Dodge Nitro. Manual - part 42

Fig. 122: Ring End Gap Measurement 
Courtesy of CHRYSLER LLC 

Before reinstalling used rings or installing new rings, the ring clearances must be checked. 

1. Wipe the cylinder bore clean.  

2. Insert the ring in the cylinder bore. 

3. Using a piston, to ensure that the ring is squared in the cylinder bore, slide the ring downward into the 

cylinder.  

4. Using a feeler gauge (1) check the ring end gap. Replace any rings not within specification. 

1 - FEELER GAUGE

NOTE:

The ring gap measurement must be made with the ring positioned at least 
12mm (0.50 inch.) from bottom of cylinder bore.

 

2007 Dodge Nitro R/T 

2007 ENGINE 3.7L - Service Information - Nitro

  

Fig. 123: Measuring Piston Ring Side Clearance 
Courtesy of CHRYSLER LLC 

PISTON RING SIDE CLEARANCE  

5. Measure the ring side clearance as shown make sure the feeler gauge (1) fits snugly between the ring land 

and the ring. Replace any ring not within specification.  

6. Rotate the ring around the piston, the ring must rotate in the groove with out binding. 

1 - FEELER GAUGE

NOTE:

Make sure the piston ring grooves are clean and free of nicks and burrs.

 

2007 Dodge Nitro R/T 

2007 ENGINE 3.7L - Service Information - Nitro

  

PISTON RING SPECIFICATION CHART

Ring Position 

Groove Clearance 

Maximum 

Clearance 

Upper Ring

0.051 - 0.094 mm

0.11 mm

 

(0.0020 - 0.0037 

in.)

(0.004 in.)

Intermediate Ring

0.04 - 0.08 mm

0.10 mm

 

(0.0016 - 0.0031 

in.)

(0.004 in.)

Oil Control Ring

0.019 - 0.229 mm

0.25 mm

(Steel Rails)

(0.0007-.0090 in.)

(0.010 in.)

Ring Position 

Ring Gap 

Wear Limit 

Upper Ring

0.20 - 0.36 mm

0.43 mm

-

(0.0079 - 0.0142 

in.)

(0.0017 in.)

Intermediate Ring

0.37 - 0.63 mm

0.74 mm

-

(0.0146 - 0.0249 

in.)

(0.029 in.)

Oil Control Ring

0.025 - 0.76 mm

1.55 mm

(Steel Rail)

(0.0099 - 0.03 in.)

(0.061 in.)

 

2007 Dodge Nitro R/T 

2007 ENGINE 3.7L - Service Information - Nitro

  

Fig. 124: Side Rail - Installation 
Courtesy of CHRYSLER LLC 

7. The No. 1 and No. 2 piston rings have a different cross section. Ensure No. 2 ring is installed with 

manufacturers I.D. mark (Dot) facing up, towards top of the piston. 

8. Install the oil ring expander.  

9. Install upper side rail (1) by placing one end between the piston ring groove and the expander ring. Hold 

end firmly and press down the portion to be installed until side rail is in position. Repeat this step for the 
lower side rail. 

1 - SIDE RAIL END

NOTE:

Piston rings are installed in the following order: 

Oil ring expander.  

Upper oil ring side rail.  

Lower oil ring side rail.  

No. 2 Intermediate piston ring.  

No. 1 Upper piston ring.  

 

2007 Dodge Nitro R/T 

2007 ENGINE 3.7L - Service Information - Nitro