Auto Mechanics Paper 2,Nov/Dec 2012.  
Questions:   1 2 3 4 5   Main
General Comments

Question 5

  (5) (a) State the function of each of the following parts in the engine lubrication system:

  1. pump;
  2. filter;
  3. relief valve;
  4. dip stick.

(b)      List three types of feed in a lubrication system.

(c)       State two purposes of oil in an engine.

This question was attempted by nearly all the candidates
who sat for the examinations.   Some wrong answers were presented by candidates to some parts of the question. 
The required responses to the various parts of the question are:

(a) (i)  Pump draws lubricating oil from the sump and circulates it to the system.
(ii)        filter removes particles and other foreign matters from oil thus ensuring the flow of clean oil.
   (iii)       Relief valve opens when the pressure reaches
the  maximum allowed, thereby protecting the system from damage.
   (iv) Dip stick is used to indicate the quantity of oil in the sump.

  (b)  Feeds in the lubricating system are:

-   splash feed;
  -  pressure or forced feed;
  - petroil system.
  (c)The purposes of oil in the engine are:

-  to separate metal surfaces thereby reducing friction;
-  to coat metal surfaces thereby preventing corrosion;
-   to carry away heat and thereby acts as a cooling agent;
-   to remove worn particles and other foreign matters thus acts as a cleaning agent.


gave wrong answer to the various parts of the question.  The required answers to the various parts of the question are:

(a and b)


(c)        The demerits of sliding mesh gearbox are:
-           nosier in operation;
-           difficult to engage the gears i. e. requires skills in double declutching;
-           gears wear faster due to frequent crash;
-           bulkier in construction.

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