Source: "On The Road" magazine. Part 77
Article 1 of 2. Page 1
If your car has covered a high mileage and is using an excessive amount of petrol and oil, lacks power and is becoming increasingly noisy, it is probably due for a major engine overhaul. If the job is carried out carefully and diligently, it will certainly result in an increase in power, a reduction in fuel and oil consumption and a quieter-running engine which will be good for many more mites of trouble-free driving.
the cylinder head retaining nuts also retain the cylinder barrels in position on the studs.
The combustion clambers are hemispherical in shape which greatly aids efficient combustion and each cylinder head has its own overhead camshaft, driven by a toothed rubber belt from a duplex drive pulley on the front of the crankshaft, which operates the inlet and exhaust valves via rockers of conventional design.
The fuel pump is of the mechanical type and is operated by the right-hand camshaft (viewed from the driver's seat).
The ignition distributor is mounted on the rear left-hand side of the engine and is driven by a skew gear on the left- hand camshaft. The oil pump is externally mounted on the front of the engine and is driven at half engine speed by the drive-belt of the left-hand camshaft. An eccentric on the oil pump shaft drives the pump which pressurizes the hydraulic which, in turn, operates the braking and system suspension systems.
The power unit is air-cooled and air is forced through sheet steel ducting, which is bolted to the engine casing, by a cooling fan mounted directly on the front of the crankshaft. Engine cooling is also aided by an oil cooler which consists of an alloy matrix mounted above the right-hand cylinder bank in the air flow generated by the fan. A thermostatically controlled by-pass valve aids the rapid warming up of the oil by closing the inlet to the cooler matrix until the engine has had time to attain its normal operating temperature.
When to overhaul the engine Before diagnosing engine faults which indicate a major overhaul is necessary, it should be noted that the Citroen GS engine is characteristically smokey, especially on startup and tends to emit fumes from the exhaust system even when in good condition. This is due to the layout of the This is the first of two articles covering the work involved in removing, overhauling and replacing the air-cooled, flat- four design of engine that is fitted to certain Citroen GS and Ami Super models.
All the early models of the GS were fitted with a 1,015 cc engine, but consequently the capacity was increased for some models by altering the bore and the stroke of the power unit to 1,220 cc during 1972. The 1,015 cc engine was covered as an option in the Ami range until 1976 and was, until then, also available in the GS range in place of the larger engine. As the 1,015 cc engine is a relatively small engine, it usually is driven hard and therefore benefits from more frequent overhauls than the 1,220 engine fitted to later models, the latter being less highly-stressed.
Engine design The Citroen GS has a light-alloy crankcase which is manufactured in two halves, split in the vertical plane and joined on assembly by a number of bolts. The cylinders are individually cast, with finned barrels and fit on to long studs screwed into either side of the crankcase assembly.
The cylinder barrels are made of cast-iron while the cylinder heads, one for each pair of cylinders, are made of aluminium alloy. The cylinder heads are mounted on the same studs that are used to locate the cylinder barrels and
Article 1 of 2. Page 1
If your car has covered a high mileage and is using an excessive amount of petrol and oil, lacks power and is becoming increasingly noisy, it is probably due for a major engine overhaul. If the job is carried out carefully and diligently, it will certainly result in an increase in power, a reduction in fuel and oil consumption and a quieter-running engine which will be good for many more mites of trouble-free driving.
the cylinder head retaining nuts also retain the cylinder barrels in position on the studs.
The combustion clambers are hemispherical in shape which greatly aids efficient combustion and each cylinder head has its own overhead camshaft, driven by a toothed rubber belt from a duplex drive pulley on the front of the crankshaft, which operates the inlet and exhaust valves via rockers of conventional design.
The fuel pump is of the mechanical type and is operated by the right-hand camshaft (viewed from the driver's seat).
The ignition distributor is mounted on the rear left-hand side of the engine and is driven by a skew gear on the left- hand camshaft. The oil pump is externally mounted on the front of the engine and is driven at half engine speed by the drive-belt of the left-hand camshaft. An eccentric on the oil pump shaft drives the pump which pressurizes the hydraulic which, in turn, operates the braking and system suspension systems.
The power unit is air-cooled and air is forced through sheet steel ducting, which is bolted to the engine casing, by a cooling fan mounted directly on the front of the crankshaft. Engine cooling is also aided by an oil cooler which consists of an alloy matrix mounted above the right-hand cylinder bank in the air flow generated by the fan. A thermostatically controlled by-pass valve aids the rapid warming up of the oil by closing the inlet to the cooler matrix until the engine has had time to attain its normal operating temperature.
When to overhaul the engine Before diagnosing engine faults which indicate a major overhaul is necessary, it should be noted that the Citroen GS engine is characteristically smokey, especially on startup and tends to emit fumes from the exhaust system even when in good condition. This is due to the layout of the This is the first of two articles covering the work involved in removing, overhauling and replacing the air-cooled, flat- four design of engine that is fitted to certain Citroen GS and Ami Super models.
All the early models of the GS were fitted with a 1,015 cc engine, but consequently the capacity was increased for some models by altering the bore and the stroke of the power unit to 1,220 cc during 1972. The 1,015 cc engine was covered as an option in the Ami range until 1976 and was, until then, also available in the GS range in place of the larger engine. As the 1,015 cc engine is a relatively small engine, it usually is driven hard and therefore benefits from more frequent overhauls than the 1,220 engine fitted to later models, the latter being less highly-stressed.
Engine design The Citroen GS has a light-alloy crankcase which is manufactured in two halves, split in the vertical plane and joined on assembly by a number of bolts. The cylinders are individually cast, with finned barrels and fit on to long studs screwed into either side of the crankcase assembly.
The cylinder barrels are made of cast-iron while the cylinder heads, one for each pair of cylinders, are made of aluminium alloy. The cylinder heads are mounted on the same studs that are used to locate the cylinder barrels and