TAPPETS - HYDRAULIC ROLLER
DIAGNOSIS AND TESTING - HYDRAULIC TAPPETS
Before disassembling any part of the engine to correct tappet noise, checkthe 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
(30-70 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 FULL mark or below the ADD OIL mark on
dipstick. Either of these two conditions could be responsible for noisy tappets.
OIL LEVEL
HIGH
If oil level is above the FULL mark, it is possible for the connecting rods todip 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 hydraulic 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 bedrawn will create 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 one tappet will
be noisy. When oil level and leaks have been corrected, operate the engine at fast idle. Run engine for a sufficient
time to allow all of the air inside the tappets to be bled out.
TAPPET NOISE DIAGNOSIS
1. To determine source of tappet noise, crank over engine with cylinder head covers removed.
2. Feel each valve spring or rocker arm to detect noisy tappet. The noisy tappet will cause the affected spring
and/or rocker arm to vibrate or feel rough in operation.
NOTE: Worn valve guides or cocked springs are sometimes mistaken for noisytappets. If such is the case,
noise may be dampened by applying side thrust on the valve spring. If noise is not appreciably reduced, it
can be assumed the noise is in the tappet. Inspect the rocker arm push rod sockets and push rod ends for
wear.
3. Valve tappet noise ranges from light noise to a heavy click. A light noiseis usually caused by excessive leak-
down around the unit plunger, or by the plunger partially sticking in the tappet body cylinder. The tappet should
be replaced. A heavy click is caused by a tappet check valve not seating, or by foreign particles wedged between
the plunger and the tappet body. This will cause the plunger to stick in the down position. This heavy click will be
accompanied by excessive clearance between the valve stem and rocker arm as valve closes. In either case,
tappet assembly should be removed for inspection and cleaning.
4. The valve train generates a noise very much like a light tappet noise during normal operation. Care must be
taken to ensure that tappets are making the noise. If more than one tappet seems to be noisy, it’s probably not
the tappets.
REMOVAL
1. Disconnect the negative cable from the battery.
2. Remove the air cleaner (Refer to 9 - ENGINE/AIR INTAKE SYSTEM - REMOVAL).
3. Remove intake manifold (Refer to 9 - ENGINE/MANIFOLDS/INTAKE MANIFOLD-REMOVAL).
4. Remove cylinder head cover (Refer to 9 - ENGINE/CYLINDER HEAD/CYLINDERHEAD COVER(S) -
REMOVAL).
5. Remove rocker arm assembly and push rods (Refer to 9 - ENGINE/CYLINDER HEAD/ROCKER ARM /
ADJUSTER ASSY - REMOVAL). Identify push rods to ensure installation in original location.
6. Remove the cylinder head (Refer to 9 - ENGINE/CYLINDER HEAD - REMOVAL).
CAUTION: 5.7L engines equipped with MDS uses both standard roller tappetsand deactivating roller tap-
pets, for use with the Multi Displacement System. The deactivating rollertappets must be used in cylinders
1,4,6,7. The deactivating tappets can be identified by the two holes in theside of the tappet body, for the
latching pins.
2. Install tappets in their original positions.
3. Install tappet retainer (1). Install the tappet retainer bolt and tighten to 12 Nꞏm (106 in. lbs.) torque.
4. Install cylinder head (Refer to 9 - ENGINE/CYLINDER HEAD - INSTALLATION).
5. Install pushrods and rocker arm assembly (Refer to 9 - ENGINE/CYLINDER HEAD/ROCKER ARM / ADJUSTER
ASSY - INSTALLATION).
6. Install cylinder head cover (Refer to 9 - ENGINE/CYLINDER HEAD/CYLINDER HEAD COVER(S) - INSTALLA-
TION).
7. Install intake manifold (Refer to 9 - ENGINE/MANIFOLDS/INTAKE MANIFOLD-INSTALLATION).
8. Install the air cleaner (Refer to 9 - ENGINE/AIR INTAKE SYSTEM - INSTALLATION).
9. Connect the negative cable to the battery.
CAUTION: To prevent damage to valve mechanism, engine must not be run abovefast idle until all hydrau-
lic tappets have filled with oil and have become quiet.
