JAC HFC4DA1-2C engine. Service Manual — part 4

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

50

e. Install the intake manifold and install and tighten the

fixing bolts, plain washers, and fixing nuts.

f. Install the intake manifold harness bracket and intake

pressure and temperature sensor.

8. Install the push rod rocker arm
subassembly and adjust the valve
clearance.

a. Dip the tip of push rod with oil and install into the

cylinder head. Install the rocker arm and pre-tighten

the rocker arm support bolts.

b. Tighten the support bolts by steps. Sequence: 2-3-4-1;

Torque: 55±5N.m

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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c. Rotate the crankshaft, till the top dead center (TDC)

line of crankshaft damping pulley is aligned with the

timing pointer. In such case, either 1

st

cylinder piston or

4

th

cylinder piston is at top dead center (TDC) of

compression stroke.

d. Check the clearance of push rod for the intake valve

and exhaust valve of 1

st

cylinder. If there is a

clearance between 1

st

cylinder intake valve and valve

push rod, the 1

st

cylinder piston is at top dead center

of compression stroke (1236). If the 1

st

cylinder

intake valve is pressed tightly by exhaust valve push

rod, the 4

th

cylinder piston is at top dead center of

compression stroke (4578).

e. Valve clearance (under cold state): 0.3-0.4 mm

f. Loosen the clearance adjustment screws for the

valves, as shown in the figure.

g. Insert the feeler gauge with appropriate thickness

between rocker arm and valve rod end.

h. Rotate the valve clearance adjustment screw, till a

light resistance is felt on the feeler gauge.

i. Securely tighten the lock nut.

j. Rotate the crankshaft for 360º.

k. Align the TDC marking of crankshaft damping pulley

with the timing pointer.

l. Adjust the clearance for other valves, as shown in the

figure.

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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9. Install other peripheral accessories.

a. In turn install the fuel injection assembly with sealing

gasket onto the cylinder head.

b. Install the fuel injector fixing pressure plate and

install and tighten the fuel injector pressure plate

bolts to 8±2N.m+40～45°.

c. Install the 1

st

cylinder high pressure fuel pipe

assembly, 2

nd

cylinder high pressure fuel pipe

assembly, fuel injection pump high pressure fuel

pipe, 3

rd

cylinder high pressure fuel pipe assembly,

and 4

th

cylinder high pressure fuel pipe assembly and

tighten the corresponding nuts. Notice: 1. Notice the

installation direction of high pressure fuel pipes; 2.

The tightening torque for nuts at fuel injector end is

27±5N.m; 3. The tightening torque is 20±5N.m for

nuts at high pressure fuel rail end, 27±2N.m for high

pressure fuel pipe nuts at fuel pump end, and

20±2N.m for high pressure nuts at fuel rail end.

d. Use accelerator cable bracket bolts to install the fuel

return three-way valve onto the gear chamber and

tighten to 7.5±2.5N.m.

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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e. Install the engine oil filter and O-ring subassembly

and tighten the fixing bolts of engine oil filter bracket

to 25±5 N.m.

f. Install the engine right bracket and shock absorber

subassembly and install and pre-tighten the fixing

bolts.

g. Install the water inlet pipe gasket and water pump

inlet pipe weldment subassembly, pre-tighten the

bolt, spring, and plain washer subassembly (of water

pump inlet pipe), and install and tighten the bracket

fixing bolts at the lower end of water pump inlet pipe

weldment.

h. Install the engine left bracket and shock absorber

assembly and tighten the fixing bolts.

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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i. Check the cylinder head shield O-ring.

j. Install the cylinder head shield and install and tighten

the cylinder head shield bolts to 13±5N.m.

k. Install the exhaust manifold gasket and install the

exhaust manifold and turbocharger subassembly.

l. Install the spring washers and hexagon nuts and

tighten the fixing nuts and fixing bolts as per

specified sequence.

