Exam 8: Cylinder Head: Springs, Valves, and Valve Sets

Technician A says that basket-type coil springs are installed with the tighter part of the coil against the head. Technician B says grinding a valve seat will not affect the installed height of the valve spring. Who is correct?

By what process are integral seats usually hardened?

What is the margin of a valve?

Valve springs are being discussed. Technician A says you should discard a 2" spring that is 1/16" out of square. Technician B says out-of-square springs can cause uneven valve guide wear. Who is correct?

When grinding valve seats, some machinists will grind the 45-degree angle after the 60-degree angle.

Technician A says there is no need to lubricate the valve stems upon reassembly. Technician B says intake and exhaust seals are the same materials and shapes. Who is correct?

Technician A says that a burned exhaust valve can result from a valve seat that is too narrow. Technician B says that an exhaust valve seat should be wider than an intake valve seat. Who is right?

Technician A says that the face of the valve should overhang slightly into the combustion chamber when the valve is closed. Technician B says that the throat angle would most likely result in a ruined valve seat if ground too much. Who is right?

Technician A says intake valves take the most punishment and should always be replaced whenever in doubt. Technician B says many exhaust valve stems have a welded on hardened tip. Who is right?

Technician A says that basket-type coil springs are installed with the tighter part of the coil against the head. Technician B says that grinding a valve seat will decrease the installed height of the valve spring. Who is right?

Two technicians are discussing the interference angle. Technician A says that it helps a reground valve to seat because it causes increased valve seat pressure. Technician B says that a 1⁰ difference between the valve face and seat angles is enough to cause the valve to leak and burn. Who is right?

Technician A says that the sodium filling used in some exhaust valve stems lightens the valve for better low-speed operation. Technician B says that a valve that has a wide margin must be replaced. Who is right?

What is the approximate width of a larger (17⁄8") intake valve seat? _____"

Install O-ring seals after the springs.

Which valve would most often have a hardened tip?

VSI shims are available in 0.015", 0.030", and 0.060" sizes.

Which length pushrod will be needed if a valve seat has been ground too deep?

Technician A says that weak valve springs can impede heat transfer between the valve faces and seats. Technician B says that wear can be evident on the top when a valve spring has too little tension. Who is correct?

Technician A says heating a pressed-fit stud before installing it into the head makes installation easier. Technician B says stud-mounted rockers are oiled through hollow pushrods. Who is right?

Technician A says that after refinishing a 45⁰ valve seat, a 30⁰ angle should be used to position the valve seat on the valve face. Technician B says that before a valve guide is repaired, the valve seat should always be ground. Who is right?