Perkins L4 Workshop Manual - L-36 Fleet

Page P2
The OU Pressure Relief Valve.
1he oil pressure reliefvalve which is incorporated
in the pump prevents the pressure becoming excessive
as might otherwise happen when the engine
is cold.
When the predetermined pressure is exceeded
the valve opens against the spring and same of the
oil is by-passed back into the sump. Tbat continues
until the oil warms up and fiows at the desired
oressure. Tbe valve then closes.
Cn early engines the oil pressure relief valve
housing was integral with the bottom cover of the
lubricating oil pump and to obtain access to the
valve for cleaning, see Page P .3.
As from Engine No. 6032453, ho wever, lubricating
oil pumps ipcorporate a detachable pressure
relief valve which is screwed into the outlet side
of the pump body, (See Fig. P.l). The action of
this valve is identical to that described above,
and cleaning instructions are given on page P.3.
Men to Renew the Oil.
Thc oil in tbc sump must be drained in accordance
witb periodical attentions Section F and
replaced by new oil of a specification suitable for
. Lubrication System-continued
the climate in which the engine is operated
Appendix).
(See
General.
Particular care must be taken to wipe oir any
water which may have splashed onto the engine ar
any time, since water, which may find its war into
the sump from the exterior, will tend to form sludge.
Failure to change the oil at the recommended
intervals is false economy even if the oil seems good
at the time of recommended change.
Dirty lubricating oil filters aggravate the formation
of sludge, which in turn will further choke the
filters. Regular filter inspection and cleaning at
the specified periods is essential, see Section F.
To Remove, Clean and Replace Sump Strainer.
Drain oil into a suitable receptacle af ter removing
the drain plug. Remove setscrews holding sump
strainer cover. This cover is situated near the
drain plug.
Drop cover and strainer will come away witb
cover.
Wash and clean strainer in clean fuel oil or
paraffin.
To re-assemble, reverse tbe order of operations.
Ensure that the oil pump suction pipe enters thc
hole provided in the strainer.
If reasonable care is taken when removing and
replacing sump strainer cover, tbc joint wiIl not
require renewing evcry time the strainer is removed.
To Remove Snmp.
Remove drain plug and drain ofT. oil.
Remove dipstick.
Remove sump strainer (as above).
Remove all setscrews securing sump to crankcase
and lower sump.
Remove all traces of old joints and sump cork
strip from timing case bottom cover and rear main
bearing cap.
To Replace Sump.
Assembie ncw joints and cork strips.
Lightly smear crankcase races with a thin
coating of jointing compound and place joints
in position ensuring all holes line up.
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When placing joints in position it is important
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