Hudson Hornet 1955 Operating manual

2
ENGINE SECTION
(6 Cylinder)
ENGINE IDENTIFICATION
The engine number is located on the upper left
hand forward portion of the cylinder block on
the "Hornet" and "Wasp" Series.
The engine number on the "Rambler" Series is
located on a machined surface on the right side
of the engine block just above the exhaust pipe.
Letter Identification, Size of Bore, Main Bearings and
Connecting Rod Bearings
In the machining of cylinder .blocks and
crankshafts, it is sometimes necessary to
machine the cylinder bores to .010" oversize,
and the crankshaft main bearing journals or
crank pins to 0.10" undersize.
These engines are marked with a three letter
code. The code is stamped adjacent to the
engine number. The letters are decoded as
follows:
First Letter Size of Bore
Second Letter Size of Main Bearings
Third Letter Size of Connecting Rod
Bearings
Letter "A" Standard
Letter "B" .010" Undersize
Letter "C" .010" Oversize
Engines (after Number F-2814 or M-3616) that
are not marked are standard in all respects.
CYLINDER HEAD AND GASKET
Whenever a cylinder head is removed, inspect
the mating surfaces on the cylinder head and
block for cleanliness and squareness with a
straight edge.
Coat the gasket with a non-hardening gasket
paste and locate the gasket on the cylinder
block. A pair of guide pins, size 3" x 1/2"-13
"Hornet" and 3" x 7/16"-14 "Wasp" Series, will
aid in the installation of the cylinder head
(Fig. 1).
FIGURE 1—Guide Pin Installation to Install
Cylinder Head
Be sure that a sealing compound is used on all
cylinder head cap screws, "Hornet" and "Wasp"
Series, and the studs on "Rambler" Series, as
they connect to water passages in the cylinder
head.
Tighten the cap screws or stud nuts with a
torque wrench in a uniform manner, following
the sequence shown in Figures 2 and 3.
The "Hornet" Series, with aluminum cylinder
head, cap screws should be drawn up to 75-80
foot pounds of torque with engine at room
temperature.
The "Wasp" Series, with cast iron cylinder
head, cap screws are drawn up to 60-65 foot
pounds of torque with engine at normal operat-
ing temperature. With aluminum cylinder head,
tighten to 60-65 foot pounds of torque with
engine at room temperature.
Tighten the "Rambler" Series stud nuts to
57-60 foot pounds torque with engine at normal
operating temperature.
FIGURE 2—"Hornet" and "Wasp" Series
Cylinder Head Tightening Sequence
FIGURE 3—Cylinder Head Tightening
Sequence "Rambler" Series
VALVES
Valve Springs
Whenever valve springs are removed, they should
be tested according to the specifications
listed below, using a valve spring tester (Fig.
4). Any spring not within the specifications
should be replaced.
Valve Spring Specifications
Series "Hornet" "Wasp" "Rambler"
Valve Spring
Approximate
Free Height 2-1/2" 2-3/16" 2-5/32"
Valve Spring
Pressure
Valve Closed 73-81 Lbs. 40-48 Lbs. 37-41 Lbs.
@ 2-1/2" @ 1-61/64" @ 1-3/4"
Valve Open 153-165 Lbs. 16-124 Lbs. 75-82 Lbs.
@ 1-27/32" @ 1-19/32" @ 1-7/16"

