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140 ENGINE
6A1-17
Fig. 6A1-43 Measuring Valve Stem Clearance
Fig. 6A1-44 Checking Valve Spring Tension
4. Check valve spring tension with Tool J 8056 spring
tester (Fig. 6A1-44).
NOTE: Springs should be compressed to the specified
height and checked against specifications. Springs
should be replaced if not within 10 Ibs. of the specified
load (without dampers).
5. The camshaft bearing journals should be measured
with a micrometer for an out-of-round condition. If the
journals exceed .OOlm out-of-round, the camshaft should be
replaced.
I
I
Fig. 6A1-45 Checking Camshaft Alignment
6. The camshaft should also be checked for alignment.
The best method is by use of "V" blocks and a dial indicator
(Fig. 6A1-45). The dial indicator will indicate the exact
amount the camshaft is out of true. If it is out more than
.0015" dial indicator reading, the camshaft should be
replaced.
7. Inspect the camshaft gear for wear or damage.
Repairs
Fig. 6A1-46 Reaming Valve Guide
Valve Guide Bores
Valves with oversize stems are available in three sizes
(.003
-
.015
-
.020) for service replacement. To ream the valve
guide bores for oversize valves, use Tool J 5830-1 for .003;
J 5830-2 for .015 and J 5830-3 for .030 (Fig. 6A1-46).
NOTE: If installing valves with oversize stems, be sure
to install oversize valve stem seals.
Valve Seats
Reconditioning the valve seats is very important,
because the seating of the valves must be perfect for the engine
to deliver the power performance built into it.
Another important factor is the cooling of the valve
heads. Good contact between each valve and its seat in the
head is required to insure that the heat in the valve head will
be properly carried away.
Valve seats should be concentric within .002" total
indicator reading and can be checked as shown in Fig. 6A1-
47. The relation of valve and seat angles is shown in Fig.
6A1-48.
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