caterpillar g3500 top end overhaulesek.pdf

137 Maintenance Section

Top End and Overhaul

G3500 Gas Engine Top End and Overhaul Intervals for Dry Natural Gas [LHV 33.72 kJ/L (905 Btufft 3)]

--Estimated Output-- --Top End Intervals-- --Overhaul Intervals--Engine Engine Gen Clock

Model kW hp kW Hours

G3516 860 1150 8oo 8,300

750 1010 700 9,700 650 860 600 11,100 540 720 500 12,500 430 580 400. 13,900 . 320 430 300 15,300 220 290 200 18,000

\ I G3512 650 860 600" 8,300

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560 760 525 9,700 480 650 450 11,100 400 540 375 12,500 320 430 300 13,900 240 320 225 15,300 160 220 150 18,000

G3508 430 575 400" 8,300

375 505 350 9,700 325 430 300 11,100 270 360 250 12,500 215 290 200 13,900 160 215 150 15,300 110 145 100 18,000

"Highest generator set rating as of 1/87. Cubic meters (m3) and cubic feet (fP) are stated in millions.

Calculating Top End and Overhaul Intervals Using Fuel Consumption

! The "cubic meters (cubic teet)" value is the most ". ..... important criteria lor determining when a Top End or

Overhaul should be performed because it compensates lor application and engine loads. Use the following formula to estimate the Top End or Overhaul clock hour interval if records have not been kept on the total cubic meters (cubic teet) of fuel consumed. Also, use it lor estimating intervals for new engines.

Overhaul interval (hours) = "cubic meters (cubic feet)" (from the chart)+ cubic meters/hour (cubic ftjhour) (").

Use actual fuel records if available. If the actual cubic meters (cubic feet) per hour is not available, use the following steps to estimate the fuel consumption rate.

Estimate the percent load of the rated engine or .. (-""'>generator set output.

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mJn Megawatt Clock mJ .. Megawatt (It')"" Hours Hours (It')"" Hours

2.2 6,600 25,000 6.5 20,000 (75.9) (228.7)

" 6,800 29,100 " 20,400 6,700 33,200 19,900 6,300 37,300 18,700

. 5;600 41,400 16,600 " 4,600 45,500 13,700

3,600 54,000 10,800

1.6 5,000 25,000 4.7 15,000 (55.5) (167.1)

" 5,100 29,100 " 15,300 5,000 33,200 14,900 4,700 37,300 14,000 4,200 41,400 12,400 3,400 45,000 10,200 2,700 54,000 8,100

1.1 3,300 25,000 3.25 10,000 (37.9) (11~.3)

" 3,400 29,100 10,200 3,350 33,200 9,950 3,150 37,300 9,350 2,800 41,400 8,300 2,300 45,500 6,850 1,800 54,000 5,400

Refer to the specification sheet to determine the cubic meters/hour (cubic fljhour) for the estimated percent load. Use this value in the overhaul interval formula.

NOTE: For engines operat'1ng at less than 50% load, use the 50% load fuel consumption rate to determine the top end or overhaul hour interval.

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138 Maintenance Section Top End and Overhaul

Adjusting Chart tor Fuels With Different Low Heat Value (LHV)

The interval and fuel consumption (cubic meter [cubic feet]) listed on the chart applies only for ~ngines operating on preferred fuels as def1ned 1n the Gas. Specification Section of this manual. The consumpt1on volume listed was established tor dry natural gas w1th a low heat value of 33.72 kJ/L (905 Btujcu It).

It your engine is operating on another preferred fuel with a different low heat value (LHV), the total volume of fuel consumed must be adjusted tor both the Top End and Overhaul using the following procedure:

Select the tuel consumption value (cubic meters [cubic teet]) from the Top End or Overhaul columns of the chart.

Example: G3516 TA overhaul occurs at a fuel consumption of 64.7 million cubic meters (228.7 million cubic feet).

Calculate the adjustment factor by dividing 33.72 kJ/L (905 Btujcu It) by the low heat value of the gas being

used.

Example: 905 Btujcu ft + 750 Btujcu ft = 1.2.

Adjust the fuel consumption value (cubic meters [cubic teet]) by multiplying it by the adjustment factor.

