Starting at the front of the engine, the cylinders of
the left bank are numbered 1-3-5 and the cylinders
of the right bank are numbered 2-4-6. The
crankshaft is supported in the engine block by four
bearings. The crankshaft is counterbalanced by the
flywheel, the crankshaft balancer, and the weights
cast into the crankshaft. Additional
counterbalancing is obtained from the balance
shaft which rides in the engine block above the
camshaft and is driven by the camshaft. All 3800
engines are even-firing, the cylinders fire at equal
120 degree intervals of crankshaft rotation. The
location of the crankshaft journals has been offset
by 30 degrees to fire the cylinders at 120 degree
intervals of crankshaft rotation. The camshaft lobes
and timing also reflect the 120 degree intervals.
The even firing crankshaft provides an equal
interval of 120 degrees between ignition of each of
the cylinders throughout the firing order. The firing
order is 1-6-5-4-3-2. The aluminum alloy pistons
have slipper skirts and are cam turned. Four drilled
holes or casted slots in the oil ring grooves permit
drain back of the oil collected by the oil ring. The
camshaft is supported by four bearings in the
engine block and is driven by the crankshaft
through sprockets and a timing chain. The cylinder
heads are cast iron and incorporate integral valve
stem guides. Right and left cylinder heads are
identical and are interchangeable, but it is good
practice to reinstall the cylinder heads on the side
from which they are removed. The intake manifold
is bolted to the inner faces of both cylinder heads
so it connects with all inlet ports.
3800 V6 Engine Mechanical Description And Operation

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Each exhaust and intake valve has a valve spring to insure
positive seating throughout the operating speed range. The valve
rocker arms for each bank of the cylinders pivot on pedestals
bolted to the cylinder head. Hydraulic roller valve lifters and
tubular push rods are used to operate overhead rocker arms and
valves of both banks of the cylinders from a single camshaft. This
system requires no lash adjustment at the time of assembly or

In addition to its normal function of a cam follower, each valve
lifter also serves as an automatic adjuster which maintains zero
lash in the valve train under all operating conditions. By
eliminating all lash in the valve train and also providing a cushion
of oil to absorb operating shocks, the valve lifter promotes quiet
valve operation. It also eliminates the need for periodic valve
adjustment to compensate for wear of parts. Oil is supplied to the
valve lifter through a hole in the side of the valve lifter body which
indexes with a groove and a hole in the valve lifter plunger. Oil is
then metered past the oil metering valve in the valve lifter,
through the push rods to the valve rocker arms. When the valve
lifter begins to move up the camshaft lobe, the check ball is held
against its seat in the plunger by the check ball spring which
traps the oil in the base of the valve lifter body below the plunger.

The plunger and the valve lifter body then raise as a unit, pushing
up the push rod to open the valve. The force of the valve spring
which is exerted on the plunger through the valve rocker arm and
push rod, causes a slight amount of leakage between the plunger
and the valve lifter body. This leakage allows a slow escape of
trapped oil in the base of the valve lifter body. As the valve lifter
rolls down the other side of the camshaft lobe and reaches the
base circle or valve closed position, the plunger spring quickly
moves the plunger back (up) to its original position. This
movement causes the check ball to open against the ball spring,
and any oil inside the plunger is drawn into the base of the valve
lifter. This restores the valve lifter to the zero lash.