Perkins 4.99 - Timing Gear Procedures; Idler Gear and Hub Refitting; Camshaft Gear Refitting

TIMING CASE AND DRIVE-J.2
2. Tap back the locking tabs and unscrew the two
idler hub securing setscrews.
3. The setscrews, idler gear and hub may now be
removed together as shown in Fig. J.1.
4. Clean and thoroughly examine the gear and hub
for signs of excessive wear, cracks, pitting, etc.
To Refit the Idler Gear and Hub
1. After ensuring that the oilways in the hub and gear
are clear, hold the gear in position with the
timing marks correctly aligned.
NOTE: If the cylinder head assembly has not been,
disturbed, then the cylinder head cover and rocker
shaft should be removed in order to allow the
camshaft to be turned to facilitate the aligning of
the timing marks.
2. Insert the hub as shown in Fig. J.2 so that the
holes in the hub and the cylinder block are in
alignment and secure with the two setscrews.
NOTE: Clearance is provided in the setscrew holes
of the idler gear hub, to provide the necessary
backlash adjustment for the timing gears.
Backlash should be set at the tightest point.
3. Using the adjustable idler gear, backlash between
both crankshaft gear/idler gear and camshaft
gear/idler gear should be set within the range
given on Page B.9 with the gears held together
in order to take up the effect of bearing clear·
ance. Blacklash may be checked by the use of
feeler gauges as shown in Fig. J.3.
4. When the backlash has been correctly set. finally
tighten the idler gear hub securing setscrews to
the torque given on Page B.2.
5. Check the gear end float as shown Fig.
the
limits are given on Page B.9.
gear
the tabwashers.
NOTE: The gears
appear as shown Fig.
7. the timing case front cover.
viously detailed in this section.
up to a
hydraulic
Remove
Remove the timing case front cover.
as pre·
2. Remove the three securing setscrews and ease
gear away from its location.
3. Examine the gear for signs excessive
cracks, pitting, etc.
J3
To Refit the Camshaft Gear
1. Remove the idler gear and hub, cylinder head
cover and rocker shaft (if not previously removed).
2. Refit the gear to the camshaft ensuring that the
'D' marks on the gear and camshaft hub respec-
tively align as shown !n Fig. J.6.
3. Refit the three securing setscrews and tighten to
a torque of 19-21 Ibf ft (2,6-2,9 kg! m).
J4
NOTE: Only the plain (non-slotted) holes in the
camshaft gear are to be used and these will align
with the tapped holes on the camshaft hub when
the 'D' marks are alignment.
Refit the idler and gear, case
etc., as detailed section.