Yuchai YC4D60-D21 User manual

1
YC4D60-D21 /YC4D85Z-D20
YC4D60-D21 /YC4D85Z-D20 SERIES DIESEL ENGINE GENERATOR
OPERATION & MAINTENANCE MANUAL
Guangxi Yuchai Machinery Co., Ltd

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Diesel Manufacturing Licence NO.：
Respected Yuchai’s customer:
Welcome you to join the jade firewood machine user ranks, heartily hope our
machine can bring the billowing source of wealth and the long-time good luck to you.
This product uses the advanced technical design, the quality reliable, the service life is
long, has the good power and the efficiency. In order to enable the machine the high
performance to obtain a better display, and guaranteed the machine the safe operation,
invites you before the use first in detail reads the textbook instruction for use below, and
specially pays attention "the safe driving matters needing attention".
CAUTIONS ON SAFE DRIVING：
1. The oil pressure gauge probe,water temperature gauge probe,and particularly the
low pressure alarm are the three very important components,of which immediate
replacement is required for any malfunction.It is desired to always maintain the normal
function of these components,any failure to comply with that may easily lead to
crankshaft burn due to oil shortage or cylinder head crack due to overheat from water
shortage.
2. After cleaning the oil filter gauze or during the process of replacing filter gauze, it
should be noted to reinstall the filter only after refilling oil fully,and start the engine on
idle running immediately after reinstallation；meantime,check if there is any sign of
leakage to any filter.Correct the leaking filters or it may easily lead to crankshaft burn
caused by oil shortage.
Company
Name
Type
specification
Licence NO.
term of
validity
issuing date
explanation
reported
agency
archive NO.
province
Yuchai
Machinery
Co.,Ltd.
Mult-cylinder
diesel(for
engineering
plant use)
XK06-205-00187
2008.07.01
2003.07.02
licence-
issuing
machinery
product
examination
department
903
guangxi

3
3．Each time you start the vehicle,first start the engine on idle running for 5 to 10
minutes till the engine warms up and all gauges working in normal function,then start to
move.Never put the vehicle to sudden acceleration from cold-start.For any dramatic
speed-up on cold status will damage the instruments and their corresponding parts and
components and accelerate the wear and tear of engine’s kinetic parts,consequently it
will shorten the engine’s life cycle.
4．Start the engine on first gear,no chuggle idling.
5．Avoid any sudden stall and quenching the engine at high speed,high load
status,the appropriate way is to gear down the engine gradually and stop the vehicle
after 5-10 minutes of engine idle running.
6．Strictly adjust the injection advance angle of the turbocharger engine according to
the requirements specified in the Operation Mannual.When the engine power is
decreasing,first check the intake pipe to find if there is any leakage and check the air
cleaner for the clog of stuff.
7．Anytime you find the vehicle and/or engine is not working normally,stop it
immediately to correct the malfunction ,never allow the vehicle running under an
abnormal state.
8．Don’t directly touch the high temperature parts (such as exhaust pipe) of the
engine when you check it,don’t open the radiator cover immediately just after stop,for
this may cause physical burn.
9．Send the engine to a consignment technical service station of Yuchai for a run-in
serviced when it reaches its first 1500-2500 km of mileage,or you will the warrantyfor
this engine.
10．Anti-freeze coolant shall be used in the cooling system; otherwise no quality
guarantee will be born by the Manufacturer.
11．The engine’s normal working condition is -15℃～40℃in temperature and below
2000m in altitude,any operation under water or in fire are prohibited. Clean the air filter
gauze during dusty and windy condition, replace the filter gauze immediately once it is
found to be damaged. Please consult Yuchai’s technical or service departments for
working below -15℃or above 40℃or over 2500m in altitude, so that effective measures
can be taken to ensure normal function.

