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SECTION
4
- DISASSEMBLY AND REASSEMBLY
4.1 CYLINDER HEAD AND VALVE MECHANISM
4-1-06
4.1.4 Valve Seat Inserts - Inspection
Inspect the valve seats for wear, pitting, cracking or incorrect seat angle.
If suitable for reuse, the seat may be reface (instructions below). If
damage is too extensive to repair, new inserts should be installed.
4.1.5 Valve and Insert Reconditioning
The correct face angle for the intake valves is 120 degrees minus 0, plus 1/4
degree. The angle for the exhaust valves is 90 degrees, minus 0, plus 15'.
Valve head thickness should not be less than the minimum values shown in the
Clearance and Wear Charts.
The correct face angle for the valve seat inserts is 120 degrees for the
intake valve seats and 90 degrees for the exhaust valve seats. Insert
grinding should be limited to a light, clean-up trueing - the depth should be
as small as possible. After grinding, a new valve should be used to check
contact pattern with Prussian Blue (as outlined above). If new inserts are
necessary, make certain that the bore is clean and that the seat is pressed
completely to the bottom of its bore. Contact pattern should be rechecked
after the new inserts are installed.
4.1.6 Valve Guides - Inspection
Clean the valve guide bores with a soft brush or solvent to remove all gum and
carbon deposits. Inspect the guides for cracks, chipping, scoring, or
excessive wear. Measure the valve guide bores and replace and that exceed the
wear limits listed in the Clearance and Wear Charts.
4.1.7 Valve Springs - Inspection
Clean the valve springs with fuel oil or other suitable solvent and dry with
compressed air. Do not use any cleaning tool that might scrach or nick the
springs. Replace any springs that are pitted or cracked.
4.1.8 Valve Crosshead and Crosshead Guide - Inspection
Measure the bore in the pusher and the diameter of the pusher guide. Replace
any parts that exceed the wear limits shown in the Clearance and Wear Charts.
4.1.9 Cylinder head installation
- Install new gaskets and seals for each of the components that has been
removed. Install a new cylinder head gasket, and carefully lower the head
down onto the gasket. Tighten cylinder head stud nuts as outlined above
under 'Cylinder Head Removal'.
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