G3306B Generator Sets Overhaul (Major) Caterpillar

Overhaul (Major)
1.1. Scheduling a Major Overhaul
2.1. Major Overhaul Information

Scheduling a Major Overhaul

The need for a major overhaul is determined by several factors.

  • An increase of oil consumption

  • An increase of crankcase blowby

  • A decrease and variation of cylinder compression

The following changes in the three conditions normally require a scheduled overhaul:

  • A 300 percent increase in oil consumption

  • A 200 percent increase in crankcase blowby

  • A 20 percent loss of cylinder compression

Note: These indications do not require an engine to be shut down for service. These indications only mean that an engine should be scheduled for service soon. If the engine operation is satisfactory, an immediate overhaul is not a requirement.

The engine does not require an overhaul if the engine is operating within acceptable limits for oil consumption, crankcase blowby, and cylinder compression.

Other factors must also be considered for determining a major overhaul:

  • The service hours of the engine

  • The wear metal analysis of the lube oil

  • An increase in the levels of noise and vibration

An increase of wear metals in the lube oil indicates that the bearings and the surfaces that wear may require service. An increase in the levels of noise and vibration indicates that rotating parts require service.

Note: It is possible for oil analysis to indicate a decrease of wear metals in the lube oil. The cylinder liners may be worn so that polishing of the bore occurs. Also, the increased use of lube oil will dilute the wear metals.

Monitor the engine as the engine accumulates service hours. Consult your Cat dealer about scheduling a major overhaul.

Note: The driven equipment may also require service when the engine is overhauled. Refer to the literature that is provided by the OEM of the driven equipment.

Major Overhaul Information

A major overhaul includes all of the work that is done for top end overhauls. A major overhaul includes additional parts and labor. Additional parts and labor are required in order to completely rebuild the engine. In some cases, the engine is relocated for disassembly.

For the major overhaul, all of the bearings, seals, gaskets, and components that wear are disassembled. The parts are cleaned and the parts are inspected. If necessary, the parts are replaced. The crankshaft is measured for wear. The crankshaft may require regrinding. Alternatively, the crankshaft may be replaced with a Cat replacement part.

Your Cat dealer can provide these services and components. Your Cat dealer can ensure that the components are operating within the appropriate specifications.

If you elect to perform an overhaul without the services of a Cat dealer, be aware of the following recommendations.

The following definitions explain the terminology for the services that are performed during an overhaul:

Inspect - Inspect the components according to the instructions that are in Cat reusability publications. Refer to Guidelines for Reusable Parts and Salvage Operations, SEBF8029, "Index of Publications on Reusability or Salvage of Used Parts". The guidelines were developed in order to help Cat dealers and customers to avoid unnecessary expenditures. New parts are not required if the existing parts can still be used, reconditioned, or repaired. If the components are not in the reusability guidelines, refer to the Service Manual, "Specifications" module.

Rebuild - The component may be reconditioned in order to comply with reusability guidelines. If the component cannot be rebuilt, replace the component.

Replace - The service life of the part is exhausted. The part may fail before the next maintenance interval. The part must be replaced with a part that meets functional specifications. The replacement part may be a new part, a AVS remanufactured part, a rebuilt part, or a used part. Some worn components may be exchanged with your Cat dealer. Consult your Cat dealer about repair options for your engine.

Table 1
Major Overhaul    
Inspect     Aftercooler    
Camshaft followers
Connecting rods
Gear train
Inlet air piping
Oil cooler
Oil pump
Rebuild     Carburetor    
Cylinder packs
Exhaust bypass (if equipped)
Gas regulator
Inlet air piping
Oil pump
Starting motor
Water pumps
Replace     Alternator and fan drive belts    
Camshaft bearings
Connecting rod bearings
Crankshaft bearings
Crankshaft seals
Crankshaft vibration damper
Cylinder liners
Cylinder head and gaskets
Exhaust manifold
Gaskets and seals
Gear train bearings
Hoses and clamps
Piston rings
Rod ends
Spark plugs
Spark plug wires
Water temperature regulators
Wiring harnesses

Information System:

2013/12/18 A New Valve Cover Base and Wiring Harnesses Are Now Used on Certain C27 and C32 Engines {1120, 1408}
12M Series 3, 140M Series 3, 160M Series 3, 140, 150 and and 160 Motor Graders Hydraulic Fan Speed - Calibrate and Adjust
12M Series 3, 140M Series 3, 160M Series 3, 140, 150 and and 160 Motor Graders Hydraulic Fan Speed - Test
C280-08 Marine Engine Catalyst (SCR) - Replace
C280-16 Marine Engines Overhaul (Top End)
C280-16 Marine Engines Overhaul (Major)
C175 Cylinder Head Lifting Device{0374, 0599, 0632, 0703, 1100}
C280-08 Marine Engine Emergency Stopping
C280-08 Marine Engine Sensors and Electrical Components
G3600 A4 Engines Fuel Pressure Problem
G3600 A4 Engines Fuel Energy Content Problem
12M Series 3, 140M Series 3, 160M Series 3, 140, 150 and and 160 Motor Graders Brake System Air - Purge
C11 and C13 Engines Muffler
C11 and C13 Engines Turbocharger
G3600 A4 Engines Oil Filter Differential Pressure Problem
G3600 A4 Engines Air/Fuel Pressure Module - Calibrate
G3600 A4 Engines Air/Fuel Pressure Module - Test - G3616
2013/12/03 New Software Is Used On Certain G3500B Engines {1901, 1902, 1920}
Remanufactured Oil Pumps May Have a Shallow Suction Tube Port on Certain 3400 Engines{1304}
G3600 A4 Engines Speed Control - Test
G3600 A4 Engines Temperature Ratio of Coolant to Oil Is Low
C280-12 Marine Engine Maintenance Interval Schedule
140, 150, 160, 12M Series 3, 140M Series 3 and 160M Series 3 Motor Graders Lifting and Tying Down the Machine
12M Series 3, 140M Series 3, 160M Series 3, 140, 150 and and 160 Motor Graders Brake Accumulator Charging Valve - Check