72-00-05
CAMSHAFT
A
steel alloy forging is machined on four journals, nine cam lobes and the gear mount flange
at the rear end. The lobes and journals are ground and hardened.
A
groove around the front
journal passes engine oil from the right crankcase cross passage to the left case passage. The
camshaft gear is attached by four unequally spaced bolts to locate its timing mark in relation
to the cam lobes. The inner teeth of the camshaft gear drive the alternator.
72-00-06
PISTONS
Pistons are aluminum alloy forgings or castings with a steel insert casted into the top ring
groove. The skirts are solid and have cylindrical relief cuts at the bottom to clear the
crankshaft
countennreights. Pistons have three ring grooves above the pin hole and one ring
groove below. Compression rings are installed in the top, second and the groove below the
pin hole.
A
center grooved and slotted oil ring is installed in the third groove, which has six
oil drain holes to the interior. Weights are limited to
1/2 ounce in opposite bays. Piston
pins are full floating ground steel tubes with permanently pressed-in aluminum or bronze end
plugs.
72-00-07
LIFTERS
The barrel type hydraulic lifters may be removed and replaced without complete disassembly of
the engine. Construction and operation of the lifters are described in Section 72-00-1 1.
72-00-08
CYLINDERS
The externally finned aluminum alloy head castings are heated and valve seat inserts installed
before the head is screwed and shrunk onto an externally finned steel alloy barrel to make
the permanent head and barrel assembly. Prefinished aluminum bronze intake valve guides and
nitralloy or niresist exhaust valve guides are pressed into the cylinder assembly. Special
18mm helical coil thread inserts are installed in upper and lower spark plug holes. The
exhaust ports are on the bottom and intake ports are on the top of the head when the
cylinder is installed. Exhaust valve faces are Stellite No.
6
and stem tips are hardened.
Valve stems are solid. The intake valve guide is equipped with a valve guide seal to prevent
oil from being drawn through the valve guide and into the cylinder. Outer retainers of the
two concentric springs surrounding each valve are locked to the stems by tapered, semi-
circular keys which engage grooves around the stems. Rotocoiis are installed on intake and
exhaust valves. The controlled rotating action of this type retainer helps prevent burring and
eroding of the valve and valve seat.
Inner spring retainers are pressed steel. Valve rocker
covers are stamped aluminum alloy. Rocker shafts are case hardened steel.
The rocker shafts
are held in place by studs in the cylinder rocker boxes. Valve rockers are steel forgings with
hardened sockets and rocker faces and pressed-in bronze bearings. They are drilled for
lubrication.
Pushrods are constructed of steel tubes and pressed-in, hardened, forged steel
ball ends, which are center drilled for oil passages. The
pushrod housings are beaded steel
tubes. The bead at the cylinder end retains a washer and packing ring.
The bead at the
crankcase end retains a heavy spring, washer, packing ring and second washer. The cylinders
are nitrided for hardening.
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