3412 Generator Set Engines Caterpillar


Basic Engine

Usage:

SPS342 2LZ

Cylinder Block Assembly

The cylinders in the left side of the block form a 65 degree angle with the cylinders in the right side. The main bearing caps are fastened to the block with two bolts per cap.

The cylinder liners can be removed for replacement. The top surface of the block is the seat for the cylinder liner flange. Engine coolant flows around the liners in order to keep the liners cool. Three O-ring seals around the bottom of the liner make a seal between the liner and the cylinder block. A filler band goes under the liner flange. This makes a seal between the top of the liner and the cylinder block. A steel spacer plate is used between the cylinder head and the block. A thin gasket is used between the plate and the block. This thin gasket seals water and oil. A thick gasket of metal is used between the plate and the head. This thick gasket seals the combustion gases, water and oil.

Cylinder Head Assembly

The cylinder heads are a one-piece cast iron head. Two inlet valves and two exhaust valves, which are controlled by a pushrod valve system, are used for each cylinder. Valve guides without shoulders are pressed into the cylinder heads. The opening for the direct injection adapter is located between the four valves. Series ports are used for both inlet and exhaust valves.

The valve lifters can be removed without the removal of the head. The removal can be made because of the size of the pushrod openings through the head.

Pistons, Rings and Connecting Rods




Illustration 1g01247047

Piston assembly (typical example)

(1) Crown assembly

(2) Piston skirt

(3) Piston pin

(4) Retainer ring

The piston assembly is of a two-piece articulated design. The crown assembly (1) is held in position in the piston skirt (2) by a piston pin (3). The piston pin is held in place by two retainer rings (4). These retainer rings (4) fit in grooves in the pin bore of the piston.

The aluminum piston has three rings which include two compression rings and one oil ring. All the rings are located above the piston pin bore. The oil ring is a standard ring. Oil returns to the crankcase through holes in the oil ring groove. The top two rings are the Keystone rings, which are tapered. Oil from the piston cooling jets flows through a chamber which is located directly behind the rings. The oil cools the piston which improves the life of the rings.

The connecting rod has a taper on the pin bore end. This taper gives the rod and the piston more strength in the areas with the most load.

Crankshaft

The crankshaft changes the combustion forces in the cylinder into usable rotating torque which powers the equipment. A vibration damper is used at the front of the crankshaft in order to reduce torsional vibrations (twist) that can cause damage to the engine.

The crankshaft drives a group of gears (front gear train) on the front of the engine. The front gear train provides power for the following components: timing gears and oil pump. Seals and wear sleeves are used at both ends of the crankshaft. The seals and wear sleeves are used for easy replacement and reduction of maintenance cost. Pressure oil is supplied to all bearing surfaces through drilled holes in the webs of the cylinder block. The oil then flows through drilled holes in the crankshaft in order to provide oil to the connecting rod bearings. The crankshaft of the engine is held in place by seven main bearings. A thrust plate at either side of the center main bearing controls the end play of the crankshaft.

Camshaft

The engine has a single camshaft that is driven at the front end. The camshaft is supported by seven bearings. As the camshaft turns, the camshaft lobes move a lifter assembly. The camshaft lobe moves either two inlet valves or two exhaust valves for each cylinder. The camshaft must be in time with the crankshaft. The relation of the camshaft lobes to the crankshaft position causes the valves and injectors in each cylinder to operate at the correct time.

A gear on the rear of the camshaft is used to drive the balancer gear. Also, this gear drives any accessory equipment that is mounted on the rear of the engine.

Vibration Damper

The twisting of the camshaft is called torsional vibration. The torsional vibration is caused by the regular power impacts along the length of the crankshaft. The fluid type vibration damper is installed on the front end of the crankshaft. This vibration damper is used to reduce the torsional vibrations. This eliminates any damage that could occur to the crankshaft.

Caterpillar Information System:

SR4 and SR4B Electric Power Generation Rewind Data Winding Data for <B>5N-9081</B> Generator through <B>5N-9432</B> Generator
G3408 and G3412 Engines Product Description
3500B Engines Exhaust Manifold
G3406 Engine Product Description
G3408 and G3412 Engines Safety Messages
SR4 and SR4B Electric Power Generation Rewind Data Winding Data for <B>5N-8891</B> Generator through <B>5N-8911</B> Generator
3126E Engine for Combat and Tactical Vehicles Flash Programming
3034 Industrial Engine Governor - Remove
G3406 Engine Refill Capacities
3126B and 3126E On-highway Engines Sensors and Electrical Connectors
325, 325B and 325L Excavators Travel Motor
SR4 HV and SR4B HV Generators Fire Prevention and Explosion Prevention
325, 325B and 325L Excavators Travel Counterbalance Valve
3034 Industrial Engine Governor - Install
C-10 and C-12 Engines Model View Illustrations
3500B Engines for Caterpillar Built Power Modules Engine Oil Pan
G3516B Engines MID 036 - CID 0017 - FMI 06 Fuel Shutoff Valve short to ground
G3516B Engines MID 036 - CID 0017 - FMI 12 Fuel Shutoff Valve malfunction
G3516B Engines MID 036 - CID 0041 - FMI 03 8 Volt DC Supply short to +batt
G3516B Engines MID 036 - CID 0041 - FMI 04 8 Volt DC Supply short to ground
2000/04/01 Use the Proper Electronic Troubleshooting Guide {1000}
325, 325B and 325L Excavators Track Roller (Single Flange)
2000/07/01 Improvements to Turbocharger Water Lines Groups Help Prevent Leaks {1052, 1380}
G3516B Engines MID 036 - CID 0100 - FMI 03 Engine Oil Pressure open/short to +batt
Back to top
The names Caterpillar, John Deere, JD, JCB, Hyundai or any other original equipment manufacturers are registered trademarks of the respective original equipment manufacturers. All names, descriptions, numbers and symbols are used for reference purposes only.
CH-Part.com is in no way associated with any of the manufacturers we have listed. All manufacturer's names and descriptions are for reference only.