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Booster gap sparkplug.

<div style="position: absolute; width: 723px; border-top: #000000 1px solid; top: 120px; left: 46px"></div><div class="im1">http://firetrucksandequipment.tpub.c...4P-1_615_2.jpg</div><div style="position: absolute; width: 723px; border-top: #000000 1px solid; top: 869px; left: 46px"></div><! text starts here >TRUCK SERVICE MANUAL TM 5-4210-230-14&P-1 ELECTRICAL INSTALLATION When installing spark plugs, always be sure gasket seats and threads are clean. Using a torque wrench, tighten plugs to 2830 ft. lbs. BOOSTER GAP PLUG For the past several years auxiliary gap (Booster Gap) spark plugs have been used in certain IH engines, Fig. 19 Prior to IH approval, the Booster Gap design was thoroughly tested and evaluated, at which time their anti- fouling characteristics were firmly established. What is a Booster Gap plug? This plug has an internal air gap between the center electrode and the terminal stud. How do they work? Most servicemen know that misfire will occur when a conventional spark plug is fouled. As the coil attempts to build up voltage on the "dirty" firing end, it "sees" an easier path to ground over the deposits. This short circuit prevents normal voltage buildup. The Booster Gap, however, isolates the coil from the fouling deposits, allowing near normal voltage build- up. The instant the Booster Gap sparks, sufficient voltage appears across the firing gap and normal ignition results. When you remove a plug wire from a fouled plug and let the spark jump from the cable to the plug terminal to make the plug fire, you are using this same Booster Gap principle. Where are Booster Gap plugs used? Maximum benefit from this design is obtained in engines that operate over a wide load and speed range. For example, a heat range cool enough for highway service will have better fouling protection during stop-start city delivery service with the Booster Gap. Furthermore, the Booster Gap has been instrumental in reducing the complaints of "break-in fouling" in new engines. In many cases misfire due to oil fouling in older engines can be relieved simply by using the recommended heat range plug incorporating a Booster Gap. A cure-all? Not at all. Booster Gap plugs used where recommended and applicable to help solve fouling problems will give excellent results. However, the need for the correct selection of plugs in the proper heat range based on type of vehicle operation is important. Where more severe conditions of fouling as a result of light service application or break-in fouling on engines occurs, the alternate recommended hotter type plug with Booster Gap should be used. Voltage Requirements While nominal in amount, the Booster Gap does require more voltage initially than conventional spark plugs. This higher requirement diminishes, however, after several thousand miles of use. Most any ignition system has more than adequate reserve to supply the bit of extra voltage requirement; if you experience misfiring with Booster Gap plugs and not with conventional plugs, chances are the ignition system is marginal. It should also be pointed out that Booster Gap plugs are not resistor plugs. If radio interference is a problem on older vehicles having nonresistor ignition cables, it may be necessary to install resistance leads (cables). Booster Gap plugs may be used in conjunction with resistance-type ignition cables to obtain interference suppression and still obtain the added benefits of the Booster Gap. This is the combination that is recommended on all gasoline powered motor truck engines. CTS-2016-J Page 8 PRINTED IN UNITED STATES OF AMERICA