Noisy Operation V-12 And V-16 Valve Silencers; Valve Spring Pressure V-12 And V-16 O I L Filters; Cleaning Oil Pan And Screen - Cadillac 1937 LaSalle VVI Information

89
Reassembly—When reassembling the silencer
parts, note the following:
1. The ball check should rattle when the
cylinder unit is shaken.
2. T h e plunger should bounce back when
pressed q u i c k l y into the cylinder and released.
3. T h e plunger spring should be locked into
the cylinder body with a twist of the plunger.
4. The cylinder should slide smoothly into the
tappet body when free of o i l .
Valve Clearance Check—There must always
be .030-.070 inch clearance between the valve
stem and the top of the plunger measured with no
oil in the hydraulic unit and w i t h the plunger and
plunger spring fully depressed. (See P l a t e 34,
F i g . 31)..
Measure this clearance w i t h a feeler gauge—
1. W h e n new silencer parts are installed.
2. If the locations of parts are changed.
3. W h e n valves are reseated.
If the clearance is less than .030 inch, grind a
few thousandths off the end of the valve stem
and check w i t h T o o l J-1055" when installing valves
as explained in N o t e 20.
Installation—After the installation has been
completed, the hydraulic units should be filled
with oil by running the engine u n t i l the valve
action becomes quiet.
23. N o i s y O p e r a t i o n V - 1 2 a n d V - 1 6 V a l v e
S i l e n c e r s
N o i s y operation of the valve silencers on series
37-85 and 90 engines m a y be due to:
1. D i r t in the mechanism.
2. Incorrect clearance between silencer plunger
and cylinder.
3. Leakage of check valve.
4. W r o n g operating clearance between rocker
arm and push rod.
5. Clogged o i l filter.
D i r t — o r carbon particles anywhere in the
silencer mechanism m a y cause noisy operation and
. excessive wear. T h e remedy is thorough cleaning
of all parts in gasoline.
Note: Whenever the valve cover is removed and
the valve silencers are exposed, they
should be kept covered to prevent dust
and dirt from settling in the mechanism.
Incorrect Clearance—between plungers and
cylinder walls m a y be due to excessive wear,
which would necessitate replacement; or to the
interchanging of the plungers.
T h e plungers and d'ashpots are not interchange-
able, and they are marked to insure correct
assembly. T h e number of marks etched on the
plunger should correspond w i t h the number of
marks appearing on the dashpot casting. (See
Plate 35, F i g . 33).
Leakage of the Check Valve—is usually due
to particles of foreign matter being lodged on
the valve seat. T h i s can be corrected by thorough
cleaning. W h e n reinstalling, revolve the check
valve on its seat to assure its being properly
seated.
T h e Operating Clearance — between the
rocker a r m and push rod is adjusted as shown in
F i g . 35.
24. V a l v e S p r i n g P r e s s u r e V - 1 2 a n d V - 1 6
T h e relation between valve spring pressure and
valve travel on series 37-85 and 90 engines is such
that each .010 inch of travel is equivalent to 2.73
lbs. of pressure. T h e seating pressure of the valves
m a y be reduced considerably by the slight increase
in travel occasioned by a valve reseating operation.
T h e valve seating pressure should accordingly
be checked after a valve refacing operation, using
T o o l N o . J-444. T h e correct seating pressure w i t h
both valve springs properly installed is from 48
to 63 lbs. If the pressure is less than this, one
or more .040 inch spacers (Part N o . 889407) should
be installed under the valve spring retainers.
E a c h spacer w i l l raise the seating pressure approx-
imately 11 lbs.
E a c h valve should be tested separately and one
or more spacers installed as required. In case of
extremely low pressure,-the valve springs should
be checked against the specifications to make sure
that they have not lost tension and shortened in
use.
Reduced valve seating pressures would affect
engine performance to a noticeable degree,
especially i n m a k i n g cold weather starting more
difficult, a n d in-some cases might cause the valves
to burn.
V a l v e seating pressure for eight cylinder
engines is tested only by testing the valve springs
according to the specifications on page 107.
25. O i l F i l t e r s
Clean engine o i l is an essential requirement to
satisfactory engine operation and all 37 series
C a d i l l a c a n d L a S a l l e cars are, therefore, equipped
w i t h an o i l filter. The filters are of the cartridge
type and should ^be replaced every 6000 miles
to insure proper protection to the engine at a l l
times.
O n V - 8 engines the o i l filter also acts as an air
trap and aids in keeping any air from entering the
hydraulic valve mechanism. T h i s is added
assurance of quiet valve,'' operation on these
engines.
26. C l e a n i n g O i l P a n a n d S c r e e n
C l e a n i n g of the engine o i l pan and screen is
recommended on all series engines at 12,000 mile
intervals.
A l l of the engine oil passes through the oil pan
and screen before reaching the o i l p u m p . Foreign
matter that m a y be in the o i l is b o t h screened
out and permitted to settle out at this point so
that the o i l reaching the pump is quite free from
abrasive particles.