ENGINE:
Type..................................... F-Head
Number of Cylinders...................... 4
Bore..................................... 3 1/8"
Stroke................................... 4 3/8"
Piston Displacement...................... 134.2 cu. in.
Bore Spacing (center to center):
1 and 2, 3 and 4........................ 3.437"
2 and 3................................. 4.938"
Firing Order............................. 1-3-4-2
Compression Ratio:
Standard................................ 6.9:1
Compression Pressure..................... 120 to 130 psi.
Number of Mounting Points:
Front.................................. 2
Rear................................... 1
Horsepower (SAE)......................... 15.63
Horsepower (Max Brake)................... 68 @ 4000 rpm.
Maximum Torque @ 2000 rpm................ 113 lb-ft.
Idle Speed............................... 600 rpm.
PISTONS:
Material................................. Aluminum Alloy
Description.............................. Cam Ground, T-slot, Tin Plated
Length................................... 3 3/4"
Diameter (near bottom of skirt).......... 3.1225" to 3.1245"
Weight................................... 13.5 oz.
Clearance Limits:
Piston-To-Cylinder Bore................. Selective Feeler Fit
Ring Groove Depth:
No. 1 and 2 Ring........................ .1593" to .1655"
No. 3 Ring.............................. .1693" to .1755"
Groove Width:
No. 1 Ring.............................. .0955" to .0965"
No. 2 Ring.............................. .095" to .096"
No. 3 Ring.............................. .1875" to .1885"
Piston Pin Hole Bore..................... .760" to .770"
Cylinder Bore - Standard................. 3.125" to 3.127"
-- max. out of round.................... .005"
-- max. taper........................... .005"
-- max. rebore.......................... .040"
PISTON RINGS:
Function:
No. 1 and 2............................. Compression
No. 3................................... Oil
Material:
No. 1................................... Cast Iron, Chrome-plated Face
No. 2 and 3............................. Cast Iron
Width:
No. 1 and 2............................. 3/32"
No. 3................................... 3/16"
Gap (Std. to .009 Cyl. Bore)............. .007" to .045"
Thickness:
No, 1and No. 2 Rings.................... .134" to .144"
No. 3 Ring.............................. .115" to .125"
Side Clearance in Groove:
No. 1 Ring.............................. .002" to .004"
No. 2 Ring.............................. .0015" to .0035"
No. 3 Ring.............................. .001" to .0025"
PISTON PINS:
Material................................. SAE 1016 Steel
Length................................... 2.781"
Diameter................................. .8119" to .8121"
Type..................................... Locked in Rod
Clearance in Piston (selective fit)...... .0001" to .0003"
CONNECTING RODS:
Material................................. SAE 1141 Forged Steel
Weight................................... 32 oz.
Length (center to center)................ 9.187"
Bearing:
Type.................................... Removable
Material................................ Steel-backed Babbitt
Length Over All......................... 1.089" to 1.099"
Clearance Limits........................ .001" to .0019"
Undersize Bearings Available............ .001"
.002"
.010"
.012"
.020"
.030"
End Play................................ .004" to .010"
Installation............................. From Above
Bore:
Upper................................... .8115" to .8125"
Lower................................... 2.0432" to 2.0440"
CRANKSHAFT:
Material................................. SAE 1040 Forged Steel
End Thrust............................... Front Bearing
End Play................................. .004" to .006"
Main Bearings:
Type.................................... Removable
Material................................ Steel-backed Babbitt
Clearance............................... .0008" to .0029"
Undersize Bearings Available............ .001"
.002"
.010"
.012"
.020"
.030"
Journal Diameter........................ 2.3331" to 2.3341"
Bearing Length:
Front.................................. 1.64"
No. 2.................................. 1.72"
No. 3.................................. 1.72"
Out of round and out of taper limits... .001"
Direction of Cylinder Offset............ Right
Amount of Cylinder Offset............... .125"
Crankpin Journal Diameter................ 1.9375" to 1.9383"
Flywheel Run Out (max.).................. .005"
CAMSHAFT:
Bearings:
Material............................... Steel-backed Babbitt (Front only)
Number................................. 4
Clearance.............................. .001" to .0025"
Journal Diameter:
Front................................. 2.1860" to 2.1855"
Front Intermediate.................... 2.1225" to 2.1215"
Rear Intermediate..................... 2.0600" to 2.0590"
Rear.................................. 1.6230" to 1.6225"
Bearing Diameter:
Front................................. 2.1870" to 2.1890"
Front Intermediate.................... 2.125" to 2.126"
Rear Intermediate..................... 2.0625" to 2.0635"
Rear.................................. 1.625" to 1.626"
End Play................................. .004" to .007"
Drive:
Type.................................... Helical Gear
Crankshaft Gear......................... Cast Iron
Camshaft Gear........................... Pressed Fiber-Steel Hub
VALVE SYSTEM:
Valve Rotators........................... On Exhaust Valve
Tappets:
Clearance -- Cold:
Intake................................. .018"
