HomeEnginesCummins/Onan KTA38-M1

Cummins/Onan KTA38-M1 Engine

The Cummins/Onan KTA38-M1 is a 37.7 L 12-cylinder turbocharged/aftercooled engine rated at 1800 rpm, producing up to 671 kW. It powers generator sets from Cummins/Onan, including the KTA38.

Also known as: CUMMINS KTA38-M1

Part of the Cummins/Onan KTA38 engine family — 13 variants share parts & fitment.

37.7 L
Displacement
12
Cylinders
1800 rpm
Rated speed
671 kW
Gross power

Engine specifications

Displacement37.7 L
Cylinders12
AspirationTurbocharged/Aftercooled
Rated speed1800 rpm
Gross power671 kW

Service intervals

31
ItemActionHoursMonthsNotes
Air cleaner element - restrictionCheck250 hr6 moReplace air cleaner element as required
All beltsCheck250 hr6 mo
Cooling fanCheck250 hr6 moCheck for cracks, loose rivets, bent or loose blades
Engine oilChange250 hr6 moWhichever occurs first
Fan idler pivot armLubricate250 hr6 moWater pump type grease until grease appears
Front engine supportLubricate250 hr6 moChevron SRI grease or equivalent
Fuel filterReplace250 hr6 mo
HosesInspect250 hr6 moCheck/replace as required
Oil filtersChange250 hr6 moChange filters with oil
Pulley tensionerCheck250 hr6 mo
BatteriesCheck1500 hr12 mo
Cold start aidsCheck1500 hr12 moSeasonal
Crankshaft end clearanceInspect1500 hr12 mo
Engine (steam clean)Clean1500 hr12 moBefore conducting any 1500 hour maintenance
Engine mounting bolts and nutsCheck1500 hr12 moTighten loose; inspect rubber
Engine protection systemCheck1500 hr12 mo
Fan idler pulley tensionerAdjust1500 hr12 mo
Heat exchanger zinc plugs (marine only)Check1500 hr12 moChange if 50 percent eroded
Valves and injectorsAdjust1500 hr12 moFirst service — Initial adjustment at 1500 hours; thereafter not again before 6000 hour injector calibration
Air compressorInspect6000 hr24 moDischarge and intake checks
CoolantChange6000 hr24 moClean and flush cooling system
Crankcase breather elementReplace6000 hr24 moClean/replace
Engine protection systemAdjust6000 hr24 moCalibrate
Fan hubInspect6000 hr24 moEnd clearance and grease leakage
Fan idler pulley assemblyReplace6000 hr24 moRebuild or replace as necessary
Fuel pumpClean6000 hr24 moClean and calibrate
InjectorsClean6000 hr24 moClean and calibrate
Thermostats and sealsReplace6000 hr24 mo
TurbochargerInspect6000 hr24 mo
Vibration damperInspect6000 hr24 moReplace after 24,000 hours; K2000 dampers replaced every 12,000 hours
Water pumpReplace6000 hr24 moRebuild or replace

