2006 DODGE RAM SRT-10 wheel

VALVE TIMING
DESCRIPTION
The timing drive system has been designed to provide quiet performance andreliability to support anon-free
wheelingengine. Specifically the intake valves are non-free wheeling and can be easily damaged with forceful
engine rotation if camshaft-to-crankshaft timing is incorrect. The timing drive system consists of a primary chain (6),
two secondary timing chain drives (1,4) and a counterbalance shaft drive.
OPERATION
The primary timing chain is a single inverted tooth chain type. The primarychaindrivesthelarge50toothidler
sprocket directly from a 25 tooth crankshaft sprocket. Primary chain motion is controlled by a pivoting leaf spring
tensioner arm and a fixed guide. The arm and the guide both use nylon plasticwear faces for low friction and long
wear. The primary chain receives oil splash lubrication from the secondary chain drive and designed oil pump leak-
age. The idler sprocket assembly connects the primary chain drive, secondary chain drives, and the counterbalance
shaft. The idler sprocket assembly consists of two integral 26 tooth sprockets a 50 tooth sprocket and a helical gear
that is press-fit to the assembly. Thespline joint for the 50 tooth sprocket is a non serviceable press fit anti rattle
type. A spiral ring is installed on the outboard side of the 50 tooth sprocket to prevent spline disengagement. The
idler sprocket assembly spins on a stationary idler shaft. The idler shaftis a light press-fit into the cylinder block. A
large washer on the idler shaft bolt and the rear flange of the idler shaft are used to control sprocket thrust move-
ment. Pressurized oil is routed through the center of the idler shaft to provide lubrication for the two bushings used
in the idler sprocket assembly.
There are two secondary drive chains, both are roller type, one to drive thecamshaft in each SOHC cylinder head.
There are no shaft speed changes in the secondary chain drive system. Each secondary chain drives a 26 tooth
cam sprocket directly from the 26 tooth sprocket on the idler sprocket assembly. A fixed chain guide and a hydraulic
oil damped tensioner are used to maintain tension in each secondary chain system. The hydraulic tensioners for the
secondary chain systems are fed pressurized oil from oil reservoir pockets in the block. Each tensioner incorporates
a controlled leak path through a device known as a vent disc located in the nose of the piston to manage chain

loads. Each tensioner also has a mechanical ratchet system that limits chain slack if the tensioner piston bleeds
down after engine shut down. The tensioner arms and guides also utilize nylon wear faces for low friction and long
wear. The secondary timing chains receive lubrication from a small orifice in the tensioners. This orifice is protected
from clogging by a fine mesh screen which is located on the back of the hydraulic tensioners.
STANDARD PROCEDURE
MEASURING TIMING CHAIN WEAR
NOTE: This procedure must be performed with the
timing chain cover removed.
1. Remove the timing chain cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT/CHAIN
AND SPROCKETS - REMOVAL).
2. To determine if the secondary timing chains are
worn, rotate the engine clockwise until maximum
tensioner piston (2) extension is obtained. Measure
the distance between the secondary timing chain
tensioner housing and the step ledge on the piston.
The measurement at point (A) must be less than
15mm (.5906 inches).
3. If the measurement exceeds the specification the
secondary timing chains are worn and require
replacement (Refer to 9 - ENGINE/VALVE TIMING/
TIMING BELT/CHAIN AND SPROCKETS -
REMOVAL).
SERVICE PROCEDURE - TIMING VERIFICATION
CAUTION: The 3.7L is a non free-wheeling design
engine. Therefore, correct engine timing is critical.
NOTE:Componentsreferredtoaslefthandor
right hand are as viewed from the drivers position
inside the vehicle.
NOTE: The blue link plates on the chains and the
dots on the camshaft drive sprockets may not line
up during the timing verification procedure. The
blue link plates are lined up with the sprocket dots
only when re-timing the complete timing drive.
Once the timing drive is rotated blue link-to-dot
alignment is no longer valid.
Engine base timing can be verified by the following
procedure:
1. Remove the cylinder head covers. Refer to the pro-
cedure in this section.

