Recommendations are given here, from preparation for repair and the purchase of spare parts to a detailed step-by-step description of the removal, fault detection and installation of assemblies.
The following paragraphs are written on the assumption that the engine has been removed from the vehicle. Repair operations that do not require removal of the engine from the vehicle are described in chapters 2A and 2B.
At the beginning of this chapter, you will find the Technical data required to carry out the repair operations described in this chapter. Additional technical data is also contained in chapters 2A and 2B.
It is not always possible to determine exactly when or why an engine needs repair. It depends on a number of circumstances.
High mileage does not necessarily mean that the engine needs to be repaired, just as low mileage does not mean that the engine does not need repair. Perhaps the best criterion is the frequency and quality of service. Frequent oil and filter changes, along with other scheduled maintenance, will likely allow the engine to go many thousands of miles in good condition. On the contrary, inattention to the engine will significantly shorten its life cycle.
The first signal of a deterioration in the condition of the engine is increased oil consumption. This means piston rings, seals and valve guides need attention (provided, of course, that oil consumption is not caused by normal leaks). First, check the compression in the cylinders (paragraph 3), as well as the level of vacuum in different operating modes (paragraph 4).
Reduced power, erratic engine operation, engine thumps or metallic noise, valve clatter, and high fuel consumption can also indicate a repair is needed, especially if all of these troubles are present at the same time. If full maintenance and adjustments do not change the situation, then repair is the only right solution.
An overhaul of the engine with the processing and replacement of parts brings the engine to a condition equivalent to a new one. During the repair, cylinders are bored or honed and piston rings are replaced. In the case of cylinder bores, the pistons are also replaced with the next repair size. As a rule, the liners of the main and connecting rod bearings are replaced, and, if necessary, the crankshaft journals are also machined. Usually, valves by the time of repair also come to a state that requires lapping or regrinding. During engine repair, external engine devices, such as a generator, starter, distributor, etc., can be repaired at the same time. A repaired engine must have all the characteristics of a new one and work for many thousands of kilometers without causing unnecessary trouble to the owner.
Note. When repairing the engine, it is also recommended to replace the least reliable components and parts of the cooling system; hoses, drive belts, thermostat and water pump. Check the radiator carefully to make sure. that it is not clogged and does not leak (see chapter 3). If you buy a remanufactured engine or block, many vendors won't warrant it unless the radiator has been professionally flushed. We also do not recommend repairing the oil pump yourself - for a rebuilt engine, it is better to replace the pump assembly.
Before starting the repair, read all about the work ahead and prepare for it. Engine repair is not difficult, but it takes a lot of time. Be prepared for the fact that you do not have to use the car for at least two weeks, especially if you have to send some parts to a workshop for restoration. Specify the possibility of purchasing spare parts, as well as the availability of the necessary tools and fixtures. Most of the work can be done with normal tools, but in some cases you may need precise measuring instruments, especially for flaw detection and rejection of replacement parts. In case of doubt, contact a service station or repair shop, where specialists will evaluate the possibility of restoring the part.
Note. Before. how to contact the workshop, completely disassemble the engine and inspect all parts, especially the cylinder block. to decide which of them should be submitted for machining.
Since the condition of the cylinder block will play a decisive role in deciding whether to repair your engine or buy a remanufactured one. never pre-purchase spare parts or give other parts for machining until the unit has been fully fault-checked. The main cost of a major overhaul is time. Therefore, do not lose it by reinstalling parts that have exhausted their resource or are close to it.
And finally, a final remark. If you want the repaired engine to serve you for a long time and not cause trouble, all repairs, and especially assembly, must be carried out in sterile conditions and only with clean tools.