10. Road test vehicle and check for leaks.
4. The coating material is applied to the piston after
the final piston machining process. Measuring the
outside diameter of a coated piston will not provide
accurate results. Therefore measuring the inside
diameter of the cylinder bore with a dial Bore
Gauge isMANDATORY. To correctly select the
proper size piston, a cylinder bore gauge capable
of reading in 0.003 mm (.0001 in.) increments is
required.
5. Piston installation intothe cylinder bore requires
slightly more pressure than that required for non-
coated pistons. The bonded coating on the piston
will give the appearance of a line-to-line fit with the
cylinder bore.
REMOVAL
1. Disconnect negative cable from battery.
2. Remove the following components:
Oil pan and gasket/windage tray (Refer to 9 - ENGINE/LUBRICATION/OIL PAN -REMOVAL).
Cylinder head covers (Refer to 9 - ENGINE/CYLINDER HEAD/CYLINDER HEAD COVER(S) - REMOVAL) and
(Refer to 9 - ENGINE/CYLINDER HEAD/CYLINDER HEAD COVER(S) - REMOVAL).
Timing chain cover (Refer to 9 - ENGINE/VALVE TIMING/TIMING BELT / CHAIN COVER(S) - REMOVAL).
Cylinder head(s) (Refer to 9 - ENGINE/CYLINDER HEAD - REMOVAL) and (Refer to 9 - ENGINE/CYLINDER
HEAD - REMOVAL).
3. If necessary, remove top ridge of cylinder bores with a reliable ridge reamer before removing pistons from cyl-
inder block.Be sure to keep tops of pistons covered during this operation.Pistons and connecting rods
must be removed from top of cylinder block. When removing piston and connecting rod assemblies from the
engine, rotate crankshaft so the each connecting rod is centered in cylinder bore.
CAUTION: DO NOT use a number stamp or a punch to mark connecting rods or caps,as damage to con-
necting rods could occur
NOTE: Connecting rods and bearing caps are not
interchangeable and should be marked before
removing to ensure correct reassembly.
4. Mark connecting rod and bearing cap positions
using a permanent ink marker or scribe tool.
CAUTION: Care must be taken not to damage the
fractured rod and cap joint face surfaces, as
engine damage may occur.
5. Remove connecting rod cap. Install Special Tool 8507 Connecting Rod Guides into the connecting rod being
removed. Remove piston from cylinder bore. Repeat this procedure for eachpiston being removed.
CAUTION: Care must be taken not to nick crankshaft journals, as engine damage may occur
6. Immediately after piston and connecting rod removal, install bearing cap on the mating connecting rod to prevent
damage to the fractured cap and rod surfaces.
7. Carefully remove piston rings from piston(s), starting from the top ring down.
CLEANING
CAUTION: DO NOT use a wire wheel or other abrasive cleaning devise to clean the pistons or connecting
rods. The pistons have a Moly coating, this coating must not be damaged.
1. Using a suitable cleaning solvent clean the pistons in warm water and towel dry.
2. Use a wood or plastic scraper to clean the ring land grooves.
CAUTION: DO NOT remove the piston pin from the piston and connecting rod assembly.
INSPECTION
Check the connecting rod journal for excessive wear, taper and scoring (Refer to 9 - ENGINE/ENGINE BLOCK/
CONNECTING ROD BEARINGS - STANDARD PROCEDURE).
Check the connecting rod for signs of twist or bending.
Check the piston for taper and elliptical shape before it is fitted into thecylinder bore (Refer to 9 - ENGINE/ENGINE
BLOCK/PISTON & CONNECTING ROD - STANDARD PROCEDURE).
Check the piston for scoring, or scraping marks in the piston skirts. Checkthe ring lands for cracks and/or deteri-
oration.
INSTALLATION
1. Before installing piston and connecting rod assemblies into the bore, install the piston rings (Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON RINGS - STANDARD PROCEDURE).
