TM 5-3895-359-14&P
Fig. 39. Spray Tip Sealing Surface Identification
Fig. 38. Comparison of Former and New Design
5. When the part is flat, wash it in cleaning solvent and
Injector Parts
dry it with compressed air.
bright and shinny (Fig. 39). It is not
6. Place the dry part on the second block. After
recommended to lap the surface of
applying lapping powder, move the part lightly across
the new current spray tip.
the block in a figure eight motion several times to give it
a smooth finish. Do not lap excessively. Again wash
Lapping Injector Parts
the part in cleaning solvent and dry it with compressed
air.
Lap the sealing surfaces indicated in Fig. 31 and Table
I as follows:
7. Place the dry part on the third block. Do not use
lapping powder on this block. Keep the part flat and
Minimum
Part Name
Thickness
Spray Tip (shoulder)
.199"
Check Valve Cage
.163" -.165"
Check Valve
.022"
Valve Spring Cage
.602"
TABLE 1. Minimum Thickness (Used Parts)
1. Clean the lapping blocks (J 22090) with compressed
air. Do not use a cloth or any other material for this
purpose.
2. Spread a good quality 600 grit dry lapping powder on
one of the lapping blocks.
3. Place the part to be lapped flat on the block as
shown in Fig. 33 and, using a figure eight motion, move
it back and forth across the block. Do not press on the
part, but use just enough pressure to keep the part flat
on the block. It is important that the part be kept flat on
Fig. 40. Tightening Injector Nut by Hand
the block at all times.
4. After each four or five passes, clean the lapping
powder from the part by drawing it across a clean piece
of tissue placed on a flat surface and inspect the part.
Do not lap excessively (refer to Table 1).
10-3-20