ENGINE 6 CYLINDER 3
1. Torque Wrench
2. Valve Spring Tester
3. Valve Spring
FIGURE 4—Valve Spring Tester
Valve Spring Position
The valve springs are installed with the closed
coils toward the head of the valve as shown in
Figure 5.
1. Correct Position, Closed Coils Up
2. Arrow Points to the Valve Seat
3. Incorrect Position, Closed Coils Down
FIGURE 5—Correct Position of the
Valve Spring
Valve Spring and Valve Removal
The valve springs and valves can be removed
after the manifolds (where necessary), cylinder
heads, and valve covers are removed.
"Hornet" 6 and "Wasp" Twin-H-Power
To remove the intake and exhaust manifolds as
an assembly with the carburetors, required
additional clearance can be obtained by remov-
ing the 5/8" nut from the top of the front
engine supports and loosening the rear sup-
ports. The engine may then be moved slightly
upward and to the left.
To assist in the installation of valve
locks, Tool J-1953 can be used on the "Hornet"
and "Wasp" Series (Fig. 6).
FIGURE 6—Valve Lock Installation "Hornet"
and "Wasp" Series
"Wasp" Hi-Torque 6
Clearance permits removal of the manifolds
without movement of the engine.
"Rambler" Series
Exhaust pipe mounted to side of engine need
not be removed.
Valve Spring Compressor J-4487 ("C" Type) will
facilitate valve spring removal and replace-
ment on the "Rambler" Series.
Valve Adjustment
After removing the intake and exhaust manifold
assembly and valve covers, the valves on the
"Hornet" and "Wasp" can be adjusted to a cold
setting clearance of .010" "go"-.011" "no-go"
on the intake valves and .014" "go"-.015"
"no-go" on the exhaust valves.
The "Rambler" valves are adjusted without
removal of the exhaust pipe to a cold setting
clearance of .016" intake valves and .018"
exhaust valves.
Valve Refacing
It is important when refacing valves that just
enough material be ground off to clean up the
face.
The valve should be replaced if there is less
than approximately 1/16" material, "Hornet"
and "Wasp" Series and 1/3
2" "Rambler" Series, left on outer diameter of
the valve head known as the valve head margin.
A heavy margin aids in the dissipation of heat
and helps avoid valve warpage (Fig. 7).
The "Hornet" Series intake and exhaust valve
seat and face angle is ground to 45°.

1. Correct Valve Refacing
2. Incorrect Valve Refacing
FIGURE 7—Correct Valve Refacing
The "Wasp" Series intake valve seat and
face angle is 45°. The exhaust valve seat and
face angle is 46°.
The "Rambler" Series intake and exhaust
valve face angle is 44°. The valve seat angle
is 45°.
Valve Guides
"Hornet" Series valve stem to guide clearance
is .0015"-.003" Intake, .002"-.004" Exhaust;
"Wasp" Series .001"-.003" Intake, .002"-
.004" Exhaust; "Rambler" Series .0018"-
.0033" Intake and Exhaust.
Replace the guides when these clearances are
exceeded. Check valve stem diameters to
determine whether or not proper stem to guide
clearance exists.
Stem diameters are:
The valve guides can be removed through
the valve seat opening with a puller.
"Rambler" Series Tool J-2814, illustrated in
Figure 8, can also be adapted to the "Hornet"
and "Wasp" Series by using the spacers from
their respective guide installing tools.
The "Hornet" Series valve guides are
installed with Tool J-883-A (Pilot J-883-8
or 9) to insure that the guides are driven
to the correct depth of 1-3/32 for the
exhaust guides, 1-7/16" intake guides, from
the top of the guide to the top face of the
block (Fig. 9).
1. Valve Guide Removing Tool J-2814
FIGURE 8—Removing Valve Guides
"Rambler" Series
FIGURE 9—Installing Valve Guides
The "Wasp" Series valve guides are in-
stalled with Tool J-883-A (Pilot J-883-101.
The guides are inserted to a depth of 1%9"
from the top of the guide to the top face of
block.
Use Tool J-1429-A to install the "Rambler"
Intake
Exhaust
“Hornet”
.3412”-.3422”
.3402”-.3412”
“Wasp”
.3412”-.3422”
3402”-.3412”
“Rambler”
.3407”-.3412
.3407”-.3412
6TECHNICAL SERVICE MANUAL

