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LP Engine G430 (3.0L)
General Information
General Description &
Operation
Engine Component Description
Engine Block
The engine block has four cylinders arranged in an “in-
line” construction. Starting at the front of the engine,
the cylinders are numbered 1-2-3-4. The firing order of
the cylinders is 1-3-4-2. The cylinders are encircled by
coolant jackets.
Cylinder Head
The cylinder head has one intake and one exhaust
valve per cylinder. A spark plug is located between the
valves in the side of the cylinder head. The valve
guides are integral and the valve rocker arms are
retained on individual threaded studs.
Crankshaft
The crankshaft is cast nodular iron and is supported
by five crankshaft bearings. The bearings are retained
by crankshaft bearing caps that are machined with the
engine block for proper alignment and clearances.
Camshaft
A billet steel one piece camshaft is supported by four
full round, sleeve-type bearings. These bearings are a
press fit into the engine block. The camshaft timing
sprocket is mounted to the front of the camshaft and is
driven the crankshaft sprocket.
Pistons and Connecting Rods
The pistons are made of cast-aluminum alloy using
two compression rings and one oil control ring
assembly. The piston pins are a press fit in the
connecting rods and a floating fit in the pistons.
Valve Train
The valve train is a ball-pivot type. Motion is
transmitted from the crankshaft through the valve lifter
and valve pushrod to the valve rocker arm. The valve
rocker arm pivots on its ball and transmits the
camshaft motion to the valve. The valve lifters keep all
parts of the valve train in constant contact. Each lifter
acts as an automatic adjuster and maintains zero lash
in the valve train. This eliminates the need for periodic
valve adjustment.
Lubrication
The oil pump is gear drive from the camshaft. Oil is
drawn from the oil pan through a pickup screen and
tube.
The gear type oil pump has a pressure regulator valve
which controls the lubrication system pressure by
bypassing excess oil back to the oil pan sump.
Pressurized oil from the oil pump flows to the full flow
filter.
A bypass valve allows oil to bypass the filter if it
becomes clogged or restricted. Oil then flows into an
oil passage that runs along the right side of the block
and intersects the lifter bosses. Oil from this passage
is routed to the crankshaft main bearings and
camshaft bearings through smaller drilled passages.
Oil is supplied to the connecting rod bearings by holes
drilled in the crankshaft. Oil is supplied to the rocker
arms through in the hydraulic lifters which feed oil up
the pushrods to the rocker arms.
The oil is metered by discs under the pushrod seat.
Many internal engine parts have no direct oil feed and
are supplied by either gravity or splash from other
direct feed components. Timing gears are lubricated
by oil supplied through a passage from the front of the
camshaft to a calibrated nozzle above the crankshaft
gear.
Thread Repair
Tools Required
General purpose thread repair kits. These kits are
available commerciall
y
VE121-3L
General Description & Operation
