Chrysler RAM TRUCK 2500 1994 Service Manual page 746

Fig. 13 Testing Valve Spring for Compressed
Length with Tool C-647
INSTALLATION
(1) Coat valve stems with lubrication oil and insert
them in cylinder head.
(2) If valves or seats are reground, check valve
stem height. If valve is too long, replace cylinder
head.
(3) Install new seals on all valve guides. Install
valve springs and valve retainers.
(4) Compress valve springs with Valve Spring
Compressor Tool MD-998772A, install locks and re­
lease tool. If valves and/or seats are ground, measure
the installed height of springs. Make sure the mea­
surement is taken from bottom of spring seat in cyl­
inder head to the bottom surface of spring retainer. If
spacers are installed, measure from the top of spacer.
If height is greater than 42.86 mm (1-11/16 inches),
install a 1.587 mm (1/16 inch) spacer in head coun-
terbore. This should bring spring height back to nor­
mal 41.27 to 42.86 mm (1-5/8 to 1-11/16 inch).
VALVE STEM SEAL / SPRING REPLACEMENT
This procedure is done with the cylinder head in­
stalled.
(1) Set engine basic timing to Top Dead Center
(TDC).
(2) Remove the air cleaner.
(3) Remove cylinder head covers and spark plugs.
(4) Remove coil wire from distributor and secure to
good ground to prevent engine from starting.
(5) Using suitable socket and flex handle at crank­
shaft retaining bolt, turn engine so the No.l piston is
at Top Dead Center on the compression stroke.
(6) Remove rocker arms.
(7) With air hose attached to an adapter installed
in No.l spark plug hole, apply 620-689 kPa (90-100
psi) air pressure.
(8) Using Valve Spring Compressor Tool
MD-998772A, compress valve spring and remove re­
tainer valve locks and valve spring.
(9) Install seals on the exhaust valve stem and po­
sition down against valve guides.
(10) The intake valve stem seals should be pushed
firmly and squarely over the valve guide using the
valve stem as a guide. DO NOT force seal against top
of guide. When installing the valve retainer locks,
compress the spring only enough to install the locks.
(11) Follow the same procedure on the remaining 5
cylinders using the firing sequence 1-6-5-4-3-2. Make
sure piston in cylinder is at TDC on the valve spring
that is being removed.
(12) Remove adapter from the No.l spark plug
hole.
(13) Install rocker arms.
(14) Install covers and coil wire to distributor.
(15) Install air cleaner.
(16) Road test vehicle.
HYDRAULIC TAPPETS
Before disassembling any part of the engine to cor­
rect tappet noise, check the oil pressure. If vehicle
has no oil pressure gauge, install a reliable gauge at
the pressure sending unit. The pressure should be
between 207-552 kPa (30-80 psi) at 3,000 RPM.
Check the oil level after the engine reaches normal
operating temperature. Allow 5 minutes to stabilize
oil level, check dipstick.
The oil level in the pan should never be above the
F U L L mark or below the ADD OIL mark on dipstick.
Either of these 2 conditions could be responsible for
noisy tappets.
OIL LEVEL
HIGH
If oil level is above the F U L L mark, it is possible
for the connecting rods to dip into the oil. With the
engine running, this condition could create foam in
the oil pan. Foam in oil pan would be fed to the hy­
draulic tappets by the oil pump causing them to lose
length and allow valves to seat noisily.
LOW
Low oil level may allow oil pump to take in air.
When air is fed to the tappets, they lose length which
allows valves to seat noisily. Any leaks on intake side
of oil pump through which air can be drawn will cre­
ate the same tappet action. Check the lubrication
system from the intake strainer to the pump cover,
including the relief valve retainer cap. When tappet
noise is due to aeration, it may be intermittent or
constant, and usually more than 1 tappet will be
noisy. When oil level and leaks have been corrected,
operate the engine at fast idle. Run engine for a suf­
ficient time to allow all of the air inside the tappets
to be bled out.