Cummins N14 – Cylinder Head – Rebuild – Inspection

Visually inspect the valve spring retainers and the valve stem seals for damaged or worn areas.
Remove the valve stem seals from the valve stem seal retainers, and visually inspect for damaged or worn areas.
Discard unserviceable parts.

Visually inspect the valves for damage. Visually inspect the collet grooves for wear. Replace damaged valves or
valves with worn collet grooves.
Measure the outside diameter of the valve stem.

Use the N14 valve head checking tool to measure the head thickness of the valves.
NOTE: Install the valve on the tool with the valve head contacting the tool as shown. If the valve head is even with,
or extends beyond the end of the tool, the valve can be reground. If the valve head is below the end of the tool, the
valve is not thick enough for regrinding.

If a valve head checking tool is not available after regrinding the valve seat surface, put the valve on a flat
surface and measure the head thickness (1) at the outside diameter.

NOTE: If the valve head is thinner than the minimum specified, the valve must be replaced.

Visually inspect the valve guides for chips or cracks.
Measure the inside diameter of the valve guides 12.7 mm [0.50-inch] from each end (1) and at the center as shown.

Measure the valve guide installed height.

NOTE: If damage is found or the valve guide(s) does not meet the limits specified, the valve guide(s) must be re-
placed. Refer to Cylinder Head – Replacing the Valve Guides (02-03).

Measure the width of the valve seat area of the valve seat inserts.

NOTE: If the valve seat area is worn wider than the maximum specified, refer to ‘‘Grinding the Valve Seats’’ later in this procedure or to Cylinder Head – Replacing the Valve Seat Inserts (02-05).

Perform the following steps to check the injector seating quality in the injector sleeve and to measure injector
protrusion past the combustion face.
Caution: Support the cylinder head to prevent damage to the injector tip which protrudes from the combustion
face.
Apply a very light film of blueing compound to the outside diameter of the injector at the injector seat area. Blueing
compound can effectively be applied with your finger or with a brush.

Caution: Support the cylinder head combustion face so that it clears the work surface to prevent damage to the
injector tips during installation.
Install the injectors in the cylinder head without o-rings. Place a 1.2-inch thick block under the injector hold down
clamp. This represents the rocker housing.
Tighten the injector hold down capscrews.
Torque Value: 54 N•m [40 ft-lb]
(STC and CELECTTM)

Turn the cylinder head over and use a depth gauge, Part No. 3823495, to measure the injector tip protrusion.

NOTE: If the injector tip protrusion does not meet the specifications given, the injector sleeve must be machined again.

Remove the injectors from the cylinder head and check the pattern of the blueing compound in the injector sleeve.

The blueing pattern in the injector seating area (1) must be visible 360 degrees around the seating area.
The injector bore seating width (2) must be a minimum of 1.52 mm [0.060-inch].
NOTE: If the injector protrusion is more than the maximum specified or if the injector sleeve blueing pattern does not
meet the specifications given, the injector sleeve(s) must be replaced. Refer to Cylinder Head – Replacing the Injector
Sleeves (02-07).