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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m. Install the EGR cooling steel pipe and tighten the

fixing bolts.

n. Install the EGR valve and tighten the fixing bolts.

o. Apply sealant onto the thread of vacuum pump oil

inlet pipe connecting bolts, install the connecting

bolts onto the cylinder block oil outlet, and tighten to

18±2 N.m.

p. Install the alternator belt and water pump pulley.

q. Install the fan and clutch assembly and install and

pre-tighten the clutch fixing nuts.

Tighten bolts as per sequence shown in figure.

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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r. Adjust the tension of alternator belt and tighten the

alternator adjustment bolts and clutch fixing nuts.

s. Tighten the alternator fixing nuts.

t. Install the vacuum pump oil inlet pipe fixing bolts I

(M8×20) and tighten the fixing bolts to 18±2N.m and

25±5N.m respectively.

u. Install the exhaust pipe heat shield and install and

tighten the fixing bolts.

v. Install the power steering pump and tighten the fixing

bolts of power steering pump.

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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w. Install the compressor bracket and tighten the bracket

fixing bolts.

x. Use perforated bolts II and copper washers II to install

the turbocharger oil inlet pipe assembly onto the

turbocharger oil inlet and use perforated bolts I and

copper washers I to install another end onto the

cylinder block oil hole and tighten the perforated

bolts I and II. 1. Tightening torque for perforated

bolts I is 55±10N.m; 2. Tightening torque for

perforated bolts II is 41±6N.m.

y. Install the fuel-gas separator bracket and intake

manifold bracket.

z. Install the fuel-gas separator assembly.

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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aa. Install the VNT electromagnetic valve and connect

various vacuum hoses.

10. Install the flywheel and related
accessories.

a. Apply oil to the outer ring and lip of the crankshaft

rear oil seal and use installation jig I to push the rear

oil seal into the oil seal groove. Then install the

installation jig II and knock with steel hammer lightly

and uniformly to install the crankshaft rear oil seal to

place.

b. Install the flywheel baffle and fixing bolts and tighten

the fixing bolts of flywheel baffle to 85±10 N.m.

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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c. Install the flywheel.

d. Install the flywheel fixing gasket and install and

pre-tighten the fixing bolts of flywheel.

e. As per the specified sequence, tighten the fixing bolts

of flywheel to 25N.m→70N.m →140N.m by steps,

in order to prevent the occurrence of false tightening

torque. This tightening torque is really high and will

easily lead to thread failure of the bolts.

f. Install the lubricated guide ball bearings into the

installation jig and knock with steel hammer

uniformly into the rear end of crankshaft.

g. Insert the clutch guide into the driven disc and install

to the rear end of flywheel. Install the clutch cover

and install and tighten the fixing bolts of clutch

cover.

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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Section III Crankshaft and Flywheel System

z It works along with the connecting rod to convert the gas pressure applied onto the piston into rotating power and

transmit to the transmission mechanism of the chassis. At the same time, it drives the valve distribution

mechanism and other accessories, such as fan, water pump, and alternator.

z The crankshaft is made of medium carbon steel alloy forging. To improve the wear resistance and fatigue

resistance, the journal surface is treated with high-frequency hardening or nitriding treatment and high-precision

grounded to meet the higher surface hardness and surface roughness requirements.

z With fully supported structure and 8 balance weights, the crankshaft is cast to an integral structure with balance

weights to improve the rigidity and bending strength of the crankshaft.

z The crankshaft is made of high strength steel alloy forging, with fillet rolled journals.
z Its front end adopts rubber-embedded crankshaft torsional shock absorber to reduce the crankshaft torsional shock

generated during the running of the engine. The signal wheel of crankshaft position sensor is installed at the last

crank.

z There are two pieces of crankshaft thrust plates installed on two sides of the 3rd main bearing block, with the face

with oil groove facing to the thrust surface of the crankshaft.

z The grouping numbers for crankshaft main journal and connecting rod journal are stamped on the first crank of

the crankshaft.

z The flywheel assembly is installed at the rear end of crankshaft and the flywheel is located by locating pin and

connected by flywheel bolts.

z The crankshaft, flywheel, and clutch assembly qualified the dynamic balance test before the factory leave.

