Foton Series Light Bus. Instruction — part 6

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·72·

Figure 3-20 Cylinder Block Parts and Crank-connecting Rod Mechanism Parts -- BJ491EQ1 Multi Point

Electronic Fuel Injection Gasoline Engine

1-Piston ring; 2-Piston; 3-Connecting rod and connecting rod cap; 4-Connecting rod bearing sleeve; 5-Rear oil seal gasket;

6-Rear oil seal cover; 7-Drain switch; 8-Main bearing shell of crank; 9-Crankshaft thrust plate; 10-Main bearing cap; 11-Engine oil

strainer; 12-Oil pan assembly; 13-Engine oil pump; 14-Crank; 15-Sprocket chamber gasket; 16-Sprocket chamber cover gasket;

17-Crank pulley; 18-Sprocket chamber cover; 19-Timing chain and sprocket; 20-Sprocket chamber casing

Chapter 3 Structure, Adjustment and Service of BJ491EQ1 Gasoline Engine

·73·

3.2.1

Check axial clearance between big end of connecting rod and end surface of crank-connecting rod journal

with a feeler or a dial indicator. Nominal clearance: 0.160~0.312mm; maximum axial clearance: 0.35mm. If the

clearance exceeds the maximum value, replace the connecting rod (see Figure 3-21).

Figure 3-21 Check End Clearance of Connecting Rod Big End

3.2.2

Check end clearance of crank with a dial indicator. Nominal clearance: 0.02~0.22mm, maximum end

clearance: 0.35mm. If the clearance exceeds the maximum value, replace with a new set of thrust plates. Nominal

thickness of thrust plate: 2.440~2.490mm.

3.2.3

The main bearing caps are not interchangeable, and their directions (front and rear) must be correct. In

order to prevent misplacement or adverse installation, the main bearing cap is marked with sequence number

and cast a “forward” arrow (see Figure 3-22).

Figure 3-22 Marks on Main Bearing Cap

Figure 3-23 Assemble a Thrust Plate

No. 3 bearing cap

No. 1,2,4 and 5 bearing caps

Forward

Forward

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·74·

3.2.4

Thrust plates are installed respectively on both sides of 3rd main bearing seat / cap of cylinder block.

●Note:

(1) When to install a thrust plate, its side with oil groove should be outward. Never install it in adverse

direction (see Figure 3-23).

(2) There are oil grooves and oil holes on the main bearing cover that is installed on cylinder block. The

upper and lower covers can not be installed adversely.

3.2.5

Check cylinder block for crack and damage, and follow Figure 3-24 to check warpage on top deck of

cylinder block with a fine ruler and a feeler (the value should be less than 0.05mm). If the warpage exceeds the

specified limit, use surface grinder to grind the top deck of the cylinder block. Or replace the unserviceable

cylinder block.

Figure 3-24 Check Warpage on Top deck of Cylinder Block

3.2.6

Measure inner diameter of each cylinder bore. Measuring position and direction see Figure 3-25. Nominal

diameter of cylinder bore is Φ91.00~Φ91.03mm. See Table 3-1 for diameters of cylinder bore groups..

Table 3-1 Diameters of Cylinder Bore Groups

First group

Φ91.00mm≤D＜Φ91.01mm

Second group

Φ91.01mm≤D＜Φ91.02mm

Third group

Φ91.02mm≤D＜Φ91.03mm

Figure 3-25 Measurement of Cylinder Bore Diameter

Maximum cylinder bore diameter: Φ91.23mm.

If diameter exceeds the maximum value, re-bore the four cylinders.

Front

Longitudinal

Lateral

Middle

Chapter 3 Structure, Adjustment and Service of BJ491EQ1 Gasoline Engine

·75·

3.2.7

If deep longitudinal score or burn-out is present on cylinder wall, re-bore the four cylinders. The increased

diameter of cylinder bore during repairing (+0.50mm) is Φ91.50~Φ91.53mm. After repair, the wear limit of

cylinder bore is Φ91.73mm.If the value exceeds this limit, replace the cylinder block.

3.2.8

Diameter of gasoline engine piston falls into three groups (see Table 3-2) , each matches the cylinder bore

in the same group. The grouping mark is on top of piston.

