frame it is
not possible to remove the reactionary lever assembly from the transmission
operating shaft while the
assembly is in the car. To remove the Cabriolet engine, follow instructions
given above in Paragraphs 1 through 10, then:
Disconnect the vacuum cylinder
piston rod and valve link from the
reactionary lever system.
NOTEŚReplace the clevis pin
through the piston rod yoke and valve link to prevent upsetting the vacuum
proceed as instructed in paragraphs 13 through 17.
pistons are cast iron surface treated, with a slipper skirt. Three ring grooves are
located above the piston pin.
The pistons are of unusual design, being cam ground out of round. This
out-of-round design compensates for heat expansion along the line of the piston pin bosses.
The truck engines use a
heavier and more rigid piston than the passenger car engines. The truck piston
may be identified by a small
forged boss on the lower center
of each piston pin boss. Since the truck piston is heavier than the
passenger piston, passenger or
truck pistons must be used in sets, and the two different types must not be used in
piston ring on the piston is an oil control ring with ports to allow excess
oil, scraped from the sides of
the cylinder walls, to be returned to the inside of the pistons and
then to the Crankcase, by means
of holes drilled in the ring grooves of the piston.
pistons are furnished in standard size as well as .003", .010", .020", .030" and
necessary to replace pistons, due to wear, the cylinder walls should be honed for
.003" oversize or rebored
and honed for .010", .020", .030" or .040" oversize
NOTEŚAny time a piston is
removed from the cylinder, it should
be examined for carbon on the inside. Chevrolet pistons do not
carbon up excessively: however, it is a good practice to inspect them and
remove any carbon that is present. This helps to keep the engine oil
By far the
best method to be used in determining the condition of the cylinder in an
engine preparatory to reconditioning is the use of a dial gauge such as is shown in Fig.