2. Immerse the piston head and rings in clean engine oil. Position a ring compressor over the piston and rings.
Tighten ring compressor.Ensure position of rings do not change during this operation.
3. Position bearing onto connecting rod. Lubricate bearing surface with clean engine oil.
4. Install Special Tool 8507 Connecting Rod Guides into connecting rod bolt threads.
5. The pistons are marked on the piston pin bore sur-
face with an raised “F” or arrow on top of piston
indicating installation position. This mark must be
pointing toward the front of engine on both cylinder
banks.
6. Wipe cylinder bore clean and lubricate with engine
oil.
7. Rotate crankshaft until connecting rod journal is on the center of cylinder bore. Insert rod and piston into cylinder
bore and carefully position connecting rod guides over crankshaft journal.
8. Tap piston down in cylinder bore using a hammer handle. While at the same time, guide connecting rod into
position on rod journal.
CAUTION: Connecting Rod Bolts are Torque to Yield Bolts and Must Not Be Reused. Always replace the
Rod Bolts whenever they are loosened or removed.
9. Lubricate rod bolts and bearing surfaces with engine oil. Install connecting rod cap and bearing. Tighten bolts to
21 Nꞏm (15 ft. lbs.) plus a 90° turn.
10. Install the following components:
Cylinder head(s). (Refer to 9 - ENGINE/CYLINDER HEAD - INSTALLATION).
Cylinderheadcovers(Referto9-ENGINE/CYLINDER HEAD/CYLINDER HEAD COVER(S) - INSTALLA-
TION).
Install the intake manifold.
Oil pan and gasket/windage tray. (Refer to 9 - ENGINE/LUBRICATION/OIL PAN- INSTALLATION).
11. Fill crankcase with proper engine oil to correct level.
12. Connect negative cable to battery.
DAMPER - CRANKSHAFT
REMOVAL
1. Disconnect negative cable from battery.
2. Remove accessory drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS - REMOVAL).
3. Drain cooling system (Refer to 7 - COOLING - STANDARD PROCEDURE).
4. Remove radiator upper hose.
5. Removefanshroud(Referto7-COOLING/ENGINE/RADIATOR FAN - REMOVAL).
6. Remove crankshaft damper bolt.
7. Remove damper using Special Tools 8513A Insert
and 1023 Three Jaw Puller.
INSTALLATION
CAUTION: To prevent severe damage to the Crank-
shaft, Damper or Special Tool 8512–A, thoroughly
clean the damper bore and the crankshaft nose
before installing Damper.
1. Slide damper onto crankshaft slightly.
CAUTION: Special Tool 8512–A, is assembled in a
specific sequence. Failure to assemble this tool in
this sequence can result in tool failure and severe
damage to either the tool or the crankshaft.
2. Assemble Special Tool 8512–A as follows, The nut
is threaded onto the shaft first (2). Then the roller
bearing (1) is placed onto the threaded rod (3) The
hardened bearing surface of the bearing (1)MUST
face the nut (2). Then the hardened washer (5)
slides onto the threaded rod (3). Once assembled coat the threaded rod’s threads with Mopar
Nickel Anti-Seize
or (Loctite No. 771).
3. Using Special Tool 8512–A, press damper onto crankshaft.
4. Install then tighten crankshaft damper bolt to 176 Nꞏm (129 ft. lbs.).
5. Install radiator upper hose.
COVER - STRUCTURAL
DESCRIPTION
The structural dust cover is made of die cast aluminum and joins the lower half of the transmission bell housing to
the engine.
OPERATION
The structural cover provides additional powertrain stiffness and reduces noise and vibration.
REMOVAL
1. Raise vehicle on hoist.
CAUTION: On manual transmission vehicles, the
7/16 inch engine block to clutch housing bolts
must be loosened before removal of the structural
dust cover (1). Clutch housing distortion will occur
if this procedure is not followed.
2. Remove the bolts retaining structural cover (1,2).
3. Remove the structural cover.