ENGINE 6 CYLINDER 5
Series valve guides. Drive the guides flush
with the opening of the guide bore in the
block.
Valve Timing
Valve timing is determined by the relation
between the sprocket on the camshaft and the
sprocket on the crankshaft.
"Hornet" and "Wasp" Series
When installing timing assembly, line up the
marked teeth on the sprockets with the marked
links on the chain. Correct installation will
result in locating 7 links or 14 pins between
marks on sprockets as illustrated in Figure 10.
1. Marked Tooth on Camshaft Sprocket
2. Marked Tooth on Crankshaft Sprocket
3. 7 Links or 14 Pins
FIGURE 10—Correct Timing Chain Installation
"Hornet" and "Wasp" Series
"Hornet" Series
Valve timing can be checked without disman-
tling the engine.
With the engine at room temperature,
locate No. 1 piston at U.D.C. exhaust stroke.
Install a dial indicator on No. 1 cylinder
exhaust valve head through spark plug open-
ing. Crank engine slowly until dial indicator
indicates valve has seated.
Place a chalk mark on the flywheel,
through the ignition timing mark opening in
line with the lower ledge of opening.
Crank engine backwards to expose both the
chalk mark and U.D.C. mark on flywheel. (This
is only possible if timing is correct or
early.) With a pair of dividers, measure the
distance between the U.D.C. mark and chalk
mark on the inner timing mark radius (5.06"
flywheel radius).
This distance should be 21/4" plus or minus 1/s"
for valve lash errors. One tooth off timing on
crankshaft sprocket will affect this dimension
by plus or minus 1-31/64". One tooth off on
camshaft sprocket will affect this dimension by
plus or minus 13/16".
FIGURE 11—Valve Timing Diagram
"Hornet" Series
"Wasp" Series
To check valve timing on the "Wasp" Series,
crank engine until No. 1 piston is at T.D.C.
exhaust stroke.
Install a dial indicator on No. 1 cylinder
exhaust valve head through spark plug opening.
Crank engine slowly until dial indicator indi-
cates valve has seated.
Place a chalk mark on outer edge of vibration
damper below pointer.
Measure distance from chalk mark back to U.D.C.
No. 1 mark with steel scale located around
circumference of damper. This distance should be
approximately 13/4" (with cold valve lash .015")
plus or minus 1/8" for valve lash errors. If the
camshaft sprocket is off one tooth, it will
affect the dimension by plus or minus 1%2". If
the crankshaft sprocket is off one tooth, the
dimension will be affected by plus or minus
13/16".
"Rambler" Series
When installing timing assembly, line up the
marked teeth adjacent to each other on a center
line drawn through the center of the camshaft
and the center of the crankshaft (Fig. 13).
Before installing the timing chain cover, check
the correct installation of the timing chain;
locate the marked tooth of the camshaft sprocket

6TECHNICAL SERVICE MANUAL
FIGURE 12—Valve Timing Diagram
"Wasp" Series
FIGURE 13—Place Marked Teeth on Center
Line When Installing Sprockets and Chain
"Rambler" Series
at approximately the one o'clock position.
This should place the marked tooth of the
crankshaft sprocket where it begins to mesh
with the chain (Fig. 14). Count the number
of links between the marked teeth of both
sprockets. There should be 91/2 links or 19
pins.
Valve timing may be inspected by locating
the No. 6 piston on T.D.C. in firing
position. Then set valves on the No. 1
cylinder to .003" clearance. Slowly rock the
crankshaft back and forth.
1. Marked Tooth on the Camshaft Sprocket
2. Marked Tooth on the Crankshaft Sprocket
3. 91/2 Links or 19 Pins
FIGURE 14—Correct Timing Chain Installation
"Rambler" Series
If the timing is set properly, the
exhaust valve should open before the D.C.
mark on the vibration damper lines up with
the pointer. Note this distance. The intake
valve should open an equal distance after the
D.C. mark passes the pointer.
FIGURE 15—Valve Timing Diagram
"Rambler" Series
TIMING CHAIN COVER
"Hornet" and "Wasp" Series
The timing chain cover oil seal is a leather
chevron design, spring loaded, to contact the
seal surface of the vibration damper under

ENGINE 6 CYLINDER 7
pressure.
Tool J-2776 is used to remove and install
the timing chain cover oil seal (Figs. 16 and
17):
FIGURE 16—Removing Timing Chain Cover
Oil Seal—"Hornet" and "Wasp" Series
Insert the collar so that slot in collar
engages depression in cover. Support the
cover when driving out the seal with the
straight side of the driver.
NOTE: The tool head is reversible on the
handle. The side with the tapered pilot
is used for installing the seal and the
large size for removal. Before installing
a new oil seal, apply a coating of white
or red lead in the well of the timing
cover. Install the oil seal in cover
using tapered pilot side of tool (Fig.
17). With J-872-5, handle screw in
opposite end of tool, and with an arbor
press or soft hammer, press the seal
tightly into place. After seal is in-
stalled, recheck to make certain that the
lip of leather is in good condition and
not curled over.
FIGURE 17—Installing Timing Chain Cover Oil
Seal—"Hornet" and "Wasp" Series
"Rambler" Series
The timing chain cover is provided with a
felt seal to prevent the leakage of oil
around the front crankshaft pulley hub. To
prevent damage to this seal, it is important
that the cover be properly aligned when
installing the vibration damper. This is
accomplished by leaving the cover to block
screws loose until the vibration damper has
been partially installed. Then tighten the
cover screws.
At time of installation of a new seal,
the rubber section of the seal must be
installed to the rear of the cover.
The oil seal installed in the timing
chain cover is replaced by driving the old
one out from the rear and installing a new
seal and retainer from the front.
An oil slinger is used inside the timing
chain cover.