0335528 JOHNSON COVER, Trunnion

The 6V3100 Engine Timing Indicator is a test instrument that can be used to measure fuel injection timing for a diesel engine, or spark plug firing on spark ignition engines, while the engine is in operation. The timing indicator can also be used to check the operation of the automatic timing advance unit, on engines that are so equipped. Electrical power to operate the unit comes either from the vehicle electrical system, or, if there is no electrical system available, from two 6 volt lantern-type batteries.The test instrument must be connected to a fuel line transducer on a diesel engine, or to a spark transducer on spark ignition engines, and a magnetic top center transducer. The fuel line transducer connects to the fuel injection pump bonnet of No. 1 cylinder, and is then connected to the engine timing indicator. The fuel line transducer can then send a signal to the 6V3100 Engine Timing Indicator when fuel is injected into No. 1 cylinder.For spark ignition engines, a spark transducer connects to the spark plug wire for No. 1 spark plug, and sends a signal to the 6V3100 Engine Timing Indicator when the spark plug fires.Most current production Caterpillar diesel engines are equipped with a static timing pin hole in the flywheel housing, and a corresponding hole in the flywheel. When the two holes are in alignment, the piston for No. 1 cylinder is at top center position. A bolt can then be put through the hole in the flywheel housing and threaded into the hole in the flywheel to lock the engine at the top center (TC) position for static timing. For dynamic timing, an adapter and a 6V2197 Magnetic Transducer are installed in the flywheel housing timing pin hole (see the installation procedure in this instruction). When the transducer is connected to the 6V3100 Engine Timing Indicator, it sets up a constant magnetic field around the end of the transducer and the flywheel. As the flywheel turns (engine running) and the timing hole in the flywheel passes the end of the transducer, a change in the magnetic field causes the transducer to send the TC signal to the 6V3100 Engine Timing Indicator.In diesel engine operation, fuel is injected before No. 1 piston reaches top center position. In spark ignition engine operation, the No. 1 spark plug fires before No. 1 piston reaches top center. The 6V3100 Engine Timing Indicator receives the fuel injection, or spark, signal first, then measures the time it takes to receive the top center (TC) signal. The timing indicator then converts these two signals, and the time between them into engine rpm, and engine timing in degrees before top center (BTC). After the 6V3100 Engine Timing Indicator receives the fuel injection, or spark, signal, the first signal that the magnetic transducer sends will be considered the No. 1 cylinder top center signal. It is, then, important for the flywheel to be free of any other holes or large nicks between the point of injection (or spark plug firing) and top center (TC). As an example, if the specifications indicate that fuel should be injected in No. 1 cylinder 15° before top center, the flywheel must be free of holes or large nicks in the area of the flywheel that is at least 15° before top center (BTC).For correct operation, the timing indicator must receive the TDC signal within 60° flywheel rotation after it receives the fuel injection, or spark, signal. If timing is actually after top center, i.e., the TC signal occurs before the injection pulse, the timing indication will be incorrect, and be a steady number between 60° and 90°.Features (Characteristics) of the 6V3100 Engine Timing Indicator Group
ADAPTABILITYThis timing indicator group is usable on engines that have a TC bolt hole in the flywheel housing, as found on 3300 and 3400 Series engines. It can also be used on 1100, 3100 and 3208 Series Engines that have a timing hole in the engine front cover. All other Caterpillar engines can be timed with the 6V3100 Indicator Group, if the engine is modified to permit a way to get a TC signal.ACCURACYThe timing indicator group can be used, and has the accuracy, to check the dynamic (engine running) timing of the entire fuel system. It can also be used to check the operation of the timing advance mechanism, on those engines that are so equipped.OPERATIONThere are no restrictions on engine speed or load, so timing can be checked during the actual operation of an engine. The digital readouts (number indications) are liquid crystal displays that have long life and high accuracy.FUEL SYSTEM CONNECTIONA fuel line injection transducer "tee" adapter is installed in the injection line, AT THE FUEL PUMP. The injection line will be moved only about .3" (8mm), which will keep bending of fuel lines to a minimum. Installation time is also held to a minimum. DO NOT ATTEMPT TO USE THE 6V4950 FUEL LINE SPEED PICKUP. IT IS NOT DESIGNED FOR THIS APPLICATION. TIMING INDICATOR CONNECTIONThe connecting cables for the timing indicator group are 18 feet (6 m) long and, if necessary, the serviceman can have the timing indicator connected and read it in the operator's station. All electrical connections can be connected in only one way, the correct way.POWER SUPPLYThe vehicle electrical system, (12V, 24V or 32V) either positive or negative ground, is the source of power for the timing indicator group. There are no internal batteries. For those engines that do not have an electrical system for a power supply, two 6 Volt lantern-type batteries, wired in series, can be used as a power supply for the timing indicator group.TROUBLESHOOTINGThe design of the timing indicator group is such that any problem with the operation of the unit can quickly and easily be found, whether the problem is with the indicator, either signal input, or with the power supply.SERVICEABILITYUsing the information given in this instruction, the single-printed circuit board used in this unit can be repaired in most electronic repair