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

60
TypeItemValueUnitCondition
ClearanceCrankshaft end clearance0.13 MIN / 0.51 MAXmm
ClearanceFan hub bearing end clearance0.03 MIN / 0.15 MAXmm
ClearanceThermostat seal installation depthno more than 0.51mmbelow top of cast edge
ClearanceTurbocharger BB (RR-151) and (RR-153) end clearance0.09 MIN / 0.13 MAXmm
ClearanceTurbocharger BB bearing radial clearance - RR-1510.75 MAXmm0.030 in
ClearanceTurbocharger BB bearing radial clearance - RR-1530.55 MAXmm0.021 in
ClearanceTurbocharger axial end play - HC5A0.05 MIN / 0.13 MAXmm
ClearanceTurbocharger axial end play - HT71000.06 MIN / 0.16 MAXmm
ClearanceTurbocharger axial end play - T18A0.10 MIN / 0.23 MAXmm
ClearanceTurbocharger radial clearance compressor impeller - HC5A0.15 MIN / 0.45 MAXmm
ClearanceTurbocharger radial clearance turbine wheel - HC5A0.20 MIN / 0.55 MAXmm
GapHeat exchanger zinc plug erosion limit Aapproximately 19mm0.75 in; new 51 mm [2 in]
GapHeat exchanger zinc plug erosion limit Bapproximately 6.4mm0.25 in; new 16 mm [0.625 in]
OtherAir compressor discharge carbon deposit thickness limit2mm1/16 in
OtherAlternator belt tension356N80 lbf, Burroughs tension gauge GT-1293
OtherMaximum vibration damper thickness - Houdaille66.38mm2.574 in
OtherMaximum vibration damper thickness - Made in England Before F-8265.91mm2.595 in
OtherMaximum vibration damper thickness - Made in England F-82 and After65.66mm2.585 in
OtherPTD injector travel verification specification7.80 MIN / 7.82 MAXmm
OtherPTD non-top stop injector travel adjustment7.82mm
OtherPTD non-top stop injector travel limits7.77 to 7.87mm
OtherTwo pulley fan drive belt tension (set)2668.9 to 2891.3N600 to 650 lbf
OtherTwo pulley fan drive belt tension (verify)2891.3 to 3336.2N650 to 750 lbf
OtherVibration damper thickness variation (four readings 90 degrees apart)must not vary more than 0.25mm0.010 in
PressureCoolant pressure cap minimum50kPa7 psi
PressureExhaust back pressure maximum75mm Hg3 in Hg, at rated speed and load
PressureMaximum allowable intake restriction - clean filter element380mm H2O15 in H2O
PressureMaximum allowable intake restriction - dirty filter element635mm H2O25 in H2O
PressureMaximum allowable restriction to fuel pump - clean filter100mm Hg4 in Hg, at rated power
PressureMaximum allowable restriction to fuel pump - dirty filter200mm Hg8 in Hg, at rated power
PressureMaximum allowable return line restriction63mm Hg2.5 in Hg
PressureMaximum allowable return line restriction with check valves and/or overhead tanks165mm Hg6.5 in Hg
PressureOil pressure, main oil rifle, maximum at rated RPM483kPa15W-40 oil at 107 C [225 F]
PressureOil pressure, main oil rifle, minimum at idle RPM138kPa15W-40 oil at 107 C [225 F]
PressureOil pressure, main oil rifle, minimum at rated RPM310kPa15W-40 oil at 107 C [225 F]
PressureThrottle air cylinder leak test pressure689kPa100 psi
PressureThrottle air cylinder test pressure560kPa80 psi
SpeedEngine speed must not exceed2400RPMunder any circumstances
TemperatureLTA modulating thermostat range74 - 82C165 - 180 F
TemperatureOil temperature maximum120C250 F
TemperatureStandard modulating thermostat range80 - 90C175 - 195 F
TorqueAir compressor unloader valve body capscrew15Nm120 in-lb
TorqueAir compressor unloader valve cap40Nm30 ft-lb
TorqueAlternator adjusting link and mounting capscrews55Nm40 ft-lb
TorqueCrosshead adjusting screw lock nut (with ST-669 adapter)35Nm25 ft-lb
TorqueCrosshead adjusting screw lock nut (without adapter)40Nm30 ft-lb
TorqueFan belt idler assembly capscrews60Nm45 ft-lb
TorqueFan hub assembly to fan support (12 pt capscrew)285Nm210 ft-lb
TorqueFan idler arm shock absorber capscrews60Nm45 ft-lb
TorqueFan idler control rod adjusting screw jam nuts55Nm40 ft-lb
TorqueFan idler control rod capscrews90Nm65 ft-lb
TorqueFuel pump drive coupling capscrews45Nm35 ft-lb
TorqueInjector adjusting screw (alignment/setting)11 then 10Nm100 in-lb then 90 in-lb
TorqueInjector adjusting screw lock nut (with ST-669 adapter)45Nm35 ft-lb
TorqueInjector adjusting screw lock nut (without adapter)60Nm45 ft-lb
TorqueInjector hold down clamp capscrew16Nm145 in-lb
TorqueInjector jumper tube connector screw25Nm20 ft-lb
TorqueOil drain plug100Nm75 ft-lb
TorqueRocker lever cover40Nm30 ft-lb
TorqueRocker lever shaft (12 pt capscrew)90Nm65 ft-lb

