Glossary “piston temperature” Definition:
Temperature of the piston at different areas, varying from over 450¡ãF (232¡ãC) at the crown, to 200¡ãF (93¡ãC) near the bottom of the skirt.
Glossary “piston to valve clearance” Definition:
The distance between the intake and exhaust valves and the piston crown when the valves are at overlap period and the piston is at top dead center.
Glossary “piston valve” Definition:
Shock absorber component used to control the flow of oil and produce the pressure and vacuum in the chamber above the piston during compression and rebound.
Glossary “piston stroke” Definition:
The distance the piston travels from TDC to BDC.
Glossary “piston slap” Definition:
Noise that is made by an undersize or loose piston skirt as it makes contact with the cylinder wall.
Glossary “piston speed” Definition:
Velocity of a piston, given in feet per minute, as it reciprocates in a cylinder.
Glossary “piston stops” Definition:
Tabs or protrusions on a backing plate, positioned as to prevent the wheel cylinder pistons from leaving the wheel cylinder.
Glossary “piston skirt” Definition:
Lower part of the piston that makes contact with the cylinder wall.
Glossary “piston skirt clearance” Definition:
The allowable space between the piston skirt and cylinder wall, usually 0.001 to 0.002 inch (about 0.025 to 0.051 mm) at room temperature.
Glossary “piston skirt expander” Definition:
Device that may be inserted behind the piston skirt to force the skirt out toward the cylinder wall to reduce skirt-to-wall clearance.
Glossary “piston rings” Definition:
Rings that fit into grooves on the outer wall of a piston, just below the crown, that seal the combustion chambers and scrape oil from the cylinder walls.
Glossary “piston rod” Definition:
Plated rod attached to the shock absorber piston, usually extending to the top of the shock to provide attachment to the vehicle.
Glossary “piston rod seal” Definition:
Non-replaceable oil seal around a movable piston rod, located at the upper end of the hydraulic cylinder.
Glossary “piston ring side clearance” Definition:
With the proper ring installed in the piston groove, measure the clearance between the ring and the groove with a feeler gauge, this will be the piston ring side clearance.
Glossary “piston ring expander” Definition:
A spring placed behind the piston ring in the groove to increase the pressure of the ring against the cylinder wall.
Glossary “piston ring gap” Definition:
Clearance between the ends of the piston rings.
Glossary “piston ring groove” Definition:
Channel or slots in the piston in which the piston rings are placed.
Glossary “piston ring land” Definition:
The surface of a piston between ring grooves.
Glossary “piston oiler” Definition:
Device that directs oil to the underside of the piston as an aid to carry away heat from the piston crown.
Glossary “piston pin” Definition:
Round, precision ground part usually hollow, used to attach the piston to the connecting rod by press fit or held in place with internal snap rings.