Dodge Nitro. Manual — part 32

1. For rocker arm installation on cylinders No. 4, Rotate the crankshaft until cylinder No. 1 is at BDC intake

stroke.

2. For rocker arm installation on cylinder No. 1, Rotate the crankshaft until cylinder No. 1 is at BDC

combustion stroke.

3. For rocker arm installation on cylinders No. 3 and No. 5, Rotate the crankshaft until cylinder No. 1 is at

TDC exhaust stroke.

4. For rocker arm installation on cylinders No. 2 and No. 6, Rotate the crankshaft until cylinder No. 1 is at

TDC ignition stroke.

5. Using the Rocker Arm Remover/Installer 8516A (2) press downward on the valve spring, install rocker

arm. See Fig. 96.

6. Install the cylinder head cover. See INSTALLATION).

SEALS-VALVE GUIDE

DESCRIPTION

VALVE GUIDE SEALS

The valve guide seals are made of rubber and incorporate an integral steel valve spring seat. The integral garter
spring maintains consistent lubrication control to the valve stems.

SPRINGS-VALVE

DESCRIPTION

VALVE SPRINGS

The valve springs are made from high strength chrome silicon steel. There are different springs for intake and
exhaust applications. The exhaust spring has an external damper. The valve spring seat is integral with the valve
stem seal, which is a positive type seal to control lubrication.

REMOVAL

VALVE SPRINGS

1. Remove the cylinder head cover. See REMOVAL).

1 - CAMSHAFT
2 - SPECIAL TOOL 8516

CAUTION: Make sure the rocker arms are installed with the concave pocket over the

lash adjusters. Failure to do so may cause severe damage to the rocker
arms and/or lash adjusters.

NOTE:

Coat the rocker arms with clean engine oil prior to installation.

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro

2. Using the Valve Spring Remover/Installer 8516A, remove the rocker arms and the hydraulic lash

adjusters.

3. Remove the spark plug for the cylinder the valve spring and seal are to be removed from.

4. Apply shop air to the cylinder to hold the valves in place when the spring is removed.

5. Using the Valve Spring Compressor 8387, compress the valve spring.

6. Remove the two spring retainer lock halves.

7. Remove the valve spring compressor.

8. Remove the spring retainer, and the spring.

9. Remove the valve stem seal.

INSTALLATION

VALVE SPRINGS

1. Apply shop air to the cylinder to hold the valves in place while the spring is installed.

2. Install the valve stem seal.

3. Install the spring retainer, and the spring.

NOTE:

All six valve springs and seals are removed in the same manner; this
procedure only covers one valve seal and valve spring.

NOTE:

It may be necessary to tap the top of the valve spring to loosen the spring
retainers locks enough to be removed.

NOTE:

The valve spring is under tension use care when releasing the valve spring
compressor.

NOTE:

The valve springs are NOT common between intake and exhaust.

NOTE:

The valve stem seals are common between intake and exhaust.

NOTE:

All six valve springs and seals are removed in the same manner; this procedure
only covers one valve seal and valve spring.

NOTE:

The valve stem seals are common between intake and exhaust.

NOTE:

The valve springs are NOT common between intake and exhaust.

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro

4. Using Valve Spring Compressor 8387, compress the valve spring.

5. Install the two spring retainer lock halves.

6. Remove the valve spring compressor.

7. Disconnect the shop air to the cylinder.

8. Install the spark plug for the cylinder the valve spring and seal was installed on.

9. Using the Valve Spring Remover/Installer Special Tool 8516A, install the rocker arms and the hydraulic

lash adjusters.

10. Install the cylinder head cover. See INSTALLATION).

ENGINE BLOCK

DESCRIPTION

ENGINE BLOCK

The cylinder block is made of cast iron. The block is a closed deck design with the left bank forward. To
provide high rigidity and improved NVH an enhanced compacted graphite bedplate is bolted to the block. The
block design allows coolant flow between the cylinders bores, and an internal coolant bypass to a single poppet
inlet thermostat is included in the cast aluminum front cover.

STANDARD PROCEDURE

CYLINDER BORE HONING

NOTE:

The valve spring is under tension use care when releasing the valve spring
compressor.

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro

Fig. 97: Cylinder Bore Crosshatch Pattern
Courtesy of CHRYSLER LLC

Before honing, stuff plenty of clean shop towels under the bores and over the crankshaft to keep abrasive
materials from entering the crankshaft area.

1. Used carefully, the Cylinder Bore Sizing Hone C-823, equipped with 220 grit stones, is the best tool for

this job. In addition to deglazing, it will reduce taper and out-of-round, as well as removing light scuffing,
scoring and scratches. Usually, a few strokes will clean up a bore and maintain the required limits.

1 - CROSSHATCH PATTERN
2 - INTERSECT ANGLE

CAUTION: DO NOT use rigid type hones to remove cylinder wall glaze.

2007 Dodge Nitro R/T

2007 ENGINE 3.7L - Service Information - Nitro