Miscellaneous Technical Information   

I N D E X

HUDSON MOTOR CAR COMPANY
DETROIT, MICH., U. S. A.

TECHNICAL SERVICE NOTICE

    No. 08-001 - 1953   

To:  All Service and Dealer Outlets
       Hudson, Essex & Terraplane Belt and Hose Numbers

    The attached sheet, Table 1, gives the Gates belt and hose numbers by their catalog AP-533, effective April 18. 1953.

    A chart at the beginning of the listing in Table1 gives the Hudson and Gates part numbers.

    Table 2 lists V-belt sizes and angles.

* Indicates two required (Order belts in matched pairs).

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Ser: 1090
Sheet #1     
                                                                                                                                                   August 19, 1929

TO HUDSON-ESSEX DISTRIBUTORS AND DEALERS:
Hudson-Essex Oil Pumps

    The circulating splash oiling system employed on Hudson and Essex cars permits the use of a simple plunger type oil pump consisting of the pump body, main plunger and spring, inlet check valve, outlet check valve and in the case of the Essex, check valve springs, distributor plunger, spring and cap.

    In operation, the actuating eccentric forces the main plunger back against its spring and the pressure exerted on the oil forces it through the upper or outlet check valve. This In turn causes the distributor plunger -- which is located immediately above the upper valve -- to rise against the pressure of Its spring and uncover the outlet passage of the pump through which the oil then passes on its way to the front of the engine. As the offset or "throw" of the eccentric passes the center of the main plunger, the spring moves the plunger outward creating a vacuum which lifts open the lower or inlet check valve and draws in
a fresh charge of oil from the reservoir through the suction pipe and strainer.

- OIL PUMP REPLACEMENTS -

    Our inspection of Hudson and Essex oil pump assemblies replaced on cars and returned to us because of alleged defects, indicates that only a very small percentage of those in actually In a condition to justify replacement. In view of this and since most of the reasons for oil pump failure can be corrected in the field, we suggest that the following points be checked before
renewing assemblies.

    1. Broken main plunger spring.
    2. Plunger sticks in pump body.
    3. Suction pipe damaged in putting on pan.
    4. Suction pipe cracked or fittings loose.
    5. Distributor plunger sticks in body.
    6. Distributor plunger spring broken.
    7. Oil pump to front motor plate pipe cracked or fittings loose.
    8. Oil pressure gauge pipe cracked or fittings loose.
    9. Check valves not seating properly.
    10. Obstructions in suction pipe or pump inlet.
    11. Air leaks at inlet connection joint.
    12. Check valve sticks in body.
    13. Check valve spring weak or broken.

    In the event of oil pump difficulty, an inspection of the foregoing items will generally disclose the cause and suggest the remedy.

    Although it is generally understood that the oil pressure gauge reading is relatively unimportant -- being In no way indicative of the amount of oil pumped -- our inspection shows that the tension of the distributor plunger spring and even the spring itself is often changed to obtain a higher reading. This should be avoided as in many instances the bellows of the oil pressure gauge is distorted and the gauge rendered inoperative.

                                                                                                     HUDSON MOTOR CAR COMPANY

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Maintenance Procedures

1931-1937 - Hudson, Essex, & Terraplane

I. Valve Guides

1933-37 - Use a special. valve stem guide remover to drive the guides out. When replacing the guides use a special valve stem replacer. This tool is especially designed to drive the guides so that the top, in the six-cylinder engines, is 1-1/16" below the top of the cylinder block and in the eight-cylinder engines, 15/16"1 This position of the guide must be accurately maintained. After the guides are replaced they should be reamed .002" larger than the valve stem.

II. Tappets

1933-37- The tappet and guide assemblies can be removed without removing the cylinder head as follows: Remove the tappet chamber from the right side of the engine. Remove the valve spring seat retainer spring seats, spring dampener, and spring. Remove the tappet adjusting screw and replace by a short screw with a thin head. Remove the tappet guide clamp screw and clamp. The tappet and guide assembly can then be lifted out. If the complete set is to be replaced, remove cylinder head and valves and then remove tappet assemblies.

III. Valve timing

1931-32 Essex - The peep hole is on the right front side of the flywheel housing. Remove No. 6 spark plug and crank the engine until No. 6 piston is coming up on the compression stroke. Crank until piston passes TDC and the line 10 on the flywheel registers with the pointer on the peep hole. At this point No. 1 intake valve tappet should be tight and the valve about to open.

