Doosan DA40 - Knocking;noise

SHOP MANUAL
Engine
Ch 1 page 242
Knocking/noise
Eect Cause Trouble shooting Action
Exhaust valves close
too late and strike
the piston crowns
Timing gears incor-
rectly meshed
Check the valve timing,
see “Service data,
engines”
The crankshaft gear has
come loose
Valve mechanism not
operating
Rapidly increasing
valve clearances
Disturbances in the sup-
ply of lubricant for the
rocker arms
The piston strikes
the cylinder head
Loosened big end cap
(wrong tightening torque
after repair)
- Tighten to the torque
specied in the Work-
shop manual
Foreign objects in the
piston crown
Piston seizure (may be
caused by clogged pis-
ton cooling nozzles)
Wrong injection timing
Worn collets on exhaust
valves
Broken upper pis-
ton rings
Incorrectly adjusted
injection pump
Disconnect one delivery pipe at a time and listen
for changes in the engine sound.
WARNING!
!
Be careful when disconnecting the delivery
pipes as the pressure is extremely high and
could cause injury
Broken delivery valve
spring (after-injection)
Connecting rod bearing
seizure
Faulty injector (seized,
worn, incorrect or
cracked tip, fatigued
spring)
Incorrectly adjusted
injector
More than 1 washer
under injector
Fuel leakage in ame
start
Check whether it leaks. (Take out the ame start
and run the engine with fuel pipe connected)
Loosened big end cap
Melting damage on
piston crown
Injection timing
extremely advanced,
30 ° BTDC or more
Check the injection tim-
ing
Incorrectly adjusted
injector