Engines on minibuses VW T4
The VW T4 has a transverse engine layout in the engine compartment. Engines are installed 4- and 5-cylinder, both gasoline and diesel.
The engines are removed downwards, with the 5-cylinder engine removed with the gearbox, and the 4-cylinder without it.
Work on the engine is complicated by a short hood cover, which makes it difficult to access the engine compartment. Therefore, in order to facilitate access, the radiator, together with the grille and the fan, simply lean forward.
Swinging out the radiator is almost always required when working on the engine and is described in subsection 2.2.
The engine block is cast in gray cast iron and houses the cylinders. In case of severe wear or scuffing on the cylinder walls, they must be honed at the factory. After that, of course, it is necessary to install pistons of increased diameter. In the lower part of the cylinder block there are supports for the crankshaft main bearing shells and the crankshaft. The connection of the crankshaft with the pistons is provided by connecting rods sitting on the crankshaft in plain bearings. At the bottom of the engine is an oil pan that contains engine oil. From above, the cylinder head, cast from an aluminum alloy, is attached to the engine block. this metal conducts heat better and has a lower specific gravity than gray cast iron.
The exhaust and intake manifolds are attached to the cylinder head. At the top of the cylinder head is the camshaft, which is driven by the crankshaft through a toothed belt. The camshaft drives the vertically positioned intake and exhaust valves via hydraulic poppets. Hydraulic tappets automatically equalize valve clearances so valve clearance adjustment is not required for service.
Engine lubrication is provided by an oil pump, which, in a 5-cylinder engine, is attached to the front of the cylinder block and is driven by the crankshaft. On a 4-cylinder engine, the oil pump is located in the oil sump and is driven by an intermediate shaft.
The oil taken from the sump is fed through holes and channels to the main bearings of the crankshaft and camshaft, as well as to the working surfaces of the cylinders.
The water pump of the 5-cylinder engine is located at the front in the crankcase and is driven by a toothed belt. In a 4-cylinder engine, the water pump is attached to the side of the cylinder block. The water pump is driven by a V-belt, which also drives the generator. An additional V-belt drives the power steering pump. Attention should be paid to the fact that a mixture of water and non-freezing anti-corrosion additives must be filled into the cooling system all year round.
The fuel-air mixture is usually prepared by a maintenance-free fuel injection system.
The electronic ignition system of gasoline engines maintains the ignition timing almost constant. Depending on the type of engine, the ignition distributor is mounted on the left side of the cylinder block or on the rear of the cylinder head. In 4-cylinder engines, it is driven by the gear rim of the intermediate shaft.
The intermediate shaft, in turn, is driven by a toothed belt from the crankshaft. In a 5-cylinder engine, the distributor operates directly from the camshaft.
The diesel engine does not have an ignition system, because as a result of strong compression, the air heats up so much that, after fuel injection, the mixture ignites spontaneously. High pressure fuel pump (injection pump) attached to the side of the block and driven by a toothed belt.
Attention! The radiator fan may spontaneously turn on even when the engine is stopped and the ignition is off. As a result of heat stagnation in the engine compartment, this can happen repeatedly. When working in the engine compartment with a hot engine, this must be taken into account and the possibility of a sudden activation of the radiator fan must be taken into account.
Brief technical characteristics of VW T4 engines
Engine code | AAS | AAF | 1X | ABL | AAB |
Start of release | 9.90 | 12.90 | 9.90 | 10.92 | 9.90 |
Working volume, cm3 | 1968 | 2459 | 1896 | 1896 | 2370 |
Power, kW / hp at rpm | 62/ 84 4300 | 81/ 110 4500 | 44/ 60 3700 | 50/ 68 3700 | 57/ 78 3700 |
Torque, N·m at rpm | 159/ 2000 | 190/ 2200 | 127/ 1700 | 140/ 2000 | 164/ 1800 |
Cylinder diameter, mm | 81,0 | 81,0 | 79,5 | 79,5 | 79,5 |
Piston stroke, mm | 95,5 | 95,5 | 95,5 | 95,5 | 95,5 |
Compression ratio | 8,5 | 8,5 | 22,5 | 22,5 | 22,5 |
Fuel | petrol 91 | petrol 91 | diesel fuel | diesel fuel | diesel fuel |
injection system | Digifant | Digifant | Diesel-VE | Diesel-VE | Diesel-VE |
The order of operation of the cylinders | 1–3–4–2 | 1–2–4–5–3 | 1–3–4–2 | 1–3–4–2 | 1–2–4–5–3 |
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