Table of Contents
Kinsler_Handbook_#32 December 2017
212 Kinsler Fuel Injection, Inc, 1834 THUNDERBIRD TROY, MICHIGAN 48084 U.S.A. www.Kinsler.com Phone (248) 362-1145 Fax (248) 362-1032 ADJUSTING THE METERING UNIT TURNBUCKLE VERSUS SHIM AND ECCENTRIC FUEL RATE CHANGES If a wide open throttle fuel rate change is made by changing shims or using the eccentric pin, it will affect the idle fuel rate since the shuttle travel at the idle position will also be changed by the same amount. Reset the idle fuel rate for best throttle response. Changing the “idle” fuel rate by using the hex link to reindex the fuel cam does not affect the wide open throttle (wot) fuel rate when using a KINSLER cam as it has no lift cut into it from 65 o to 90 o past it’s nominal idle position. This is not only convenient, but proper, as a throttle plate does no throttling after about 65 o of opening, so the engine is at wot air flow from that point on, and needs no additional fuel. ANGLES The throttle plates are cut at a 14 o angle so they won’t stick in the throttle bore. Idle is about 1 o , or 15 o total, so the throttle shaft only rotates about 75 o to wide open throttle (90 o ) from an idle. The fuel cam is connected to the throttle shaft with a parallel four bar linkage (see Page #62) so it also rotates about 75 o to go from idle to wot. Since it has no lift from 65 o of travel to 90 o , it can be reindexed to set idle fuel rate without affecting the wot fuel rate at all. It is rare to reindex the fuel cam more than 5 o from the as shipped position to change the idle fuel rate significantly. Some fuel cams have reference lines placed on them for checking the nominal, or “as shipped” cam position. The marks should be aligned as shown in Fig. 1 when the throttles are wide open on small block Chevrolets. On big block Chevrolet units, the throttle would be closed. TO MAKE LARGE MIXTURE CHANGES Remove the four nuts securing the top of the metering unit and remove it. Adding shims makes the unit richer (moves fuel cam farther from lifter). A .002” shim change will usually take care of a large change in atmo- spheric conditions. SETTING IDLE FUEL RATE Note : The “idle” fuel rate should be set for best throttle response as you quickly open the throttles; not for a smooth nonsmoking idle. The Lucas unit does not have an “accelerator pump shot”, so the idle must be rich to compensate for this. 1. Start the engine and synchronize the throttle blades by using a Uni-syn air flow meter. 2. To richen the idle fuel rate, adjust the hex link to the cam to move it in the direction it moves as you open the throttles. HOOKING UP THROTTLE LINKAGE On units not having a rollerized fuel cam follower, the ideal place to attach the throttle linkage is on the throttle shaft, close to the arm that activates the fuel cam. This will prevent putting the torque required to move the fuel cam through the weakened section of the throttle shaft where it is milled to accept the throttle blade. On units that have a rollerized lifter (which takes very little force to move), it is acceptable to attach the throttle linkage to one of the spring-screw links at the center of the manifold as long as the torque is pulling against the screw in the spring-screw link, not against the rivit - spring. Always attach the throttle return springs so that they pull at the same point where the linkage is attached, so that they do not put torque through a throttle shaft. This will eliminate the possibility of putting the shaft under a cyclic strain, which could eventually result in a fatigue failure. The arrangement above puts torque through the throttle shaft while the setup below does the same job without putting any torque on the shaft. CORRECT !! Fig. 1 © 2017 NOT CORRECT !!
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