system is functioning properly. If the ball settles in the
Use the center mark on the pointer scale as the stop
REPAIR (red) area, clean or replace the
timing point instead of the original stop timing mark
malfunctioning components as required.
at the top of the scale.
6. Repeat the test ALTER repairs are made to make
Work the valve lifter plunger up and down until the
sure that the crankcase ventilation system is
lifter fills with fluid and all traces of air bubbles have
Clean and replace the malfunctioning components as
6. Allow the ram and weight to force the valve lifter
required. Repeat the test to ensure that the crankcase
plunger downward. Measure the exact time it takes
ventilation system is operating satisfactorily.
for the pointer to travel from the start timing to the
stop timing marks on the tester.
7 .A valve lifter that is satisfactory must have a leak-
CRANKCASE VENTILATION REGULATOR VALVE
down rate (time in seconds) within the minimum and
maximum limits specified.
Install a known good regulator valve (PCV) in the
8. If the valve lifter Is not within specifications. replace it
crankcase ventilation system.
with a new lifter. It is not necessary to test a new lifter
Start the engine and compare the engine idle
before installing it in the engine.
condition to the prior Idle condition.
POSITIVE CLOSED-TYPE VENTILATION SYSTEM
If the idle condition is found to be satisfactory. use the
A malfunctioning closed crankcase ventilation system
new regulator valve and clean the hoses, fittings. etc.
may be indicated by loping or rough engine idle. Do not
If the loping or rough Idle condition remains when the
attempt to compensate for this idle condition by
good regulator valve is installed. the crankcase ventilation
disconnecting the crankcase ventilation system and
regulator valve is not at fault. Check the crankcase
making carburetor adjustments. The removal of the
,ventilation system for restriction at the intake manifold or
carburetor spacer. If the system is not restricted. further
crankcase ventilation system from the engine will
engine component diagnosis will have to be conducted to
adversely affect the fuel economy and engine
find the malfunction.
ventilation with resultant shortening of engine life. To
CRANKSHAFT END PLAY
determine whether the loping or rough idle condition is
1. Force the crankshaft toward the rear of the engine.
caused by a malfunctioning crankcase ventilation system,
2. Install a dial indicator so that the contact point rests
perform either of the following tests.
against the crankshaft flange and the indicator axis is
AIR INTAKE TEST
parallel to the crankshaft axis (Figure 7).
This test is performed with the crankcase ventilation
3. Zero the dial indicator. Push the crankshaft forward
tester C8AZ-6B627-A (Figure 6) which is operated by the
and note the reading on the dial.
engine vacuum through the oil fill opening. Follow the
4. If the end play exceeds the wear limit. replace the
procedures described below to install the tester and check
thrust washers. If the end play is less than the
the crankcase ventilation system for faulty operation.
minimum limit inspect the thrust hearing faces for
nicks, or dirt.
FIG. 6 Crankshaft Ventilation System Tester
FIG 7 Checking Crankshaft End Play
With the engine at normal operating temperature,
TIMING CHAIN DEFLECTION I. Rotate the crankshaft in
remove the oil filler cap.
a counterclockwise direction (as viewed from the front) to
Hold the tester C8AZ-6B627-A over the opening in
take up the slack on the left side of the chain.
the valve cover. Make sure the surface is flat to form
2. Establish a reference point on the block and measure
a seal between the cover and tester. If the cover is
from this point to the chain (Figure 8) 3. Rotate the
distorted, shape it as required to make an air tight
crankshaft in the opposite direction to take up the slack on
seal. An air leak between the cover and tester will
the right side of the chain. Force the left side of the chain
render the tester inoperative.
out with the fingers and measure the distance between
Start the engine and allow it to operate at the
the reference point and the chain. The deflection is the
recommended idle speed.
difference between the two measurements.
Hold the tester over the oil filler cap opening making
deflection exceeds specifications. replace the timing chain
sure that there is a positive seal between the tester
If the ball settles in the GOOD (green) area. the