Example: 228.7 million cubic feet x 1.2 = 274.44 million cubic feet.

Use this adjusted fuel consumption for your overhaul interval formula.

U If your engine is operating on a fuel other than a preferred tuel, contact your Caterpillar dealer for assistance. He can help determine the effect of the fuel on engine lite.

Top End Determined by Measure of Exhaust Valve Wear

Monitoring exhaust valve wear by measuring valve stem projection and crankcase blowby can help determine when a Top End Overhaul is required.

Base line exhaust valve projection measurements should have been recorded at initial start-up of the engine. The valve take-up should then have been monitored and recorded at the Every Two Months or 1500 Hours interval to keep a record of the valve wear over time.

The measurement of each valve stem projection and recording the adjustment will help to determine when the cylinder heads need Top End overhaul maintenance.

The Top End cylinder head maintenance should have been scheduled when the valve adjustment take-up total was 1.78 mm (.070 inch). The Top End maintenance work should be completed before allowing the total measurement to reach 2.9 mm (0.090 inch).

Refer to the Exhaust Valve Data Sheet in this manual tor the form to record valve stem wear, crankcase

. blowby and cylinder pressure.

Refer to the Service Manual or your Caterpillar dealer for more information on this procedure.

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.Top End 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 Programs

Your Caterpillar dealer may be offering a variety of options regarding overhaul programs and Caterpillar recommends that an Overhaul be performed at this maintenance interval.

Overhaul Before Failure

(_) planned overhaul 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 costfvalue relationship per hour of extended life

-flat Rate Overhaul

To further control your overhaul costs, Caterpillar recommends that you contact your dealer ior information regarding the availability of a Flat Rate Overhaul.

Flat rate prices on preventive maintenance programs or major repair options are available from many dealers lor all Caterpillar engine models.

G Overhaul Options

Caterpillar Dealer - Contact your Caterpillar dealer to schedule a Before Failure Overhaul.

Overhaul Kit - This useful kit was developed for those users that prefer to perform their own overhaul. This kit includes a combination of new, reused and remanufactured parts. Also included is a step-by-step instruction regarding how to perform an overhaul. An Overhaul Kit simplifies parts ordering, helps speed repairs and reduces parts cosls.

Contact your local Caterpillar dealer for information regarding the Overhaul Kit.


Top End Overhaul

Overhaul Recommendation

To minimize downtime and provide you with the lowest cost and highest value, Calerpillar recommends that the engine be scheduled for an overhaul with your Caterpillar dealer.

NOTE: Overhaul programs vary 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.

Top End Overhaul Instructions

If you elect.to perform a top end overhaul yourself, without having a Caterpillar dealer perform the overhaul for you, or without using an overhaul kit, then you should perform the following maintenance.

140 Maintenance Section Top End Overhaul

Cylinder Head Assembly

Rebuild or Exchange

The Cylinder Head Assembly should be inspected according to the instructions found in Caterpillar reusability publications. Refer to the Index Of Publications On Reusability Or Salvage Of Used Parts section of the Guideline For Reusable Parts and Salvage Operations, SEBF8029, to determine the reusability publications needed for inspecting your parts.

The Guideline For Reusable Parts and Salvage Operations is part of an established Caterpillar parts reusability program. These guidelines were developed to assist Caterpillar dealers and customers reduce costs by avoiding unnecessary expenditures for new parts when existing parts can be used as is, repaired or salvaged.

, Failure to salvage, repair or replace out-of-spec parts '---'will result in unscheduled downtime and could result in

costly repairs caused by potential damage to other engine parts.

Flame Arrestors

Caterpillar recommends that while performing this maintenance procedure, the flame arrestors be removed and cleaned. They are subject to plugging during normal operation, which can cause a loss of engine andjor cylinder-to-cylinder power, and variations in exhaust temperatures.

A solvent cleaning is recommended for best results. After cleaning, inspect the arrestors for cracked andjor missing fins and replace if necessary.

Maintenance Options

New Parts - Genuine Caterpillar parts are constantly tested and modified to incorporate the latest design advances. Your Caterpillar dealer can provide the parts needed for rebuilding the components. Your benefit: Long-lasting replacement parts at competitive prices.