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12．Operate and maintain the engine improperly will lower the engine performance
of power,economy,emission and life cycle,and also do harm to the environment.The
cause and troubleshooting can be founded in the table I、table II、table III and “safety
caution”.
13．Hoisting and transporting the engine according to the notes on the engine’s
package, and store the engine in a condition of dry,clean,good ventilate and with no
corrosiveness things. The engine’s storge is no longer than 12 months (counted from the
ex-factory date)
14．Please open the radiator cap in the meantime while adding water to the diesel
engine.

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Foreword
YC4D60-D21、YC4D85Z-D20 series diesel engines are developed by Yuchai in the
purpose of satisfying the diesel generator set market requirement. This model bases on
the foundation of high-quality product YC4108Q、YC4108ZQ, and assimilate the diesel
engine technique characteristics of generator set,which is the amalgamation of our
company’s abundant experience and overseas advanced technology.YC4D85Z-D20
engine bases on the model of YC4D60-D21 engine, adopt exhaust gas turbocharging
technique ,which is good in motive force and fuel efficiency and meet the emission and
low noise requirement. The series has good performance in motive force 、fuel
efficiency and dependency. The model, compact, simple, easy maintenance.
This manual introduces the main technical specifications、the basic assemblage
requirements 、the engine adjustment、the operation and maintenance and the
troubleshooting of the YC4D60-D21、YC4D85Z-D20 engine. Proper operation and
maintenance will prolong the use life and ensure safety in operation. Please read this
Manual carefully before use, and pay special attention to CAUTIONS ON ENGINE USE. To
ensure the engine use properly and maximize the client’s economic effectiveness, please
make the engine maitenance work actually.
This manual is only about the basic model of this series generator set ,which is the
same for operation and maintenance the modified models.As requirements for
technology is developed so fast,modification will be carried out without information.
This manual is explained by YUCHAI Technology Centre and YUCHAI Technology
Service Centre takes charge of the technology consults and advices.
Guangxi Yuchai Machinery Co. Ltd

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Contents
I YC4D60-D21
II YC4D85Z-D20
III YC4D60-D21
ⅣYC4D85Z-D20
Chapter one Engine specifications and accessories………………………………………………
E n g i n e s p e c i f i c a t i o n s … … … … … … … … … … … … … … … … … …
Technical data of adjustment and control for engine………
Tightening torques of the connecting screw thread……………………
Main parts fit clearances ……………………………………………
S p e c i f i c a t i o n s o f m a i n p a r t s a n d a c c e s s o r i e s ……………
C har ter t w o M a in i ns ta ll ing r e q uir e me n ts …………………………………………
I n s t a l l a t i o n o f t h e c r a n k s h a f t ……………………………………………………
Installations of the piston and the connecting rod …………………………
I n s t a l l a t i o n o f t h e c a m s h a f t … … … … … … … … … … … … … … … … … … … … …
I n s t a l l a t i o n o f t h e v a l v e s a n d v a l v e g u i d e s ……………………………
I n s t a l l a t i o n o f t h e i n j e c t o r s ………………………………………………………
I n s t a l l a t i o n o f t h e c y l i n d e r h e a d ………………………………………………
I n sta l l at i o n o f t he g ea r t ra i n ………………………………………………………
Charter three Engine adjustments……………………………………………………………………
Fuel supply advance angle adjustment……………………………………
A d j u s t m e n t o f t h e v a l v e c l e a r a n c e … … … … … … … … … … … … … … … … …
F u e l i n j e c t i o n p r e s s u r e a d j u s t m e n t ……………………………………………
O i l p r e s s u r e a d j u s t m e n t ……………………………………………………
O p e r a t i o n o f d i e s e l e n g i n e … … … … … … … … … … … … … … … … … … … …
S e l e c t i o n o f f u e l , l u b r i c a t i n g o i l a n d c o o l a n t … … … … … … …
Preparations before starting the diesel engine ……………………………………
S t art i n g th e die s el en gine … … … … … … … ………… … … … … …… ………………