INSTALLATION
CAUTION: Do not use oil based liquids to clean
timing cover or block surfaces. Use only rubbing
alcohol, along with plastic or wooden scrapers.
Use no wire brushes or abrasive wheels or metal
scrapers, or damage to surfaces could result.
1. Clean timing chain cover and block surface using
rubbing alcohol.
CAUTION: The 3.7L uses a special anerobic sealer
instead of a gasket to seal the timing cover to the
engine block, from the factory. For service repairs,
Mopar
Engine Grey RTV must be used as a sub-
stitute.
2. Inspect the water passage o-rings for any damage,
and replace as necessary.
3. Apply Mopar
Grey Engine RTV sealer (3) to front
cover(1)followingthepathprovidedusinga3to
4mm thick bead (3).
4. Install cover. Tighten fasteners in sequence as
showninto58Nꞏm(43ft.lbs.).
5. Install crankshaft damper (Refer to 9 - ENGINE/
ENGINE BLOCK/VIBRATION DAMPER - INSTAL-
LATION).
6. Install the A/C compressor (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/A/C COM-
PRESSOR - INSTALLATION).
7. Install the generator (Refer to 8 - ELECTRICAL/
CHARGING/GENERATOR - INSTALLATION).
8. Install accessory drive belt tensioner assembly
(Refer to 7 - COOLING/ACCESSORY DRIVE/BELT
TENSIONERS - INSTALLATION).
9. Install radiator upper and lower hoses.
10. Install both heater hoses.
11. Install electric fan shroud and viscous fan drive
assembly (Refer to 7 - COOLING/ENGINE/FAN
DRIVE VISCOUS CLUTCH - INSTALLATION).
12. Fill cooling system (Refer to 7 - COOLING - STANDARD PROCEDURE).
13. Connect the battery negative cable.

CAUTION: Care should be taken not to damage
camshaft target wheel. Do not hold target wheel
while loosening or tightening camshaft sprocket.
Do not place the target wheel near a magnetic
source of any kind. A damaged or magnetized tar-
get wheel could cause a vehicle no start condition.
CAUTION: Do not forcefully rotate the camshafts
or crankshaft independently of each other. Damag-
ing intake valve to piston contact will occur.
Ensure negative battery cable is disconnected to
guard against accidental starter engagement.
13. Remove left and right camshaft sprocket bolts.
14. While holding the left camshaft steel tube with
Special Tool 8428 Camshaft Wrench (2), remove
the left camshaft sprocket. Slowly rotate the cam-
shaft approximately 5 degrees clockwise to a neu-
tral position.
15. While holding the right camshaft steel tube with
Special Tool 8428 Camshaft Wrench (2), remove
the right camshaft sprocket.
16. Remove idler sprocket assembly bolt.
17. Slide the idler sprocket assembly and crank sprocket forward simultaneously to remove the primary and sec-
ondary chains.
18. Remove both pivoting tensioner arms and chain guides.
19. Remove primary chain tensioner.
INSPECTION
Inspect the following components:
Sprockets for excessive tooth wear. Some tooth markings are normal and nota cause for sprocket replace-
ment.
Idler sprocket assembly bushing and shaft for excessive wear.
Idler sprocket assembly spline joint. The joint should be tight with no backlash or axial movement.
Chain guides and tensioner arms. Replace these parts if grooving in plasticfaceismorethan1mm(0.039in.)
deep. If plastic face is severely grooved or melted, the tensioner lube jetmay be clogged. The tensioner
should be replaced.
Secondary chain tensioner piston and ratcheting device. Inspect for evidence of heavy contact between ten-
sioner piston and tensioner arm. If this condition exist the tensioner tensioner arm and chain should be
replaced.
Primary chain tensioner plastic faces. Replace as required.

DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - MECHANICAL
CONDITION POSSIBLE CAUSES CORRECTIONS
NOISY VALVES 1. High or low oil level in
crankcase.1. (Refer to LUBRICATION &
MAINTENANCE -
SPECIFICATIONS)
2. Thin or diluted oil. 2. Change oil and filter.
3. Low oil pressure. 3. Check oil pump, if Ok, check rod
and main bearings for excessive
wear.
4. Dirt in lash adjusters. 4. Replace as necessary.
5. Worn rocker arms. 5. Replace as necessary.
6. Worn lash adjusters 6. Replace as necessary.
7. Worn valve guides. 7. (Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES
& SEATS - STANDARD
PROCEDURE)
8. Excessive runout of valve seats
on valve faces.8. (Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES
& SEATS - STANDARD
PROCEDURE)
CONNECTING ROD NOISE 1. Insufficient oil supply. 1. (Refer to LUBRICATION&
MAINTENANCE -
SPECIFICATIONS)
2. Low oil pressure. 2. Check oil pump, if Ok, check rod
and main bearings for excessive
wear.
3. Thin or diluted oil. 3. Change oil and filter.
4. Excessive bearing clearance. 4. Replace as necessary.
5. Connecting rod journal
out-of-round.5. Service or replace crankshaft.
6. Misaligned connecting rods. 6. Replace bent connecting rods.
MAIN BEARING NOISE 1. Insufficient oil supply. 1. (Refer to LUBRICATION &
MAINTENANCE -
SPECIFICATIONS)
2. Low oil pressure. 2. Check oil pump, if Ok, check rod
and main bearings for excessive
wear.
3. Thin or diluted oil. 3. Change oil and filter.
4. Excessive bearing clearance. 4. Replace as necessary.
5. Excessive end play. 5. Check thrust washers for wear.
6. Crankshaft journal out-of round. 6. Service or replace crankshaft.
7. Loose flywheel or torque
converter.7. Tighten to correct torque
DIAGNOSIS AND TESTING - CYLINDER COMPRESSION PRESSURE
The results of a cylinder compressionpressure test can be utilized to diagnose several engine malfunctions.

