1.2.1 Valve Operating Mechanism
DETROIT DIESEL 53
Fig. 7 - Removing or lnstalling Cam Follower Roller and Pin with Tool J 5840
cam followers and related parts are removed for
Inspection
inspection.
The current push rod spring is made from .192 "
Proper cam follower inspection and service are
diameter wire and was first used only in the injector
necessary in obtaining continued efficient engine
cam follower position. effective with engine
performance. When any appreciable change in
3D-3792.
injector timing or exhaust valve clearance occurs
during engine operation, the cam followers, and their
Effective with engine
related parts, should be removed and inspected for
3D-6128
excessive wear. This change in injector timing or
the new spring is also used in the
exhaust valve cam follower position. The former push
exhaust valve clearance during engine operation can
usually be detected by excessive noise at idle speed.
rod spring was made from .177 " diameter wire.
After the cam followers are removed, wash them with
Use spring tester J 9666 and an accurate torque
lubricating oil or Cindol 1705 and wipe dry. Do not
wrench to check the push rod spring load (Fig. 4).
use fuel oil. Fuel oil working its way in between the
Replace the current type spring when, a load of less
roller and bushing may cause scoring on the initial
than 250 pounds will compress it to a length of 2-9/
engine start-up since fuel oil does not provide
64 ". Replace the former type spring when a load of
adequate lubrication. Wash only the cam follower
less than 172 pounds will compress it to a length of
associated parts with fuel oil and dry them with
2-1/8 ".
compressed air.
It is recommended that if one former type push rod
Inspect the rounded end of the push rods for wear.
spring requires replacement, all of the former type
Replace any push rod which is worn or bent.
springs in either the injector or valve cam follower
positions be replaced by the current type spring. A
new design upper spring seat is required with the use
The purpose of a push rod spring is to maintain a
of the current push rod spring.
predetermined load on the cam follower to insure
contact of the cam roller on the camshaft lobe at all
times. Check the push rod spring load whenever the
Examine the cam follower bores in the cylinder head
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