The big block Chevrolet, or BBC 454, otherwise known as a "Rat motor" needs disassembly if you want to upgrade it for more horsepower or if something inside the engine wears out or breaks. The disassembly is an easy task as long as you have the proper tools, but does require some muscle. When removing bolts, keep them with the parts you removed or label them in small bags so you know where they go when you put the engine back together.
Instructions
- 1
Slide one of the drain pans under the radiator petcock. Ensure that the engine is cold, then open the petcock and allow the coolant to drain. Remove the radiator cap to allow faster draining. Jack up the vehicle, using the floor jack, and then support it with jack stands. Slide the other drain pan under the oil pan. Remove the oil pan drain bolt and allow the oil to drain. Dispose of the fluids in an appropriate manner -- most auto parts stores have disposal tanks for fluids.
2Lower the vehicle off the jack stands, using the floor jack. Remove the bolts, holding the fan shroud onto the radiator. Push the fan shroud over the fan. Break the fan bolts loose, but do not remove them. Pull the fan shroud back into place. Loosen the adjusting bolts on the alternator and power steering pump brackets. Push the accessories toward the center of the engine to loosen tension on the belts. Lift the belts off the engine. Push the fan shroud toward the engine and remove the bolts in the fan. Lift the fan and shroud out of the engine as an assembly.
3Disconnect the negative battery cable, using the appropriate wrench. Follow the negative cable down to where it attaches. If attached to the engine, remove it, but if attached to the frame or body, leave it attached. Remove the positive battery cable from the battery. Remove the battery hold down, using the appropriate socket. If the hold down still has the wing nuts, simply remove them with your fingers. Lift the battery out of the engine compartment.
4Loosen the clamps on the upper and lower radiator hoses, using the screwdriver. Pull the hoses off the radiator and the engine. Unplug the alternator's wiring harness connector. Remove the power wire from the back of the alternator, using the appropriate wrench. Remove the alternator from the engine, using the appropriate socket. Remove the power steering pump, using the appropriate sockets, but do not remove the lines. Set the pump out of the way and prop it up so that the fluid doesn't leak out.
5Mark all the wires and vacuum hoses with the tape and marker. Unplug all wiring harness connectors and remove the vacuum hoses from the carburetor, intake manifold and engine.
6Jack the vehicle up and support it with jack stands. Remove the starter wiring using the appropriate wrench. Put the nuts back onto the studs, so you don't lose them. Remove the starter, using the appropriate sockets. Remove the torque converter access cover, if equipped. Turn the crankshaft until you can see one of the torque converter bolts through the cover. Remove the bolt. Turn the crankshaft again, until you can see the next bolt, and then remove it. Continue the process to remove all the torque converter bolts.
7Slide an empty drain pan under the transmission tail housing. Unbolt the driveshaft at the rear. Slide the driveshaft out of the transmission tail housing. Stuff a rag into the tail housing to prevent excessive loss of fluid. Remove the bell housing-to-engine bolts, using the appropriate socket. Remove the transmission mount, then pull the transmission back enough to separate it from the engine.
8Lower the vehicle off the jack stands. Remove the engine mount bolts, using the appropriate socket. Remove the distributor hold down bolt, using the distributor wrench. Carefully lift the distributor assembly out of the engine.
9Remove the bolts on the exhaust manifolds. Move the exhaust manifolds away from the engine. Depending on the BBC 454 year working on and the state it is in, you may have to remove the bolts from the collectors to get the exhaust manifolds to move far enough away from the engine.
10Remove the fuel lines from the carburetor, using the appropriate line wrench. Remove the carburetor linkage, using the screwdriver. Unbolt and remove the carburetor, using the appropriate socket.
11Check that there are no wires and vacuum lines attached to the engine. Hook the engine hoist up to the engine, using the bolt-holes in the heads. Lift the engine out of the vehicle, watching to ensure nothing is still hooked up to it. Transfer the engine to the engine stand. Support the bottom of the transmission with a block or floor jack.
12Remove the water pump, using the appropriate sockets. Remove the intake manifold, using the appropriate sockets. Remove the valve covers, using the appropriate sockets. Remove the rocker arm nuts, using the appropriate sockets. Lift the rocker arms off, and then pull the pushrods out of the engine. Remove the head bolts, and then pry the heads off the engine. Remove the crankshaft pulley, using the appropriate sockets, then the harmonic balancer, using the balancer puller. Remove the camshaft sprocket and crankshaft sprocket bolts, using the appropriate socket. Pull the timing chain, camshaft sprocket and crankshaft sprocket off the engine as an assembly.
13Remove the camshaft. Remove the oil pan, using the appropriate socket. Flip the engine over on the stand, and then unbolt the bearing caps. Remove the caps -- keep them in order, as they must reinstall in the same spot from which they were removed. Lift the crankshaft out of the engine.
