Repair work that can be carried out without removing the power unit from the vehicle
Without removing the engine from the car, you can perform many repair operations. Before starting any work, it is advisable to wash the engine compartment and engine with a jet of water. It is easier to work with a clean engine; in addition, contamination of the internal engine elements is prevented.
To expand the working space and not damage the paintwork of the body, remove the hood and mud flaps.
If there are traces of oil or coolant leakage indicating the need to replace the gaskets, then all work is usually carried out without removing the engine. Without removal, you can replace the oil pan gasket, cylinder head, intake and exhaust manifold gaskets, front and rear covers, crankshaft seals.
Without removing the engine, you can also remove attachments such as the coolant pump, starter, generator, distributor, intake and exhaust manifolds, fuel pump and carburetor.
Since the cylinder head can be removed without removing the engine, it is possible to repair the valve mechanism.
Without removing it, you can replace or check the condition of the timing belt, timing shaft drive gears, oil pump, and front engine cover seal.
In extreme cases, when the necessary equipment is not available, piston rings, pistons, connecting rods and connecting rod bearings can be replaced, and cylinders can be honed without removing the power unit. However, it is not recommended to perform these works without removing the power unit, as it requires thorough cleaning of a number of parts and some preparatory work.
Engine overhaul
It is not always easy to come to a conclusion about the advisability of an engine overhaul, since it is necessary to rely on a number of signs. High mileage is not a sufficient indicator of the need for a major overhaul, while low mileage does not exclude the need for a major overhaul. The most important indicator, apparently, is the timeliness of routine (scheduled) engine maintenance. With timely replacement of oil and air filter, performance of all other necessary maintenance work, the engine can reliably serve for many thousands of kilometers. On the contrary, insufficient maintenance can cause a sharp reduction in engine life. Increased oil consumption indicates wear of piston rings or valve guides. You should make sure that the cause
increased oil consumption is not due to leaks, and only then can we conclude that the piston rings and guide bushings are unsuitable.
To determine the scope of the upcoming work, measure the compression in the engine cylinders or check the tightness of the combustion chamber, for which it is recommended to contact an experienced specialist.
If increased noise or knocking is heard during engine operation, the probable cause may be wear of the connecting rod or main bearing shells.
Unscrew the standard oil pressure indicator sensor and measure the oil pressure with a pressure gauge, compare the obtained value with the one specified in the manual. If the pressure is low, the cause may be wear of the crankshaft main bearings or wear of the oil pump.
Loss of power, "dips" in engine operation, increased noise from the valve timing mechanism, increased fuel consumption indicate the need for a major overhaul, especially if all these factors occur simultaneously. If performing all adjustments does not lead to improvement, then the most appropriate means of eliminating the indicated faults is repair.
Major repairs involve restoring engine parts to the condition specified in the technical documentation for a new engine. During a major repair, piston rings are replaced, and cylinder walls are bored to the next repair size (or honed).
After repairing the cylinders, it will also be necessary to install new pistons. The connecting rod and main bearings are also subject to replacement; if necessary, the crankshaft journals should be ground to restore the necessary clearances with the connecting rod and main bearings. As a rule, the valve mechanism is not replaced, since its condition at the time of repair is quite satisfactory. During a major overhaul of the engine, the carburetor, ignition distributor, starter and generator are also repaired. As a result, after a high-quality repair, the engine should have the qualities of an almost new unit and serve reliably for a long time.
Before starting a major engine overhaul, read the description of the relevant repair procedures to roughly estimate the upcoming scope of work and requirements for them. Major repairs are not complicated, but they are time-consuming. It will take approximately two weeks, especially if you have to go to a specialized workshop to repair and restore parts (grind, bore). Check the availability of spare parts and take care of purchasing the necessary special tools and equipment in advance.
Almost all work can be done with a standard set of tools, although precise measuring instruments will be needed to check and determine the suitability of certain parts. Often, the condition of parts is checked in specialized workshops, where recommendations for replacement or restoration of parts are also received.
Note: To decide which maintenance and repair operations will be performed in the workshops, contact specialized workshops and service stations after completely disassembling the engine and checking all parts, especially the cylinder block.
Since the condition of the cylinder block is a determining factor for making a decision on its further repair or purchasing a new or reconditioned cylinder block, spare parts should be purchased or machining operations should be performed only after a thorough inspection of its technical condition. Make it a rule that the true cost of repair is time, then you will not have to pay for the installation of worn or repair parts.
In conclusion, we note that the assembly of any units should be carried out very carefully, in a clean room, to avoid further failures of the repaired engine.
Engine Overhaul: Alternatives
When performing a major overhaul on your own, there are various options. The decision to replace the cylinder block, connecting rod and piston group, and crankshaft depends on a number of factors, the most important of which is the condition of the cylinder block. Other considerations include the cost of repairs, the ability to access the equipment of a car service workshop, the availability of spare parts, time to perform the work, and the relevant experience.
Below are some of the options for performing major repairs.
Purchase of individual spare parts
If the inspection shows that the cylinder block and most of the parts are in satisfactory condition and can be used in the future, then the most economically feasible option is to purchase individual spare parts. The cylinder block, connecting rod and piston group and crankshaft should be carefully examined. Even if minor wear of the cylinder block is detected, the cylinders are subject to mandatory honing.
Complete crankshaft
This rebuild kit includes a reground crankshaft and a set of matched pistons and connecting rods. The pistons are already installed on the connecting rods. The kit also includes a set of piston rings, main bearings and connecting rod bearings. These kits typically include pistons in both standard and all oversize sizes.
Incomplete cylinder block
The incomplete cylinder block consists of a cylinder block with a crank mechanism and piston group installed. The kit includes new main and connecting rod bearings, the clearances in them correspond to the standard. The existing camshaft, valve mechanism, cylinder head and attachments are mounted on the kit. The costs for mechanical processing are minimal or not required at all.
Complete cylinder block
The complete cylinder block contains the entire set of the incomplete cylinder block, as well as the oil pump, oil pan, cylinder head, camshaft bearing housing cover, camshaft, valve mechanism, camshaft drive gears, toothed belt and belt covers. All bearings, seals and gaskets are new. Only the intake and exhaust manifolds, attachments are installed on the set.
Think carefully about which option is best for you. Before purchasing parts, consult with the car service station, with spare parts sellers.