Removal; Cleaning And Inspection; Installation; Valve Stem Oil Seal/Valve Spring - Mercury 305 CID Service Manual

Removal

IMPORTANT: Keep push rod and hydraulic valve
lifter from each valve together as a matched set
and mark them so they can be reinstalled in the
same location later.
Remove as outlined:
1. Remove rocker arm covers.
2. Remove intake manifold.
3. Remove lifter restrictor retainer on roller lifter
models.
4. Remove rocker arm assemblies and push rods.
NOTE: Engines with roller lifters have additional
valve train components shown below.
a
a - Lifter Restrictor Retainer
b - Fasteners
a
a - Roller Lifter Restrictor
b - Roller Lifter
5. Remove lifter restrictors on roller lifters models.
Index
3A-30 - ENGINES
b
72329
b
72340

Cleaning and Inspection

Thoroughly clean all parts in cleaning solvent and in-
spect them carefully. If any parts are damaged or
worn, entire lifter assembly should be replaced. If
outer lifter body wall is scuffed or worn, inspect cylin-
der block lifter bore. If bottom of lifter is scuffed or
worn, inspect camshaft lobe. If push rod seat is
scuffed or worn, inspect push rod.

Installation

IMPORTANT: It is recommended that the engine
oil be changed and a new oil filter be installed
whenever servicing valve lifters or camshaft.
IMPORTANT: Before installing lifters/rollers, coat
the bottom of the lifter/roller with engine oil. If
new lifters or a new camshaft have been in-
stalled, an additive containing EP lube (such as
General Motors Cam and Lifter Prelube or equiv-
alent) should be poured over camshaft lobes be-
fore installing lifters.
IMPORTANT: Before installation, coat entire
valve lifter with engine oil.
IMPORTANT: DO NOT install used valve lifters if
a new camshaft has been installed.
1. Install hydraulic valve lifters and components.
Torque roller lifter restrictor retainer plate fasten-
ers to 12 lb. ft. (16 N·m) on roller lifter engines.
2. Install intake manifold.
3. Install and adjust valve mechanism as outlined.
4. Install rocker arm cover.
5. Start engine and check for leaks.
Valve Stem Oil Seal/Valve
Spring

Removal - Head Installed

1. Remove:
a. Rocker arm cover.
b. Spark plug of affected cylinder.
c. Rocker arm assembly.
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