Signal gear of flywheel

crankshaft position sensor

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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Section IV Piston and Connecting Rod Group

z The piston crown is of ω type combustion chamber;

Depending on the performance and reliability requirements, the piston
profile designed can guarantee the normal working of engine under high
speed, high temperature, and high pressure conditions. The good skirt sizes
can reduce the frictional power consumption of piston and improve the
economic performance of the engine.

z The HFC4DA1-2C piston rings include two compression rings and one
oil control ring:

The first ring adopts the trapezoid tubbish ring, which can effective reduce
the consumption of engine oil.

The second compression ring adopts the torsional trapezoid ring to increase
the flexibility of piston ring and improve the capability of piston ring for
adapting to deformation of cylinder sleeve.

The oil control ring is of coil spring expander type and adopts the combined oil ring composed of two side guide rings
(upper and lower) and the middle expander, featuring the advantages of low mass and outstanding oil scraping effect.
It can reduce the consumption of engine oil and the grain emission while meeting the Euro-IV emission standard.

40~50% of the frictional power consumption of the engine is attributed to the pistons and piston rings. The piston
rings of 4DA1 engine can effectively arrange the engine oil, reduce the friction power of piston subassembly, and
improve the fuel economy.

z The piston is stamped with mark, which shall
face upward during assembly. During assembly, take
caution to position the spring connector 180º away
from the opening of oil control ring. Notice the
opening direction of the ring while installing the
cylinder sleeve. The openings of the piston rings shall
separate 120º from each other and the ring opening
shall not face towards the piston pin. Apply an
appropriate amount of lubricating oil during the
assembly. The piston rings shall rotate flexibly after
being installed in the ring grooves.

a. The arrow on the piston crown shall point to the
front of the engine.

b. It adopts variable section connecting rod to effectively reduce the force applied onto the connecting rod.

c. The piston pin is of full-floating structure and adopts retainer ring for limiting. The piston pin can be directly
assembled during installation.

d. The body of connecting rod adopts H-shaped cross section, featuring good bending strength and light weight.

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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Section V Valve Distribution Mechanism

z It’s a device that opens and closes at fixed times the intake and exhaust valves of all cylinder to enable the

ingress of fresh air into cylinders and the exhaust of exhaust gas from the cylinders.

z The front valve distribution timing adopts gear drive, featuring stability and reliability.

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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Section VI Lubrication System

While the engine is working, all motion parts apply one specific force onto another part and generate relatively high
speed motion. With the relative motion, the friction is necessarily generated on the part surfaces, which will accelerate
the wear. Therefore, to relieve the wear, reduce the friction resistance, and prolong the service life, the engine must be
fitted with lubrication system.

z The engine oil filter is functioned to filter out the metallic wear dust, mechanical impurity, and engine oil oxide

from the engine oil. The ingress of these impurities into the lubrication system along with the engine oil will
speed up the wear of engine parts and may block the oil pipe or oil passage.

z The engine oil pump is of externally engaged gear pump and is driven by the crankshaft.

z The cooling nozzle of piston is arranged on the main oil passage to realize the stable oil spray for cooling. The

spray of engine oil into the cold oil passage within the piston can effectively reduce the thermal load of the
piston.

Valve

mechanism

Splash

Rocker arm bearing

Oil way

o

f

cy

li

nde

r bl

ock

Various cam

tappets

Splash

Various camshaft bearings

Various crankshaft

main bearings

Splash

Piston group

Timing gear

Turbocharger

Oil w

ay

o

f

cy

li

nde

r b

loc

k

O

il w

ay

of

cy

lin

de

r blo

ck

Co

olin

g noz

zle

By

pass

Engine oil filter

Engine oil cooler

Engine oil pump

T

u

rboc

har

g

er

o

il i

n

le

t

pi

p

e

T

u

rb

oc

har

g

er oi

l

ret

urn

p

ip

e

R

eli

ef

va

lv

e

Re

li

ef

va

lv

e

Main oil way

Oil ou

tle

t

pi

p

e

St

ra

in

er

Oil sump

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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Section VII Cooling System

z The cooling system is functioned to maintain the engine within an appropriate temperature range under all

working conditions.