Repair Kits - These useful kits can be obtained from your Caterpillar dealer. These kits include all the necessary parts and instructions to repair the components, in either the owner's maintenance shop or at a Caterpillar servicing dealer's facility. Repair kits simplify parts ordering, help speed repairs and reduce parts cost.

Remanufactured - This process uses manufacturing techniques and procedures to restore the components to like-new performance capability. This process always involves an end product which conforms to the manufacturer's "original" functional specifications. Remanufactured parts may not be available in your area. Contact your Caterpillar dealer for information.

New Components - Replace worn or failing components with new components.

Before deciding which method is best, make sure all of the options and costs associated_ with repair have been considered. Some considerations 'are:

The costs associated with using separate parts from inventory versus the cost of a repair kit.

Downtime costs while the product is being rebuilt or repaired.

Total parts and labor costs for repairs versus the actual Remanufactured cost.

Remanufactured components from Caterpillar (if available) are covered by a standard, factory warranty.

Caterpillar Recommendation

To minimize downtime, Caterpillar recommends that the use of Remanufactured components (subject to availability) is the most cost effective option ..

Removal and Installation

Refer to the established procedure in the Service Manual for this engine to remove and install these components or contact your Caterpillar dealer for assistance.

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Cooling System

Performing maintenance on the cooling system is important because the cooling system has a direct effect on the operation and service life of the engine. Improper maintenance can result in a variety of problems that could shorten the engine's service life, reduce the efficiency of the cooling system, result in poor engine performance, and in some cases, result in an increase in fuel consumption.

NOTICE Caterpillar does not recommend the use of cooling system solutions that are intended to stop leaks. Use

( l these products may result in excessive internal '-deposits that could reduce the engine's heat transfer

characteristics as well as damage to the water pump seals.

Add Cooling System Cleaner

Approximately 250 Hours prior to draining the cooling system,-add 5 liter (5 U.S. quart) of Caterpillar Cooling stem Cleaner (6V4511) for every 60 liter (16 U.S.

)ion) of cooling system capacity. Continue to operate The engine for 250 hours before draining and/or performing maintenance of the cooling system.

Replace Cooling System Lines

Cooling system lines (piping and hose) replacement prior to failure is a recommended preventive

. n:)aintenance practice. Inspect all system components ( )r leaks due to cracking, softness next to clamps and loose clamps. Replace any component that is cracked

or soft and tighten loose clamps.

Replacing the items (and associated clamps and hardware) before failure reduces the chances for unscheduled downtime. By replacing a system component that is cracked, soft or leaking, major repairs can be avoided that could result in severe engine overheating problems.

Before Replacing Lines

Drain the coolant from the cooling system (or drain coolant to a level below the lines that are replaced if replacing system lines ONLY). Remove clamps, disconnect the old components and.replace with new.

--,--'~tall clamps. See the Torque Specifications section ( ! the appropriate torque values. Refer to Clean/Flush \.._6olant topic in this publication.

After Replacing Lines


Top End Overhaul

NOTE: Perform Cooling System Clean{Fiush procedure unless replacing cooling system lines ONLY. If performing top end overhaul interval, continue to

Cooling System Clean/Flush procedure. If replacing cooling system lines prior to the top end

overhaul interval, perform following steps.

1. Add coolant to the cooling system to bring it to the proper level by mixing a solution of acceptable water, Caterpillar Antifreeze (and coolant additive if not using Caterpillar Antifreeze). Install the filler cap. Refer to the Cooling System Specifications section in this publication for information about the appropriate maintenance of the cooling system or contact your Caterpillar dealer for assistance.

2. Start the engine, inspect for leaks and check water temperature gauge for proper operating temperature.

3. After water temperature gauge has stabilized, stop the engine and check coolant level to ensure it is at the proper level.

Clean/Flush Coola.nt

NOTICE. Do not perform this maintenance until you read and understand the material in the Safety and Cooling System Specifications sections of this publication.

This procedure is to be used for normal maintenance of cooling systems to return to "like new" condition. For heavy build-up of scale. and deposits, a severe acid-type, commercial cleaner or mechanical cleaning will be required.

With the engine shut down and cool, use the following procedure:

1. Disable the starting system and place a DO NOT OPERATE tag on the start valve or start switch.

2. Shut off separate Circuit inlet water flow. Slowly turn the cooloing system pressure cap to the first stop to release the system pressure. Then push down and turn the cap until it is released.