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O p era t i ng t h e di e s e l e n g i ne … … … … … … … …… … … … … …… … … … … …… …
Stopping the d ie sel engi ne …………………………………………………………………
Storage……………………………………………………………………………………………
Charter Diesel engine maintenance……………………………………
B r e a k - i n o f t h e d i e s e l e n g i n e ……………………………………………………
R e q u i r e m e nt s o f t e c h n i c a l m a i n t e n a n c e … … … … …… … … … … …… … 3 0
M a i n t e n a n c e m e t h o d s …………………………………………………34
C h a r t e r 6 N o r m a l t r o u b l e a n d T r o u b l e s h o o t i n g … … … 4 1
D i es e l e n g i n e c a n n o t s ta r t o r s ta r t d i f f ic u l t l y ……………………41
I n s u f f i c i e n t p o w e r o u t p ut……………………………………………………43
A b n o r m a l n o i s e d u r i n g e n g i n e o p e r a t i o n ……………………………45
Exhaust with abnormal smoke color…………………………………………46
Too low oil pressure……………………………………………………………… 48
Too high oil pressure, much diluted oil, excessive oil
consumption……………………………………………………………………………………
Too high water outlet temperature………………………………………………50
Engine stops by itself……………………………………………………………52
Engine over-speeding（Speed rises sharply）………………53
Common trouble and troubleshooting remedies for injection
pump………………………………………………………………………………………………… 54
Com mon trouble and tro ublesho oting rem edi es for governor …55
C o m m o n t r o u b l e f o r f u e l s u p p l y p u m p …………………………………57
Common trouble and troubleshooting remedies for injector…………58
A n ne x : A n t i - f r e ez e s o l ut i o n a n d i t s a p p l ic a t i o n g u i d e …………………61

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Engine specifications and accessories
Engine specifications
No.
Name
Specifications
1
Model code
YC4D60-D21
YC4D85Z-D20
2
Type
vertical, in-line, liquid-cooled and four-stroke
engine
3
Liner
wet type
4
Combustion chamber
directing injection and reentrant ωtype
5
Intake
natural aspirated
turbocharged
6
Cylinder number
4
7
Cylinder bore (mm)
108
8
Stroke (mm)
115
9
(L) Displacement
4.214
10
Compression ratio
17：1
11
Rated power (kW)
37
45
12
Rated speed (r/min)
1500
13
Rated fuel consumption
(g/kW.h)
≤240
≤230
14
Min. continuous idle speed
(r/min)
≤700
15
Steady speed regulation (％)
≤3
16
Transient speed regulation
(％)
±7

9
18
Speed fluctuation (％)
0.5
19
Oil consumption (g/kW.h)
≤1.8
20
Soot ( FSN)
≤4.0
21
Exhaust temperature (℃)
≤550
22
Noise limit [dB(A)]
≤108
≤109
23
Fire order
1-3-4-2
24
Piston average speed(m/s)
5.75
25
Rotation direction of
crankshaft
counterclockwise (face to output end)
26
Lubrication system
combination of splash and pressure
27
Cooling system
pressurized circulating liquid cooling
28
Start system
24v electric
29
Net weight (kg)
360
370
30
Dimensions
(length×width×height) (mm)
1032×722×948
1032×704×1254
17
Stabilizing time (s)
≤5

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Technical data of adjustment and control for engine
Item
YC4D60-D21
YC4D85Z-D20
(MPa)
Oil pressure
at rated speed
0.25～O.6
at idle speed
≥0.1
Oil temperature
≤100
Cooling water outlet temperature
75～95
Static fuel supply advance angle
(ºCA )
14±2
Cold valve
clearance (ºCA)
Intake valve
O.40±0.05
Exhaust valve
0.45±0.05
Valve timing
(ºCA)
Intake valve
advance open
angle
14
Exhaust valve
lag close angle
44
Exhaust valve
advance open
angle
56
Intake valve
lag close angle
12
Valve recession height (mm)
1±O.2
Protrusion height of fuel injector
over cylinder head bottom surface
(mm)
3.6±O.1

