Page 452
REPAIR INSTRUCTIONS, PART 3
557
Figure 557 — Checking Yoke Adjustment
Exhaust Valve Lash Adjustment
(J-Tech™-Equipped Engines)
When adjusting exhaust valve lash on an engine
equipped with a J-Tech™ engine brake, the
same procedure is used as on a
non-brake-equipped engine except that the
14 mm crow’s foot wrench, adapter and long
extension are required in place of the
screwdriver. These tools are required because
the spherical nut covers the top of the adjusting
screw, so the 14 mm hex at the bottom side of the
adjusting screw must be used.
558
Figure 558 — Adjusting Valve Lash on Engines
Equipped with a J-Tech™ Engine Brake
The J-Tech™ exhaust rocker arm adjusting
screw spherical jam nut is a through-hardened
nut. When tightening these nuts, be aware of the
following:
앫
Always use the proper 20 mm size wrench
to tighten the spherical jam nut. Tighten the
nut to 45 lb-ft (61 N
폷
m). Using an improper
size wrench will lead to jam nut breakage.
앫
Overtightening the spherical jam nut when
adjusting the valves may result in jam nut
breakage. If there is too much or too little
drag on the thickness gauge, loosen the jam
nut and readjust valve lash. Do not
overtighten the spherical nut in an attempt to
obtain correct valve lash.
Alternate Valve Lash Adjustment Procedure
(J-Tech™ Brake Engines)
If an oz-in or lb-in torque screwdriver or torque
wrench is not available, valve lash can be
adjusted (for both brake and non-brake engines)
in the same manner as described above (by
installing the appropriate thickness gauge and
tightening the adjusting screw). Use a 5 mm
internal hex wrench in place of the torque
screwdriver to turn the adjusting screw. Turn the
screw clockwise until a large increase is felt,
indicating that the push rod is fully compressed
and the spring has hit the stop. At this point, valve
lash should be properly set and the adjusting
screw jam nut can be tightened to 45 lb-ft
(61 N폷m). Always recheck the adjustment by
exerting downward pressure by hand on the
adjusting screw end of the rocker arm to fully
compress the push rod while rechecking with the
thickness gauge.
5-111.bk Page 452 Monday, July 10, 2006 2:26 PM
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