The relief throttle (2) is a plate valve opening in direction of injection nozzle and provided with a throttle bore of 0.6 mrn dia. The plate valve (3) is riveted in space above pressure valve spring.
The relief throttle permits the fuel to pass in direction of injection nozzle. The pressure wave from injection nozzle in direction of injection pump, which is caused upon injection by the afterpumping effect of the nozzle needle while closing, is damped by the relief throttle. This will prevent the pressurewave from subsequently flowing back to injection nozzle and from setting up a re-injecting effect there. Re-injection would result in an increase of hydrocarbons in emissions.
Modified pipe connection on MIRSF-injection pump (engine 615,616 and 617)
Since May 1980 a modified pipe connection with 17.4 mm 00 (formerly 16 mm) i s installed. For this
connection and the former pipe connection, socket 617 589 01 09 00 is valid.
The socket 61 7 589 00 09 00 supplied up to now can be refinished as required by machining the 10 to 17.7 mm. Then change part number of wrench to 617 589 01 09 00.
A. Engine 61 5, 616, 61 7 M-injection pump with pneumatic governor and M/RSF-injection pump with mechanical governor
Removal
1. Clean injection pump on coupling nuts of injection lines and on pipe connections.
2. Unscrew injection lines, clamping jaws or locking plate and pipe connection.
3. Remove compression spring, copper sealing ring and pressure valve with pressure valve carrier.
4. Flush suction chamber of injection pump by actuating manual delivery pump. Remove foreign particles, if any.
Installation
5. Clean pressure valve and pressure valve carrier, pay attention to easy operation and damage.
6. Insert pressure valve carrier (6) with ring groove in downward direction, pressure valve (4) and new copper sealing ring (5).
7. Mount compression spring (3) on pressure valve.
8. Slightly lubricate pipe connection and screw in with new rubber sealing ring (2).
9. For perfect seat of copper sealing ring (5), tighten pipe connection as follows:
Tighten pipe connection t o 30 Nrn and release again. Tighten once again to 30 Nm and also release again.
Then tighten to 35 Nm.
10. Mount injection lines and clamping jaws or locking plate and vent injection system (07.1-140).
11. Run engine, check for leaks and quiet idle speed.
B. Engine 616, 617 MW-injection pump with mechanical governor
Note
In the event of leaks between pipe connection and element connection proceed as follows:
a) Pipe connection with ring groove on hex head
Replace rejected pipe connection only.
b) Pipe connection without ring groove on hex head
Replace all 5 pipe connections, even if only a single pipe connection i s leaking.
A. Pipe connection without ring groove
B. Pipe connection with ring groove
Start of production: Pipe connection (B) with ring groove engine 61 6 @model year 1977 starting begin
of production.
Engine 617 starting November 1975. l njection pump production date 531.
Removal
1. Clean injection pump on coupling nuts of injection lines and on pipe connections.
2. Unscrew injection lines and pipe connection.
Attention!
Do not loosen element connection (21, since otherwise a basic adjustment of injection pump on injection pump test bench will be required.
3. Remove compression spring, copper sealing ring and pressure valve with pressure valve carrier.
4. Flush suction chamber of injection pump by actuating manual delivery pump. Remove foreign
particles, if any.
Installation
5. Clean pressure valve and pressure valve carrier, check for easy operation and damage.
6. l nsert new copper sealing ring (5) under pressure valve carrier (6). lnstall pressure valve carrier (6) with ring groove in downward direction. Mount pressure valve (4) and compression spring (3) again.
7. Slightly lubricate pipe connection (1) on threads, screw in and tighten in one step to 40-50 Nm.
8. Mount injection lines and vent injection system (07.1-1 40).
9. Run engine, check for leaks and quiet idle speed.
