Perkins 4.99 - Timing Procedures and Checks; Timing Pin Usage and Valve Timing Check

TIMING-K.2
K2
NOTE: When the timing has been reset, great
care should be exercised when first turning the
engine,
for should the timing be incorrectly set,
even by
only one tooth, there is the possibility that
a valve head will
strike the piston crown.
TIMING PIN
A timing pin is fitted at the bottom of the timing case
cover on the left hand side. When it is unscrewed it
locates in a hole machined in the rear face of the
crankshaft pulley (as shown in Fig. K.2l, when Nos. 1
and 4 pistons are at T.O.C.
With
some applications, two holes are provided in the
rear face of the crankshaft pulley, i.e., one for the
T.O.C.
position and the other for the static fuel pump
timing position.
Always return this pin to its
normal location im-
mediately T.O.C. has been
determined and before any
attempt is made to turn
or start the engine.
Checking Fuel Pump Timing-See Page N.S
Checking Valve Timing
To check the valve timing proceed as follows:
1. Turn the crankshaft until the valves of No. 4
cylinder are 'on overlap'.
2. In this position set the valve clearance of No. 1
inlet valve to 0.039 in (1 mm).
3. Turn the engine slowly in the normal direction of
rotation until the clearance No. 1 inlet valve is
just taken up. (In this condition it will just be poss-
ible
to rotate No. 1 inlet valve push rod between
the thumb and the forefinger).
4. Nos. 1 and 4 pistons will now be at T.O.C. if the
timing has been correctly set.
NOTE:
No adjustment is provided for valve timing,
should the timing be incorrect and the camshaft
gear has been correctly fitted to the camshaft hub,
the error will probably be due to incorrect align-
ment of the original timing marks on the drive
gears. Recheck as detailed on Page K.1.
When valve
timing is originally set and checked
during production a timing tolerance of plus or
minus 2~ (flywheel) degrees is allowed for item
(4) above. When the timing has been correctly
set, do not forget to reset No. 1 inlet valve clear-
ance to the correct figure also to return the timing
pin to its correct location if it has been used to
check T.O.C.