VALVE-INLET 2335469 - Caterpillar

ENGINES
ALL 3300 ENGINES IN ALL APPLICATIONSProblem:
There are instances where the performance of a 3300 engine could be improved with the correct fuel injection timing. Unfortunately, the conventional fuel pump pin timing method of checking/adjusting the timing is relatively inaccurate when compared to other methods such as the use of a dynamic timing indicator or by flow timing. Less accurate measurement of 3300 engine timing can lead to increased exhaust emissions, reduced engine performance, and shorter engine life.Solution:
Use a 6V-3100 Engine Timing Indicator Group as per Special Instruction, SEHS7742-03, to accurately measure and set the engine timing. ONLY use pin timing to get close to the static timing specification as per the test specification. In addition, when using the dynamic timing indicator to check and adjust static fuel injection timing, the plotting of the entire timing map across the engine speed range is not necessary. Only check timing at 1000 rpm for this procedure. When it is necessary to plot the entire map at engine speeds of 1200 rpm and greater, (For example, to determine if the timing advance is working) the plunger port effects are given in the chart under "Degrees Per 100 rpm". Use the nominal port effect value at 1000 rpm, given in the following chart, to convert the measured dynamic timing (from the 6V-3100 Engine Timing Indicator Group) to measured engine static timing. Refer to the Technical Marketing Information (TMI) system, Parts Manual, or Service Information System (SIS) to break down the top level fuel pump group to determine the individual pump group part number for your engine. For example, a 3306 engine with six 4P-9827 Pump Groups in the top level pump group, and a static timing specification of 6.2 degrees BTC, requires a dynamic timing reading of 9.0 degrees at 1000 rpm engine speed.After the initial checking of the fuel pump injection timing with the dynamic timing indicator, use trial and error to readjust the timing, and repeat the measurement. Use a tolerance of " 0.5 degrees" when setting the final engine static timing to factory specification. After resetting the engine timing by adjusting the fuel pump drive gear position on the fuel pump camshaft taper, the timing pin may or may not fit into the slot in the fuel pump camshaft with the flywheel pinned. This is a natural consequence of using the dynamic timing indicator to set timing rather than the less accurate pin timing method. COPYRIGHT 1998 CATERPILLAR ALL RIGHTS RESERVED