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Drain

When you drain, clean, flush and replace the coolant, small particles, undesirable chemicals, scale and other deposit formations are removed. These deposits reduce the necessary heat transfer characteristics of the cooling system.

3. Remove the drain plug or open the drain valve from cooling water system andjor bottom of jacket water pump housing. Remove the drain plugs to drain the tank, the pump(s), the aftercooler, thermostatic valve, engine cylinder block drain plug(s) and all lines. Allow coolant to drain.

Lett Side View-Cylinder Block Drain Plug

If the outside temperature is expected to go below freezing, drain the water line between the heat exchanger and the separate circuit water pump to empty the aftercooler housing.

Separate Circuit Water Pump Drain

NOTE: Check the water pump seal. If coolant is leaking, make repairs to the pump(s).

Dispose of used engine coolant or recycle. Various methods have been proposed to reclaim used coolant for reuse in engine cooling systems. Filtering methods for reclaiming the used engine coolant do not reduce the level of chemicals in the water. The full distillation. procedure is the only method acceptable by Caterpillar to reclaim the used coolant. Refer to your Caterpillar .dealer for information regarding disposa:J and recycling of used coolant.

4. Clean and install all drain pl~gs andjor close the cooling system drain valve(s).

Flush

5. Refill the cooling system with clean water mixed with the proper concentration of Caterpillar Cooling System Cleaner. Install cooling system filler cap.

NOTE: The system requires 5 liter (5 U.S. quart) of Caterpillar Cooling System Cleaner for every 60 liter (16 U.S. gallon) of cooling system capacity for proper cooling system cleaning.

6. Start and allow the engine to run to circulate fluid in the cooling system for 90 minutes.

7. Stop the engine and allow to cool. Remove cooling system filler cap and system drain plugs.

8. Drain the cleaning solution. Flush the cooling system with clean water until draining water is clear. Clean and install all drain plugs andjor close the drain valve.

NOTE: Repeat Steps 5 thru 8 if necessary until the draining water is clear.

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~ce Thermostats, Gaskets and Seal

:'17.;#dng your thermostats prior to failure is a ";1 / J


Install Thermostats

6. Replace thermostats, gaskets and seals. Make sure that you have the correct thermostats for your jacket water and afiercooling systems.

NOTICE If the thermostats are installed incorrectly, it will cause the engine to overheat.

7. Install the housings in position. Install tubes, .. gaskets and new hoses.

U NOTE: Before proceeding with following steps, ensure Cooling System Clean/Flush and Coolant Hose replacement procedures are complete unless replacing defective thermostats ONLY.

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Fill System with Coolant

NOTICE All water is corrosive at engine operating temperature. The cooling system should be protected with a 3 to 6 percent concentration of cooling system conditioner at all times. Use Caterpillar liquid cooling system condi-tioner to treat the coolant mixture.

Refer to the Cooling System Specifications in this publication for all information regarding acceptable water, antifreeze and supplemental coolant additive (Conditioner) requirements.

NOTE: When refilling the aftercooling system, open the vent plug on the aftercooler, to allow the aftercooler to fill. Failure to do this will cause an air lock and engine damage. After the aftercooler is filled, close the vent plug before operating the engine.

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8. Be certain all drain plugs are clean and installed. Add coolant solution to the cooling system to bring it to the proper level by mixing a solution of acceptable water, Caterpillar Antifreeze and coolant additive (if not using Caterpillar Antifreeze). See Cooling System Specifications and Refill Capacities for the capacity of your engine's system.

9. Start and run the engine witli the cooling system filler cap removed. Operate the engine and allow the coolant to warm, the thermostats to open and the coolant level to stabilize. Inspect for leaks and proper operating temperature.

NOTICE To prevent engine damage, never add coolant to an overheated engine. Allow the engine to cool first.

10 .Add coolant mixture if necessary to bring the coolant to within 13 mm ('12 inch) below the bottom of the fill tube or the correct level on the sight glass, if equipped.

NOTE: Upon initial fill the sight gauge can indicate an incorrect coolant level. Be sure the coolant is to the bottom of the fill tube.

