How to Replace the Hydraulic Lifters on a BBC Engine
- 1). Place a drain pan beneath the radiator petcock (drain valve) and drain all engine coolant. While the coolant is draining, remove the air-filtration assembly and disconnect all spark plug wires and electrical connections leading to the distributor. Remove the distributor cap and note the position of the rotor and distributor housing -- this is the position the distributor must be in when re-installed. Loosen the distributor retaining bolt and clamp, and remove the distributor.
- 2). Once the coolant has drained, remove the valve-covers, disconnect all lines leading to the carburetor/intake assembly and remove. Do not let any coolant get into the crankcase. If this does happen, the oil will need to be drained and replaced.
- 3). Loosen the nuts on the rocker arms enough to be able to move them to the side so that the pushrods can be pulled out. Note that there are two different-length pushrods for the intake and exhaust rocker arms, and be certain to organize them for proper re-installation. If the engine has hydraulic roller lifters, remove the spider plate. (The spider holds the lifters in the correct position).
- 4). Remove the old lifters and insert the new lifters into each of the bores. If flat-tappet lifters are being used, be certain to apply a generous amount of the recommended assembly/break-in lube to the face of the lifter (Roller lifters require engine oil only). Re-install the roller lifter spider, if so equipped. Insert the pushrods in the proper locations.
- 5). Clean the gasket surfaces on the intake manifold, cylinder heads and front and rear lifter-valley rails. Set the intake manifold on the engine and tighten to proper torque values. Re-install the distributor so that the housing and rotor are in the same position as when removed. (If the distributor does not drop fully into place, it will once the engine is turned over when adjusting lifter preload).
- 6). Adjust the lifter preload as described in the engine assembly manual. This requires turning the engine over by hand, so remove the spark plus first to rotate it more easily. Re-install the valve-covers, make all connections for the fuel and ignition system, re-fill the engine coolant and test-run the engine. Adjust the ignition timing, check for leaks and remedy as needed.
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