Exam 6: Cylinder Heads and Valve Train Mechanisms

Technician A says that overhead cam engines with unit injectors can provide the greatest actuation force for the highest injection pressures. Technician B says that pushrod engines that use a low-mounted camshaft can provide the same force as an overhead camshaft engine to its unit injectors. Who is correct?

Which valve guide in a turbocharged diesel engine will more likely not have valve stem seals?

A shorter, stiffer valve train permits unit injectors to be actuated to higher injection pressures of:

Technician A says that rear geartrains are used on engines because they operate with less noise. Technician B says that rear geartrains are used because they have less wear than a front geartrain mechanism. Who is correct?

Technician A says that the cam gear rotates two times faster than the crank gear. Technician B says the cam gear rotates at half the engine speed. Who is correct?

An extra intake valve is used to:

Timing belts do not require lubrication but have a much shorter service interval, requiring replacement at approximately:

The purpose of a variable intake swirl mechanism is to __________.

Most valves recede into the valve face and seat, often causing valve adjustments to:

What is produced from powdered iron alloys squeezed into molds at high pressures and then heated to bond the metal particles together?

What are cylinder head bolts that have been tightened past their yield strength or elastic point called?

While examining a valve spring from an engine that is being overhauled, technician A says that valve springs should be checked for free length and cracks. Technician B says the spring should be checked for compressed spring pressure, nicks, and straightness. Who is correct?

Technician A says that fiber gaskets are the best and most commonly used gaskets in modern diesel engines. Technician B says that MLS gaskets are now the most commonly used head gaskets. Who is correct?

Valve overlap occurs during _____________.

Two technicians are explaining the torque turn method. Technician A says that this method requires initial bolt tightening with a torque wrench and then turning the bolt an additional number of degrees past this point. Technician B says that clamping forces with this method are the most consistent and widely preferred method. Who is right?

Rocker arms are heat treated to resist:

Which of the following cylinder head valve train arrangements can provide the highest injection pressures?

When you rotate the engine 360 degrees in the correct direction of rotation until cylinder 6 is at TDC (end of compression stroke), cylinder 1 should be on:

A valve failure with a break between the head and stem was likely caused by _______.

What is the most common type of valve used in diesel engines?