
3. Cause of Abnormal Piston Knock Noise and Elimination Method
2. Cause of Abnormal Slap Noise in Piston Ring and Elimination Method
No.
Cause of abnormal noise
Elimination method
Abnormal noise in
connecting rod
bearing
Abnormal noise in
main bearing
Abnormal axial
play noise in
crankshaft
Abnormal Impact
noise in flywheel
Bolt on connecting rod cap is loose
Dimension of connecting rod bearing
bushing is not consistent, which causes
rotation or rupture
Connecting rod bearing bush is
burned
Connecting rod bearing is lubricated
poorly
Radial gap of main bearing is too large
Bolt on main bearing cap is loose
Main bearing bushing is burned
Main bearing is lubricated poorly
Dimension of main bearing bush is not
consistent, which causes rotation or rupture
Axial gap of crankshaft is too large
Crankshaft thrust washer is abraded too
much
Fixed bolt of flywheel is loose
Replace main bearing
Tighten
Replace bushing
Dredge lubricating oil passage
or enlarge the oil hole
Replace the main bearing
bushing
Adjust (add shim) to normal
Replace the thrust washer
Fasten
Drill the lubricate hole to normal, improve
lubricating oil passage
Tighten
Replace bushing
Replace the bushing
Radial gap between connecting rod
bearings is too large
Replace the bearing
Part with
abnormal noise
1
Piston ring is broken
Back lash of piston ring is too large
Piston ring lines up
Piston ring is locked
Elasticity of piston ring is insufficient
Airtightness between piston and cylinder wall is poor
Knock occurs
when the engine
is cold
Knock occurs
when the engine
is warm;
Knock occurs no
matter the
engine is cold or
warm
Depth and width of main bearing oil bath is
inaccurate or oil pressure is insufficient, so
cylinder wall is not lubricated well
Repair, or adjust oil pressure to meet
requirement
Gap between piston and cylinder wall is too
large
Connecting rod is bent
Rod journal is not parallel to the main journal
Connecting rod bushing is deflected in axial
direction
Piston is reverse elliptic
Gap between piston and cylinder wall is too
small
Back lash and end play of piston ring is too small
Cylinder wall and piston are poorly lubricated
Piston pin and small end of connecting rod is
mounted too tightly
Connecting rod bearing is assembled too tightly
Cylindricity at train of piston is too large
Replace the piston
Repair the cylinder or replace the piston
Repair or replace the piston ring
Dredge oil passage and improve splash
lubrication
Adjust tightness of piston pin to normal
Adjust the tightness of bearing to normal
Replace with a piston that has normal
cylindricity
Replace the piston to obtain normal gap
Correct or replace the connecting rod
Replace the connecting rod
Replace the bushing
Replace
Replace
Correct (reinstall to be staggered)
Replace
Replace
Replace
2
3
4
Cause of abnormal noise
Problem
Cause
Elimination method
Elimination method
172
Содержание JL481Q
Страница 1: ......
Страница 9: ...5 Fig 3 Components Assembly Drawing of MR479Q MR479QA Engine ...
Страница 10: ...6 Fig 4 MR479Q MR479QA Engine and Its Power System ...
Страница 11: ...7 Fig 5 Assembly Drawing of Engine and Its Auxiliaries MR479Q MR479QA ...
Страница 12: ...8 Fig 6 Electronic Control Fuel Injection System in Engine MR479Q MR479QA ...
Страница 13: ...9 Fig 7 Front view of Engine JL481Q MR481QA ...
Страница 14: ...10 Fig 8 Sectional elevation of Engine JL481Q MR481QA ...
Страница 15: ...11 Fig 9 Electronic Control Fuel Injection System in Engine JL481Q MR481QA ...
Страница 21: ...17 Fig 13 Exterior Feature of JL481Q Engine Power Me N m Torque Pe Kw ge g kwh Fuel Consumption Ratio ...