Clean engine head:

TM 3-1040-279-12&P

NOTE

Engine head is still usable if chromate coating is removed. However, head

must have sharp (not rounded or chamfered) seating face corner edge.

Inspect engine head (6) for wear, burrs on engine head index slot (8), clogged ports (9), and

carbon deposits on valve seating face (10). If ports are clogged, wipe ports with twisted comer of

rag soaked with dry cleaning solvent. Remove carbon deposits on valve seating face as described

in step 5. If badly damaged, notify organizational maintenance.

5. Clean engine head:

CAUTION

Do not attempt to remove carbon deposits on valve seating face of engine

head with scraper or abrasive cloth.

(a) Place lapping board on flat surface.

(b) Place a few drops of fog oil on lapping board.

engine head seating surface stays flush on lapping board. Do not round edges.

(d) Rotate engine head or engine valve so even pressure is applied to different parts until carbon

deposits are removed. Wipe dry with rag.

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Change 4