CHRYSLER SERVICE MANUAL
ENGINE—17
NOTE:
If valves and/or seats are reground,
check the installed height of springs. Make sure
measurement is taken from full depth of coun-
terbore in cylinder head to bottom surface of
spring retainer. (If spacers are installed meas-
ure from top of spacer). If height is greater
than 1 11/16 inches, install a 1/16 inch spacer
(Part No. 1400482) in head counterbore to
bring spring height back to normal 1 5/8 to
1 11/16 inch.
15.
HYDRAULIC TAPPETS
a. Preliminary to Checking Hydraulic Tappets
Before disassembling any part of engine to
check for tappet noise, check oil pressure at
gauge and oil level in oil pan. The pressure
should be between 40 to 65 pounds at 2,000
r.p.m. The oil level in pan should never be
above "full" mark on dip stick, nor below "add
oil" mark. Either of two conditions could be
responsible for noisy tappets.
Oil Level Too High—If oil level is above
"full" mark on dip stick, it is possible the con-
necting rods can dip into oil when engine is
running and create foaming. This foam is fed
to the hydraulic tappets by the oil pump, caus-
ing them to go flat and allowing valves to seat
noisily.
Oil Level Too Low—Low oil level may allow
pump to take in air which, when fed to tappets,
causes them to lose length and allows valves to
seat noisily. Any leaks on intake side of pump
through which air can be drawn will create the
same tappet action. When tappet noise is due
to aeration, it may be intermittent or constant,
and usually more than one tappet will be noisy.
When oil level leaks have been corrected, the
engine should run at fast idle for sufficient time
to allow all of air inside of tappets to be worked
out.
b.
Tappet Noises
To determine source of tappet noise, run en-
gine at idle with cylinder head covers removed.
Feel each valve spring to detect the noisy
tappet.
NOTE:
Worn valve guides or cocked springs
are sometimes mistaken for noisy tappets. If
such is the case, noise may be dampened by ap-
plying side thrust on valve spring. Inspect rock-
er arm push rod sockets and push rod ends for
wear. If noise is not appreciably reduced, it can
be assumed the noise is in the tappet.
Valve tappet noise can be separated into two
types,
light noise and heavy noise. A light noise
is usually caused by excessive leakdown around
the unit plunger, or by plunger partially stick-
ing in cylinder. A heavy noise is caused either
by a tappet check valve not seating, or by for-
eign particles becoming wedged between plung-
er and tappet body, causing plunger to stick
in down position. This heavy noise will be fur-
ther evidenced by clearance between valve stem
and rocker arm as valve closes. In either in-
stance, the unit assembly should be removed
for inspection and cleaning.
c. Removal of Tappets (with Rocker Anns In
Position)
NOTE:
If all of tappets are to be removed, it
will be advisable to remove rocker arms and
shaft. If only one or two tappets are to be re-
moved, proceed as follows:
Install valve spring compression Tool C-3024,
over rocker arm (Fig. 22) so heel of tool rests
on valve stem side. Make certain valve is seated
and tappet body is resting on low point of cam-
shaft lobe. Refer to Paragraph 17, "Locating
the Low Point of Camshaft Lobe in Conjunc-
tion with Valve Tappet Face." Using handle
TOOL C-3024
Fig.
22—Compressing Valve Spring (FirePower)
(Typical of SpitFire)
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