Questions and Answers

Couple Of General Questions Q. What is a key way? How does it work and why is it advantageous? Why are "Seals" used at mating surfaces? Explain please, why they are needed and how they work?

A. A key way is a slot machined in two parts that usually turn together. A "key" is used in these slots to insure that both parts turn together without slipping. A good example of this is the front crankshaft pulley. The pulley has a groove machined to the inside and the crankshaft has a matching groove. A key is inserted inside the groove and the pulley is installed with the key so both the crankshaft and pulley rotate together.

This system is used where ever two parts need to be kept synchronized or where slippage is not desired, such as timing gears and power steering pump pulleys.

Seals are needed when ever you have a rotating part such as the timing chain cover. The cover stays stationary and has a seal through which the crankshaft extends. The seal prevents oil from leaking out of the engine while allowing the crankshaft to rotate. There are a lot of different types of seals used in an engine. They differ in size and shape, but they all perform the same function.

Where two parts are mated, like a water pump to the block, a gasket is used. This gasket insures a seal between two metal parts and takes up any irregularities in the mating surfaces to produce a leak proof seal. On most newer engines a liquid sealer is used and when it cures, gives the same sealing ability as a gasket.

Additional Information provided courtesy of ALLDATA