VIETNAM NATIONAL UNIVERSITY – HCM CITY
FACULTY OF TRANSPORTATION ENGINEERING
Ho Chi Minh City University of Technology
Department of Automotive Engineering
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EXPERIMENTS ON ENGINE & AUTOMOBILES
SECTION 1: ENGINE EXPERIMENTS
LESSON 2:
Experimentally Investigate Structural
Parameters of Valvetrain System
Objectives:

Determine structural parameters of valvetrain system that are the basics for
repair, maintenance and design of valvetrain system.

Practice skills of experimental investigation on structural parameters of
valvetrain system.
Expected outcomes of the lesson:
Upon completion of this lesson, the student will be able to

recognize the components of valvetrain system;

list basics structural parameters of valvetrain system that are essentially
important for repair, maintenance and design purposes;

describe the measurement procedure using specialized instrumentations;

experimentally determine structural parameters of valvetrain system;

describe structural features of valvetrain system;

make a report on experimentally investigating valve and valvetrain system.
– HCMUT/2020 –
Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
CONTENTS
1
BASICS & TERMS................................................................................................................. 3
2
EXPERIMENT SETUP .......................................................................................................... 4
3
4
2.1
Introduction ...................................................................................................................... 4
2.2
Experimental apparatus .................................................................................................... 4
2.3
Experimental instrumentations ......................................................................................... 6
EXPERIMENTAL METHOD & DATA POST-PROCESSING ........................................... 7
3.1.1
Measurement of outer diameters ............................................................................... 7
3.1.2
Measurement of length and thickness ....................................................................... 7
3.1.3
Data post-processing ................................................................................................. 7
EXPERIMENTAL PROCEDURE.......................................................................................... 7
4.1
Preparation ........................................................................................................................ 7
4.2
Measure the structural parameters of valvetrain system .................................................. 9
4.3
After experiment ............................................................................................................. 10
5
SELF – TEST ........................................................................................................................ 11
6
EXPERIMENT REPORT ..................................................................................................... 13
6.1
Measure the structural parameters of camshaft .............................................................. 13
6.2
Measure the structural parameters of cam lobe .............................................................. 15
6.3
Measure and inspect the structural parameters of valve spring ...................................... 16
6.4
Measure and inspect the structural parameters of valve ................................................. 17
Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
1 BASICS & TERMS
Attention:
IMPORTANCE


Students MUST fully understand the content of the lesson
before doing experiment.

Students who cannot pass the screening test are NOT allowed to
do experiment.

SELF-TEST before and after experiment is highly requested.
Type of valve:
 Flat head.
 Over - Head Valve (with or without pushrod).

Components of valvetrain system, including:
 Camshaft.
 Valve assembly (valve, valve guide, valve spring, valve spring collar, valve split
collar).
 Tappet.
 Pushrod.
 Rocker arm and rocker arm shaft.

Structural parameters of components of valvetrain system, including:
 Camshaft.
 Valve assembly (valve, valve guide, valve spring, valve spring collar, valve split
collar).
 Tappet.
 Pushrod.
 Rocker arm and rocker arm shaft.

Technical usage including (1) Safety caution, (2) Measurement procedure and (3) Record
the value) of the following specialized instrumentations:
 Outside micrometer.
 Caliper.
 Tape measure.
Page 3/17
Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
2 EXPERIMENT SETUP
2.1 Introduction

Experimentally investigate structural parameters of valvetrain

Lesson title:
system
Time duration:

No. student:
5 students/experimental model
2.5 periods
2.2 Experimental apparatus
Figure 1. The experimental apparatus used in the lesson
Page 4/17
Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
Table 1. Components of valvetrain system investigated in the lesson.
No.
Component
Unit
Quantity
1
Camshaft
piece
01
2
Cam lobe
piece
08
3
Valve spring
piece
08
4
Tappet
piece
08
5
Valve spring
collar
piece
6
Valve split
collar
piece
7
Intake valve
piece
04
8
Exhaust valve
piece
04
1
Camshaft
piece
01
2
Cam lobe
piece
08
3
Valve spring
piece
08
4
Tappet
piece
08
5
Pushrod
piece
08
6
Rocker arm
piece
08
7
Rocker arm
shaft
piece
8
Valve spring
collar
piece
9
Valve split
collar
piece
10
Intake valve
piece
04
11
Exhaust valve
piece
04
Page 5/17
08
16
01
08
16
Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
2.3 Experimental instrumentations
Attention:

Students refer to the User manual of workshop tools and
equipments before doing experiment.

ALWAYS comply with safety regulations and technical
requirements of using tools and equipments.

