F510 & F525 Cylinder Head and Valves – INSPECT VALVES

1. Remove carbon from valve head, face and stem with a power-operated wire brush. Be sure carbon is removed, not merely burnished.
2. Check valve faces, heads and stems for defects.
3. Replace warped valves (A) or valves with less than 0.6 mm (0.02 in.) margin (B). Valve stem ends (C) should be ground square before you check valve-to-tappet clearance.
4. Measure valve stem outside diameter. Replace valve if outside diameter is less than wear limit specifications.

VALVE STEM O.D. SPECIFICATIONS—WEAR LIMIT
Intake valve . . . . . . . . . . . . . . . . . . . . . . . . 6.930 mm (0.2728 in.)
Exhaust valve . . . . . . . . . . . . . . . . . . . . . . . 6.915 mm (0.2722 in.)
VALVE STEM O.D. SPECIFICATIONS—NEW PARTS
Intake valve (Minimum) . . . . . . . . . . . . . . . . 6.972 mm (0.2745 in.)
(Maximum) . . . . . . . . . . . . . . . 6.987 mm (0.2751 in.)
Intake valve to guide
clearance (Minimum) . . . . . . . . . . . . . . . . . . 0.013 mm (0.0005 in.)
(Maximum) . . . . . . . . . . . . . . . . . 0.043 mm (0.0017 in.)
Exhaust valve (Minimum) . . . . . . . . . . . . . . . 6.965 mm (0.2742 in.)
(Maximum) . . . . . . . . . . . . . . 6.980 mm (0.2748 in.)
Exhaust valve to guide
clearance (Minimum) . . . . . . . . . . . . . . . . . . 0.020 mm (0.0008 in.)
(Maximum) . . . . . . . . . . . . . . . . . 0.050 mm (0.0020 in.)

5. Inspect valve stem for bend using V-blocks and a dial indicator. Turn valve slowly and read variation on indicator. Replace if variation is greater than 0.03 mm (0.001 in.).

04. June 2021 by samuel07042012
Categories: F510-F525 | Leave a comment

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