Keep the gasket material, and any other foreign materials out of the air intake.
If removed, clean the cylinder head sealing surfaces where the air intake manifold seals.
NOTE: On engines equipped with EGA, it is common to have soot buildup in the air intake section of the cylinder
head. If the cylinder head is removed as part of another repair, it is not necessary to clean the soot from the air
intake.
Use an injector bore brush, Part Number 3822510, or equivalent, to clean the carbon from the injector seat.
Use a bristle brush to clean the inside diameter of the valve guide bore.
Blow out with compressed air.
If required, clean the buildup of deposits in the coolant passages.
Clean the cylinder head combustion deck with an abrasive hand pad, Part Number 3823258, or equivalent, and
solvent.
NOTE: An inferior-quality wire wheel will lose steel bristles during operation, causing additional contamination.
Clean carbon deposits from the valve pockets with a high-quality steel wire wheel installed in a drill or die grinder.
Use a wire brush and solvent to clean the deposits from the valve seat insert bores, if it was necessary to remove
the valve seat inserts.
Dry with compressed air.
Wash the cylinder head in a hot, soapy water solution.
Rinse the cylinder head with clean water.
Dry the cylinder head with compressed air.
Cylinder Head Cracks- Reuse Guidelines
With the cylinder head cleaned, inspect the cylinder head for signs of cracks, fretting, and discoloration that would
prohibit reuse.
To help identify cracks in the cylinder block, use the Crack Detection Kit, Part Number 3375432.
Pay close attention to areas of the cylinder head that include:
– Injector bore
– Combustion face
– Valve seats
– Valve guides.
The reuse guidelines for a cylinder head with a crack extending from the injector bore to the intake valve seat
are as follows:
โข If the crack does not extend into the valve seat, the cylinder head is reusable.
โข If the crack extends into or through the valve seat, the cylinder head must be replaced.
If still installed, inspect the valve seats for cracks or burnt spots.
If the valve seat inserts are damaged, for some cylinder heads, the valve seat inserts can be replaced.
โข Verify replacement valve seat inserts are available.
โข If replacement valve seat inserts are available and require placement, see the Disassemble section of this procedure.
โข If replacement valve seat inserts are not available, the cylinder head must be replaced .
If the valve seat insert was removed in the Disassemble section, measure the inside diameter of the valve seat
insert bore in the cylinder head.
NOTE: Before cutting the cylinder head, verify valve seat inserts are available for the engine being serviced. If none
are available, the cylinder head must be replaced.
If out of specification, the valve seat insert bore can be oversized 0.254 mm (0.01 0 in) or 0.508 mm (0.020 in).
Use valve seat cutter, Part Number ST257, or Valve Seat Insert Tool Kit with Valve Guide Arbor, Part Number
3165184, to cut the cylinder head to accept oversize valve seat inserts. Use valve seat cutter, Part Number 3165183,
for 0.254 mm (0.010 in) or 3165184 for 0.508 mm (0.020 in).
Valve Guide – Reuse Guidelines
Inspect the valve guides for scuffing or scoring.
Measure the valve guide inside diameter (I.D.)
If the valve guide bore is worn larger than the maximum specified, or if inspection reveals damaged valve guides,
the cylinder head must be replaced.
Clean the valve heads with a soft wire wheel.
NOTE: Keep the valves in a labeled rack to prevent mixing. This will aid in analysis and assembly.
Polish the valve stems with an abrasive pad, Part Number 3823258, and solvent.
Valve – Reuse Guidelines
Inspect the valves for:
– Excessive wear on the heads and stems
– Excessive wear on the valve stem tip
– Bends and distortion.
Inspect the valves for damage and the collet grooves for wear.
Measure the outside diameter of the valve stem.
Three measurements must be taken of each valve stem at 40 mm [1.57 in], 90 mm [3.54 in], and 140 mm [5.51 in]
from the tip end.
If the valves are damaged or the stems are worn smaller than the minimum specified, the valves must be replaced.
Valve Spring – Reuse Guidelines
Inspect the valve springs.
Measure the valve spring. Place a square adjacent to the spring and use a feeler gauge to measure the clearance
at the top spring coil.
Approximate Free Length (L): 47.75 mm [ 1.88 in ]
Maximum Inclination: 1.5 mm [ 0.059 in ]
Use valve spring tester, Part Number 3375182, to compress the valve spring. A load of 320.8 to 358.8 N [72
to 80.71b] is required to compress a spring to a height of 35.33 mm (1.39 in].
NOTE: If the valve spring is not within specification, a new valve spring must be used.
Inspect the valve spring retainers and valve collets for damage or worn areas.
Discard and replace damaged or worn parts.
Use a petroleum-based solvent to clean the capscrews.
Clean the capscrews thoroughly with a wire brush, soft wire wheel, or nonabrasive bead blast to remove deposits
from the shank and threads.
Cylinder Head Capscrew – Reuse Guidelines
Inspect the cylinder head capscrews for damaged threads, corroded surfaces, or a reduced diameter (due to
capscrew stretching).
Do not reuse cylinder head capscrews under the following conditions:
โข Visible corrosion or pitting exceeding 1 sq em [0.155 sq in] in area.
Example:
Acceptable is 9.525 x 9.525 mm [3/8 x 3/8 in].
Unacceptable is 12.700 x 12.700 mm [V2 x V2 in].
โข Visible corrosion or pitting exceeds 0.12 mm [0.005 in] in depth.
โข Visible corrosion or pitting is located within 3.2 mm [1/8 in] of the fillet or thread.
โข Stretched beyond 11free-length” maximum. See the measurement procedure below:
Free-Length Measurement
NOTE: If the capscrews are not damaged, they can be reused throughout the life of the engine, unless the
specified free length is exceeded.
To check the capscrew free length using capscrew length gauge, Part Number 3164057, place the head of the
capscrew in the appropriate slot, with the flange against the base of the slot.
NOTE: Most new cylinder head gaskets and upper engine gaskets include the capscrew length gauge, Part Number
3164057.
If the end of the capscrew touches the foot of the gauge, the capscrew is too long and must be discarded.
