Porting heads is an art and science. It takes a craftsman's touch to shape the surfaces of the head for the optimal flow characteristics and the best performance. Porting demands the right tools, skills, and application of knowledge. Few other engine builders have the same level of knowledge and skill porting engine heads as David Vizard. All the aspects of porting stock as well as aftermarket heads in aluminum and cast-iron constructions are covered. Vizard goes into great depth and detail on porting aftermarket heads. Starting with the basic techniques up to more advanced techniques, you are shown how to port iron and aluminum heads as well as benefits of hand and CNC porting. You are also shown how to build a high-quality flow bench at home so you can test your work and obtain professional results. Vizard shows how to optimize flow paths through the heads, past the valves, and into the combustion chamber. The book covers blending the bowls, a basic porting procedure, and also covers pocket porting, porting the intake runners, and many advanced procedures. These advanced procedures include unshrouding valves, porting a shortside turn from the floor of the port down toward the valve seat, and developing the ideal port area and angle. All of these changes combine to produce optimal flow velocity through the engine for maximum power.
ISBN-13: 9781934709641
Media Type: Paperback
Publisher: CarTech
Publication Date: 02-23-2012
Pages: 160
Product Dimensions: 8.40(w) x 10.90(h) x 0.40(d)
David Vizard is a revered engine builder, technical writer, and author. In fact, he has authored more than 30 highly respected engine building and automotive books, penned about 4,000 magazine articles, and contributed scores of web pieces to popular sites. Often referred to as Vizard the Wizard, his work is often the subject of blogs and editorial pieces in popular automotive magazines. Currently, he owns and runs MotorTec Magazine in Charlotte, North Carolina.
Table of Contents
Table Of Contents:
About the Author 4
Acknowledgments 6
Introduction 7
Chapter 1: What It Takes to Make Power 14
Point of Maximum Flow 15
Seat and Port Priorities 15
Do You Need a Flow Bench? 16
Chapter 2: Flow Testing Procedures 18
The Standard Pressure Drop 18
Real-World Test Pressures 21
Corrections 21
Floating Pressure-Drop Testing 22
Intake Fixation? 23
Flow Efficiency 24
Chapter 3: A Flow Bench—Build or Buy 25
A Rethink on Matters 26
Current Conclusions 28
Flowing the Exhaust 28
Establishing the Numbers 29
Summary 31
Budget Computerization 31
Audie Technology 32
Performance Trends 35
Other Bench Sources 37
Chapter 4: Wet-Flow Testing 38
Wet-Flow Testing—What’s it Worth? 38
Six Wet-Flow Mistakes to Avoid 40
Chapter 5: Porting Aftermarket Heads 47
Air Flow Research 48
Dart 49
Edelbrock 51
EngineQuest 54
Racing Head Service 54
Trick Flow Specialties 55
Chapter 6: Porting Tools, Consumables and Safety 67
Eye and Lung Safety 67
Grinders—Air or Electric 68
Carbide Cutters 69
Support Porting Tools 69
Sourcing Consumable Supplies 74
Chapter 7: Five Golden Porting Rules 79
Rule Number 1 80
Rule Number 2 80
Rule Number 3 80
Rule Number 4 81
Rule Number 5 81
Chapter 8: Developing Functional Ports 82
Valve Seat Forms 82
Working Valve Seat Shapes 83
Alternative Seat Angles 84
Seats on Valves 87
Valve Shapes 87
Clearances and Temperatures 89
Cutting Valve Seats 91 Chapter 9: Valve Shrouding 96
Practical De-shrouding 97
Chapter 10: Developing Functional Heads 100
Optimizing Cylinder Head Airflow 100
Valve and Flow 101
Ports 101
Cross-Sectional Area 103
Port Velocity 105
Applied Basic Porting 108
Compression Increase 113
Modified 170s on the Dyno 113
The Virtual Flow Bench 114
Chapter 11: The Combustion Process 124
Defining Combustion 124
Combustion Efficiency 126
British Touring Car Championship Year 129
Finally: The Chambers 131
More Combustion Curiosities 132
Atomization Optimization 133
Thermal Barriers 135
Swirl and Quench 135
More Thermal Management 137
Small Crevice Volume—Big Consequences 138
Conclusions 143
Chapter 12: Maximizing Compression Ratio 144
Thermodynamics Made Easy 146
Dynamic Compression 148
Intake- to Exhaust-Valve Ratios 153
Containing the Pressure 157
Source Guide 158
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