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11. Recheck the coolant level and fill the cooling system to the bottom of the fill tube if the system was low.

NOTICE In cold weather, frequently check the specific gravity of the coolant solution to ensure adequate protection.

If the engine is to be operated, stored in, or shipped to an area with freezing temperatures, the cooling system must be either protected to the lowest expect-ed outside temperature. Always check your cooling system before operating ther engine.

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12. Check the condition of the filler cap gasket. If the gasket is damaged, discard the old filler cap and install a new filler cap. If the gasket is not damaged, use a 9S8140 Service Tool to pressure test the filler cap. This tool is available from your Caterpillar dealer.

The correct filler cap pressure is stamped on the face of the filler cap. If the filler cap does not hold the correct pressure, install a new filler cap.

; Stop the engine and check the coolant to ensure it is at the proper level.


Top End Overhaul

Water Pumps (Jacket & SCAC)

Inspect for Proper Operation

Jacket Water Pump

SCAC Water Pump

Inspect for wear, cracks, pin holes and proper operation. If repairs or replacement is needed, see the Service Manual or contact your Caterpillar dealer.

If the engine is operated until the component fails, it could cause additional damage to the engine. A failed water pump might cause severe engine overheating problems that could result in cracks in the cylinder head, a piston seizure or other potential damage to the engine.

Caterpillar recommends that the most cost effective method of operation for components is to inspect the unit before it fails.


Maintenance Options

New Parts - Genuine Caterpillar parts are constantly tested and modified to incorporate the latest design advances. Your Caterpillar dealer can provide the parts needed for rebuilding the components. Your benefit, long-lasting replacement parts at competitive prices.


V Remanufactured - This process uses manufacturing techniques and procedures to restore the components to like-new performance capability. This process always involves an end product which conforms to the manufacturer's "original" functional specifications. Remanufactured parts may not be available in your area. Contact your Caterpillar dealer for information.


Before deciding which method (rebuild or exchange) is best, make sure all of the options and costs associated with repair have been considered. Some considerations are:



1 Total parts and labor costs for repairs versus the \......; actual Remanufactured cost.



To minimize downtime, Caterpillar recommends that the use of Remanufactured components (subject to availability) is the most cost effective option.



Oil Cooler and Aftercooler Core

Clean/Test

Caterpillar recommends that the water-to-air or air-to-air aftercooler core (if equipped) and the oil cooler core be cleaned and pressure tested at each overhaul. For additional specifications and/or pressure test information, contact your local Caterpillar dealer.

Cleaning Procedure for Cooler Cores (Oil Cooler and Aftercooler)

Caterpillar recommends that the cooler cores be removed, cleaned, and tested at overhaul or if a turbocharger failure has occurred, or if at any time the turbocharger develops an oil leak.

To clean the aftercooler or oil cooler system:

1. Remove the cooler cores. Turn the core upside down to remove debris from the inlet side.

NOTICE Do not use caustic cleaners to clean the air-to-air aftercooler core. Caustic cleaners will attack the inter-nal metals of the core and cause leakage.

2. Back flush internally with a solvent to loosen foreign substances and to remove oil, dirt and debris.

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Caterpillar recommends the use of Caterpillar Hydrosolv 4165 or Hydrosolv 100 Liquid Cleaners.

Part No. Description Size

8T7570 Hydrosolv 4165 208L (55 U.S. Gal.l Drum

8T7571 Hydrosolv 100 208L (55 U.S. Gal. I Drum

For more information refer to General Instructions and Application Guide, LEHQ61 01 or contact your Caterpillar dealer.

3. Shake the core vigorously to eliminate any trapped 'iebris. u

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 normal flow. Use all necessary

_ safety equipment while using compressed air.

6. Inspect the system to ensure cleanliness and install the core.


Top End Overhaul

Ignition Transformers

The ignition transformer causes an increase of the magneto voltage. For good operation, the connections (terminals) must be clean and tight. The negative transformer terminals, with (-) mark, for each transformer are connected together and to ground.

Test Resistance

Check the ignition transformers for loose connection, moisture, short or open circuits. Check the low and high tension wiring resistance using the procedures established in the Service Manual, or contact your Caterpillar dealer.

