Building a car engine from scratch takes time and patience--and you should also have an experienced mechanic to help you with this venture. Building a car engine entails more than just throwing parts together. Depending on the type of engine, there are different tolerances and torque settings on nuts and bolts that need to be maintained. There are many different types of engines, though the most popular you will run across are 4-cylinder, 6-cylinder and 8-cylinder engines. Engines are further broken down into the type, i.e. carburettor or fuel-injected, single overhead cam, double overhead cam, or conventional cam engines. No matter which engine you have, the major components are all the same.
Soak the new lifters in engine oil for at least five or six hours--but preferably overnight. While the lifters are soaking, line up all the new parts and the nuts and bolts and get all the tools you will need to put the engine together.
Install the piston rings on the piston. Make sure you stagger the three rings. If the break in the rings is lined up, you will incur blowby when the engine is started, and the engine will constantly burn oil. Coat the cylinder walls with STP oil treatment. Though other oils may be used, STP is thick and goopy and sticks to the walls, not only while you are working, but will stay there through start-up, protecting the new engine until the oil pump can properly lubricate everything.
Flip the block over and install the top half of main and rod bearings. Coat the visible side of all bearings with STP oil treatment. Lay the crank in place, then put the bottom half of the main bearings on the bearing caps. Install the main bearing caps. This will hold the crank in. Refer to the engine's manual for main bearing spacing and torque values.
Flip the block back over. Put the rod bearings in the bearing caps on one of the piston-rod assemblies. Note the markings on top of the piston. This will tell you which way the piston goes into the block. Using a ring compressor, compress the rings into the piston and set the piston into the cylinder hole. Gently tap the piston with a rubber mallet until it fits into the hole. Guide the rod onto the crank journal as you are tapping the piston. Repeat this step for the seven other pistons.
Flip the block over. Put the bearings on the bearing caps, coat them with STP oil treatment and install pursuant to the engine's spacing and torque specifications. Install the camshaft. Coat the cam with STP oil treatment, then gently slide the camshaft into the block. Make sure to install the cam button. Install the timing chain and timing cover. Make sure the timing marks are lined up properly before attaching the cover. Install the oil pump and the oil pan.
Install the lifters. They should already be coated with oil, as they should have been soaking up to this point. Paint the intake galley. This will help the oil slide back into the block easier. Install the heads. Make sure the head gaskets are in place and they do not cover any of the holes in the water jacket. They only work one way, but may fit on more than one way. Torque the heads down using the specifications for the particular year engine you are working on.
Install the pushrods and rocker arms. Refer to the engine's manual for torque specs on the rocker arms. If you are building an overhead cam engine, you will not have pushrods to install. The cam lobe pushes directly on the lifter. Install the intake manifold. You can use a bit of RTV on the gaskets to help hold them in place.
Install the valve covers. You are now ready to set the engine into the car. The rest of the accessories (fuel pump, carburettor and distributor or fuel injection) can be installed once the engine is bolted securely into the engine compartment.