All 4 and 6 cylinder engines have gear driven camshafts, while all V8 camshafts are driven by a timing chain. 4 or 6 cylinder timing gear replacement requires camshaft removal.
The six-cylinder engine uses a harmonic balancer that closely resembles the V8 type. The removal procedure for this damper will be the same as that used for the V8. Driving the damper back onto the crankshaft without supporting the pulley can cause damage. A replacing tool must be used during the reassembly operation.
REMOVAL & INSTALLATION
- Drain and remove the radiator.
- If necessary for access, remove the water pump as outlined later in this section.
- Remove the harmonic balancer (six- and eight-cylinder) or crankshaft pulley (four-cylinder) using a puller.
- Drain the engine oil and remove the oil pan on all engines through 1972, and on small block V8s through 1974. Remove the V8 water pump. If the oil pan isn't to be removed, cut the pan seal off flush with the block.
- Remove the timing cover attaching screws, cover, and gasket.
- Reverse this procedure for installation for all engines except 1975-79 V8 engines.
This balancer must be drawn back into place.Cover Installation
1975-79 V8 Engines
The installation procedure for these engines has been revised. Use the following procedure.
- Clean the block and timing cover gasket surfaces.
- Use a sharp knife to remove any excess oil pan gasket material which may be protruding at the oil pan-to-engine block junction.
- Apply a 1 / 8 in. bead of silicone rubber sealer to the joint formed at the oil pan and cylinder block, as well as the entire oil pan front lip.
- Coat the cover gasket with gasket sealer and place it in position on the timing cover.
- Place the timing cover on the block. Loosely install the top four bolts (approximately three turns). Install two 1 / 4 -20X 1 / 2 in. screws one on each side at the lower hole in the front cover. Apply a bead of silicone sealer on the bottom of the seal and install the cover.
- Tighten the cover screws alternately and evenly while using a drift to align the dowel pins in the block to the corresponding holes in the cover.
- Remove the two screws which were used in Step 5 to draw up the cover and install the rest of the cover screws, torquing them to 80 in. lbs.
OIL SEAL REPLACEMENT
- After removing the gear cover, carefully pry the oil seal out of the front of the cover with a large prytool.
- Install a new lip seal with the lip (open side of seal) inside, then drive or press the seal into place.