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