Camshaft Sprocket; Hydraulic Valve Tappets; Leakdown Testing - Ford LRG-423 Service Manual

01-26
Engine Service
01-26
SERVICE PROCEDURES (Continued)
Camshaft Sprocket
Inspect camshaft sprocket for worn or broken teeth. If
necessary, remove and replace as outlined.
Hydraulic Valve Tappets
Valve tappet (6500) assemblies should be kept in
proper sequence so that they can be installed in their
original position. Inspect and test each valve tappet
separately. Do not intermix tappet positions.
If any part
of the tappet assembly is worn or otherwise
damaged, replace the entire assembly.
Cleaning
Thoroughly clean all the parts in clean solvent and
wipe them with a clean, lint-free cloth.
Inspection
Inspect the parts and discard the entire tappet/lash
adjuster assembly if any part shows pitting, scoring or
excessive wear. Replace the entire assembly if the
plunger is not free in the body. The plunger should
drop to the bottom of the body by its own weight when
assembled dry and check ball assembly removed.
Assemble the hydraulic tappet/lash adjuster assembly
and check for freeness of operation by pressing down
on the plunger. The lash adjusters can also be
checked with a hydraulic tester to test the leakdown
rate. Follow the instructions of the test unit
manufacturer or Valve Train Analysis - Dynamic,
Hydraulic Valve Tappet Leakdown Test.
Leakdown Testing
Assembled valve tappets (6500) can be tested with
Hydraulic Tappet Leakdown Tester TOOL-6500-E, or
equivalent, to check the leakdown rate. The leakdown
rate specification is the time in seconds for the plunger
to move a specified distance of its travel while under a
22.7 kg (50 lb.) load. Test the valve tappets as follows:
Remove lash adjusters or tappets.
1. NOTE: Do not mix parts from different valve
tappets (6500). Parts are select-fitted and are not
interchangeable.
NOTE: Tappets cannot be checked with engine
oil in them. Only testing fluid can be used.
Disassemble and clean valve tappet to remove
all traces of engine oil.
2. Place valve tappet in tester, with plunger facing
upward. Pour hydraulic tester fluid into cup to a
level that will cover tappet assembly. The fluid
can be purchased from tester manufacturer.
Using kerosene or any other fluid will not provide
an accurate test.
3. Place a 7.94mm (5/l 6-inch) steel ball provided
with tester in plunger cap.
A
A8507-B
4. Work tappet plunger up and down until tappet fills
with fluid and all traces of air bubbles have
disappeared.
5. Adjust length of ram so that pointer is 1.59mm
(l/l 6 inch) below starting mark when ram
contracts tappet plunger, to facilitate timing as
pointer passes Start Timing mark.
ADJUSTING NUT
HYDRAULIC TAPPET
A8508-B
Use center mark on pointer scale as Stop Timing
point instead of original Stop Timing mark at top
of scale.
6. Allow ram and weight to force tappet plunger
downward. Measure exact time it takes for
pointer to travel from Start Timing to Stop Timing
marks of tester.
7. A valve tappet that is satisfactory must have a
leakdown rate (time in seconds) within minimum
and maximum limits specified in Section 02.