Automotive engine- assembly and installation practice(20151111).ppt

Action PlanFor Capacity Development Programe for the Teachers of Vocational Training Institutions in Sri Lanka

Professor : Lee Il Kwon

University Overview

1. Cylinder head

2. Timing system

3. Crankshaft

4. Piston, piston ring, cylinder

5. Appendix-measure instruments

6. Symbol unit

University Overview1. Cylinder Head?

Summary of this Chapter

1.1 Measuring deformation of cylinder head 1. Purpose of Checking

a. To check the cylinder head deformation to prevent the less compression pressure. b. To check the leaking of the coolant or the engine oil.

2. Checking method a. Remove and clean the foreign matters attached at the cylinder head bottom surface. b. Measure at the 7 portions using a straight scale and thickness gauge as below picture.

* Measure the clearance between cylinder head surface and the straight scale, avoid the coolant passage and the oil passage.



2. Checking the bending of the Camshafta. Place the camshaft on the V-shaped block on the flat base.

b. After installing the dial gauge at the center journal of the shaft, calibrate the zero setting.

c. Rotate the camshaft at one turn.

d. Read the dial gauge while the rotating of camshaft.

e. The amount of the bending shall be 1/2 of the amplitude of the vibration.



3. Measuring the cam lift

a.Measure the height of the cam with a micrometer

b. Measure the diameter of the basic circle of cam with a micrometer.

c. Cam Lift = Height of the Cam – Diameter of basic circle

University Overview2. Timing System?


1.1. Timing belt inspection

1.Check the belt for oil or dust deposits. Replace, if necessary. Small deposits should be wiped away with a dry cloth or paper. Do not clean with solvent.



1.1. Timing belt inspection

2. When the engine is overhauled or belt tension adjusted, check the belt carefully. If any of the following flaws are evident, replace the belt.



1.2. Cautions for Timing belt installation 1.Do not bend, twist or turn the timing belt inside out when the timing belt is removed.

2. Do not allow the timing belt to come into contact with oil, water and steam.

3. If the timing belt is reused, make an arrow indicating the turning direction to make sure that the belt is reinstalled in the same direction as before.



4. Align the timing marks of the camshaft sprocket and crankshaft sprocket with the No. 1 piston placed at top dead center and its compression stroke.

5. Inspect the tensioner pulley and the idler pulley for easy and smooth rotation, check for play or noise and the grease leak from its bearing.

6. When the timing belt is installed on the camshaft sprocket, make sure that the tension side is tightened by pushing the timingbelt tensioner pulley toward the water pump.

7. Turn the crankshaft one turn in the operating direction (clockwise) and realign crankshaft sprocket timing mark. Do not turn the crankshaft in a counterclockwise direction. The crankshaft should be turned smoothly.

University Overview3. Crankshaft


1.Cautions for Removing and tightening main bering caps

a. Put the marks at main bearing caps in order of their original position and direction for easier reassembly.

b. Remove the main bearing caps and remove crankshaft bearing. Keep the bearings in order by cap number.

c. Install bearing caps and tighten the cap bolts to the specified torque from the center.

d. The crankshaft bearing caps should be installed with the arrow mark directed toward the crank pulley side of engine. Cap numbers must be correct.



2. Measuring crankshaft oil clearance 1) Purpose

To make the proper oil clearance for reduction of bearing wear, reduction of noise, built up a proper oil pressure.

2) Oil clearance

The minimum gap between the crank shaft journal and the main bearing after the engine is manufactured or the crank shaft journal is modified (under size bearing).

3) Measuring by Plastic Gauge a.Clean the crankshaft and the bearing.

b. Cut the plastic gauge and lay down on the crankshaft journal along to the axis direction not cover the oil hole of the journal.

c. Tighten the cap with regulated torque. (Don’t rotate the shaft.)

d. Release the cap, and measure the width of the most enlarged portion with a scale.



4) Measuring by Telescoping Gauge and the Micrometer

a.After taken out the crankshaft, assemble and tighten the cap with the specified torque.

b. Measure the inner diameters (crankshaft bore) of the crankshaft cap at four points with a telescoping gauge and the outside diameter of the crankshaft journal with a micrometer at four points. c. Measure the thickness of crankshaft bearing.

d. Calculate the tolerance of them.

Oil clearance = Minimum Inner Diameter of cap (telescoping gauge) – Maximum Outside Diameter of the Journal (Micrometer) – Thickness of crankshaft bearing



3. Measuring thrust bearing clearance (End Play)

1) When the thrust bearing clearance is too big

a.Noise will be occurred

b. Abnormal wear on the cylinder, the piston and the connecting rod

c. Off-side wear on the timing gear or clutch

d. Oil leak through the oil seal

2) When the thrust end play is too smallThe face of the thrust bearing will be damaged by insufficient lubrication



3) Measuring by Filler Gaugea.Assemble the crank shaft to the cylinder block. (Tighten all crankshaft bearing caps with specified torque)

b. Push the crankshaft to the thrust direction.

c. Measure the clearance between the thrust bearing and crankshaft using a filler gauge.

4) Measuring by Dial Gaugea.Assemble the crank shaft to the cylinder block with the bearing.

b. Install the gauge body to the cylinder block with a magnet and install the dial gauge at the front or rear portion of the crankshaft.

c. After calibrating the zero setting, push the crankshaft to the front or rear side. At this time, the indicating point of the dial gauge needle is the clearance along to the thrust direction.