Table 3-2 Piston Diameter Group

First group

Φ90.938mm≤D＜Φ90.948mm

Second group

Φ90.948mm≤D＜Φ90.958mm

Third group

Φ90.958mm≤D＜Φ90.968mm

Measuring position for piston diameter: at skirt section, 24mm from top along the direction vertical to piston

pin (see Figure 3-26).

The increased piston diameter for repair is Φ91.438~Φ91.468mm.

The fitting clearance between piston and cylinder is 0.052~0.072mm. Follow the following formula to

calculate the required re-boring dimension.

Cylinder re-boring dimension = piston diameter + cylinder fitting clearance with piston – boring margin

The boring margin should be less than 0.02mm, because excessive boring may destroy finely machined

roundness and cylindricity.

Figure 3-26 Measurement of Piston Diameter

3.2.9

The main bearing hole dimensions fall into three groups. The grouping numbers for first to fifth holes are

marked on rear end of bottom plane of cylinder block. The main bearing shells also fall into three groups. During

assembly, select the main bearing shell with the same grouping number as main bearing hole, and install it into

corresponding main bearing hole (see Figure 3-27).

Check for fitting clearance between crankshaft main journal and main bearing shell. The nominal clearance is

0.020~0.051mm, the maximum value is 0.1mm. If the clearance exceeds the maximum, replace the main bearing

shell, or replace the crankshaft if necessary.

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·76·

Figure 3-27 Matching of Main Bearing shell

3.2.10

Follow Figure 3-28 to check run-out of main journal at middle of crankshaft (the maximum run-out is

0.06mm). If the run-out exceeds the maximum value, replace the crankshaft.

Nominal diameter of crankshaft main journal is Φ57.985~Φ58.000mm; nominal diameter of connecting rod

journal is Φ47.985~Φ48.000mm; cylindricity limit of main journal and connecting rod journal is 0.020mm.

Replace the crankshaft if it is out of these range.

Figure 3-28 Check Crankshaft

3.3 Crank-connecting rod mechanism

The crank-connecting rod mechanism of BJ491EQ1multi point electronic fuel injection gasoline engine is as

shown in Figure 3-20.

3.3.1

Check fitting clearance between crank-connecting rod journal and connecting rod shell. The nominal

clearance is 0.020~0.051mm, and the maximum value is 0.100mm. If the fitting clearance exceeds this maximum

value, replace the connecting rod shell or replace the crankshaft if necessary,

3.3.2

Both connecting rod big end holes and connecting rod bearing shells fall into three groups with marks as 6,

7, 8. Assembly should be made within same group.

Mating numbers are marked on sides of connecting rod body and connecting rod cap. Interchanged assembly

is prohibited. The semicircle heaves on connecting rod body and connecting rod cap should be on the same side

with that of piston that has a depression mark on top. They should all face engine front (see Figure 3-29).

Front

1, 2 or 3

Chapter 3 Structure, Adjustment and Service of BJ491EQ1 Gasoline Engine

·77·

Figure 3-29 Semicircle Heaves on Connecting Rod Body and Connecting

Rod Cap and Depression Mark on Top of Piston

3.3.3

Check bending extent (see Figure 3-30) and distortion (see Figure 3-31) of connecting rod with a

connecting rod corrector. Maximum bending extent: 0.05mm for every 100mm; maximum distortion: 0.05mm for

every 100mm. If bending extent or distortion exceeds the maximum value, replace the connecting rod.

Figure 3-30 Check Bending Extent of Connecting Rod with a Connecting Rod Corrector

Figure 3-31 Check Distortion of Connecting Rod

●Note: When to replace the connecting rod, its cover and bearing shell should be replaced at the same time.

3.3.4

Check piston and piston ring groove for wear. Replace piston if necessary.

●Note: If piston has to be replaced, the ring on it should also be replaced.

The clearance between piston and piston ring (ring groove clearance) is 0.03~0.07mm. If the ring groove

clearance does not comply with the specified value, replace the piston.