Clean and re-arrange tools and equipments after use.
IMPORTANCE

Measurement equipments of this chapter are presented in the Table 2 below.
Table 2. Measurement equipments.
No.
Parameter
Symbol
Unit
1
Outer diameter
D/d
mm
Measurement equipment
Micrometer
Caliper
2
Length
L, l
mm
Tape measure
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Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
3 EXPERIMENTAL METHOD & DATA POST-PROCESSING
3.1.1 Measurement of outer diameters
Outer diameter is measured by using micrometer and caliper.
3.1.2 Measurement of length and thickness
Length and thickness are measured by using caliper.
3.1.3 Data post-processing
Each parameter should be measured at least 3 times. The result is the average value of all
measurements
4 EXPERIMENTAL PROCEDURE
4.1 Preparation
 Clean and arrange the experiment area.
 Check ventillation of the experiment area and arrange fan if needed.
 Wear neat costume.
 Assign individual task for each member of experiment group.
 Check the quantity and condition of experimental tools and instrumentations.
 Recognize each component of valvetrain system in the experimental apparatus.
Table 3. Results of checking experimental tools and instrumentations
No.
Equipment
Quantity
1
Micrometer 0-25 mm
02
2
Micrometer 25-50 mm
02
3
Micrometer 75-100 mm
02
4
Caliper 0-150mm
02
5
Caliper 0-300mm
02
6
Caliper 0-500mm
01
7
Tape measure 0-5m
02
Condition
* Pay attention to the measurement range of the measurement equipment.
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Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
Table 4. Results of checking experimental apparatus.
Condition
No.
Task
Unit
Quantity
Passed
Gasoline engine
1
Camshaft
piece
…/01
2
Cam lobe
piece
…/08
3
Valve spring
piece
…/08
4
Tappet
piece
…/08
5
Valve spring collar
piece
…/08
6
Valve split collar
piece
…/16
7
Intake valve
piece
…/04
8
Exhaust valve
piece
…/04
Diesel engine
9
Camshaft
piece
…/01
10
Cam lobe
piece
…/08
11
Valve spring
piece
…/08
12
Tappet
piece
…/08
13
Pushrod
piece
…/08
14
Rocker arm
piece
…/08
15
Rocker arm shaft
piece
…/01
16
Valve spring collar
piece
…/08
17
Valve split collar
piece
…/16
18
Intake valve
piece
…/04
19
Exhaust valve
piece
…/04
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Not passed (Note)
Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
4.2 Measure the structural parameters of valvetrain system
Attention:
IMPORTANCE

Students MUST define position of the 1st cylinder

Define the rotational direction of the engine with the 1-3-4-2
firing order

Precisely define the position of intake and exhaust cam
lobes
 Step 1: Measure structural parameters of the camshaft and record values in Table 5 &
6.
Lcam
Di
dt
Where:
Lcam
: length of camshaft
Di
: diameter of journal
dt
: diameter of camshaft
 Step 2: Measure structural parameters of the cam lobes and record values in Table 7 &
8.
hc
Dcs
Where:
Hc
Hc
: maximum lift
Dcs
: base diameter
hc = Hc – Dcs
: lift
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Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
 Step 3: Measure structural parameters of the valve springs and record values in Table
9 & 10.
dlx
Where:
Llx
Dlx
Llx
: Free length
Dlx
: Outer diameter
dlx
: Wire diameter
 Step 4: Measure structural parameters of the valves and record values in Table 11 &
12.
Where:
Lxp : Valve height
dxp
Lxp
Dxp : Head diameter
dxp : Stem diameter
α
: Seat angle
*Note: +. Seat angle varies from 30 to 450

