Cummins ISX11.9 CM2250 – Service Manual 002-999   Cylinder Head – Overview

General Information

The ISX11.9 utilizes a stemless crosshead design. The design does not require adjustment. Engines with compression brakes must use a unique exhaust crosshead.		SMALL | MEDIUM | LARGE

The ISX11.9 cylinder head is a single slab head design.

The cylinder head group consists of the cylinder head, valves, valve guides, valve stem seals, valve springs, valve spring retainers, 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 and have different seat angles.

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 with a paint pen to facilitate installing the correct parts in the correct locations.

CAUTION  If the oil passages are not plugged or covered before cleaning, a crankshaft malfunction can occur.

Prior to scraping off the delaminated remains of the head gasket from the cylinder block, place clean, lint-free rags over the cam followers and above the pistons to prevent dirt from falling into the engine. Then, plug or mask the coolant and oil passages in the cylinder block deck.

The ISX11.9 has 8 cylinder head capscrews per cylinder as compared to the 7 on the ISM. There are 7 smaller M10 capscrews that are installed on the left side of the engine to secure the push tube cavities.

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Cylinder Head Capscrew Sequence – Top View of Cylinder Head

The ISX11.9 uses a torque-turn method for tightening all primary cylinder head capscrews. The method provides better control of the load on the capscrews.

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Cylinder Head Intake and Exhaust Valve Pattern – Bottom View of Cylinder Head

E = Exhaust Valve

I = Intake Valve

NOTE: The intake and exhaust valve locations of cylinders 1, 2, and 3 are symmetric of cylinders 4, 5, and 6.