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Cylinder compression clearance
(mm)
1±O.1
Oil volume (L)
13(11 in oil sump)
Tightening torques of the connecting screw thread
1．Tightening torques of main bolts and nuts are shown below:
Description
Tightening torque(N•m)
Description
Tightening torque(N•m)
Cylinder head
bolt
210～250
Flywheel bolt
170～210
Main bearing
bolt
220～260
Crankshaft belt
pulleyfastening bolt
≥300
Connecting
rod bolt
160～200
Camshaft gear locking
bolt
≥300
2．Except for the important connecting screw thread, tightening torque of other bolts and
nuts can be selected according to the table below:
Screw thread
specifications
M6
M8
MlO
M12
M14
Tightening
torque(N·m)
10～20
20～30
35～55
70～90
110～130

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Main parts fit clearances
No.
Description
Prescribed dimensions (mm)
Type of fit
Assembly
tolerance (mm)
1
Exhaust valve seat
insert/exhaust valve
Φ44.5
025.0
0

/Φ44.5
095.0 070.0 

interference
0.045～0.095
2
Intake valve seat
insert/exhaust seat
Φ48.5
025.0
0

/Φ48.5
139.0 114.0 

interference
0.089～0.139
3
Valve guide/cylinder
head valve guide hole
Φ16
018.0
0

/Φ16
046.0 028.0 

interference
0.010～0.046
4
Valve guide/exhaust
valve stem
Φ9.5
019.0
0

/Φ9.5
04.0 062.0 

radial
clearance
0.040～0.081
5
Valve guide/intake
valve stem
Φ9.5
019.0
0

/Φ9.5
025.0 047.0 

radial
clearance
0.025～0.066
6
Rocker arm bush/
rocker arm shaft
Φ25
021.0
0

/Φ25
02.0 041.0 

radial
clearance
0.020±0.062
7
Cylinder
bore/diameter of the
lower part of the
piston skirt
Φ108
022.0
0

/Φ107.86±0.01
radial
clearance
0.130～0.172
8
Valve tappet/cylinder
block tappet hole
Φ28
052.0
0

/Φ28
02.0 041.0 

radial
clearance
0.020～0.093

13
9
Camshaft bearing
bore in cylinder block
/camshaft bearing
bush
Φ62
03.0
0

/Φ62
106.0 087.0 

interference
0.057～0.106
10
Camshaft bearing
bush/camshaft
journal
Φ58.5
03.0
0

/Φ58.5
03.0 06.0 

radial
clearance
0.03～0.09
11
Timing idle gear
bush/idle gear shaft
Φ55.5
03.0
0

/Φ55.5
03.0 06.0 

radial
clearance
0.03～0.09
12
Timing idle gear/idle
gear shaft
28
008.0
/28
17.0 07.0 

axial
clearance
0.07～0.25
13
Top ring groove
height/top gas ring
height
2.695±0.015 / 2.605
01.0 03.0 

axial
clearance
0.085～0.135
14
Second ring groove
height/second gas
ring height
2.5
10.0 08.0 

/2.5
010.0 025.0 

axial
clearance
0.09～0.125
15
Oil ring groove height
/oil ring height
3.5
04.0 02.0 

/3.5
010.0 025.0 

axial
clearance
0.030～0.065
16
Connecting rod
bearing (with
shell)/crankpin
Φ66
089.0 040.0 

/Φ66
0019.0
radial
clearance
0.040～0.108
17
Connecting rod
bush/piston pin
Φ38
036.0 025.0 

/Φ38
0011.0
radial
clearance
0.025～0.047

14
18
Piston pin/pin boss
Φ38
012.0 005.0 

/Φ38
0011.0
radial
clearance
0.005～0.023
Φ40
012.0 005.0 

/Φ40
006.0
0.005～0.076
19
Cylinder block main
bearing (with shell)
/crankshaft journal
Φ85
122.0 060.0 

/Φ85
0022.0
radial
clearance
0.060～0.144
20
Camshaft
spacer/thrust disk
5
12.0 06.0 