To set the sprockets, remove the chain case cover# the sprockets each have a punch mark. When Nos. 1 and 6 pistons are at TDC there should be 21 links between the marks on the sprocket, with pins Nos. 1 and 21 in the teeth with the marks.

1931-33 Hudson - Same as 1931-32 Essex only remove No. 8 spark plug.

1933 Terraplane & 1934-37 all - Correct timing is obtained by meshing the punch marked tooth of the crankshaft gear between the two punch marked teeth of the camshaft gear.

IV. Pistons and Rods.

1930-31 - Hudson 8 - Move assembly upward until pin is exposed and remove pin. Remove piston from top; rod from bottom.

1931 Essex, 1932-37 all - The piston and rod assemblies are removed from above after removing the cylinder head. Be sure to mark the assemblies so that they will be returned to the bore from which they were removed.

 V. Pistons, Renew

1934-37 - The code letters stamped on the cylinder block along the lower flange of the valve chamber designate the original size of each cylinder. The piston size, code letter, and weight in ounces and quarter ounces stamped on the head of the piston will help in selecting pistons correctly from stock * In addition to size and weight marks all original piston installations ire numbered to indicate the cylinder block number and the number of the cylinder in which the piston is fitted. Use 1935 type piston with one ring below pin, in 1934 cars.

Where a single piston is selected it should be of the same weight as the piston removed. Complete sets of new pistons should always carry the same weight stamp on all pistons. Unequal piston weight will cause rough engine operation.

After selecting a piston by the code letters, place it in the cylinder in which it is to be used with a 0015" feeler directly opposite the skirt slot. The position of the feeler is important due to the cam grinding of the skirt. If the piston is the correct size, the feeler can be removed by exerting from 3 to 4 pounds pull.
The table (below) gives the cylinder bore sizes from standard to .020" oversize for which pistons are available. Opposite each cylinder size is given the cylinder code (if any), the code letter of the correct piston size, and piston ring size.

It will be noted that the same ring size may be d6signited for more than one piston size. It is advisable to hone the cylinder to the smallest dimension for which a given ring is recommended. This gives a minimum piston ring gap. Always check rings to se that the gap is not less than .005".

Piston & Ring Fitting Table
1931-1937 Hudson

VI. Pins, renew

1934-37 - Select the pin so that it can be pushed into the piston boss with the heel of the hand when the piston is heated to 200º F. Heat the piston in boiling water or in an electric furnace. Heating with a blow torch or other concentrated heat or driving the pin in or out of the bosses will distort the piston. After the proper sized pin is selected, replace the connecting rod upper bushing and ream or burnish to .0003" larger than the pin. If this fit is correct the connecting rod will just turn on the pin under its own weight. when the rod is held in a horizontal position.

VII. Rings, renew

1934-37 - When fitting the pinned type piston ring, the gap between the ends of the ring and the clearance between the pin and the ends of the ring are equally important. The rings are cut and matched to fit the pin so that the clearance at the pin is equal to the gap between the ends of the ring. In other words, if the ring is compressed so that the ends come together there will be no clearance on the pin. If the ends of the ring are filed in fitting it is necessary to file an equal amount in the pin notch to maintain pin clearance. Filing should, however, not be necessary.

Piston rings of the pinned type are supplied in exact sizes to give a minimum gap of .005" when installed in a cylinder of the size for which the ring is designated. When oversize pistons are being fitted, the bores should be brought to a stock ring oversize. For example, a cylinder may clean up at .009" oversize. However, since no ring is available in this size it is advisable to hone the cylinder to .010" oversize rather than file the gap of - 1 set of .010" oversize rings to permit their use in a .009" oversize cylinder.

VIII. Main Bearing Caps

1934-37 - Use a puller to remove the front and rear bearing caps as sufficient force must be applied to shear the packing in the horizontal groove. After the cap is removed the packing should be throughly cleaned from the groove in the case and cap. After the bearing caps have been replaced and the stud nuts tightened and keyed, the packing should be replaced. Drive cotton wicking into the vertical holes of both the front and rear bearing caps.
After the rear main bearing cap has been installed, the lower half of the oil retainer should be checked to see that it fits tightly against the upper half. A gap between the two halves of the retainer will permit loss of oil. The rear main bearing oil return tube is soldered in the rear of the reservoir and registered with the rear main bearing drain hole. Be sure the gaskets used between the reservoir and dip trough tray, and also between the tray and crankcase have holes in line with the drain tube. If these holes are not open, oil will be lost out of the rear main bearing oil slinger. A flapper valve is located on the bottom of the oil return tube to prevent oil from being thrown up the tube and out of the rear main bearing. When the reservoir is level, this valve should be slightly open. check the valve to see that it moves freely against the end of the tube