Dxp
+. Without specialized supporting device,
measuring the seat angle is neglected in
this experimental lesson.
4.3 After experiment
 Clean all components on the experiment model.
 Re-arrange each component on its own position on the experiment model.
 Clean and gather all experiment tools and equipments.
 Clean the experiment area.
 Complete the experiment report.
Page 10/17
Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
5 SELF – TEST
CAMSHAFT
K
CAM LOBE
Type?
Type?
Type?
Structure of component?
Position in the overall diagram?
Position in the overall
diagram?
Define
valve?
Crucially structural parameters
of valve spring?
Position in the overall
diagram?
Purpose of valve spring?
Exhaust valve is smaller than
intake valve?
Position in the overall diagram?
Purpose of each section of
camshaft?
A
and
exhaust
Lubrication of camshaft?
The difference in lift between
intake and exhaust cam lobe?
Parameters affect the stiffness
and working length of valve
spring?
Standard value
clearance?
The causes of wear of camshaft
journal?
The causes of uneven wear
among cam lobes?
The effect of spring stiffness
on the engine?
Crucial parameter of valve?
Method of fabrication?
The effect of uneven cam lift on
the performance of engine?
The effect of broken valve
spring on the engine?
Replacement
valve?
K
U
Purpose of cam lobe?
intake
The effect of cam lobe lift on the
working behavior of valve?
A
MEASURE &
INSPECT
INTAKE & EXHAUST
VALVE
Type?
RECOGNIZE
U
VALVE SPRING
Page 11/17
of
indicator
valve
of
VIETNAM NATIONAL UNIVERSITY – HCM CITY
FACULTY OF TRANSPORTATION ENGINEERING
HCM City University of Technology
Department of Automotive Engineering
----------
----------
EXPERIMENTS ON ENGINE & AUTOMOBILES
SECTION 1: ENGINE EXPERIMENTS
EXPERIMENT REPORT
LESSON 2:
Experimentally Investigate Structural
Parameters of Valvetrain System
Instructor: ...................................................................
Student:
Name:................................................................
ID: .....................................................................
Class: ................................................................
Group: ...............................................................
HCMUT - …/ …/ 20…
Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
6 EXPERIMENT REPORT
6.1 Measure the structural parameters of camshaft
Table 5. Structural parameters of gasoline – engine camshaft
No.
Parameter
Symbol
Unit
1
Diameter of the 1st journal
D1
mm
2
Diameter of the 2nd journal
D2
mm
3
Diameter of the 3rd journal
D3
mm
4
Diameter of the 4th journal
D4
mm
5
Diameter of the 5th journal
D5
mm
6
Diameter of camshaft
dt
mm
7
Length of camshaft
Lcam
mm
Value
Table 6. Structural parameters of diesel – engine camshaft
No.
Parameter
Symbol
Unit
1
Diameter of the 1st journal
D1
mm
2
Diameter of the 2nd journal
D2
mm
3
Diameter of the 3rd journal
D3
mm
4
Diameter of the 4th journal
D4
mm
5
Diameter of the 5th journal
D5
mm
6
Diameter of camshaft
dt
mm
7
Length of camshaft
Lcam
mm
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Value
Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
Comment:
 Illustrate structure of the camshaft on the experiment model (indicate the position of
intake and exhaust cam lobe according to the cylinder order):
-
Gasoline engine
-
Diesel engine
 Compare the structure of those 2 camshafts?
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Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
6.2 Measure the structural parameters of cam lobe
Table 7. Structural parameters of gasoline – engine cam lobe
Cylinder
order
Intake cam lobe
Hc (mm)
Dcs (mm)
Exhaust cam lobe
hc (mm)
Hc (mm)
Dcs (mm)
hc (mm)
1
2
3
4
Table 8. Structural parameters of diesel – engine cam lobe
Cylinder
order
Intake cam lobe
Hc (mm)
Dcs (mm)
Exhaust cam lobe
hc (mm)
Hc (mm)
Dcs (mm)
hc (mm)
1
2
3
4
Comment:
 Compare maximum lift of intake and exhaust cam lobe of the same engine? Explain the
difference?
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Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
 Explain the difference in cam lift between gasoline and diesel engine?
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6.3 Measure and inspect the structural parameters of valve spring
Table 9. Structural parameters of gasoline – engine valve spring
No.
Parameter
Symbol
Unit
Llx
mm
n
coils
1
Free length
2
Number of active coils
3
Outside diameter
Dlx
mm
4
Wire diameter
dlx
mm
Value
Table 10. Structural parameters of diesel – engine valve spring
No.
Parameter
Symbol
Unit
Llx
mm
n
coils
1
Free length
2
Number of active coils
3
Outside diameter
Dlx
mm
4
Wire diameter
dlx
mm
Value
 What is the effect of free length of valve spring on the operation of valve?
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Lesson 2: Experimentally Investigate Structural Parameters of Valvetrain System
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6.4 Measure and inspect the structural parameters of valve
Table 11. Structural parameters of gasoline – engine valve
Intake valve
Exhaust valve
No.
Hn (mm)
Dn (mm)
dn (mm)
Ht (mm)
Dt (mm)
dt (mm)
Value
Table 12. Structural parameters of diesel – engine valve
Intake valve
No.
Hn (mm)
Dn (mm)
Exhaust valve
dn (mm)
Ht (mm)
Dt (mm)
dt (mm)
Value
Comment:
 Compare head diameter D of intake and exhaust valve? Explain the difference?
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