Install piston ring into cylinder bore, use piston to press it to the position where is 110mm from top of

Depression

Semicircle heave part

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·78·

cylinder block, and then measure ring opening clearance (end clearance) with a feeler. Nominal end clearances:

first ring 0.27~0.39mm; second ring 0.40~0.55mm; oil ring: 0.20~0.70mm. Maximum end clearance: first ring:

1.11mm; second ring: 1.07mm; oil ring: 1.10mm (see Figure 3-32).

Figure 3-32 Check Piston Ring Opening Clearance

3.3.5

Use special tools to disassemble and assemble piston and connecting rod assemblies. The usage for

special disassembling tools are as shown in Figure 3-33. The usage for special assembling tools are as shown in

Figure 3-34.

Figure 3-33 Special Tools to Dismantle Piston and Connecting Rod Assemblies

1-Special tools; 2-Piston pin

Figure 3-34 Special Tools to assemble Piston and Connecting Rod Assemblies

1-Special tools; 2-Piston pin

3.3.6

After three piston rings are installed onto ring grooves, their opening positions should be interleaving as

shown in Figure 3-35 with marks on first ring and second ring facing upwards.

Chapter 3 Structure, Adjustment and Service of BJ491EQ1 Gasoline Engine

·79·

Figure 3-35 Opening Positions of Piston Rings

3.3.7

Check for fitting clearance between bearing hole and journal of camshaft. Inner diameters of bearing

holes (counting from front end) are as follows:

First hole: Φ46.500~Φ46.570mm;

Second hole: Φ46.250~Φ46.320mm;

Third hole: Φ46.000~Φ46,070mm;

Fourth hole: Φ45.750~Φ45.820mm;

Fifth hole: Φ45.500~Φ45.570mm;

Nominal fitting clearances: 0.025~0.111mm;

Maximum fitting clearance: 0.140mm.

If the clearance exceeds the maximum value, replace the camshaft bearing, and replace the camshaft when

necessary.

3.3.8

Measure diameter of hydraulic tappet hole. The value should be Φ21.417~Φ21.443 mm. Nominal fitting

clearance between tappet hole and tappet is 0.017~0.056mm, the maximum value is 0.100mm. If the clearance

exceeds the maximum, replace the tappet.

3.4 Valve Train

3.4.1

Using a wire, follow the procedures in figure 3-36 to take out the valve tappet.

Figure 3-36 Take out Valve Tappet

● Note: Place orderly the valve tappets with heads up for easy re-assembly.

3.4.2

Using a spring scales to pull the timing chain with a force of 98N (Figure 3-37). Measure the clearance

“△” between chain tensioner plug and support, the value should not exceed 13.5mm. Otherwise replace with new

timing chain and sprocket.

Second ring

Oil ring lower blade

Front

Oil ring upper blade

First ring and oil ring
bushing spring

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·80·

Figure 3-37 Check timing chain slackness

3.4.3

Measure journal run-out at middle of camshaft (Figure 3-38), the maximum value should be 0.06mm.

Otherwise replace the camshaft.

Figure 3-38 Measure Journal Run-out at Middle of Camshaft

Check cam height, the nominal heights of cams should be as follows:

Intake cam: 38.620~38.720mm;

Exhaust cam: 38.629~38.729mm;

Minimum cam height:

Intake cam: 38.26mm;

Exhaust cam: 38.27mm;

If cam height is less than the minimum value, replace the camshaft.

Check camshaft journal, the nominal diameters are (count from front end):

First journal: Φ46, 459~Φ46.475mm;

Second journal: Φ46.209~Φ46.225mm;

Third journal: Φ45.959~Φ45.975mm;

Fourth journal: Φ45.709~Φ45.725mm;

Fifth journal: Φ45.459~Φ45.475mm.

If journal dimension of is not within the specified range, follow the procedures indicated in 3.3.7 of this

chapter to check the fitting clearance between camshaft bearing hole and journal.

3.4.4

Install the thrust plate and camshaft sprocket onto camshaft, tighten the fixing bolts of camshaft sprocket

with a 90N.m tightening torque, and then measure axial clearance between thrust plate and first journal thrust

surface with a feeler (see Figure 3-39). The nominal axial clearance is 0.07~0.22mm. The maximum axial

Chapter 3 Structure, Adjustment and Service of BJ491EQ1 Gasoline Engine

·81·

clearance is 0.30mm. If the clearance exceeds the maximum value, replace the camshaft bearing. Or replace the

camshaft if necessary.

