DETROIT DIESEL 53
1.2.2 Exhaust Valves
Fig. 14 - Checking Relative Concentricity of
Valve Seat Insert with Relation to Valve Guide
the valves will be flush with the bottom surface of the
Fig. 15 - Former and Current Design Exhaust
cylinder head.
Valves (Four Valve Head)
NOTE: The distance from the top of the four
4. Install the valve guide oil seals, if used, on the valve
valve cylinder head to the bottom of the valve
guides as follows:
spring seat counterbore is 1-11/64 " in current
design cylinder heads or 1-5/64 " in former
a. Place the plastic seal installation cap on the end of
design heads.
the valve stem. If the cap extends more than
1/16 " below the groove on the valve stem,
Be sure and install the correct parts in the four valve
remove the cap and cut off the excess length.
cylinder head. Current design cylinder heads are
equipped with the thin valve spring seats (.060 ") and
b. Lubricate the installation cap and start the seal
current design exhaust valves (Fig. 15). To facilitate
carefully over the valve stem. Push the seal down
replacement of a four valve head on an engine using
slowly until it rests on top of the valve guide.
the former exhaust valves, the proper quantity of the
thick spring seats (.150 ") must be used.
c. Remove the installation cap.
Service cylinder heads are of the current design. The
5. Install the valve springs and valve spring caps.
current thin valve spring seats (.060 ") are included
with each cylinder head as a shipped loose item.
6. Thread the valve spring compressor J 7455 into one
of the rocker shaft bolt holes in the cylinder head
1. Lubricate the valve stems with sulphurized oil (E.P.
(Fig. 2).
type) and slide the valves all the way into the guides.
7. Apply pressure to the free end of the tool to
IMPORTANT: If reconditioned valves are used,
compress the valve spring and install the two-piece
install them in the same relative location from
tapered valve lock. Exercise care to avoid scoring the
which they were removed.
valve stem with the valve cap when compressing the
spring. Tap the end of the valve stem lightly with a
2. Hold the valves in place temporarily with a strip of
plastic hammer to seat the valve locks.
masking tape. Then, turn the cylinder head right side
up on the work bench. Place a board under the head to
NOTE: If valve guide oil seals are used,
support the valves and to provide clearance between
compress the valve spring only enough to
the cam followers and the bench.
permit installation of the valve locks. Com-
pressing the spring too far may result in
damage to the oil seal.
3. Install the valve spring seats
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