4. Checking the bending of the Crankshaft

a. Setting the front and rear main journals (No. 1 and No.5) on the V-shaped block and installing the dial gauge at the middle journal (No.3) perpendicularly, measure the bending amount with rotating the crank shaft. b. The amount of the bending shall be 1/2 of the amplitude of the vibration.

University Overview4. Piston, Piston ring and cylinder


1. Measuring piston ring end gap 1) End gapThe gap compensating the changed length by heat expansion

2) End gap is too bigThe blow by gas will be increased, the compressing pressure will be decreased, the consumption of the oil will be increased, the engine power will be decreased etc.

3) End gap is too smallThe piston ring will be adhered by the heat or the cylinder wall shall be worn more, etc.



4) Measuring a. Clean the cylinder wall.

b. Insert the piston ring in the cylinder. c. Insert the piston in the cylinder with being upside down and push the piston until the ring is reached to the piston pin boss.

d. When the piston ring is inserted in the cylinder, the end gap should not be located at the direction of the axis or perpendicular direction of crankshaft.

e. When the piston ring is inserted in the cylinder, the piston ring with facing the mark to the cylinder head.

f. Measure the piston ring end gap

5. Cautions for measuring the piston ring end gap

a.Be careful not to break the piston ring.

b. Measurement shall be performed at the least worn portion.



2. Measuring piston ring side clearance

1) Clearance too bigThe oil consumption will be increased, the carbon will be deposited, or the compressed gas will be leaked.

2) Clearance too smallThe piston may be deformed or the resistance against the piston movement will be increased.

3) Measurment a. Insert the filler gauge until it reaches at the ring groove. b. Check at least 3-4 points



3. Cautions for assembling the piston ring

a. Be careful not to exchange the ring position (Distinguish the NO. 1 and 2 – compression ring).

b. Be careful not to exchange the ring to upside down (Mark should be faced with cylinder head side.

c. Do not set the end point at the axis direction or perpendicular direction to the axis. Assemble with the 120~180 degree between the end gap of each ring. Assemble with the expander or hand.



4. Measuring cylinder worn-out 1) Piston gap As the gap between the cylinder wall and the piston, it is the minimum gap between the cylinder and the piston just after the engine is manufactured or the boring is completed. Generally, it is 0.05% of the diameter of the cylinder.

2) For the oversized pistonTo prevent from decreasing the compressing pressure by the ware of the cylinder wall after long life used and from decreasing the power of the engine by the blow by gas. Replace the old piston with the over size piston after boring the cylinder wall

3) Tendency of Wear of the cylinder wallThe ware of the perpendicular portions of the crankshaft and at the top dead center is biggest and the ware at the bottom dead center position is also big.



When the movement direction is changed, the oil film shall be easy to be broken. It comes from the breathing operation of the piston ring and the lateral pressure about the perpendicular direction to the crankshaft generated at the explosion stroke



4) Cylinder wall too much worn outThe compressing pressure will be decreased, the fuel consumption will be increased, the lubricant oil will be more spent, the piston may be slapped, or the engine power will be decreased.

5) Measuring by Cylinder gauge

1. Install the extension and washer to the gauge 2. Set zero 3. Insert the gauge in the cylinder 4. Read the minimum value of indicator while moving the gauge 2~3 times.

University Overview4. Appendix


1.Vernier caliper usage

1) The vernier caliper is used in length measurements to gain higher precision readings compared to a simple ruler.

2) Use proper caliper for the purpose (kinds, range, precision)

3) Do not give a shock (dorp, hit)



6) Confirm the 0 setting

7) Outer mesurment - Close to the object as possible



6) Inner measurment – Deeply insert the jaw - Read maximum value for inner diameter.

7) Depth measurment – Close the depth gauge to the surface properly



9) Read the scale a. The left end of the vernier scale indicates the

measurement.

This position corresponds to a measurement of 9+xx b. The 3rd line of the vernier scale lines up with the main

scale. This gives a reading of 0.06mm. (3 -> 3x0.02=0.06mm)

c. So, the value is 9.06mm



2. Micrometer usage

1) A micrometer is a device for precisely measuring small distances or thicknesses. The precision is often achieved by a screw mechanism.





4) Cleaning the measuring surface.



5) Confirm the 0 setting

6) Use the ratchet stopper to set the object for measuring.

7) Read the scale from the proper position



3. Dial gauge usage

1) Using dial gauge a. Flatness



b. Right angled

c. Circularness



d. Bending

e. Thickness



f. Depth





4) Choose and use a lid for the proper purpose.



5) Install the dial gauge properly

6) Read the scale from the proper position. Value = Short indicator + Long indicator

University Overview6. Unit simbol


Unit simbol

Power of ten Prefix Prefix symbol1018 exa E1015 peta P1012 tera T109 giga G106 mega M103 kilo k102 hecto h10 deca da10-1 deci d10-2 centi c10-3 milli m10-6 micro μ

10-9 nano n10-12 pico p10-15 femto f10-18 atto a

University Overview

Thank you

Automotive engine- assembly and installation practice(20151111).ppt

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