Service manual

04-5
Hydraulic Tappets (Roller Hydaulic Valve Lifter (RHVL)
WHAT IS HYDRAULIC TAPPET :
Hydraulic tappet (also called RHVL -
Roller Hydraulic Valve Lifter) is the ele-
ment connects between cam profile to
push rod and it operates with aid of the
hydraulic pressure to eliminate the clear-
ance and noise between valve train parts.
BENEFIT OF HYDRAULIC TAPPET :
1. Roller follower on cam with
hydraulic tappet avoid sliding
motion and friction, provides
improved tappet and cam life.
2. Control of valve train lash
adjustment. The RHVL compensates
for changes in the length of valve
train components by wear or
variations in engine temperature.
ESCAPING OIL
(D) PUSHROD
SEAT
(B) OVER HEAD
OIL FLOW PATH
(C)DISC VALVE
OIL INLET
OIL HEAD, OIL DELIVERY CONTROL
VALVE, LOCKING ACTION
CHECK BALL
(A) HIGH PRESSURE CHAMBER OIL
FLOW PATH
(H) HIGH PRESURE CHAMBER
(F) TRAPPED AIR VOLUME
AIR ESCAPE PATH THROUGH
PLUNGER CLEARANCE
CHECK BALL
SEAT
PLUNGER
OIL TRANSFER ANULUS
OUTER BODY
ROLLER
PUSH ROD OIL
(E) LOW
PRESSURE
CHAMBER
CUT SECTION
VIEW OF RHVL
RHVL
CAM
ROLLER