From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
General instructions and adjustments for the Delco-Remy Vacuum Starting Switch on 1940 Buick models.
| Identifier | ExFiles\Box 122\3\ scan0212 | |
| Date | 2nd August 1939 guessed | |
| STROMBERG CARBURETOR VACUUM STARTING SWITCH (DELCO-REMY MODEL 1990127) GENERAL INSTRUCTIONS AND ADJUSTMENTS 1940 BUICK ALL MODELS FOREWORD The vacuum starting switch used on all models of 1940 Buick cars is a DELCO-REMY MODEL 1990127. The switch is assembled onto the Stromberg Carburetor by the Bendix Products Division and is properly adjusted to eliminate all manufacturing tolerances. Therefore, if any parts of the switch assembly require replacing or if the entire switch is assembled on another carburetor other than the original installation, it is necessary to check the timing of the switch. The following description and instructions should be carefully read and followed. GENERAL DESCRIPTION The switch is operated by the throttle shaft and vacuum of the engine. The electrical circuit is opened and closed by means of a contact rotor on the throttle shaft and two contact springs, one of which is combined with the lock-out lever. After the engine is started, the circuit is kept open by the lock-out lever contacting the guide pin, which is part of the diaphragm assembly. All electrical contacts and movable parts are located on the opposite side of the diaphragm from the vacuum chamber and are thus protected from gasoline fumes, gum deposits, etc. Air for the "breathing" action of the diaphragm is drawn through a felt gasket under the cover plate. The felt gasket serves as an air cleaner and no other type of material should be substituted. Two screws underneath the cover plate hold the switch to the throttle body. A gasket is used between the switch body and the throttle body to seal against the loss of vacuum. The contact rotor is directly connected to the throttle shaft and is correctly positioned by means of a timing washer. The diaphragm is located at the top of the assembly and is held in place by a die cast cover, which is attached to the switch housing. This cover forms the vacuum chamber and also positions the diaphragm return spring. A vacuum passage connects the diaphragm vacuum chamber to the carburetor barrel below the throttle valve. The function of the diaphragm is to operate the guide pin and prevent the contacts from closing when the throttle is open and the engine is running. In wiring the switch, always connect the wire having red crossing tracers to the terminal on the front of the switch. This is the "hot" wire and when so connected protects the lock-out lever from being accidentally short-circuited if it is bent back against the housing during the timing operation. Form 10C-635 Page 5 --- PAGE BREAK --- ing a lower number. Always recheck timing after replacing washer. ANOTHER PROCEDURE THAT CAN BE USED 1. (Same as above.) 2. (Same as above.) 3. Start engine and pull out hand throttle until clearance between throttle stop screw and cold idle cam, when cam is held in fast idle position, is approximately 1/4". 4. Turn off ignition. 5. Slowly close throttle by tapping lightly on the hand throttle lever until guide pin and lock-out release. 6. With throttle in this position, measure the clearance between the idle screw and the cold idle cam when the cam is held in the fast idle position. This clearance should be not less than 3/64" or more than 3/32". If clearance is less than 3/64", replace the timing washer with a higher numbered washer. If more than 3/32", replace washer with one having a lower number. Always recheck timing after replacing washer. LESS CLEARANCE THAN 3/64" MAY RESULT IN FAILURE TO ESTABLISH CONTACT IN COLD WEATHER. MORE CLEARANCE THAN 3/32" MAY RESULT IN CLASHING OF GEARS DURING ACCELERATION AT LOW SPEED. Page 8 Form 10C-635 BENDIX PRODUCTS DIVISION OF BENDIX AVIATION CORPORATION SOUTH BEND INDIANA Printed in U. S. A.{Mr Adams} | ||