Centinel System – Repair Manual – 001-999   Cylinder Block – Overview

General Information

Some Signature, ISX, and QSX15 engines are equipped with articulated pistons. The articulated piston is a two-piece piston consisting of a forged steel crown and an aluminum skirt. An open chamber oil gallery is located on the underside crown of the piston to provide more oil contact with the piston and give better piston cooling. Piston cooling nozzle targeting is critical because the oil is captured in shaker trays.		SMALL | MEDIUM | LARGE
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Some engines are equipped with single-piece pistons. The single-piece piston is a one-piece piston, that does not have a bushing and is forged from a high-strength, alloy steel. A cover plate, that is not removable, is located on the underside of the piston to capture oil and cool the piston. Do not remove this cover plate under any circumstances.		SMALL | MEDIUM | LARGE
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CAUTION  All pistons within a given engine must be of the same design. All are to be either the articulated design or the single piece design. Do not mix piston designs in the same engine. Single piece pistons must have drilled connecting rods and connecting rod bearings. Articulated pistons can use either drilled or non-drilled connecting rods and connecting rod bearings.		SMALL | MEDIUM | LARGE
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Connecting Rod

The ISX connecting rods big bore is straight-cut with a four capscrew design. With the introduction of the single-piece piston the connecting rod I-beam is drilled to provide oil to the piston pin. Single piece pistons must use drilled connecting rods.

Cylinder Liner

The cylinder liners are of a mid-stop cylinder liner design. The EGR engine cylinder liners are induction hardened.

There are two different designs of cylinder liners used in the Signature, ISX and QSX15 engines. The design used in a particular engine is dependent on the engine’s production vintage.

Engines assembled prior to engine serial number 14022615 have groove-top cylinder liners. They are characterized by a groove machined into the top surface of the cylinder liner flange.

Engines assembled with engine serial number 14022615 and after have flat-top cylinder liners. They are characterized by a cylinder liner flange that is flat, except for the fire dam.