STUDEBAKER 1938-39
1938 MODEL NOTE:—First 7A cars called Studebaker
Six, later cars Commander. First 8A cars called
Commander, later cars State Commander.
SERIAL NUMBER:—Stamped on plate on frame under
left front fender. First numbers as foUows:
7A
8A
9A
South Bend
5,582,001
4,090,001
4,110,001
Los Angeles
5,857,501
4,800,001
4,802,301
ENGINE NUMBER:—First number H-101 C38), H-42501
C39). Stamped on boss on left side of block at rear.
ENGINE SPECIFICATIONS:—6 cylinder, 'L' head.
Bore—3 5/16". Stroke—4%".
Displacement—226 cubic inches.
Rated Horsepower—26.35 (NACC).
Developed Horsepower—90 HP. (Std. head), 94 HP.
(Optl. high altitude head) at 3400 RPM.
Compression Ratio—6.0-1 Std. cast-iron head.
7.0-1 aluminum hd. Optl. (high altitude only).
See Studebaker
Shop Note for Head
installation.
Compression Pressure—105 lbs. (Std. head), 110 lbs.
(Optl. head )at 150 RPM. (cranking speed).
Vacuum Reading—18-20" at 450 RPM. or 8 MPH.
PISTONS:—Lynite, aluminum aUoy,
tin-plated, T-slot,
cam ground type. Length—334".
Removal—Pistons and rods removed from above.
Clearance—.0005" new. Measure %" up on skirt 90°
from pin bosses. See Fitting New Pistons.
Original Bore Sizes:—See Studebaker Shop Notes.
Replacement Pistons:—Finished pistons (pins fitted)
furnished std. and .002", .004", .010", .015", .020", .030"
oversize. Exact size stamped on piston head.
Fitting New Pistons:—Insert .002" X 1" feeler between
piston and wall on camshaft side (pin paraUel to
crankshaft, T-slot away from camshaft). PuU to
withdraw feeler must be between 7-15 lbs.
InstaUing Pistons:—T-slot away from camshaft.
PISTON RINGS:—2 (P-C#70) compression, 1 (#85) oU
ring per piston, all above pin. Narrow heat-dam
groove (no ring fitted) above top ring. OU ring
groove drUled with ten 5/32" oU drain hole.
Ring
Width End Gap Side Clearance
Compression
%"
013-.018"
0015-.002"
OU Control
3/16" 013-.018" -....0015-.002"
NOTE—Install compression rings with step down.
Replacement Rings:—Oversizes .010", .020", .030".
PISTON PIN:—Diameter—%". Length—2%".
Pin locked in connecting rod.
Pin Fit in Piston—Light push fit (rod should rock
in piston of own weight. Clearance .0001-.0003".
NOTE—Replacement pistons have pins fitted.
CONNECTING ROD:—Weight—33.2 ozs. Length—8%".
Crankpin Journal Diameter—2.18675-2.18775".
Lower Bearing—Spun babbitt. Rods exchanged.
Clearance— .0005-.002". Sideplay—.005-.009".
Bearing Adjustment:—None. Replace rods. Rods furnished std. and .010", .020" undersize. Ream to give
Clearance Of .0005-.002". See Studebaker
for 'Palnut' installation (some
cars).
Shop
Notes
InstaUing Rods:—InstaU rods with narrow half of
bearing toward front in cylinders # 1 , 3, 5, toward
rear in #2, 4, 6. Marks on caps and rods must be
together and oU hole toward camshaft.
CRANKSHAFT:—4 bearing, integral counterweights
with vibration dampener at forward end.
Journal Diameters—2.4995-2.500" aU bearings.
Journal Diameters—2%".
Bearing Type—Removable steel-backed, babbittUned type. Clearance—.0005-.0025".
Bearing Adjustment:—None (no shims). Replace
bearings. Furnished Std., .010", .020" undersize.
Tighten bearing cap bolts to 1100 in. lbs.
