve clearance.
- After the heads are reassembled, make sure the engine sits for approximately 5 minutes to allow the hydraulic tappets to reach the proper oil level.
- Remove the spark plugs and crank the engine, feel for compression at each cylinder at the spark plug holes. It may be necessary to crank the engine through several cycles to confirm compression.
- If any cylinder does not have compression, it may be necessary to disassemble the head and check the suspected tappet.
- If all cylinders have compression, reinstall the plugs and start the engine.
- Remove the cylinder head cover.
- The hydraulic lifters are in the rocker arms where they contact the valves. Each rocker arm has a letter A or B stamped into the side. Before disassembling the rocker arms, note the position of each letter so they can be reassembled the same way.
- Remove the rocker arm assembly using the torque sequence described in the section on camshaft removal. This is important to avoid bending the rocker arm shafts.
- Do not remove the hydraulic tappets unless they are to be replaced, they cannot be repaired or tested. Handle the rocker arms carefully so the oil does not drain out of the lifters. If replacing the lifters, also replace the O-ring.
- Place a new camshaft seal on the end of the camshaft, lubricate the journals and set the camshaft in place on the head.
- Apply liquid gasket to the mating surfaces of the end camshaft holders.
- Set the rocker arm assemblies in place and start all the bolts. Make sure the rocker arms are properly positioned and turn each bolt in the correct sequence, 2 turns at a time till the holders are seated on the head. This is the only way to avoid damaging the valves or rocker assemblies.
- When all the camshaft and rocker holders are seated, torque the bolts in the same sequence. Torque the 8mm bolts to 16 ft. lbs. (22 Nm) and the 6mm bolts to 9 ft. lbs. (12 Nm).