Excessive oil consumption indicates that the piston rings and/or valve guides need to be checked. Measure the compression in the engine cylinders to determine the amount of work required.
If the engine detonates or rattles, the connecting rod and/or main bearings are likely damaged. Check the oil pressure by installing a pressure gauge in place of the oil pressure gauge sender and compare the readings to Specifications. If the pressure is extremely low, the bearings and/or oil pump are likely worn out.
Loss of power, rough running, excessive valve knock, noise and increased fuel consumption also indicate the need for an engine overhaul, especially if all of these occur at the same time.
The process of rebuilding an engine means restoring the internal parts to the specifications of a new engine. During a rebuild, piston rings are replaced and cylinder walls are repaired (cylinders are bored and/or honed). If the cylinders were bored during engine repair, new pistons had to be installed. The main and connecting rod bearings are replaced with new ones and, if necessary, the crankshaft can be reground to restore the journals. The valves are usually also serviced as they are likely to be in poor condition. During an engine rebuild, other components such as the carburetor, distributor, starter, and alternator can also be rebuilt. As a result, the engine should be like new and able to operate without interruption for a long time.
Before you begin overhauling the engine, carefully study the entire procedure and familiarize yourself with the work requirements. Engine repair is not a difficult, but time-consuming procedure. Prepare all necessary replacement parts and special tools in advance. Most work can be done with common power tools, although many parts require precision measuring instruments to check.
Note: Do not begin disassembling the engine until you have determined the necessary operations to be performed. Since the condition of the block is a major factor in determining whether an engine needs rebuilding, never purchase replacement parts until you have completely inspected the block.
Finally, please note that to ensure maximum service life and minimum problems with your rebuilt engine, everything must be assembled with care and in a spotlessly clean condition.