F
OR
M
ODELS
: JGI, JGM, JGN, JGP
AND
JGQ
S
ECTION
4 L
UBRICATION
PAGE 4-38
Pressure Testing For Divider Valve By-Passing
Divider valve piston to bore are metal to metal sealing surfaces. Lubricant by-passing can
result from excessive clearance between the piston and bore due to wear. Pressure test all
divider blocks that are in service yearly, and replace any divider valves that fail to pass. Test-
ing helps to ensure the piston to bore clearances are close enough to build adequate pres-
sure to force oil into the injection point.
All new Ariel divider valves are provided pressure
tested by the supplier.
To test divider blocks for valve by-passing, a manual purge pump equipped with a pressure
gauge, and capable of developing 5000 psig (350 bar
g
) is necessary. Such a force feed
lubrication system purge gun (hand pump kit) with a pressure gauge is available from Ariel
as an optional purchase tool. For pressure testing the divider block use a 10-weight oil at
room temperature to simulate a hot lubricant. Test each divider block assembly complete
with pin indicators installed. Test only one divider valve at a time.
Place the divider block assembly in an open container with all base outlets open. Connect
the purge pump to the inlet of the divider block assembly. Operate the purge pump to cycle
the divider block several times to purge air from the assembly and verify that oil will flow
freely from all outlets. Divider blocks should cycle at less than 300 psig (21 bar
g
). See Figure
4-15 “Divider Block All Outlets Open”.
Divider valves stamped with a “T” are to have only one outlet on the base plugged during
testing of that side of the piston. Each base outlet of the divider valves stamped with a “T”
must be plugged and tested one side at a time. See Figure 4-15 “Testing “T” Divider Valve”.
Individual testing of each outlet ensures both sides of the piston will build adequate pres-
sure. All divider valves stamped with an “S” on the front are to have both outlets on the base
plugged to test for by-passing. See Figure 4-15 “Testing “S” Divider Valve”. This will test both
sides of the piston at the same time.
Plug the outlet on the base behind the divider valve being tested with a 1/8 inch pipe plug. If
a tubing fitting is installed in the base, plug the fitting with a tubing plug. Leave all other out-
lets open. Operate the purge gun until the pressure gauge indicates 3000 psig (207 bar
g
).
The block may cycle once or twice, but should pressurize to 3500 psig (241 bar
g
) immedi-
ately. Stop pumping oil into the divider block at 3500 psig (241 bar
g
). Check the plug(s) in
the discharge outlet(s) to confirm there are no external leaks. If the pressure gauge on the
purge gun drops suddenly and oil squirts from the other outlets, a by-pass condition exists.
The piston is worn and is allowing oil to by-pass. The pressure gauge should not lose more
than 1000 psig (69 bar
g
) during a 30-second test period. Note: Testing the divider blocks at
higher pressures is necessary if the application dictates a higher system operating pressure.
If a divider valve does not pass, it must be replaced. Discard worn divider valves. If the
tested valve does not lose more than 1000 psig (69 bar
g
) in 30 seconds, relieve the pres-
sure, move the plug to the next outlet and repeat the test for all divider valves. When divider
valves have passed pressure testing to this procedure or have been replaced, a divider
block may be reassembled, purged with the proper force feed lubricant being used and put
into service.
By the nature of this divider block pressure testing procedure, in a static position through the
divider valves above, it is not infallible. Periodic testing for proper lubrication rates in the cyl-
inder bore and/or aftermarket devices that measure flow are recommended.
