Excessive oil consumption is an indication that the piston rings, valve seals and/or valve guides need attention. Make sure the seals are OK before assuming the rings and/or guides are in bad condition. Perform a compression test on the cylinders to determine the work needed.
Remove the oil pressure sensor and check the oil pressure with a measuring device inserted in its place. Compare the results with the reference values. If the pressure is extremely low, the bearings or oil pump are probably badly worn.
Lack of power, rough running, knocking or metallic sounds in the engine, loud valve noise and excessive fuel consumption may also indicate the need for an engine overhaul, especially if they are present at the same time. If a full tune-up and adjustment does not improve the situation, then the only way to solve the problem is to overhaul the engine.
Engine reconditioning involves bringing the internal engine components to a new condition. During reconditioning, piston rings are replaced and cylinder bores are ground. When resurfacing the cylinders in a specialized auto repair shop, larger pistons will also need to be installed. Main and connecting rod bearings are usually replaced with new ones, and, if necessary, the crankshaft can be ground to restore the journals. Valve repairs are also usually necessary, as their condition usually leaves much to be desired. When reconditioning an engine, its external components, such as the starter or alternator, can also be reconditioned. The end result should be as good as new, providing a large number of kilometers without
Caution: Cooling system components such as hoses, drive belts, thermostat and water pump should always be replaced when performing major engine repairs. The radiator should be carefully checked to ensure that it is not clogged or leaking. We also recommend that the oil pump be overhauled.
Before you begin rebuilding an engine, read the entire process description carefully to familiarize yourself with the skills required to perform the job. Rebuilding an engine may not be that difficult if you follow all the instructions carefully, use the necessary tools, and strictly observe the control dimensions; however, this can take a very long time. Plan to keep the car out of service for at least two weeks, especially if there are parts that need to be repaired at a specialist workshop. Check that the necessary parts are available and make sure that you have all the necessary tools and equipment ready in advance. Most of the work can be done using common tools, but special precision measuring tools are also required to determine whether parts need to be replaced. A specialist workshop can often take the necessary measurements and advise on the need for replacement and/or repair.
Caution: Always wait until the engine has been completely disassembled and all components, especially the engine block and cylinders, have been inspected before deciding which operations should be delegated to a specialist workshop. Since the condition of the cylinders is a major factor in deciding whether to rebuild an old piston group or purchase a new one, never purchase parts or machine components until the cylinders and block have been thoroughly inspected.
In conclusion, it must be said that in order to ensure maximum service life and a minimum number of problems on the engine after repair, it is necessary to carry out assembly very carefully and in conditions of complete cleanliness.