A. Outside lap is that portion of valve which extends beyond the ports when valve is placed on the center of travel, and inside lap is that portion of valve which projects over the ports on the inside or towards the middle of valve.
Q. What is the use of lap?
A. To give the engine compression.
Q. Where is the dead center of an engine?
A. The point where the crank and the piston rod are in the same right line.
Q. What is the tensile strength of American boiler iron?
A. 40,000 to 60,000 pounds per square inch.
Q. What is very high tensile strength in boiler iron apt to go with?
A. Lack of homogeneousness and lack of toughness.
Q. What is the advantage of toughness in boiler plate?