TM 5-3895-346-14
ENGINE OVERHAUL
EXHAUST VALVES
(Fig. 16). To facilitate replacement of a four-valve head on an engine using the former exhaust valves, the
proper quantity of the thick spring seats (0.150 inch) must be used.
Service cylinder heads are of the current design. The current thin valve springs seats (0.060 inch) are included
with each cylinder head as a shipped loose item.
1. Lubricate the valve stems with sulphurized oil (E.P. type) and slide the valves all the way into the guides.
CAUTION
If reconditioned valves are used, install them in the same relative location from
which they were removed.
2. Hold the valves in place temporarily with a strip of masking tape. Then, turn the cylinder head right side
up on the workbench. Place a board under the head to support the valves and to provide clearance between
the cam followers and the bench.
Figure 16. Former and Current Design Exhaust Valves (Four-Valve Head)
3. Install the valve spring seats.
4. Install the valve guide oil seals, if used, on the valve guides as follows:
a. Former Oil Seal (retained by a spring and retainer)
(1) Place the plastic seal installation cap on the end of the valve stem. If the cap extends more than 1/16
inch below the groove on the valve stem, remove the cap and cut off the excess length.
(2) Lubricate the installation cap and start the seal carefully over the valve stem. Push the seal down
slowly until it rests on top of the valve guide.
(3) Remove the installation cap.
b. Current Oil Seal (Fig. 17) (metal case and reduced inner diameter)
NOTE
To properly install the current oil seal, use oil seal installer J 29579.
(1) Lubricate the oil seal and the valve stem with engine oil and start the oil seal carefully over the valve
stem.
(2) Using installer J 29579, drive the seal down slowly until the tool bottoms on the cylinder head (spring
seat washer removed).
CAUTION
The tool positions the seal so that it does not bottom out on the valve guide. If the
oil seal is installed too far, so as to contact the top of the guide, it will be distorted
and will not function as an effective seal.
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