USN_Green_Addict
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Can anyone point me in the right direction for specs to get the heads surfaced? my machine shop needs the min/max distance from the surface to the valve.
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Head surfaced
- Thread starter USN_Green_Addict
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Correct technical manual: TM 9-2815-210-34-2-1
Summary:
Maximum allowable warpage:
Cylinder head warpage must not exceed 0.003 inch (0.076 mm) across the surface.
Minimum cylinder head thickness after resurfacing:
The head must not be machined below 4.725 inches (120.06 mm) in overall thickness.
Flatness check:
Use a precision straightedge and feeler gauge across multiple planes of the head surface. If warpage exceeds the limit, resurfacing is required.
Surface finish:
After machining, the surface finish should be smooth and free of tool marks, suitable for a composite or multi-layer steel head gasket.
Also note, with respect to the valve seats:
Maximum allowable valve stem protrusion (from spring seat to tip):
1.940 inches (49.28 mm)
If resurfacing causes this to exceed the limit, valve seat recession is required to restore geometry.
Installed valve spring height (spring seat to retainer):
1.750 inches (44.45 mm) ± 0.015 inches (0.38 mm)
If the head is resurfaced and this height is reduced below spec, you may need to:
Summary:
Maximum allowable warpage:
Cylinder head warpage must not exceed 0.003 inch (0.076 mm) across the surface.
Minimum cylinder head thickness after resurfacing:
The head must not be machined below 4.725 inches (120.06 mm) in overall thickness.
Flatness check:
Use a precision straightedge and feeler gauge across multiple planes of the head surface. If warpage exceeds the limit, resurfacing is required.
Surface finish:
After machining, the surface finish should be smooth and free of tool marks, suitable for a composite or multi-layer steel head gasket.
Also note, with respect to the valve seats:
Maximum allowable valve stem protrusion (from spring seat to tip):
1.940 inches (49.28 mm)
If resurfacing causes this to exceed the limit, valve seat recession is required to restore geometry.
Installed valve spring height (spring seat to retainer):
1.750 inches (44.45 mm) ± 0.015 inches (0.38 mm)
If the head is resurfaced and this height is reduced below spec, you may need to:
- Recess valve seats
- Shim valve springs