Figure 3-39 Measure Camshaft Axial Clearance

3.4.5

Check length of timing chain. Using a spring scales( Figure 3-40) to pull (49N) the chain.The maximum

chain length is 291.4mm. Select 3~4 measurement points at random to measure. If chain length exceeds the

maximum value, chain should be replaced.

3.4.6

Using a caliper (Figure 3-41) to measure diameters of crankshaft timing sprocket and camshaft timing

sprocket ( with chain). Minimum diameters are:

Crankshaft sprocket of: Φ59mm;

Camshaft sprocket: Φ114mm;

If sprocket diameters are less than the minimum value, replace the chain and two sprockets.

Figure 3-40 Check Timing Chain Length

Figure 3-41 Measure Diameters of Crankshaft Timing Sprocket and Camshaft

Timing Sprocket (with Chain)

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·82·

3.4.7

Use a caliper to check the thickness of rubber damper. The damper is on the head of chain tensioner plug

(see Figure 3-42). The nominal thickness is 15.0mm, and minimum thickness is 12.5mm.

Figure 3-42 Check the Thickness of Chain Tensioner Rubber Damper

If the thickness is less than the minimum value, replace the plug or chain tensioner assembly. When to

replace or re-instal the plug, operator should first apply a layer of engine oil onto chain tensioner body hole and

plug’s sliding surface.

3.4.8

Check thickness of rubber layer on damper. The nominal thickness is 6.6mm and minimum thickness is

5mm. If the thickness is less than minimum value, replace the damper.

3.4.9

Check outer diameter of valve tappet. The value should be 21.387~21.404mm. Otherwise check fitting

clearance between tappet hole of cylinder block and valve tappet by following procedures in 3.3.8 of this chapter .

3.4.10

Before installing valve tappet onto gasoline engine, discharge the air its inner chamber first and recheck

to ensure air is discharged completely. The methods are as follows (see Figure 3-43):

Figure 3-43 Discharge air from tappet

1-Push rod support; 2-Plunger

Dip the plunger into an engine oil pan, depress push several times to discharge air from tappet inner chamber.

Then fill the chamber with engine oil. Depress push rod again, if push rod is very hard or even fail to move the

plunger, this indicates tappet is in good condition; if plunger is easy to be pressed down, that indicates the tappet is

leaking and should be replaced.

● Note: Tappet body and plunger are precise coupler, which are not allowed to disassemble or interchange at

will. Be sure to use clean oil to perform these procedures.

3.4.11

Leak down test for valve tappet: if possible, use a leak down tester to check tappet leak down(Figure 3-44).

The test oil is industrial alcohol or special test oil. Apply a pressure (196N) on the plunger, and measure the time

required for another 1mm plunger leak down after the plunger has dropped by 2mm (the value should be 7~50s).

Chapter 3 Structure, Adjustment and Service of BJ491EQ1 Gasoline Engine

·83·

(testing ambient temperature is 20℃).

Figure 3-44 Valve Tappet Leak down test

3.4.12

Installation tips for timing sprocket and timing chain:

(1) When to install camshaft thrust plate, its side with two depressions should direct to engine front;

(2) Rotate the crankshaft to move sprocket key to the top, let the key on camshaft top and align with the

depression mark on thrust plate (see Figure 3-45).

Figure 3-45 Installation of Timing Sprocket and Timing Chain

1-Aligning key of sprocket on camshaft; 2-Aligning key of sprocket on crankshaft

(3) Put the timing chain onto the timing sprockets on camshaft and on crankshaft, and let the two bright

white nodes on the chain respectively align with the depressions on two sprockets.

(4) Let key notches on two sprockets respectively align with the aligning keys on crankshaft and camshaft,

and then install the two sprockets and timing chains evenly and simultaneously (see Figure 3-46).

Mark

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·84·

Figure 3-46 Installation of Sprocket and Chain

3.5 Lubrication system

3.5.1 Check quality of engine oil

Check engine oil in lubrication system for deterioration, moisture, color change or thinning. Change any

inferior oil. Inferior oil may affect the performance and service life of a gasoline engine.

