PGO BR-500, Руководство по обслуживанию

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Thelubrication system is divided into two sections:
-high pressure
-low pressure
The high pressure section includes allcomponents located on the engine crankcase, while the low pressure section
onlyrefers to the thermal unit.
The trochoidal pump is installed in the sump andis controlled by a pair of gears.
A pre-filter is used to ensure the pumpintegrity.
The pre-filter is of the extractable type andits cap also serves for engine oil drainage.
Delivery to the pump is controlled by a 4-barcalibrated piston by-pass. This is located before the cartridge filter,
andboth are installed on the flywheel cover, for this reason the gasket is subjectto the system pressure.
The by-pass located before the cartridge filterimproves the filter working conditions, especially with cold oil.
The filter is provided with an anti-emptyingvalve and with an overpressure valve; the latter trips when the filtering
masscauses a pressure drop of more than 1 ?0.2 bar.
Of course, these conditions are only reachedwith cold oil and engine at a high speed, or with a dirty filter.
The filtered oil is used to lubricate the waterpump shaft and once the engine crankcase is reached, to lubricate the
benchends, the connecting rod head and the piston cooling nozzle, obtained on thetransmission-side connection.
The transmission-side bench connection isprovided with sealing oil guard and relevant drainage duct.
The timing feeding duct is found at the flywheelside connection; delivery to the head is controlled by the specific jet
startedin the engine crankcase.
The timing components work with low pressurelubrication.
The camshaft ends are directly obtained in thehead aluminium; the camshaft axial clearance is partly recovered by the
oilsent to the connection with smaller diameter.
The camshaft lubricates the rockers throughspecific holes obtained in such position as to ensure that lubrication
ismaintained after the vehicle stops. This result is obtained thanks to theposition taken by the camshaft with higher
probabilities when the engine stops.
The oil used for head lubrication returns to thesump through the chain housing channel and therefore lubricates the
chain aswell.
A unidirectional valve and a decantation chamberare used to prevent the gases recovered from the base from carrying
quantitiesof oil. The unidirectional valve is of the metal reed type; the decantationchamber is provided with a drainage
hole. A failure of these components cancause the presence of oil in the engine air feeding duct.
An excess of oil vapours can cause clogging ofthe channels obtained on the throttle body.
A pressure switch located close to the filteroutput indicates the system minimum oil pressure.
The lubrication circuit doers not concern thecounter-shaft, which is lubricated by the oil carried by the gears or by
theoil centrifuged by the driving shaft.
The same occurs for the piston or pin, eventhough in this case the cooling nozzle is especially important.
PGO BR-500 ENGINE
P.10-123
Lubrication