Engine JAC HFC4DA1-2C. Manual — part 9

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

35

Section II Assembly of Engine

I. Basic Technical Requirements for Assembly

The assembly of the engine is one important step for service of the engine. The service performance of the engine is
closely related to the assembly accuracy, assembly technical requirements, and the assembly quality. Make sure to pay
attention to following items:

Before the assembly, make sure to thoroughly clean and thoroughly blow dry all parts and components. All friction
surfaces of the parts with relative movement are applied with lubricating oil (grade CE diesel engine oil or above).
Carefully remove all oil dirt and carbon deposit, till the base metal is exposed. Never use electric wire brush to clean
the sealing surfaces of any sealing gasket. Remove the residues from all used sealing gaskets. It’s absolutely
prohibited to use wire brush to clean the piston.

a. Remove the carbon deposit, oil dirt, and water scale and clean all lubricating oil pipes and pipelines.

b. Check the wear state of valve, push rod, and rocker arm contact surfaces and when necessary repair or replace.

c. Check the wear state of piston rings, cylinder sleeves, connecting rod small end bushes, and connecting rod bushes
and when necessary replace.

d. Check the wear state of main bushes and thrust plates.

e. Check the wear state of engagement surfaces of transmission mechanism and drive gear and measure the
engagement clearance and when necessary repair or replace.

f．Check the wear state of intake and exhaust valves and intake and exhaust valve seats and repair, grind, and test the
leakage and when necessary replace.

g．Check the mist injection state of the fuel injector and when necessary grind or replace the fuel injector coupler.
While installing the used fuel injector, clean the carbon deposit with ultrasonic and do not wipe with silk or scrape
with knife, in order to prevent damaging the injector nozzle and blocking the injector orifice.

h. Check the engine oil pump and disassemble for checking or measure the wearing parts and adjust accordingly.

i. Check the cylinder gasket and intake and exhaust pipe gaskets and replace any damaged or failed gasket.

j. Check the alternator and starter, clean all parts and bearings, blow dry and apply new lubricating grease, and check
the wear state of starter gear and check the transmission mechanism for flexible functioning.

k. Check and clean the turbocharger.

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

36

II. Illustration for Assembly of Engine

1. Install the piston cooling fuel injector
subassembly.

a. Install the piston cooling fuel injector subassembly:

Install the piston cooling fuel injector subassembly
onto the engine block;

b. Tighten the hexagon socket screws to 12.5±2.5N.m;

2. Install the crankshaft, thrust plates,
and main bearing caps.

a. Install the upper and lower main bushes: Align the

stop opening of upper main bush with the slip groove
of the main bearing block bore of engine block and
push 5 upper main bushes to place;

Notice: While installing the main bushes, make
sure to differentiate the upper and lower bushes,
of which the upper bush has oil grooves and the
lower bush has not. Do not install the bushes
reversely.

a.

Apply an appropriate amount of clean engine oil onto
the upper bearing bush;

b. Lift up and place the crankshaft onto the engine

block.

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

37

c. Install the crankshaft thrust plates to the 3

rd

main

journal portion (The surface with oil groove faces to
crankshaft thrust surface and the oil groove shall be
sprayed with lubricating oil).

d. Spray oil to the main journal portion and install the

1~4 main bearing caps of crankshaft as per the
marked sequence. The arrow markings on the bearing
caps shall face to the front of the engine.

e. Apply the liquid sealant onto the fitting surface

between 5

th

bearing cap and cylinder block and install

the 5

th

bearing cap * text: Notice: 1) Before applying

the sealant, the fitting surface of main bearing cap
shall be thoroughly free of any engine oil; 2) Never
block the cylinder threaded holes and bearings by the
sealant.

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

38

f. Apply engine oil onto the threads of main bearing cap

bolts, install into the main bearing caps, and tighten
the bolts to 170 N.m torque as per the specified
sequence. Tighten to 20 N·m for the 1

st

step, to 120

N·m for the 2

nd

step, and 170 N·m for the 3

rd

step.

Tightening sequence: (From center to two sides)

8415 9

7326 10

g. Adhere the magnetic dial gauge onto the cylinder

block, position the pointer of the dial gauge to the
rear end face of crankshaft, and use a straight
screwdriver to pry lightly the crankshaft to check the
axial clearance of crankshaft (or push the crankshaft
left and right and measure with feeler gauge). If the
thrust clearance is out of the limit, replace the thrust
bearings in pair. Standard value: 0.040mm-0.201mm;
Limit: 0.30mm

h. Rotate the crankshaft and check for flexible rotation

and presence of noise. Alternatively, use a digital
wrench to measure the net torque of crankshaft, listen
for presence of noise, and check whether the torque is
≤6N.m.

a

Insert the lubricated tappets in turn into the tappet
holes.