Altronic Solid State Magneto

Check the resistance of the ignition transformer primary coil between (-) negative and ( +) positive post. The value should be 0.15 0.05 ohms.

Check the resistance of the ignition transformer secondary coil between (-) negative post and spark plug wire connection. The value of the high current (tension) should be 6,500 1 ,500 ohms.

Refer to the Service Manual for your engine to obtain additional information on the ignition system.


Carburetor, Gas Pressure Regulator

Inspect/Replace

Carburetor

Check the operation of the carburetor. Make sure the throttle plate does not bind. Inspect the diaphragm for wear, cracks, and pin holes.

Clieck the throttle shaft bearings. Check and inspect all linkage bearings, replace if necessary. Replace the bearings in the linkage between the carburetor and governor.

Your engine may be equipped with an actuator which will have additional maintenance points.

After replacing bearings, follow the adjustment procedures established in Engine Adjustments-Initial On-Site or refer to the Service Manual to ensure your engine is set up properly. If further assistance is

required, contact your Caterpillar dealer. \.._.)

Gas Regulator

Inspect for wear, cracks, pin holes and proper operation. If repairs or replacement is needed, see the Service Manual or contact your Caterpillar dealer.

Maintenance Options

New Parts - Genuine Caterpillar parts are constantly tested and modified to incorporate the latest design advances. Your Caterpillar dealer can provide the parts needed for rebuilding the components. Your benefit: Long-lasting replacement parts at competitive prices.




Before deciding which method is best, make sure all of the options and costs associated, with repair have been considered. Some considerations are:









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Prelube Pump

Inspect for Proper Operation

Inspect the brushes, replace if necessary. Inspect hoses and fittings for leaks and electrical connections for damaged or frayed wires.

Refer to the Service Manual for the correct procedure to replace the brushes.

Turbochargers


Top End Overhaul

NOTICE Turbocharger bearing failures can cause large quanti-ties of oil to enter the air intake and exhaust systems. Loss of engine lubricant can result in serious engine damage.

Minor leakage of a turbocharger housing under ex-tended low idle operation will not cause problems as long as no turbocharger bearing failure occurred.

When a turbocharger bearing failure is accompanied by a significant engine performance loss (exhaust smoke or engine speed up at no load), DO NOT con-tinue engine operation until the turbocharger is re-paired or replaced.

Inspect/Rebuild or Exchange

Damage to the turbocharger compressor wheel could cause parts from the compressor wheel to enter the engine cylinder and cause additional damage to the piston, valve and cylinder head. The excessive cost of additional engine damage could have been prevented.

Turbocharger components require precision clearances and balancing due to operation at high rotational speeds. Severe service applications can accelerate component wear and may suggest the need to lnspect;Repair/Replace the cartridge at reduced intervals to ensure maximum reliability and retention of full core value.

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The following conditions can indicate severe service operation.

High altitude operation above 1525 m (5,000 ft). Arctic operation (regular cold starts at temperatures

below O'C [32'F]). Extending lube and air system maintenance intervals. Frequent hot shutdowns .(minimum cool down periods

after high load !actor operation).

Maintenance Options

New Parts - Genuine Caterpillar parts are constantly tested and modified to incorporate the latest design

. '\dvances. Your Caterpillar dealer can provide the parts L1eded tor rebuilding the components. Your benefit:

Long-lasting replacement parts at competitive prices.



New Components - Replace worn or failing components with new components. / -., .

~elore deciding which method is best, make sure all of the options and costs associated with repair have been considered. Some considerations are:







NOTE: There are two levels of pricing for Remanufactured turbochargers. The first level is primarily based on damage to the turbocharger before failure. The second level is primarily based on damage to the turbocharger after failure.


Refer to the established procedure in the Service Manual for this engine to remove and install these . components or contact your Caterpillar dealer for assistance.

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Exhaust Bypass Valve

Inspect/Clean

1. Inspect for proper operation.

2. Clean the breather.

3. Remove the breather element and wash in nonflammable solvent.

4.. Install the breather.

-~,efer to the Service Manual or contact your Caterpillar dealer for assistance for removal and maintenance options if the bypass valve is not operatinQ correctly.


