NHRA RACING Ford Stock Replacement 735 CFM Class Legal Carburetor P/N

Transcription

1 NHRA RACING Ford Stock Replacement 735 CFM Class Legal Carburetor P/N Primary Venturi: Secondary Venturi: Throttle Bore: Service Carburetor Installation and Adjustment Instructions Congratulations on your purchase of the Holley NHRA Racing Carburetor! This carburetor is being built as a new carburetor for NHRA Super Stock and Stock Eliminator competition. It has a choke plate and shaft per NHRA rules, but is locked open for racing use. This carburetor is in no way meant to be a reproduction replacement for the carburetor. WARNING: To preserve the warranty, these instructions must be read thoroughly and completely, BEFORE, DURING, and AFTER installation. The carburetor is designed as a universal-type carburetor. It is a "square" carburetor and should NOT be used with adapters on spread-bore manifolds, since adapters may have an adverse effect on cylinder-to-cylinder distribution. WARNING: This carburetor is NOT designed for use with ANY automatic overdrive transmissions. IMPORTANT NOTE: The carburetor is not designed to pass any emission laws. It is to be used only for competition/off road vehicles or vehicles not required to comply with any exhaust emissions standards. IMPORTANT NOTE: The is not legal for street / highway use. INSTALLATION: 1

2 1. Remove the air cleaner, exercising care to carefully detach any vacuum lines to the cleaner and marking them, so they can be reassembled to the cleaner in the same manner. 2. Remove the existing carburetor by following the procedure outlined below: A. Carefully disconnect the fuel line. B. Disconnect and mark all the vacuum lines to the carburetor. (Note: The lines that ultimately go to the distributor, temperature sensing valve, etc.) C. Disconnect the PCV hose. D. Disconnect the choke rod or heat tube. E. Disconnect and remove the throttle linkage and the automatic kickdown linkage. Save all the retaining clips. F. Unbolt and remove the carburetor from the manifold. G. Remove the old flange gasket and clean the manifold face, being careful to keep particles from falling into the manifold. 3. Before installing the Holley carburetor on the manifold, remove the transmission lockout screw on Ford vehicles with automatic transmission. Ford Applications: Figure 1 Most Ford applications require the use of P/N Remove the throttle cable ball from the original carburetor and mount it in a similar location on the Holley. (There is one throttle ball provided in the unassembled parts, if the original is unavailable. Different size balls can be purchased under Holley P/N 20-2.) Applications with automatic transmissions, will remove the lockout screw from the actuating lever and install the transmission adjusting screw and the screw lock (black clip). Fasten the spring perch, P/N 20-91, as shown in Figure 2. Make certain that the locating pin on the perch is in the hole of the throttle body. Install the transmission kickdown spring between the kickdown lever and spring perch. Hold the carburetor throttle in the extreme wideopen position and back out the transmission kickdown adjusting screw, until it just contacts the tang on the throttle stop lever. Recheck this with the carburetor on the car. 2

3 Figure 2 4. Place the new carburetor flange gasket provided in the proper position on the intake manifold. 5. Place the carburetor on top of the flange gasket on the manifold. Install the holding down nuts and snugdown nuts in a "crisscross" pattern (Figure 3). Snug down nuts in a progressive manner (tighten each nut twice). Do not overtighten nuts, as damage to the throttle body could result. 6. Reconnect the throttle and transmission kickdown linkage, throttle, (and kickdown, if so equipped), return springs. Operate the linkage to ensure correct travel by opening to wide-open throttle and back to closed throttle. Operate the linkage from inside vehicle and have someone check to ensure the complete opening of the throttle plates. Readjust the throttle cable, if necessary. WARNING: Check assembled linkage for sticking and/or binding throttle action by holding the primary open and manually operating the secondaries. Any sticking, binding, or other interference in the throttle linkage could result in uncontrolled engine speed. Figure 3 7. Reconnect the appropriate vacuum hoses to the carburetor, noting the correct fitting from Figures 5 and 6. A. Plug any vacuum source not used. B. The timed spark fitting does not provide vacuum for distributor advance at idle. Vacuum for advance is available as soon as the throttle is opened from idle and the engine is placed under a load, such as acceleration or cruise. C. If the vacuum for more than one component is needed, use the small plastic vacuum T s available at most automotive stores. 3