18. Remove the cylinder head access plug (1).
19. Remove the right side secondary chain guide
(Refer to 9 - ENGINE/VALVE TIMING/TIMING
BELT/CHAIN AND SPROCKETS - REMOVAL).
20. Remove the retaining bolt and the camshaft drive
gear.
CAUTION: Do not allow the engine to rotate.
severe damage to the valve train can occur.
CAUTION: Do not overlook the four smaller bolts
at the front of the cylinder head. Do not attempt to
remove the cylinder head without removing these
four bolts.
CAUTION: Do not hold or pry on the camshaft tar-
get wheel for any reason. A damaged target wheel
can result in a vehicle no start condition.
NOTE: The cylinder head is attached to the cylin-
der block with fourteen bolts.
21. Remove the cylinder head retaining bolts using
the sequence provided.
22. Remove the cylinder head and gasket. Discard the gasket.
CAUTION: Do not lay the cylinder head on its gasket sealing surface, do to the design of the cylinder head
gasket any distortion to the cylinder head sealing surface may prevent thegasket from properly sealing
resulting in leaks.
CLEANING
To ensure engine gasket sealing, proper surface preparation must be performed, especially with the use of alumi-
num engine components. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
INSPECTION
1. Inspect the cylinder head for out-of-flatness, using a straightedge and a feeler gauge. If tolerances exceed
0.0508 mm (0.002 in.) replace the cylinder head.
2. Inspect the valve seats for damage. Service the valve seats as necessary.
3. Inspect the valve guides for wear, cracks or looseness. If either condition exist, replace the cylinder head.

CAUTION: Do not hold or pry on the camshaft target wheel (Located on the right side camshaft sprocket)
for any reason, Severe damage will occur to the target wheel resulting in a vehicle no start condition.
4. Loosen butDO NOTremove the camshaft sprocket retaining bolt. Leave the bolt snug against the sprocket.
NOTE: The timing chain tensioners must be secured prior to removing the camshaft sprockets. Failure to
secure tensioners will allow the tensioners to extend, requiring timing chain cover removal in order to reset
tensioners.
CAUTION: Do not force wedge past the narrowest point between the chain strands. Damage to the tension-
ers may occur.
5. Position Special Tool 8350 (4) timing chain wedge between the timing chain strands, tap the tool to securely
wedge the timing chain against the tensioner arm and guide.
NOTE: When gripping the camshaft, place the pli-
ers on the tube portion of the camshaft only. Do
not grip the lobes or the sprocket areas.
6. Hold the camshaft (3) with adjustable pliers (2)
while removing the camshaft sprocket bolt and
sprocket (1).
7. Using the pliers, gently allow the camshaft to rotate
15° clockwise until the camshaft is in the neutral
position (no valve load).

CAUTION: Do not hold or pry on the camshaft tar-
get wheel for any reason, Severe damage will
occur to the target wheel. A damaged target wheel
could cause a vehicle no start condition.
4. Loosen butDO NOTremove the camshaft sprocket
retaining bolt (2). Leave bolt snug against sprocket
(3).
NOTE: The timing chain tensioners must be secured prior to removing the camshaft sprockets. Failure to
secure tensioners will allow the tensioners to extend, requiring timing chain cover removal in order to reset
tensioners.
CAUTION: Do not force wedge (3) past the narrowest point between the chain strands. Damage to the ten-
sioners may occur.
5. Position Special Tool 8350 timing chain wedge (3) between the timing chain strands. Tap the tool to securely
wedge the timing chain against the tensioner arm and guide.