Mazda CX-5 Service & Repair Manual: Valve, Valve Spring, Valve Seal, Valve Guide

Purpose, Function

Valve

• The intake valve is pressed down by the cam, the intake air passage is opened, and air is introduced into the cylinder.

• The exhaust valve is pressed down by the cam, the exhaust air passage is opened, and combustion gas is exhausted from the cylinder.

Valve spring

• The valve spring adheres to the valve seat by pulling up the valve by spring force, and air tightness in the combustion chamber is maintained.

Valve seal

• The valve seal prevents engine oil from entering combustion chamber through the valve guide, and engine oil consumption is suppressed.

Valve guide

• The valve guide maintains the valve stem to open and close the valve smoothly.

• The valve guide cools the valve by transmitting valve heat to the cylinder head.

Construction

• The valve, valve spring, valve seal, and valve guide are assembled to the cylinder head as a single unit.

  

  
  

• The sliding resistance has been reduced by setting the valve spring load to the required minimum.

• The intake valve and exhaust valve are subjected to a salt-bath, soft-nitriding treatment to enhance wear resistance.

• Unequal pitch valve spring has been adopted. In addition, the upper diameter is smaller compared to the bottom diameter.

• The valve guide is made of sintered alloy with excellent wear resistance.