FUEL INJECTOR 1077733 - Caterpillar

1100, 3100, 3200, 3300, 3400 Family Engines 137 mm (5.4") and 158.8 mm (6.25") Bore Engines, 3500 Family Spark Ignited EnginesIntroduction
The 8T5250 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 8T5300 Engine Timing Indicator Group must be used with an 8T5301 Diesel Timing Adapter Group on a diesel engine, or, a 6V9060 Spark Timing Adapter Group on spark ignition engines.In the 8T5300 Engine Timing Indicator Group, 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 8T5250 Engine Timing Indicator when fuel is injected into No. 1 cylinder.For spark ignition engines, a spark transducer connects to the primary coil for No. 1 spark plug, and sends a signal to the 8T5250 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 TDC 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 8T5250 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 8T5250 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 8T5250 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 8T5250 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