Top End Overhaul

152 Maintenance Section Overhaul

Overhaul

Overhaul is defined as the interval at which the major wear items in the engine should be replaced. The overhaul interval represents overhaul of a non failed engine. In other words, the engine is being rebuilt with certain new parts replacing worn parts. The major wear items include piston rings, engine rod and main bearings, valves, and valve seats, etc.

Incidental to the changeout of these relatively few parts is the complete inspection of all other parts that are visible during the opening up of the engine. The disassembly required to perform an overhaul means that disturbed seals and gaskets, etc., will be replaced and the internal passages of the engine and block be

uleaned.

The interval in the Top End and Overhaul chart gives C'!terpillar's recommendation for doing an Overhaul. Refer to the chart in the Top End and Overhaul section in this publication.

The chart suggests intervals in hours and calendar time for overhaul. These intervals are average values and there will be engines that may require overhauling at shorter intervals and many which could go longer.

The other interVal" is expressed in fuel consumption. The best figure to use is total fuel consumed, even if this figure is estimated. Fuel consumption more closely follows the load upon the engine.

The hours (or calendar figure) will be too high if the engine is run at high load and too low if the engine is lightly loaded. Use the clock hour figure only as a guideline. Other factors, such as how conscientiously

. preventive maintenance has been performed, fuel (_)uality, operating conditions, SOS results, etc., are

1mportant in deciding when to perform an overhaul.

The real measure of when to overhaul an engine is performance as measured by output, fuel consumption, oil consumption, blowby and compression. When an engine's oil consumption has risen to three times the initial (new engine) consumption due to normal wear, then the engine should be scheduled for overhaul. We would expect to see a corresponding increase in blowby figures and may also see slight increase in fuel consumption.

Your Caterpillar dealer may be offering a variety of options regarding overhaul programs and Caterpillar recommends that an Overhaul be performed at the maintenance intervals listed in the chart for your engine.

Overhaul Instructions

If you elect to perform an overhaul yourself, without having a Caterpillar dealer perform the overhaul for you, or without using an overhaul kit, then you should be aware of the following:

Rebuild or Exchange

Cylinder Head Assembly and Cylinder Packs.

These components should be inspected according to the instructions found in various Caterpillar reusability publications. Refer to the Index Of Publications On Reusability Or Salvage Of Used Parts section of the Guideline For Reusable Parts and Salvage Operations, SEBF8029 to determine the reusability publications needed for inspecting your parts.

These guidelines were developed to assist Caterpillar dealers and customers avoid unnecessary expenditures for new parts when existing parts can be used as is, repaired or salvaged.

Install New

Crankshaft Bearings and Crankshaft Seals.

In most probability, your thrust,.main and rod bearings and crankshaft seals will not last until your second overhaul. Therefore, Caterpillar recommends the installation of new thrust, main and rod bearings at each overhaul period.

Inspect

Crankshaft, Camshaft, Camshaft Followers and Bearings, Damper, Gear Train Gears and Bushings and Driven Unit Alignment.

The ideal time for inspecting these items is while your 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 your main and rod bearing wear patterns.

Camshaft - Inspect the camshaft for joumal and/or lobe damage.

NOTE: If camshafts or crankshafts are removed for any reason, use the magnetic particle inspection process to check the components for cracks.

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Camshaft Followers and Bearings - Inspect the cam bearings for fatigue and wear.

Damper - It is our recommendation to replace the damper for any of the reasons that follow.

1. The engine has had a failure because of a broken crankshaft. 2. The crankshaft front bearing is badly worn. 3. There is a large amount of gear train wear that is not caused by a lack of oil.

If none of the above conditions is found, dampers can be used again at. overhaul, providing the damper is not damaged.

U Gear Train Gears and Bushings- Inspect for worn

. gear teeth, unusual fits and unusual wear.

Driven Unit Alignment -Upon reassembly of the drive line and driven unit, check alignment as outlined in the:

LEBX6213-Building Services Application and Installation Guide

LEBH9324-Agricultura/ and Material Handling ~pplication and Installation Guide

-.osEHS7654-Aiignment-General Instructions

NOTE: For additional information regarding these items, contact your local Caterpillar dealer for assistance.