ELECTRIC SYSTEM

I.       Ignition Timing

All sixes - With No. 1 piston near the end of the compression stroke, the breaker points should open when the DC 1-6 or UDC 1-6 mark on the flywheel lines up with the peephole pointer.

All eights - With No. 1 piston near the end of the compression stroke, the breaker points should open when the DC 1-8 or UDC 1-8 mark on the flywheel lines up with the peephole pointer.

If the car has two breaker points, the foregoing refers to the stationary points. To set the movable points, crank the engine a quarter turn until the DC 3-6 or UDC 3-6 line registers with the peephole pointer.
To synchronize the points with a gauge, set them to the correct gap and time the stationary points. Two timing lines will be found on top of the rotor. Place the gauge on the housing so that its pointer registers with the forward mark on the rotor. Then loosen the adjustable plate fastening screws and move the plate until the points just open.

1933-37 - After timing the ignition, adjust the octane selector as follows: When running about 8 mph in high gear open the throttle quickly -and fully. If a slight ping is heard between 10 and 15 mph the setting is satisfactory but if there is no ping, advance the distributor one graduation at a time until a slight ping appears but never advance the unit beyond the 3/4" advance mark.

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Carburetor Maintenance Notes:

      Downdraft-single - Turning the idle mixture screw in gives a leaner mixture. If the engine stalls while idling, reset the idle adjusting screw and the throttle lever adjusting screw. The normal position for the idle adjusting screw is shown in the table. If a good idle cannot be obtained in this manner, remove the low speed jet tube and inspect for dirt on foreign matter under the idle adjusting screw. If the needle end of the screw is badly scored, inspect for a chip in the needle seat and replace the scored needle with a new part. Clean the tube and all idle passages with compressed air. See that the tube seats air tight in the body casting, top and bottom.. If not, replace with a new tube of identical specifications. Never change a low speed jet from one carburetor to another.
  

      The accelerating pump am is provided with three holes for the connector link, giving short, medium and long strokes. The medium stroke is correct for ordinary temperatures and standard gasoline. The short stroke should be used in extremely hot climates, high altitudes, or with high test fuel. To set the pump arm lever it is necessary to remove the cover from the top of the accelerating pump. It is important that the countershaft operating the accelerating pump be lubricated when the cover is removed and at least every 5,000 miles. To lubricate the shaft, remove the screw attaching the dust cover and fill the threaded hole with a good grade of gvaphite grease. Increased resistance on the accelerator pedal indicates a clogged pump jet or bent connector link. The pump jet and ball check strainer should be removed and cleaned with compressed air. All jets and ball checks must be seated gasoline tight. In all cases when the pump jet is found plugged the metering rod setting should be checked with a metering rod gauge to be sure that it is as specified in the table.
  

      Poor accelerating, stumbling on jerking may be due to loose plunger, worn or damaged plunger leather, or sediment in the pump cylinder, dirt under the ball checks, or defective relief disc checks. If it is necessary to replace the plunger spring or leather, make certain that the nut inside the plunger cup is screwed down tight to avoid air leaks. If the pump leather is stiff and not sealing properly, correct it by flaring out the bottom edge. Before replacing the bowl cover, depress the pump plunger to check for fuel by-passing back into the bowl through the relief disc, Not more that three or four drops should escape past the disc check. Always use a loading tool when replacing the plunger in the cylinder to avoid damage to the leather.
  

      If the carburetor loads up after considerable service, the float level should be checked, Wear on the lip of the float lever will raise the float level. To check the float level, remove the dust cover. Disconnect the metering rod, throttle connector rod and plunger shaft. Take off the float chamber cover and remove the cork gasket fro# the cover. Invert the cover, holding needle seat away and the float in a horizontal position. Place a steel scale on the metal rim which holds the pump gasket. Measure to the nearest point on the float. The correct distance is shown in the table. To reset the float, bend the lip of the float lever. A very slight bend is sufficient. Be sure that the lugs on the float lever permit the float to drop at least ill from the specific level when the float bowl is empty. When replacing the float bowl cover,, use a new gasket and be sure the gasket seals air tight against the body.
  

