3406B AND 3406C INDUSTRIAL AND GENERATOR SET ENGINES

CAT 3406 Overhaul

You must read and understand the warnings and instructions contained in the Safety section of this manual before performing any operation or maintenance procedures.

Overhaul Considerations

Reduced hours of operation at full load and/or operating at reduced settings result in lower average power demand. Lower average power demand should increase the length of operating time before an engine overhaul is required.

An overhaul is generally indicated by increased fuel consumption and reduced power. Overhaul includes completely reconditioning the cylinder heads, but the cylinder components are not worn enough to need repair.

Factors such as: conscientious preventive maintenance, fuel quality used, operating conditions, S·O·S oil analysis results, etc., are important considerations in deciding when to perform an overhaul.

Estimating Oil Consumption

Oil consumption, fuel consumption, and maintenance information can be used to estimate the total operating cost for your Caterpillar engine. Oil consumption can also be used to estimate the capacity of a makeup oil system required to accommodate your maintenance intervals.

Oil consumption is proportional to the engine operating percent load. The higher the percent load, the higher the amount of oil consumed per hour.

The oil consumption rate, or brake specific oil consumption (BSOC) is measured in grams/brake kW-hour (lb/bhp-hour). The BSOC varies depending on the load on your engine. Contact your Caterpillar dealer for assistance in determining typical oil consumption for your engine.

Oil Consumption as an Overhaul Indicator

When an engine's oil consumption has risen to three times the initial (new) consumption rate due to normal wear, then the engine should be scheduled for overhaul. There may be a corresponding increase in blowby and a slight increase in fuel consumption.

Overhaul Before Failure

A planned Overhaul Before Failure may be your best value, because you can:

* Avoid costly unplanned downtime.

* Reuse as many original parts as standards permit.

* Extend your engine's service life without the risk of a major catastrophe had you continued to operate to failure.

* Get the best cost/value relationship per hour of extended life.

After Failure Overhaul

If you experience a major engine failure which requires removal of the engine from the hull, there are also many After Failure Overhaul options available. An overhaul should be performed if you block or crankshaft needs to be repaired.

If the block and/or crankshaft is repairable, overhaul cost should be between 40 and 50 percent of the cost of a new engine (with like exchange core).

This lower cost can be attributed to Caterpillar "designed-in" features, Caterpillar dealer and Caterpillar Remanufactured exchange components.

Overhaul Recommendation

To minimize downtime and provide you with the lowest cost and highest value, Caterpillar recommends that the engine be overhauled before failure by scheduling an overhaul with your Caterpillar dealer.

NOTE: Overhaul programs vary with engine application and from dealer to dealer. Therefore, Caterpillar recommends that you confer with your dealer to obtain specific information regarding the types of programs offered and overhaul services provided for extending the life of your engine.

If you elect to perform an overhaul without Caterpillar dealer overhaul service, you should be aware of the maintenance that follows.

Inspect/Rebuild or Exchange

Cylinder Head, Connecting Rods, Pistons, Cylinder Liners, Turbocharger, Oil Pump, Spacer Plates, Fuel Ratio Control, Cam Followers, Fuel Transfer Pump, and Timing Advance.

These components should be inspected according to the instructions found in various Caterpillar reusability publications. The Index of Publications on Reusability or Salvage of Used Parts, SEBF8029, lists reusability publications needed for inspecting parts.

If the parts comply with established inspection specifications expressed in the reusable parts guideline, the parts should be reused.

If the parts are not within specification, the parts should be salvaged, repaired, or replaced. Failure to salvage, repair, or replace out-of-spec parts can result in unscheduled downtime, costly repairs, and damage to other engine parts.

In addition, using out-of-spec parts can reduce the engine's efficiency and increase fuel consumption. Reduced engine efficiency and increased fuel consumption translates into higher operating costs. Therefore, Caterpillar recommends salvage, repair, or replacement of out-of-spec parts.

