Piston Ring

WARNING: This page is about a different car, the 2006 Subaru Outback. However, it is still accessible from the selected car via links, so may be relevant.

If the piston ring is broken, damaged or worn, or if its tension is insufficient, or when the piston is replaced, replace the piston ring with a new part of the same size as piston.
CAUTION:
- Marks are displayed on the end of top and second rings. When installing the ring to piston, face this mark upward.
- Oil ring consists of the upper rail, expander and lower rail. When installing on the piston, be careful of the direction of each rail
  
  Fig 1: Identifying Piston Ring

Squarely place the piston ring and oil ring in cylinder, and measure the piston ring gap with a thickness gauge.

PISTON RING GAP SPECIFICATION

		Standard mm (in)
Piston ring gap	Top ring	0.20 - 0.35 (0.0079 - 0.0138)
	Second ring	0.35 - 0.50 (0.0138 - 0.0197)
	Oil ring	0.20 - 0.60 (0.0079 - 0.0236)

Fig 2: Identifying Piston Ring And Oil Ring

Measure the clearance between piston ring and piston ring groove with a thickness gauge.

NOTE: Before measuring the clearance, clean the piston ring groove and piston ring.

PISTON RING SPECIFICATION

		Standard mm (in)
Clearance between piston ring and piston ring groove	Top ring	0.040 - 0.080 (0.0016 - 0.0031)
Clearance between piston ring and piston ring groove	Second ring	0.030 - 0.070 (0.0012 - 0.0028)
Clearance between oil ring and oil ring groove		0.045 - 0.125 (0.0018 - 0.0049)

Fig 3: Measuring Clearance Between Piston Ring And Piston Ring Groove With A Thickness Gauge