1.2.2 Exhaust Valves
DETROIT DIESEL 53
Fig. 14 - Checking Relative Concentricity of
Valve Seat Insert with Relation to Valve Guide
Fig. 15 - Former and Current Design Exhaust
Valves (Four Valve Head)
the valves will be flush with the bottom surface of the cylinder head.
NOTE: The distance from the top of the four valve cylinder head to the bottom
of the valve spring seat counterbore is 1-11/64" in current design cylinder heads
or 1-5/64" in former design heads.
Be sure and install the correct parts in the four valve cylinder head. Current design cylinder heads are equipped with the
thin valve spring seats (.060 ") and current design exhaust valves (Fig. 15). To facilitate replacement of a four valve
head on an engine using the former exhaust valves, the proper quantity of the thick spring seats (.150 ") must be used.
Service cylinder heads are of the current design. The current thin valve spring seats (.060") 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.
IMPORTANT: 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
work bench. Place a board under the head to support the valves and to provide clearance between the cam followers and
the bench.
3.
Install the valve spring seats.
4.
Install the valve guide oil seals, if used, on the valve guides as follows:
a. Place-the plastic seal installation cap on-the end of the valve stem. If the cap extends more than 1/16 " below
the groove on the valve stem, remove the cap and cut off the excess length.
b. 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.
c.
Remove the installation cap.
5.
Install the valve springs and valve spring caps.
6.
Thread the valve spring compressor J 7455 into one of the rocker shaft bolt holes in the cylinder head (Fig. 2).
7. Apply pressure to the free end of the tool to compress the valve spring and install the two-piece tapered valve lock.
Exercise care to avoid scoring the valve stem with the valve cap when compressing the spring. Tap the end of the valve
stem lightly with a plastic hammer to seat the valve locks.
NOTE: If valve guide oil seals are used, compress the valve spring only enough
to permit installation of the valve locks. Compressing the spring too far may
result in damage to the oil seal.
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