Description And Operation - Piston Assembly
WARNING: This page is about a different car, the 2025 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
| 1 - Upper Compression Ring |
| 4 - Full Floating Wrist Pin |
| 2 - Intermediate Compression Ring |
| 5 - Wrist Pin Locking Clip |
| 3 - Three Piece Oil Control Ring |
| 6 - Piston Skirt |
CAUTION:
Do not use a metal stamp to mark connecting rods as damage may result, instead use ink or a scratch awl.
The pistons are a lightweight design with ultra low tension piston rings for improved fuel economy:
- The pistons are made of a high strength aluminum alloy and the piston skirt has a MolyT® coating.
- The top piston ring land has an anodized coating for improved wear performance.
- The piston is connected to the rod using a full floating wrist pin with a locking clip on both sides.
- The connecting rod is powder-forged steel with a bolted cracked cap design. The connecting rod bolts are not reusable.
- Pistons are available in two diameters (A and B) with grade markings for each bore indicated on the side of the cylinder block.
- The upper compression ring is a 1.2 mm steel ring with Physical Vapor Deposition (PVD) coating.
- The intermediate compression ring is 1.2 mm micro napier design and has a greater radial wall thickness than the upper compression ring.
- Both compression rings have a TOP mark on the piston ring. The marked side of the ring must face the top of the piston.
- The 2 mm three piece oil control ring is very thin. Both the rail segments and the expander are nitride steel.