Exam 7: Cylinder Head: Parts and Service

When heating an aluminum OHC head to prepare for straightening, a(n) _____ should be used to correctly gauge the temperature.

Technician A says use kerosene as a spray lube before resurfacing aluminum heads. Technician B says belt sanders are the best method for resurfacing aluminum heads. Who is right?

Technician A says that OHC cylinder heads often have oil galleries in them. Technician B says that pushrod engine cylinder heads often have oil galleries in them. Who is right?

An aluminum head is discovered to have cracks. Technician A says to repair it by welding with an oxyacetylene welder. Technician B says to use a TIG welder to repair the cracks. Who is right?

Technician A says surfacing the head increases combustion chamber CCs. Technician B says the volume is increased by grinding metal from the surface of the combustion chamber or by excessive grinding on valve seats. Who is correct?

For a positive seal to work properly, the inside of the valve guide must be concentric with the outside (O.D.).

A valve guide has 0.015" bellmouth wear. Technician A says to knurl and then ream the guide to size. Technician B says to repair the guide with a replaceable guide insert. Who is right?

What is the name given to an inexpensive metal displacement method of resizing a valve guide?

Cracks in iron heads can be repaired with threaded plugs. What is this process called?

Name four methods of crack detection.

Technician A says that on some engines, guide seals have to be installed on exhaust valves only. Technician B says that even though two valve guide seals might look alike, one could be made of a rubber that will survive longer under higher temperature. Who is right?

When performing procedure 2, care should be taken so as not to bend what part?

Technician A says bronze valve guides wear better than iron ones. Technician B says to use SAE 90 oil as a lubricant when machining bronze. Who is right?

An engine has excessive valve guide wear. Technician A says to ream the guide and install a new valve with an oversized stem. Technician B says to knurl the valve stem and reinstall it in the guide. Who is right?

Name three types of valve guide seals.

Switching to aluminum heads requires lowering the compression ratio.

What name describes the shape in which valve guides wear?

Technician A says that if a camshaft does not turn easily, the head probably requires straightening. Technician B says that if the cam side of an OHC head is warped excessively, the head can be straightened. Who is right?

Removal of 0.020" from OHC surfaces will result in 1° of advance in valve timing.

When cracks are repaired using tapered, threaded plugs, what is this called?