/5
04.0 08.0 

axial
clearance
0.10～0.20
21
Width of the oil
pump rotor /depth of
bore in oil pump body
22
0021.0
/22
08.0 05.0 

axial
clearance
axial
clearance
0.05～0.101
22
Outer diameter of
outer rotor/ bore in
oil pump body
Φ69.7
008.0
/Φ69.8
15.0 05.0 

radial
clearance
0.15～0.33
23
Oil pump shaft
bushing(I)/oil pump
shaft
Φ19
075.0 050.0 

/Φ19
025.0 012.0 

radial
clearance
0.025～0.063
24
Oil pump shaft
bushing(II)/oil pump
shaft
Φ15.8
075.0 050.0 

/Φ15.8
024.0 012.0 

radial
clearance
0.026～0.063
25
End gap when ring
inserted in gauge
clearance
0.4～0.6
clearance
0.35～0.55
clearance
0.30～0.55
26
Crankshaft axial
clearance
axial
clearance
0.1～0.27
27
Backlash of gear in
mesh
clearance
0.07～0.25

15
Specifications of main parts and accessories
No.
name
type / model code
YC4D60-D21
YC4D85Z-D20
l
Fuel
injection
pump
assembly
model code
type
plunger
diameter
plunger stroke
governor type
4JⅠ203
①9.5mm
9mm
mechanical
variable-speed governor
4JⅠ203
①9.5mm
9mm
mechanical variable-speed
governor
2
Fuel
injector
assembly
model code
type
precision pairs
type
injection
pressure
CKBL685004
long multi-hole nozzle
ZCKl55S529
23±0.5MPa
CKBL685004
long multi-hole nozzle
ZCKl55S529
23±0.5MPa
3
Fuel filter
CX0710 paper element and rotation
4
Oil filter
CX0818 paper element and rotation
5
Thermostat
model code : 145
type : wax
opening temperature : 70±2℃
full opening temperature 78±2℃
6
Fan
φ450 axial flow
7
Starter generator
voltage : 24V
power : 4.8kW
8
Charging generator
voltage : 28V
power : 750kW
9
Belt
8PK1760 V-ribbed belt used in vehicle
1O
Turbocharger
TB28

16
Charter two Main installing requirements
Installation of the crankshaft
Figure 1 Tightening order of the main bearings
During crankshaft installation, the main
bearing bolts should be tightened from thrust
gear (the third gear) to both ends in order, and
in three steps: First, tighten to 60~80N.m;
Then, tighten to 160~180N.m;
Finally, tighten to 220~260N.m.
During every time, the crankshaft should be
rotated to check the mobility. It should be able
to rotate freely after the final tightening. The
axial clearance should be between 0.1 and
0.27mm.
Installations of the piston and the connecting rod
Figure 2 Orientation of the gap of piston rings
When installing the piston rings, put the surfaces
marked upward (the second positive twist ring inner
fillet upward). During positioning the piston-connecting
rod assembly into the cylinder bore, stagger the joints
in turn as shown in Figure 2, and put the arrow marked
on the top surface of piston towards the front end of
the engine. Remember spreading some clean oil before
tightening connecting-rod bolts. The tightening torque
should be between 160~200N.m, and completed in
three steps:
First, tighten to 50~70N.m;
Then, tighten to 100~120N.m;
Finally, tighten to 160~200N.m.

17
Installation of the camshaft
Figure 3 Camshaft axial clearances
Position the camshaft into the cylinder body
with caution to make sure not scratch the
surfaces of the journals, cams, and liners.
And then install the circlip, cam thrust plate,
cam gear, and cam retainer. Finally, tighten
fastening bolt with more than 300N.m
tightening torque. The camshaft should be
able to rotate freely, and its axial clearance is between 0.1~0.2mm.
Installation of the valves and valve guides
Figure 4 Installation of the valves and valve
guides
The valve guides should be pressed in at
normal state with 20±0.3mm distances
between their top surfaces and the surfaces
of the cylinder head spring seats. Both the
valve face angles of intake and exhaust valves
are 45°. The valves and valve seat inserts
should be grinded in pair, and checked through kerosene. It must be guaranteed that
kerosene don’t leak within three minutes. The valve recession heights of the valves
should be between 1±0.2mm.