Exhaust................................ .016"
Clearance for Timing (intake)........... .026"
Over All Length:
Intake................................. 2 3/4"
Exhaust................................ 2 7/8"
Stem Diameter............................ .6245" to .6240"
Clearance in Block....................... .0005" to .0002"
Timing:
Intake:
Opens.................................. 9° BTC
Closes................................. 50° ABC
Duration............................... 239°
Exhaust:
Opens.................................. 47° BBC
Closes................................. 12° ATC
Duration............................... 239°
Value Opening Overlap................... 21°
Valves:
Intake:
Material............................... SAE 5150
Length Over All........................ 4.781"
Head Diameter.......................... 2"
Angle of Seat.......................... 45°
Stem Diameter.......................... .3733" to .3738"
Stem-to-Guide Clearance................ .0007" to .0022"
Lift................................... .260"
Exhaust:
Material............................... Uniloy 21-12
Length Over All........................ 5.909"
Head Diameter.......................... 1.47"
Angle of Seat.......................... 45°
Seat Insert Material................... Eatonite EMS 58
Stem Diameter.......................... .371" to .372"
Stem-to-Guide Clearance................ .0025" to .0045"
Lift................................... .351"
Springs:
Intake:
Free Length............................ 1.97"
Standard:
Pressure @ Length:
Valve Closed......................... 73 lb. @ 1.66"
Valve Open........................... 153 lb. @ 1.40"
Service Minimum:
Pressure @ Length:
Valve Closed......................... 66 lb. @ 1.66"
Valve Open........................... 140 lb. @ 1.40"
Exhaust:
Free Length............................ 2 1/2"
Standard:
Pressure @ Length:
Valve Closed......................... 53 lb. @ 2.109"
Valve Open........................... 120 lb. @ 1.750"
Service Minimum:
Pressure @ Length:
Valve Closed......................... 47 lb. @ 2 7/64"
Valve Open........................... 110 lb. @ 1 3/4"
LUBRICATION SYSTEM:
Type of Lubrication:
Main Bearings........................... Pressure
Connecting Rods......................... Pressure
Piston Pins............................. Splash
Camshaft Bearings....................... Pressure
Tappets................................. Splash
Timing Gears............................ Nozzle
Cylinder Walls.......................... Nozzle
Oil Pump:
Type.................................... Internal Rotor
Drive................................... Camshaft Gear
Minimum Safe Oil Pressure:
At Idle................................ 6 psi.
At 2000 rpm. (35 mph.)................. 20 psi.
Relief Valve Opens...................... 40 psi.
Normal Oil Pressure..................... 35 psi. @ 2000 rpm.
Oil Pressure Sending Unit................ Electric
Oil Intake............................... Floating
Oil Filter System........................ Partial Flow
CARBURETER SPECIFICATIONSFor Willys 4 Cylinder Engine: 3 1/8 Inch Bore, 4 3/8 Inch Stroke | ||
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Dimensions: Flange size, 1 1/4 inch S. A. E. Primary venturi, 11/32 inch I. D. Secondary venturi, 19/32 inch I. D. Main venturi, 1 1/4 inch I. D. Float Setting: Distance from seam of float to float chamber cover, with weight of float on needle and spring: 9/64 inch. Vents: Balanced thru air horn to air cleaner via tubing external to carbureter. Vent: Bowl chamber to carbureter bore, size No. 68 (.031 inch) drill. Gasoline Intake: Square vertical (spring loaded) needle No. 53 (.0595 inch) drill size in needle seat. Bleeder tube, as- sembled over idle tube, with 2 side holes--No. 65 (.035 inch) drill. Low Speed Jet Tube: Jet size, No. 70 (.028 inch) drill (in end of tube). Auxiliary jet (on side of tube) size: No. 75 (.021 inch) drill. By-pass (in air horn) size: No. 52 (.0635 inch) drill. Economizer (in body) size: No. 54 (.055 inch) drill. Idle Port: Upper port: slot type, length, .165 inch. Width, .030 inch. Idle Port Opening: Top of port--.125 to .129 inch above top edge of valve with valve tightly closed. |
Lower Port (For Idle Adjustment Screw): Size, .053 to
.057 inch diameter. Set Idle Adjustment Screw: 1/2 to 1 1/2 turns open. For richer mixture, turn screw out. Idle engine at 700 R.P.M. with deep fording vents open. Main Nozzle: In primary venturi, angle 20°. Discharge jet size, .0935 inch inside diameter. Main nozzle bleed (tube in air horn) Size: No. 70 drill. Metering Rod (Diaphragm operated): Economy step, .070 inch. Power Step .054 inch diameter. Vacuum passage restriction, size: No. 50 (.070 inch) drill Vacuum passage bleed to bore, size: No. 65 (.035 inch) drill. Metering Rod Jet: Size: .096 inch diameter. Accelerating Pump: Diaphragm type, vacuum operated. Dis- charge jet size, No. 72 drill. Intake ball check size: No. 40 drill. Discharge ball check under needle, size No. 50 drill. Vacuum passage restriction, in flange size: No. 52 (.0635 inch) drill. Vacuum passage air bleed to bore, size: No. 62 (.038 inch) drill. Pump Stroke: No adjustment. Choke: Manual--Offset, butterfly type with poppet valve. Vacuum Spark Port: None. | |
The engine specs come from the Repair Manual for the M38A1 CDN 2 and CDN 3.
The carb specs come from a one page bulletin from Carter Carburetor Form 4960B released March 1953, revised March 1956.
In both cases I have tried to keep as close as possible to the layout of the original.