4 4 Figure 4

5 Figure 5 8. The fuel line will have to be cut and connected to the carburetor using a "dual feed" fuel line. When cutting the fuel line use a tube cutter to provide a clean cut. WARNING: In all cases where the fuel line has been cut, it is essential that it be clean to ensure that no metal particles enter the fuel bowl after a new carburetor installation. This is performed by disconnecting the fuel line at the pump and blowing the line clean with compressed air. 5

6 Holley does not recommend the procedure where the coil wire is disconnected, the engine is cranked for a few revolutions, and the fuel is collected in a container. This procedure is unsafe because sparking can occur either at the coil, or at the distributor end of coil wire, and then ignite any fuel spilled in the engine compartment. CAUTION: It is mandatory that a quality inline fuel filter, such as Holley P/N or (Figure 6) be installed between the fuel pump and carburetor. This is mandatory as a safeguard against possible flooding, which could result from unfiltered foreign particles becoming lodged between the fuel inlet needle and its seat. Absence of such a fuel filter, voids the carburetor warranty. Filter elements should be blown clean with compressed air every 6,000 miles and replaced every 12,000 miles to ensure maximum protection. 6

7 NOTE: Holley Trick Kit P/N contains all the necessary parts and instructions to tune your carburetor for peak OFF ROAD USE ONLY performance. 9. Start the engine and check the fuel line and inlet fittings for possible leaks. At this time, recheck to ensure that all existing vacuum hoses are reattached properly. Plug any fittings not used. Set the idle to the manufacturer's specifications. 10. Remove the air cleaner stud from the original carburetor and install on the Holley. Use the original air cleaner gasket on the Holley. Install the air cleaner and attach the vacuum hose. With some air cleaner configurations, it may be necessary to use an air cleaner spacer to provide adequate clearance between the carburetor and air cleaner. Holley has a spacer available under P/N Figure 6 Quality Inline Fuel Filter WARNING: Inadequate clearance between the air cleaner and throttle lever could result in uncontrolled engine speed. Check the clearance between the manual choke lever and air cleaner for proper operation. CAUTION: Check the clearance between air cleaner and hood before closing hood completely. ADJUSTMENTS: 1. Fuel Level: On level ground with the engine running, remove the primary and secondary fuel level sight plugs. Loosen the lock screw and turn the adjusting nut clockwise to lower the fuel level and counterclockwise to raise the level. The fuel level will be properly adjusted when fuel begins to trickle out of sight hole. Tighten the lock screw and replace the fuel level sight plugs. 2. Choke: If the fast idle speed provided during the choke operation needs any adjustment, turn the engine off. Close the choke exposing the fast idle adjusting screw. Use a small open wrench for the ease of adjustment. MAINTENANCE WARNING: Fuel systems components, which are required to operate under severe conditions such as high underhood temperatures, should be periodically inspected to ensure no fuel leakage and the soundness of hoses. High temperatures promote faster aging of non-metallic materials. Hoses, which exhibit surface cracks when bent 180, should be replaced. The presence of liquid fuel demands the tightening of fittings, hose replacement, and retorquing of the fuel system component flange nuts. Tightening of the carburetor fuel bowl screws should provide in./lbs. of torque in a clockwise direction. Periodically recheck the bowl screw torque to ensure proper fuel metering. Inadequate bowel screw torque is often characterized by a condition similar to a defective power valve (i.e. black smoke from the exhaust at idle and cruise). GENERAL: Correct the engine timing, spark plug gap and heat range, distributor point condition and wiring, valve lash, condition of PCV valve, and correct operation of the exhaust heat valve are very important to optimum efficiency and performance. For additional information, consult Holley Carburetors (H.P. Books) and Holley Service Guide No. 2 (Holley P/N 36-71). 7

8 Holley Performance Products P.O. Box Bowling Green, KY Technical Service: Fax: For online help, please refer to the Tech Service section of our website: Printed in U.S.A. Holley Copyright 2002 Performance Products Date: R