After Failure Overhaul

( 1 you experience a major engine failure which requires '-removal of the engine, there are also many After

Failure Overhaul options available. An overhaul should be performed if your block or crankshaft needs to be repaired. If the block and/or crankshaft is repairable, then the cost of an overhaul should be between 40 and 50% of the cost of a new engine (with like exchange core).

This lower cost can be attributed to Caterpillar "designed-in" features that include:

Regrindable crankshaft Undersize bearings Cat dealer and Caterpillar Remanufactured exchange

components


Overhaul

Dealer Exchange Components - This is exchanging worn engine components for quality Cat dealer rebuilt components on an over-the-counter basis.

Caterpillar Remanufactured Components -Manufacturing techniques and processes are used to restore components to "like-new" performance capabilities, conform to original functional specifications and are exchanged for your existing parts.

The following is a list of (R)Remanufactured' components currently being offered by Caterpillar in many countries:

Cylinder head - bare Cylinder head - assembly. and group Connecting rods Crankshaft - undersized Crankshaft - upgrade to new Complete turbocharger Turbocharger cartridges Water pumps Oil pump Oil cooler and aftercoo/er cores Alternator Starting motor Governor and Carburetor Gas Pressure Regulator

NOTE: If the component you need is not listed here, contact your Caterpillar dealer to see if it is offered under a dealer exchange component program.

Current Parts Manuals will asterisk a part number when a (R)Remanufactured unit is offered by Caterpillar.


To further control your overhaul costs, Caterpillar recommends that you contact your dealer for information regarding the availability of a Flat Rate After Failure Overhaul.

154 Maintenance Section Gas Engine Standby Generator Preventive Maintenance Recommendations

Gas Engine Standby Generator Preventive Maintenance Recommendations

!_, t

Introduction

The objective of this topic is to assist users in establishing a Preventive Maintenance Program for Standby Gimerator Sets or as an aid in evaluating their present programs.

Standby Generator Sets may not be needed very often, but when they are, it is usually under emergency conditions. Maintenance of these standby units is very important. They must always be in excellent operating condition, ready to work under load at any time.

Establishing a Preventive Maintenance Program will provide maximum availability of a standby generator

uset when needed, longer engine and generator life, and a minimum of expensive repairs.

The recommended weekly maintenance checks can be performed by an operator. All yearly and three year maintenance should be performed by an authorized mechanic or your Caterpillar dealer.

These guidelines are to be used with the information contained in the Operation and Maintenance sections of this manual. The Operation and Maintenance sections of the manual will provide the necessary information on how to perform the checks and routine m.aintenance. Additional information can be obtained from the SR4 Generator and Engine Service Manuals, or contact your Caterpillar dealer for assistance.

Inspection and Maintenance Agreements

Your Caterpillar dealer can establish an Inspection and i preventive Maintenance Program for your generator set "'-"'to provide maximum reliability, increased engine and

generator life, and minimize expensive repairs. Contact your Caterpillar dealer for details.

General Recommendations

Safety

A WARNING The stop-manual-automatic switch on the cranking panel must be set at STOP position when perform-ing maintenance or repair work on a standby gener-ator set. This prevents the unit from starting if a power failure or voltage drop should occur while working on the unit.

To prevent personal injury due to accidental start-ing of the engine, disconnect the batteries or disa-ble the starting system before doing maintenance or repair work.

Lock out all switch gear and a!Jtomatic transfer switches associated with the generator while per-forming any generator maintenance or repairs. ~ Make sure no shock hazard exists.

Failure to comply could result in personal injury or death.

Always make repairs with the engine stopped and the starting system disabled. When s.ervicing the generator, make sure that switch gear and automatic transfer switches will not present a shock hazard. Lock them out on the generator being serviced.

Record Keeping

Maintain a log or record keeping system to document all gauge readings, problems, repairs, and maintenance performed on the equipment.

Space Heaters

Moisture is a natural enemy of generators and all electrical equipment. Every effort must be made to keep the generator as dry as possible. Space heaters should be operated inside the generator when it is not in use to maintain lhe integrily of the generator windings.

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caterpillar g3500 top end overhaulesek.pdf

Documents

cubic meters cubic teet

cubic metershour cubic

actual cubic meters

overhaul intervals

cubic meters m3

cubic feet fp

overhaul interval hours

end intervals