Relief Valve; Operation 10-13 To Dismantle And To Assemble - Perkins 900 Series Workshop Manual

10
900 Series

Relief valve

The relief valve (A) is fitted in the lubricating oil pump body and prevents too much pressure in the lubricating
oil system.
As engine speed increases the output of the oil pump increases, and more oil flows into the system. The
increase in flow causes an increase in pressure in the system. When the oil pressure on the plunger of the
relief valve is greater than the spring pressure, the valve will open. When the valve opens, surplus oil is
returned to the sump. This action will reduce the oil pressure and the valve will close. Oil that passes the relief
valve reaches the oil filter.
To dismantle and to assemble Operation 10-13
1 Apply pressure to the end plate (A1) of the spring assembly, release and discard the split pin (A5). Carefully
release the pressure to remove the end plate and the spring (A2) from the valve body (A4). Remove the
plunger (A3) from the bore of the body.
2 Ensure that all the components are cleaned and then lubricated lightly with clean engine lubricating oil.
3 Fit the plunger into the bore with its hollow end to the inside. Fit the spring and the end cap into the bore
with the ends of the spring fitted around the bosses of the plunger and the end plate. Apply pressure to the end
plate and fit a new split pin into its hole.
4
3
2
1
5
A
C0086
160 Workshop Manual, TPD 1345E, issue 3
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