Install New

Piston Rings, Main Bearings, Rod Bearings, Valve Rotators and Crankshaft Seals.

The thrust, main, and rod bearings, valve rotators, and crankshaft seals will probably not last until the second overhaul. Caterpillar recommends the installation of new parts at each overhaul period.

Inspect/Replace

Crankshaft, Camshaft, and Cam Bearings, Crankshaft Vibration Damper, Governor, Fuel Pump Camshaft, and Fuel Racks.

The ideal time for inspecting these items is while the engine is disassembled for overhaul. Inspect each component for potential damage as follows.

* Crankshaft-Inspect for deflection, journal damage, and bearing material seized to the journal. At the same time, check the taper and profile of the crankshaft journals by interpreting the main and rod bearing wear patterns.

NOTE: If the crankshaft is removed for any reason, use the magnetic particle inspection process to check the crankshaft for cracks.

* Camshaft-Inspect the camshaft to journal damage and lobe damage.

NOTE: If the camshaft is removed for any reason, use the magnetic particle inspection process to check the camshaft for cracks.

* Camshaft Followers and Bearings-Inspect the Cam Bearings for scuffing and wear.

* Crankshaft Vibration Damper-Refer to the Crankshaft Vibration Damper topic in the Every 3000 Hour section of this publication for inspection information.

* Fuel Pump-Inspect the camshaft and fuel racks for excessive wear.

Clean/Test

Oil Cooler and Aftercooler Cores

Caterpillar recommends that the oil cooler and aftercooler cores be removed, cleaned and pressure tested at Overhaul.

NOTE: This cleaning procedure may be used for both the oil cooler and the aftercooler cores.

1. Remove the core. Turn the core upside down to remove debris from the inlet. 2. Back flush internally with cleaner to loosen foreign substances and to remove oil. Caterpillar recommends the use of Caterpillar Hydrosolv Liquid Cleaners. The following chart lists part numbers and quantities of recommended cleaners available from your Caterpillar dealer.

3. Steam clean the core to remove cleaner film. Flush the aftercooler core fins. Remove any other trapped debris. 4. Wash the core with hot, soapy water. Rinse thoroughly with clean water. 5. Dry the core with compressed air. Blow air in reverse direction of the normal flow. Use all necessary safety equipment while working with compressed air. 6. Inspect the system to ensure cleanliness. The core should be pressure tested. Test and repair the core as necessary. Install the core.

For more information on cleaning the cores, contact to your Caterpillar dealer.

Fuel Injection Pump and Fuel Injection Nozzles

Test

Fuel costs are 80 to 85 percent of the total engine operating cost. Caterpillar recommends testing the fuel injection pump and fuel injection nozzles at Overhaul. Your Caterpillar dealer can test these components in order to ensure they are operating within specifications.

Obtain Coolant Analysis

The concentration of SCA should be checked regularly for over or under concentration. This should be done with test kits, or Caterpillar's S·O·S Coolant Analysis (Level I) at the Every 250 Hours interval.

Further coolant analysis is recommended at Overhaul.

For example, suppose considerable deposits are found in the water jacket areas on the external cooling system, yet coolant additive concentrations were carefully maintained. Chances are that the coolant water had minerals which deposited on the engine over time.

One way to verify the water condition, or to be sure of new water at fill time, is to have a coolant analysis conducted. Full water analysis can sometimes be obtained locally by contacting your local water utility company or an agricultural agent. Private laboratories are also available.

Caterpillar recommends S·O·S Level II Coolant Analysis.

Level II: Comprehensive Cooling System Analysis

Completely analyzes coolant and coolant effects on the cooling system. Level II analysis provides:

* full Level I analysis

* visual properties inspection

* metal corrosion and contaminant identification

* identification of built-up impurities that point to corrosion and scaling problems BEFORE they lead to costly repairs

Level II analysis provides a report of results, and makes recommendations.

For more information on coolant analysis and how it can help you manage your equipment, see your Caterpillar dealer.