Centinel System – Repair Manual – 002-999   Cylinder Head – Overview

General Information

The cylinder head is a single slab head design with dual overhead camshafts.

The cylinder head group consists of the cylinder head, valves, valve guides, valve springs, valve seat inserts, crossheads, and injector sleeves. The exhaust valves are manufactured from a material capable of operating at a higher temperature than the intake valves. In addition to being made from different materials, the intake and exhaust valves are different sizes.

Mark, label, or tag the cylinder head parts such as crossheads, valves, and valve springs with the cylinder number and location from which they were removed. It is also recommended that the intake and exhaust valve positions be marked on the combustion face of the cylinder head using a paint pen to facilitate installing the correct parts in the correct locations.

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.

CAUTION  Cylinder head gaskets are different depending on the cylinder liner design. The cylinder head gasket designed to be used with groove-top cylinder liners can not be used with flat-top liners, and the cylinder head gasket designed to be used with the flat-top cylinder liners can not be used with groove-top cylinder liners.

Engines built with groove-top cylinder liners must use a cylinder head gasket and fire rings.

Engines built with flat-top liners must use a one-piece cylinder head gasket without fire rings.

Two different valve guides and valve guide seals are used on Signature, ISX, and QSX15 engines. Engines built prior to engine serial number 14010274 use non-grooved valve guides and small valve guide seals. These engines require the valve stem seal installer, Part Number 3163294, to be used when installing the valve guide seals.		SMALL | MEDIUM | LARGE
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Engines with serial number 14010274 and all engines built after use a larger valve guide seal. These seals are designed to be installed by hand without the seal driver. The new seals snap into a groove machined on the valve guide. The new style seals are not compatible with the old style non-grooved valve guides.		SMALL | MEDIUM | LARGE
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