      Correct setting of the metering rod is important. If the metering rod is set to high in the jet, the fuel economy will be poor. If the metering rod is set low, operation at part throttle will be jerky and missing may occur. The metering rod position should be checked when carburetors are serviced or when other than standard rods are installed. A gauge is necessary for checking the setting of the metering.

Carburetor Maintenance
1933-1937 Hudson & Terraplane

      The mixture quality is controlled by a metering rod which operates within the metering rod jet, and is operated by the throttle lever. There are two or three steps of different diameters on this metering rod. The larger diameter, or economy step, controls the fuel flow to about seven-eights throttle, when the smaller diameter, or power step, becomes effective, giving full power for either high speed or hard low speed pulling.
   

      Metering rod position should be checked when carburetor is serviced or when leaner than standard rod is installed, To make a check, remove dust cover and disengage upper end of throttle connector rod. Back out throttle lever adjusting screw so that throttle closes tight.   Remove metering rod, turning rod 1/4 turn to disengage it from pump arm. Insert gauge shown in specification table in place of metering rod, seating beveled end in metering rod jet. Hold gauge verticle to insure seating. Metering rod pin in pump am should rest on top of gauge with throttle fully closed and upper end of connector rod centering freely in hole. Remove gauge and replace metering rod and disc and metering rod spring. Be sure that the metering rod is in the jet. If metering rod shows wear, replace it. Fill threaded hole under dust cover with a good grade of graphite grease and replace dust cover.

      If the carburetor is equipped with an anti-pereolator, always recheck the adjustment after gauging the metering rod setting.

Downdraft-Dual
      The operation and adjustments for these dual carburetors are practically the same as already described for the single barrel carburetors, the main difference being that there are two idle adjusting screws.
   

      To check the float level, remove the air horn assembly and float bowl cover and disengage the metering rods by removing the metering rod am and pin. The level of the float is then measured as already described.
  

      The countershaft operating the accelerating pump is lubricated by turning the metal cap covering the two oil holes on the top of the cover.

ANTI-PERCOLATOR  ADJUSTMENT 

   HUDSON 6, 8; TERRAPLANE 6, 1936 - The anti-percolating unit should be adjusted after the metering rod has been set but the setting of the metering rod should not be disturbed when adjusting the anti-percolator unit. The anti-percolator cap should be off its seat when the throttle is closed to idling position. If the cap does not open under this condition, bend the anti-percolating cap arm upward slightly to allow the pump arm to depress  bracket.

   The cap must be on its seat when the throttle is opened slightly beyond the idling position or with a .030" opening between the edge of the throttle valve and the carburetor bore opposite the port. To check this setting insert a .030" gauge between the valve and the wall of the carburetor. Now adjust the rocker arm for .005" to .015" clearance between the rocker arm tip and the pump arm.

UNLOADER AND FAST IDLE

   HUDSON 6, 8; TERRAPLANE 6, 1936 - With the throttle wide open, adjust the curved lip on the fast idle block so that the lower edge of the choke valve is the distance shown below from the inner wall of the air horn. With the throttle and choke valve wide open, adjust the lip on the choke lever to hold the choke valve in its wide open position. When the throttle is closed, the choke valve is released. The fast idle mechanism requires no adjustment.

Hudson 6, 8 - 7/16" - Terraplane 6 - 7/16"

1931-1932 Essex 6 - Marvel VE3

   All jets have fixed openings and are not adjustable. Adjusting the air valve screw is the only mixture adjustment. To make an adjustment, turn the air screw so that its end is flush with the end of the ratchet spring bearing against it. Run the engine until it is warm. Turn the air valve screw out clockwise until the engine hesitates from too lean a mixture. Now turn the air screw in three or four notches at a time until the engine runs smoothly.

   Next open the throttle a small amount and immediately allow it to snap back to its closed position to see if the engine will continue to idle smoothly. If it stalls, the air screw should be turned slightly to the right. If the engine rolls the air screw should be turned slightly to the left. When the setting is correct, the carburetor is in complete adjustment for the entire range of engine speeds and loads.

   To check the float level, remove the carburetor bowl cover assembly and turn it upside down. The distance from the surface of the bowl cover to the top of the cork float should be 11/32" for the VE3 carburetor. The over-all length of the air valve spring should be 1-1/2", If the length is not correct, the spring should be replaced, never altered.

