Volvo Penta TD520GE Workshop Manual page 22

Checks and adjustments
32
The order for removing parts is:
1 Cap nut
2 Injection nozzle
3 Adapter
4 Pressure pin
5 Compression spring
6 Shim
8. Set the pressure by selecting an appropriate
shim. (A thicker shim increases the opening pres-
sure.) Tighten the cap nut to 40 ±5 Nm (33 ±3.7
lbf ft). Recheck the injector in the nozzle tester.
9. Check the seal
Dry the nozzle and nozzle holder with
compressed air. Press down the tester handle
until you obtain a pressure of around 2.0 MPa
below the previously measured opening pressure.
Example: Pressure gauge:
For opening pressure, see Technical Data (1MPa
= 145 psi).
10. If no leaks appear within 10 seconds the nozzle is
sealed.
11. If the nozzle is leaking, dismantle and clean the
injector to prevent it from leaking. If the nozzle
still is leaking, replace the injector. Reuse is not
permitted.
12. Chatter characteristic and spray pattern tests.
NOTE! Shut off the tester pressure gauge, for this
test.
The chatter test provides an audible check of how
easily the nozzle needle is moving in the nozzle
body. New injectors give a different sound com-
pared with used injectors. It worsens due to wear
in the needle seat area. If an injector nozzle does
not make the chatter noise despite having been
cleaned, it must be replaced.
A used injector chatters clearly when the handle
is moved quickly, and shows a well-distributed
spray pattern. The condition of the nozzle is diffi-
cult to establish concerning spray pattern.
Incorrect spray pattern may cause engine
damage.
Group 20
27.5 MPa (3988 psi)
-2.0 MPa (-290 psi)
reading:
25.5 MPa (3698 psi)
set to: