1. Determination and Elimination Method of Major
Abnormal Noises in Valve Train
II. Determination and Elimination Method of Major Abnormal
Noises in Crankshaft Linkage Mechanism
Valve mechanism mainly consists of intake, exhaust camshaft, valve, valve bushing, tappet and driven transmission gear
etc.
1. Abnormal Noise of the Camshaft
(1) Axial gap of camshaft is too large (normal value for intake camshaft: 0.030-0.085mm, exhaust camshaft: 0.035-
0.090mm), when the gap exceeds 0.11mm, abnormal noise often occurs, it must be replaced;
(2) Bending of camshaft is also a cause of abnormal noise, align it; otherwise discard it.
(3) Journal of camshaft is abraded excessively, so the radial gap between camshaft and bearing is too large which leads
to abnormal noise, replace it;
2. Slap Noise in Valve Set
(1) Abnormal noise in valve is mainly caused by too large valve gap and damaged spring seat flange in valve, it must be
replaced;
(2) Abnormal slap noise in valve spring is mainly caused by broken valve spring, it must be replaced;
(3) Abnormal free play noise in valve is mainly caused by dropout of valve lockpin or broken valve head, it must be
replaced;
(4) Abnormal noise generated between intake, exhaust valve and their bushing is mainly caused by jamming between the
valve and its bushing, valve cannot be closed, repair bushing or replace it;
(5) Abnormal noise is caused by untight close between valve and valve seat, engine cannot work normally, now grind the
valve for good fitting, otherwise replace it.
3. Abnormal noise in gear is mainly caused by too large backlash due to abrasion of gear,
so noise generates during operation, now replace the mated gear.
3. Exhaust Smoke Is White
This is caused by water vapor or fuel vapor in the exhaust gas. The main cause is that head gasket is broken, thus allowing
cooling water to permeate slowly into the cylinder and participate in combustion, then water vapor enters exhaust pipe.
Now replace the head gasket in time, restore it to normal condition.
Section 3 Determination and Elimination of
Abnormal Noises in the Engine
The engine gives out abnormal noises during operation, such as slap, clang, metallic friction sound, beep etc, which are
called abnormal noises.
Abnormal noises of engine are generated mainly in valve train, assy. of connecting rod, piston, crankcase and other acces-
sory systems. Below we mainly discuss determination and elimination method of major abnormal noises in valve train and
crankshaft linkage system
1. Cause of Abnormal Noise in Crankshaft Linkage and Elimination Method
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Содержание JL481Q
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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 ...