   When a heat control is fitted, the control lever on the dash must be set at "ON" when the adjustment is being made.

CARBURETOR NOTES: CARTER

261S (1933Essex-Terraplane 8) - Idle port: Keyhole type. Length .176: width .040". #54  drill  at bottom. Idle port opening: .018” to .022” with valve closed tight.

282S (1934 Hudson all) - Idle port: Length, .200", width, .030”. Idle port opening - .016” to .020” with valve closed tight

309S (1935 Hudson 6, Terraplane GU) - Idle port: Length, .200"; width .030". Idle port opening: .016” to .020” with valve closed tight.

311S (1936 Hudson 6, 1935 Terraplane G) - Idle port: Length, .200", width .030". Idle port opening: .016” to .020” with valve closed tight.

329S (1936 Hudson 6, 1936 Terraplane 62) - Idle port: Length, .200"; width, .030. Idle port opening: .016” to .020” with valve closed tight.

330S (1936 Hudson 8) - Idle port: Length .200", Width .030". Idle port opening .016 to .020" with valve closed tight.

331S (1936 Terraplane 61) - Idle port: Length .200", Width .030". Idle port opening .016” to .020" with valve closed tight.

345S (1937 Hudson early; 1937 Terraplane 72) - Idle port: Length .145", Width .030". Idle port opening .013" to .019" with valve closed tight.

348S (1937  Terraplane 70, 71, 78) - Idle port: Length .200", Width .030". Idle port opening .016" to .020" with valve closed tight.

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Piston and Ring Data
1935-1950 Hudson Built Cars

Distributor Specifications - Auto-Lite
1935-1950 Hudson

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Note A - Generator number stamped on plate riveted to housing
Note B - CL - Clockwise (viewed from drive end.
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1950-1957
Hudson Distributor Specifications
Auto-Lite & Delco-Remy Distributors

PLEASE SEE THAT THIS LETTER REACHES YOUR SERVICE MANAGER OR HEAD MECHANIC IMMEDIATELY

TO HUDSON DISTRIBUTORS AND DEALERS

Following is the step by step outline covering the carburetor and linkage adjustment for Hudson 7-B with Twin Carburetors:

1. Remove front and rear air cleaners.

2. Install linkage adjusting pin J-2544-1 through accelerator pedal link bellcrank lever and into hole in cylinder block provided for adjustment purposes.

3. Connect tachometer to distributor but before warming up the engine remove the clevis pins from the yokes at the ends of both throttle shaft to carburetor rods. While holding the front carburetor fast idle cam in the "off" position, turn the throttle stop screw until it just touches the cam. Repeat with the rear carburetor.

Turn the idle mixture adjustment screws down until they are seated lightly and then back them out 2 turns. Warm up the engine and bring the engine idle to 500 rpm for Hydra-Matic transmissions, 550 for standard transmissions and 575 for overdrive by turning the two throttle stop screws in or out equal amounts.

Adjust the mixture adjustment screw on each carburetor to get the maximum increase in idling speed and if necessary, readjust the throttle stop screws to cut the idling speed down to the recommended rpm. When adjusting the idle speed always turn each throttle stop screw an equal amount.

4. Adjust front and rear throttle shaft to carburetor rod clevises so that clevis pins pass freely through clevis and cross shaft levers. Install clevis pins and clevis cotter pins.

On cars equipped with Hydra-Matic transmission, adjust throttle rod by disconnecting transmission throttle rod trunnion from accelerator pedal link bellcrank. Push rearward on transmission throttle rod to hold transmission T. V. lever against stop in transmission and adjust throttle rod trunnion so pin of trunnion slips freely into bellcrank. The throttle rod should then be shortened by 1/16" or 1-3/4 turns clockwise of the top trunnion jam nut. Lock this adjustment by tightening the lower jam nut against the trunnion.

6. Remove the linkage adjusting pin J-2544-1.

7. Adjust the length of the accelerator pedal to bellcrank rod to get 1/64" to 1/16" clearance between the pedal and the pedal Stop at wide open throttle.

8. Reinstall air cleaners.

Ref: Hudson Service Merchandiser

June 1952

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Hudson Motor Car Company Shipments (1909-1954)
& Registratons (1922-1957)

1. Hudson – 1909-1954 (Shipments)