End Thrust:—Thrust plate assembled between front
bearing and crankshaft gear. ControUed by shims
six, COMM.,
STATE COMM. 7A, SA
between plate and bearing. Endplay .003-.006".
CAMSHAFT:—Four bearing. Helical gear drive.
Bearings—Steel-backed, babbitt-lined, split type
bushings. When replacing, oU holes in block and
bushing must be in alignment.
Clearance— .00075-.00225" (#1), .002-.00375" (others).
End Thrust:—Steel thrust washer and spacer between
gear hub and front bushing.
Timing Gears:—Crankshaft (cast-iron). Camshaft
(Celeron F a b r i c ) . See Studebaker Shop Notes for Gear
Removal & Replacement Gear size
selection.
Camshaft Setting:—Mesh marked camshaft gear
tooth with two marked teeth on crankshaft gear.
VALVES:
Head Diameter Stem Diameter Length
Intake
1 15/32"
11/32"
5 7/32"
Exhaust
1 9/32"
_
11/32"
5 7/32"
Seat Angle
Lift
Stem Clearance
AU valves
45°
11/32"
001-.003"
Tappet Clearance—.016" aU valves (cold). Remove
right hood side panel for work on valves. See Studebaker Shop Notes for Side Panel Removal.
Valve Guides:—Pressed in block from above (1 5/32"
below upper edge of valve seat) with stepped end
down. Ream to inside diameter of .3435-.3445".
Valve Springs:—InstaU with closed coU at top. Damper on top of spring. Replace spring if 10% weak.
See Studebaker Shop Notes for Valve Spring
tion
instructions.
Installa-
Spring Pressure Spring Length
Valve Open
125-135 lbs
134"
Valve Lifters:—Barrel type (no separate guides). Can
be removed from top. Furnished .0005", .001" ov'size.
Valve Timing:—See Camshaft Setting above.
Intake Valves—Open 15° BTDC. Close 49° ALDC
Exhaust Valves—Open 54° BLDC Close 10° ATDC.
To Check Timing—Set tappet clearance # 1 intake
valve at .020". This valve should open with piston
15° or .0942" before top dead center when mark
TN-OP.1-6/' on vibration damper at front of engine
lines up with pointer on gear case cover. Reset tappet clearance at .016" (cold).
Motor Gauge—Weidenhoff Adapter #104, Rod #2.
LUBRICATION:—Pressure system with oU pump
mounted on right of engine. See Studebaker Shop
Notes for Oil Pump installation
instructions.
Normal OU Pressure:—40 lbs. (min.) at 40 MPH.
OU Pressure Regulator:—Located on right front corner of engine. Operates at 40 lbs. Not adjustable.
Crankcase Capacity:—5y2 qts. C38), 6 qts. C39).
COOLING SYSTEM:—Capacity—14% qts.
Water Pump:—Centrifugal with adjustable packing.
See article in Mechanical
Equipment
Section
for
Equipment
Section
for
9A (1939)
brake release or lengthen rod for later release.
Removal:—Remove transmission (see Transmission
Removal foUowing), support engine at rear, remove
rear engine mountings, remove clutch housing. Take
out mounting screws and remove clutch.
TRANSMISSION:—Warner. Synchro-mesh, aU helical
gear, 'horizontal' type with conventional shift lever
Std. Overdrive Transmission Optl. (1939 type has
electrical 'kick-down' control).
See article in Mechanical
Equipment
Section
for
data.
See article in Mechanical
Equipment
Section
for
data.
1939 Overdrive Note—Adjust Overdrive control
whenever accelerator pedal linkage disturbed.
Transmission Control:—Evans-Studebaker vacuum
type (1938), Own remote control (1939) Optional.
Removal:—Remove shift lever or disconnect shifter
shafts, disconnect drive shaft at front and rear
universals, disconnect rear support at frame ends
(Overdrive transmissions). Remove transmission
mounting screws at clutch housing, puU transmission back and lift OUt. See Studebaker Shop Notes for
Overdrive
Rear Support
Installation
directions.