18
Installation of the injectors
Figure 5 Installation of the injector
Before mounting the cylinder head, the
injectors should be installed in the
cylinder head first. The nozzles should
protrude 3.4±0.1mm from the bottom
surface of the cylinder head, which can
be ensured by adjusting the width of the
injector washer. And then remove the injectors to prepare for following installation. As
long as adjusted, the injectors and washers cannot be exchanged during installation.
Installation of the cylinder head
Figure 6 Tightening orders of the
cylinder bolts
During cylinder head installation, the
cylinder head bolts should be tightened
to a tightening torque of between
210~250N.m, don’t finish that in once time and following the sequence shown in Figure
6 in three steps:
First, tighten to 60~80N.m;
Then, tighten to 120~140N.m;
Finally, tighten to 210~250N.m
Installation of the gear train
The crankshaft timing gear, injection pump gear, and camshaft gear should all be
accordance with the timing requirement, so there are timing marks, which should be
aligned during installing the gears, on them and timing idle gear. Oil the tooth surface
after installing. The range of the gear meshing clearance is between 0.07~0.25mm.

19
Caution
Figure 7 Installation of the gear system
1. Every component should be cleaned
before being installed, especially the
oil passages, no dirt is permitted in
them.
2. No corrosion, burr, or scratch is
permitted on the fit surfaces of every
component.
3. Friction surfaces and important fit surfaces should be oiled before installing.
4. Fit clearance (or interference) should be accordance with the requirement offered
in the main fit clearance (or interference) in chapter 1.
Charter three Engine adjustments
Fuel supply advance angle adjustment
Technical data : Static fuel supply advance angle is 14±2℃A before TDC.
Fuel supply advance angle check: Unscrew the nut which connects the high pressure fuel
line for the No.1 cylinder and fuel injection pump, crank the crankshaft slowly until the
fuel level in the delivery valve holder begins to fluctuate. At this time, the timing value
indicated by the pointer on the gear housing and the dial on the belt pulley damper is the
fuel supply advance angle.
a、adjustment for the b、adjustment for the flange of fuel injection
shaft of fuel injection of pump of pump

20
Figure 8 Fuel supply advance angle
adjustment
Figure 9 Adjustment of the valve
clearance
Fuel supply advance angle adjustment:
There are three rectangle slots in the
joint flange of the fuel injection pump,
through which three bolts are used to
fasten the fuel injection pump to the
gear housing. After unscrewing these
bolts, the fuel injection pump can be
rotated around its axis with small
angle in order to adjust properly the
fuel supply advance angle. Crank the
crankshaft to the position at which
the fuel will be delivered to the No. 1
cylinder according to the above method, unscrew these bolts on the flange and all the
joint nuts for the high pressure fuel lines, rotate the pump a certain angle as required
(inner direction which means to increase the fuel supply advance angle, outer direction
which means to decrease the fuel supply advance angle), then fasten the bolts on the
flange. Check and adjust the fuel supply advance angle to prescription, then fasten the
bolts on the flange.
If the bolts is adjusted to the dead position on the rectangle slots in the flange and
the fuel supply advance angle still does not meet the prescription, remove the gear
housing cover plate of the fuel injection pump, unscrew the three bolts used to fasten
the gear of the fuel injection pump, rotate the pump (inner direction which means to
decrease the fuel supply advance angle, outer direction which means to increase the fuel
supply advance angle). At last fasten the bolts. Check and adjust the fuel supply advance
angle to prescription according to the above method, then recheck whether the bolts are
fastened and install the gear housing cover plate. Pay attention to not damaging the
gasket during adjustment in order to avoid the fuel leakage.