Dodge Nitro. Manual - part 20

1. Using a suitable dial indicator measure the center of the valve seat. Total run out must not exceed 0.051 

mm (0.002 in).  

2. Apply a small amount of Prussian blue to the valve seat, insert the valve into the cylinder head, while 

applying light pressure on the valve rotate the valve. Remove the valve and examine the valve face. If the 
blue is transferred below the top edge of the valve face, lower the valve seat using a 15 degree stone. If 
the blue is transferred to the bottom edge of the valve face, raise the valve seat using a 65 degree stone.  

3. When the seat is properly positioned the width of the intake seat must be 1.75 - 2.36 mm (0.0689 - 0.0928 

in.) and the exhaust seat must be 1.71 - 2.32 mm (0.0673 - 0.0911 in.).  

4. Check the valve spring (6) installed height after refacing the valve and seat. The installed height for both 

intake and exhaust valve springs must not exceed 40.74 mm (1.6039 in.)  

5. The valve seat and valve face must maintain a face angle of 44.5 - 45° angle.  

REMOVAL 

VALVES AND VALVE SPRINGS 

5 - EXHAUST VALVE
6 - VALVE SPRING

NOTE:

Valve seats that are worn or burned can be reworked, provided that correct 
angle and seat width are maintained. Otherwise the cylinder head must be 
replaced.

NOTE:

When refacing valves (4) and valve seats, it is important that the correct size 
valve guide pilot be used for reseating stones. A true and complete surface 
must be obtained.

 

2007 Dodge Nitro R/T 

2007 ENGINE 3.7L - Service Information - Nitro

  

Fig. 63: Removing/Installing Rocker Arm 
Courtesy of CHRYSLER LLC 

1. Remove rocker arms and lash adjusters. See REMOVAL.  

2. Remove the camshaft bearing caps and the camshaft. 

1 - CAMSHAFT
2 - VALVE SPRING COMPRESSOR 10102

NOTE:

The cylinder heads must be removed in order to perform this procedure.

NOTE:

All valve springs and valves are removed in the same manner; this 

 

2007 Dodge Nitro R/T 

2007 ENGINE 3.7L - Service Information - Nitro

  

3. Using Valve Spring Compressor C-3422-B or C-3422-C and Adapter 8519, compress the valve spring. 

4. Remove the two spring retainer lock halves. 

5. Remove the valve spring compressor.  

6. Remove the spring retainer, and the spring. 

7. Remove the valve from the cylinder head. 

8. Remove the valve stem seal. Mark the valve for proper installation.  

TESTING VALVE SPRINGS 

procedure only covers one valve 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:

Check for sharp edges on the keeper grooves. Remove any burrs from the 
valve stem before removing the valve from the cylinder head.

NOTE:

The valve stem seals are common between intake and exhaust.

 

2007 Dodge Nitro R/T 

2007 ENGINE 3.7L - Service Information - Nitro

  

Fig. 64: Testing Valve Spring 
Courtesy of CHRYSLER LLC 

Inspect the valve springs for physical signs of wear or damage. Turn table of tool C-647 (1) until surface is in 
line with the 40.12 mm (1.579 in.) mark on the threaded stud and the zero mark on the front. Place spring over 
the stud on the table and lift compressing lever to set tone device. Pull on torque wrench until a Ping is heard. 
Take reading on torque wrench at this instant. Multiply this reading by two. This will give the spring load at test 
length. Fractional measurements are indicated on the table for finer adjustments. Refer to SPECIFICATIONS 
to obtain specified height and allowable tensions. Replace any springs that do not meet specifications.

1 - SPECIAL TOOL C-647

NOTE:

Whenever the valves are removed from the cylinder head it is recommended 
that the valve springs be inspected and tested for reuse.

 

2007 Dodge Nitro R/T 

2007 ENGINE 3.7L - Service Information - Nitro