1935 Cadillac - GM Heritage Center

103
ENGINE
through the connecting rod, file it flush with the
rod before burnishing.
(4) Burnish bushing by passing burnishing tool
No. HMJ-250-2 through the bushing. When
expanding or burnishing a bushing, use a heavier
bench arbor press of about 4 tons capacity.
Use kerosine as a lubricant when expanding
and burnishing the bushing.
If the bushing moves during the burnishing
process, it is too loose and another one should
be used.
If the proper clearance between the piston pin
and the bushing is not secured after the burnishing
tool is passed through the bushing, the burnishing
operation should be repeated to increase the size
of the piston pin hole.
The press plate (Tool No. HMJ-250-4) should
be used for expanding and burnishing the bushing.
This plate has two holes—one which is used for
assembling, expanding and burnishing a'nd the
other for removing the bushing.
After installing the bushing the parts should be
thoroughly cleaned and the oil passages blown out
with air to remove chips and dirt.
9. Fitting Oil Rings
In fitting new rings, the edge clearance should
be from perfectly free to a clearance of .0035 in.
maximum, measured with a .0035-in. feeler inserted
opposite the solid section of the ring. The ring
must be pressed into the groove when this measurement
is taken.
10. Installing Cadillac 355-D Cylinder Head
Gaskets.
Proper installation of the steelbestos type
cylinder head gasket is essential to secure maximum
effectiveness. When installing these gaskets,
the following procedure should be observed.
First, saturate both sides of the gasket with
engine oil. This will prevent the gasket from
sticking to the head or block. Then install the
gasket and securely tighten down the head. Next
start the engine and run it until it is hot, and once
more tighten the cap screws, turning them down
as tightly as is possible without danger of stripping
the threads.
11. Care of Valve Silencers
The automatic valve silencers used on the 370-D
and 452-D cars are built to very close limits.
The mechanism must, therefore, be kept clean and
free from particles of carbon and other foreign
matter.
Whenever the valve cover is removed and the
valve silencers are exposed, they should be covered
to prevent dust and dirt from lodging on the
mechanism and finding its way into the dashpots.
Small particles of dirt or carbon becoming lodged
in the mechanism may cause noisy operation.
Other possible causes for improper operation ol
the valve silencers are:
1. Leakage of the check valve.
2. Incorrect clearance between the plunger and
the cylinder walls.
3. Damage due to improper installation.
Leakage of the check valve in the plunger is
most generally due to particles of foreign matter
being lodged on the seat of the valve. This can
ordinarily be corrected by washing it carefully
with gasoline and blowing it out with compressed
air.
To assure the check valve being seated properly,
it should be revolved on its seat by hand.
Incorrect clearance between the plunger and the
cylinder wall may result from the interchanging of
the plungers. It should be noted that the plungers
and dashpots are marked to insure correct
assembly. The number of marks etched on the
plunger should correspond with the number of
marks appearing on the dashpot casting.
12. Adjustment of Valve Spring Pressure on
V-12 and V-16 Engines
The relation between valve spring pressure and
valve travel on V-12 and V-16 engines is such that
each .010 inch of travel is equivalent to 2.73
pounds of pressure. In consequence, the seating
pressure of the valves may be reduced considerably
by the slight increase in travel occasioned by
a valve refacing and reseating operation. Reduced
valve seating pressures would, moreover, affect
engine performance to a noticeable degree,
especially in making cold-weather starting more
difficult, and in some cases might cause the valves
to burn.
To control the valve seating pressure it should
accordingly be checked after valve refacing operations
on V-12 or V-16 engines. Tool, Part No.
J-444 should be used for making this test.
The correct seating pressure for the valves on
V-12 and V-16 engines, with both valve springs
properly installed, is from 48 to 63 pounds. If
the pressure is less than 48 pounds, one or more
spacers should be installed under the valve spring
retainers. A spacer .040 inch thick is available
for this purpose, under Part No. 889407. Each
spacer will raise the seating pressure 10.9 pounds.
Each valve should be tested separately and
one or more spacers installed as required. In
case of an extremely low seating pressure, the
valve springs should be checked against the
specifications given on Page 117 to make sure that
they have not lost tension and shortened in use.
13. Burning Carbon on 370-D and 452-D Cars
While the most satisfactory way of removing
carbon from automobile engines is by scraping,
the labor involved in removing the cylinder heads
with the overhead valve mechanism on the V-12
and V-16 engines sometimes render scraping im-