mechanical engineering

INTRODUCTION This presentation is about the 3500 Series Engine. One arrangement of the 3516 Vehicular Engine is used for most illustrations. The 3500 Series Engine is a diesel engine with a 4-stroke cycle. It has a 60 degree “Vee” angle between the cylinders of the block. The cylinder bore is 170 mm (6.7 inch) and the piston stroke is 190 mm (7.5 inch). Each cylinder has approximately 4310 cu. cm. (263 cu. in.). Standard engine rotation is counterclockwise. See the Service Manual for Firing under specs (V8 and V16). ORIENTATION Looking at the right side of the engine, we see the: 1. cylinder heads, block and oil pan 2. valve covers 3. rear lifting eye 4. turbocharger (one of two) 5. oil cooler and oil pump 6. fuel priming pump, two secondary fuel filters, and fuel transfer pump 7. crankcase filler opening and dipstick 8. air starting motor 9. water pump; and 10. alternator NOTE: This is the first Caterpillar engine designed to metric dimensions. All engines in the series have the same...

This picture shows the difference between the Mechanical Unit Injection (MUI) and current Electronic Unit Injection (EUI) installation in the cylinder head. Notice the Helper Spring on the injector pushrod. This arrangement is designed to keep the follower in constant contact with the camshaft. The helper spring is required due to the increased injection pressures of 151 MPa (22000 psi) and the steeper, high lift camshaft lobe profile. The 3500B has a larger diameter camshaft to accommodate the higher injection pressures generated in the unit injector pumps.

Coupling Alignment Good service life of the pump and driver depends upon good alignment through the flexible coupling. If the electric motor was mounted at the factory, the pump and motor were in alignment when shipped. The alignment between the pump and driver should be inspected after installation to ensure that transportation or other handling has not caused misalignment of the unit. Poor alignment may cause failure of the coupling, pump, motor, or bearings. Alignment must not be attempted until the base is in position and the mounting and flange bolts have been tightened. The recommended procedure for coupling alignment is with the use of a dial indicator, as illustrated in Figures 1 and 2. The dial indicator is attached to one coupling halfwith the indicator button resting on the O.D. of the other coupling half to measure offset HALCO 1780 “W” Maintenance Page 3 misalignment. To measure angular misalignment, the indicator is positioned so that the buttons rest on the face, near th...

A SPUR GEAR is cylindrical in shape, with teeth on the outer circumference that are straight and parallel to the axis (hole). There are a number of variations of the basic spur gear, including pinion wire, stem pinions, rack and internal gears. (See Figure 1.17) PINION WIRE is a long wire or rod that has been drawn through a die so that gear teeth are cut into its surface. It can be made into small gears with different face widths, hubs, and bores. Pinion wire is stocked in 4 ft. lengths. (See Figure 1.18) STEM PINIONS are bore-less spur gears with small numbers of teeth cut on the end of a ground piece of shaft. They are especially suited as pinions when large reductions are desired. (See Figure 1.19) RACK are yet another type of spur gear. Unlike the basic spur gear, racks have their teeth cut into the surface of a straight bar instead of on the surface of a cylindrical blank. Rack is sold in two, four and six foot lengths, depending on pitch, which you will learn about starting i...

For most rotating machines used in the process industries, the trend is toward higher speeds, higher horsepowers per machine, and less sparing. The first of these factors increases the need for precise balancing and alignment. This is necessary to minimize vibration and premature wear of bearings, couplings, and shaft seals. The latter two factors increase the economic importance of high machine reliability, which is directly dependent on minimizing premature wear and breakdown of key components. Balancing, deservedly, has long received attention from machinery manufacturers and users as a way to minimize vibration and wear. Many shop and field balancing machines, instruments, and methods have become available over the years. Alignment, which is equally important, has received proportionately less notice than its importance justifies. Any kind of alignment, even straightedge alignment, is better than no alignment at all. Precise, two-indicator alignment is better than rough alignment, ...