z The cooling system can prevent the engine against overheating and prevent the engine from being too cold in

winter.

z After the cold start of the engine, the cooling system can guarantee the rapid temperature rise of the engine to

reach normal working temperature as soon as possible.

z Composition: Water pump, cooling fan, silicone oil fan clutch, thermostat, engine cylinder block, water jacket in

cylinder head, and other accessories.

z The cooling system is of enclosed forced recirculation water cooling type. Its structure is mainly composed of

radiator (water tank), water pump, fan, thermostat, cooling water jacket, and pipeline.

z The cooling recirculation of the heater system and engine oil cooler is always under working state and is not

subject to the restraints of large or small recirculation.

Dual thermostat control: When the water temperature is less than 82ºC, the thermostat is under natural state (namely
the cooling water from the water tank is closed and the cooling water from the cooling module is opened). In such
case, the cooling circuit works in the small recirculation circuit and the cooling water from the cooling module enters
into the engine block and cylinder head for recirculation through the water pump so that the temperatures of the water
and oil in the engine block and the cylinder head will rise. When the water temperature reaches 82ºC, the thermostat
starts to open. When the thermostat is opened, the small valve closes the small recirculation circuit. As the thermostat
is not fully opened, the cooling water from water tank enters into the cylinder block for large recirculation through
water pump. If the water temperature continues to rise to 95ºC, the thermostat valve is fully opened.

Water tank

Radi

ator

Cylinder head

Cylinder block

Thermostat

Water pump

Heat

er

Oil cooler

Inlet of

water

Maintenance manual for sunray hfc4da1-2c china-IV diesel engines

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Section VIII Turbocharger and Inter-Cooler System

The turbocharger technology utilizes the motion energy of engine exhaust gas to drive the rotation of turbine. At the
same time, the coaxial air compressor compresses the air and provides more air to the cylinder so that more fuel can
combust to generate higher power, promote the engine torque, and reduce the fuel consumption.

The common turbocharger is of bypass valve turbocharger, which can’t provide sufficient pressure while the engine is
running at low speed and thus restrains the torque output at low speed and influences the engine performance. To
change this situation, the 1.9CTI engine adopts variable nozzle turbocharger (VNT) control system to promote the
turbocharger pressure at low speed of engine and at the same time adopts inter-cooler system to exert higher torque at
low speed of engine and promote the engine performance.

Theory of inter-cooler: The temperature of the air compressed at high speed may reach 100~120ºC. The high
temperature air will impair the intake efficiency of the engine and lead to power drop of the engine. Therefore, it’s
necessary to cool down the air to approximate 60ºC. The inter-cooler is located in front of the radiator or at windward
position easily arranged, in order to reduce the temperature of air entering into the cylinder, further improve the
combustion of diesel engine, and promote the performance and emission of the diesel engine.

Variable nozzle turbocharger (VNT): The VNT is functioned similar to one turbine housing in which the size is
varying steplessly. The VNT actuator can accurately control the nozzle area within the entire working condition range
so that the engine can not only maintain the turbine efficiency at high speed, but also increase the turbine efficiency at
low speed, promote the torques at low speed, maximum torque output, and nominal working condition, improve the
cold start performance and low speed performance of turbocharged diesel engine, realize high specific power and low
speed torque of the engine simultaneously, and greatly reduce the smoke intensity and improve the economy.
Meanwhile, the VNT can reduce the turbine lag, improve the engine response, and enhance the braking capability and
safety.

Adjustment theory for variable nozzle turbocharger (VNT): There are two passages, one is in constant section and one
is in variable section. If the pressure is same for two passages, the speed of airflow passing through the variable

Engine

Inter-cooler

Compressed air

Intake

Exhaust gas of engine

Exhaust

Turbocharger