UNIVERSAL JOINTS:—Thompson (1938). Spicer Models 1271-OIX front, 1278-OIX rear (1939).
See article in Mechanical
Equipment
Section
for
data,
See article in Mechanical Equipment
R a t i o — 4 . 5 5 - 1 S t d . , 4.82-1 Optl.°
Section
for
data.
REAR AXLE:—Spicer Model 41-2. Semi-floating, hypoid
gear type with Hotchkiss drive.
Backlash—.005-.007". Shim adjustment
Removal:—Hoist rear of car, disconnect propeller
shaft at rear universal, brake line, and shock absorbers, remove spring U-bolts, disconnect rear
spring shackles, withdraw axle assembly.
Wheel Bearing Adjustment—Shims provided between flanged end of axle housing and brake backing plate. To adjust, remove wheel, hub, drum, and
backing plate (retained by 6 nuts). Remove shims
to decrease endplay, add shims to increase. Shim
thickness at both wheels must be equal within .005".
Endplay— .001-.005". Measure with dial indicator.
SHOCK ABSORBERS:—Houdaille.Front>-BEDVS C38),
BBFS C39), Rear—ASC C38), ACHS C39). Double
acting, hydraulic, adjustable type with thermostatic
control (rear only).
See article in Mechanical
Equipment
STEERING:—Steering Gear—Ross
Lever type. Model T-14.
Section.
Cam-and-Twin-
See article in Mechanical
Equipment
Section
for
data.
See article in Mechanical
Equipment
Section
for
data.
See article in Mechanical
Equipment
Section
for
data.
See article in Mechanical
Equipment
Section
for
data.
data.
Front Suspension:—Planar type independent suspension with transverse spring. Specifications below apply with car unloaded on level floor.
data.
Kingpin IncUnation—5%°.3
Caster—Minus %° to plus A°. Not adjustable.
Camber—%-%°. Adjustable.
Toe In—1/16-%". Adjusted by turning right hand
C38), center ('39) tie rod. Other tie rods not adjustable.
BRAKES:—Service—Lockheed hydraulic, double anchor
type. Hand lever applies rear service brakes.
Removal—With water drained and fan belt removed, disconnect pump inlet hose, take out pump
mounting bolts, lift fan and pump assembly off.
Thermostat:—Bishop & Babcock or Fulton. In cylinder head water outlet. InstaU with bellows down.
Setting—Starts to open 148-153° C38), 156-160° ('39).
CLUTCH:—Borg & Beck Model 9A6. Model #869
stamped on cover. Single plate, dry disc type.
See article in Mechanical
(1938), COMMANDER
Facings—Moulded (flywheelside), Woven (opposite
side). Inside Diam. 5%". Outside Diam. 9%". Thickness .133"
Adjustment—Free travel 1" (min.). Sleeve adjustment on rod connecting pedal to shaft lever. Turn
sleeve out for greater travel, in for less. Check HUlHolder after adjusting clutch.
HUl-Holder Adjustment:—On cars with HUl-Holder
check action after adjusting clutch to see that
brakes release just before clutch engages. Adjust by
loosening locknut and turning adjusting nut at end
of hUl-holder control rod. Shorten rod for earUer
Wheel Cylinders—Stepped or two-stage bore type:
Front Wheels—Front shoe cylinder 1%". Rear 1".
Rear Wheels—Front shoe cyUnder VA". Rear 1".
NOTE—Wheel cylinder bore size marked on casting.
Drum—Budd composite. Diameter—11".
Lining—Front shoe—woven. Rear—moulded. Width
2". Thick. 3/16". Length per wheel 19 11/16".
Clearance—.010" toe, .005" heel, for each shoe.
Hand Brake Adjustment:—See Service Brakes.
HUl-Holder:—Optional equipment.
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