● Note:

(1) Dispose properly changed oil to protect environment.

(2) The engine oil used in lubrication system should comply with the specification in this instruction (see

3.2.2)

3.5.1 Check volume of engine oil

Check the volume of engine oil in oil pan with the dipstick. The oil level should be within upper and lower

scales of the dipstick. If the oil level is below the lower mark (L), check for leakage and fill with engine oil till the

oil level reaches upper scale (F) (see Figure 3-47).

Figure 3-47 Check Oil Volume in Oil Pan with the Dipstick

● Note: The oil level could not be higher than the upper scale (F) on dipstick. Otherwise, oil consumption

would become high and the service life of three-way catalytic converter would be shortened as well.

Chapter 3 Structure, Adjustment and Service of BJ491EQ1 Gasoline Engine

·85·

3.5.3 Replace engine oil filter

Use special wrench to remove the oil filter. Check and clean the installation surface on filter seat. Coat clean

engine oil on new oil filter gasket (see Figure 3-48).

As shown in Figure 3-49, spin on the new filter onto the filter seat by hand until some resistance is felt, and

then use a special wrench to rotate for 3/4 turn.

● Note: Engine oil filter is one-time service part, which can not be used repeatedly. Dispose the used engine

oil and engine oil filter properly to protect environment.

3.5.4 Check engine oil pump

The engine oil pump is installed on lower front right side of cylinder block and is driven by a impeller.

Figure 3-48 Replace Engine Oil Filter

Figure 3-49 Installation of Engine Oil Filter

(1) Dip the oil strainer into engine oil, rotate the pump shaft clockwise. Engine oil should flow out from oil

outlet of oil pump.

(2) Block the oil pump outlet with thumb and rotate the pump shaft with a slotted point screwdriver. It

should be hard to be rotated.

3.6 Cooling system

3.6.1 Check coolant volume in reservoir

The level of coolant in reservoir should be within upper and lower scales. Add coolant if necessary.

3.6.2 Check coolant quality

(1) Check coolant for cleanness. Change any dirty coolant.

Special tool

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·86·

(2) Check if rust is present around radiator cap and radiator opening.

(3) Check coolant for smear.

3.6.3 Check cooling system

(1) Check cooling system for leakage.

(2) Check radiator and hose for damage and distortion.

(3) Check hose clamps for looseness.

3.6.4 Check fan belt

(1) Check fan belt for crack, extending, deterioration or serious wear. Replace if necessary.

(2) As shown in Figure 3-50, make sure the fan belt engages correctly into pulley.

Figure 3-50 Check Engagement of Fan Belt into Pulley

(3) Check and adjust fan belt tension (see Figure 3-51): Use a force of 98N to press the belt at middle spot

between alternator and water pump. If the deflection is 7~8mm (for a new belt 5-7mm), belt tension is nominal;

otherwise adjust it.

Figure 3-51 Check and Adjust Fan Belt Tension

(4) In cold region, replace with low temperature proof belt in winter.

3.6.5 Check thermostat

Dip the thermostat into water under heating. Gradually to heat up water while checking its opening

temperature and valve stroke (see Figure 3-52).

Correct

Incorrect

Incorrect

Chapter 3 Structure, Adjustment and Service of BJ491EQ1 Gasoline Engine

·87·

Figure 3-52 Check Thermostat

Opening temperature of the valve: 76℃;

Stroke of the valve: more than 8mm at 88℃.

If the opening temperature and stroke do not comply with specification, replace the thermostat.

The oscillating valve on the thermostat should be turn to upper left position during thermostat installation

(see Figure 3-53).

Figure 3-53 Installation of Thermostat

3.6.6 Check water pump

Check water pump and timing sprocket chamber body for crack; check fitting surface for damages, and check

water pump bearing for free rotation and noise (see Figure 3-54).

● Note: Observe if there is coolant leaking trace from overflow opening.

3.6.7 Check silicon oil fan clutch

Check silicon oil fan clutch (excl. rigid coupling fan) for damage and silicon oil leak. If any, replace the

silicon oil clutch. See Figure 3-55.

Oscillating valve