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Recommended fluids

FluidGradeStandardAmbientCapacityNotes
Coolant50/50 low-silicate antifreeze and quality waterASTM D4985 (less than 0.10% silicate as Na2SiO5)Must be pre-charged with supplemental coolant additives (DCA4) to 1.5 units per gallon; never below 1.2 or above 3 units per gallon. Do not use soluble oils.
Engine oilSAE 15W-40API CE or CF4 (CD or CD/SF where CE/CF4 not available)Multigrade preferred; sulfated ash limit must not exceed 1.85 mass percent. Arctic operation (below -23 C) use synthetic CE/SF 5W-30.
FuelASTM No. 2 dieselBelow 0 C use blends of No. 2D and No. 1D. Viscosity must be kept above 1.3 cSt. Do NOT mix gasoline or alcohol with diesel fuel.
GreaseWater pump type grease (Amoco Rykon Premium No. 2 / Chevron SRI / Exxon Unirex N2 / Shell Dolium R / Texaco Premium RB)Fan idler pivot arm and front engine support lubrication

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

12
Alternator Belt Adjustment adjustment

⚠ Over-tensioning of alternator belts can result in premature accessory drive bushing wear and seal leakage.

Tools: GT-1293 Burroughs Tension Gauge

  1. Loosen the alternator and adjusting link mounting capscrews.
  2. Loosen the jam nuts on the adjusting screw.
  3. Turn the adjusting screw clockwise to tighten the belt tension.
  4. Check the belt tension with a gauge.
  5. Tighten the jam nuts on the adjusting screw to 55 Nm [40 ft-lb].
  6. Tighten the adjusting link and alternator mounting capscrews to 55 Nm [40 ft-lb].
  7. Check the belt tension again.
Crossheads - Adjustment adjustment

Tools: ST-669 Torque Wrench Adapter

  1. Adjust the crossheads on the cylinder that has both valves closed.
  2. Loosen the crosshead adjusting screw locknuts on the intake and exhaust valve crossheads.
  3. Turn the adjusting screw out at least one turn.
  4. Hold the crosshead down against its guide.
  5. Turn the adjusting screw in until it touches the top of the valve stem but does not raise the crosshead.
  6. Hold the adjusting screw and tighten the lock nut to the torque value.
Dipstick Calibration adjustment

⚠ The dipstick will break if the scribe mark is too deep.

Tools: scribe

  1. Drain the oil from the pan.
  2. Install the dipstick in the dipstick tube.
  3. Use clean 15W-40 oil to fill the oil pan to the specified low level.
  4. Remove the dipstick and scribe a mark across the dipstick at the oil level. Mark the low level with an L.
  5. Install the dipstick and add additional oil to the specified full level.
  6. Remove the dipstick and scribe a mark across the dipstick at the oil level. Mark the high oil level with an H.
PT (type D) Injector - Adjustment adjustment

⚠ The injector plunger is under spring tension. Do NOT allow the tool to slip.

⚠ Prevent damage to the indicator by allowing the lever to return slowly.

Tools: 3822575 injector and valve adjustment kit, 3822574 rocker lever actuator, ST-669 Torque Wrench Adapter

  1. Assemble the parts of an injector and valve adjustment kit, Part No. 3822575, or equivalent, and install it on the cylinder.
  2. Adjust the indicator so the tip touches the top of the injector plunger.
  3. Lower the indicator 12.25 mm [0.5 inch] to allow for travel. Lock the indicator support to the post.
  4. Use a rocker lever actuator, Part No. 3822574, or equivalent. Depress the lever until the injector bottoms two or three times.
  5. Hold the lever with the injector plunger firmly bottomed and set the indicator to ZERO.
  6. Turn the adjusting screw until the indicator reads the specified travel.
  7. Tighten the locknut to the torque value.
  8. Check the injector adjustment and repeat if not within specification.
Valves - Adjustment adjustment

⚠ Use the correct chart for the engine being serviced or the parts will be damaged.

Tools: 3376592 Inch Pound Torque Wrench, ST-669 Torque Wrench Adapter, feeler gauge

  1. Select a feeler gauge for the correct valve lash specification and insert the gauge between the rocker lever and the crosshead.
  2. Torque wrench method: use Part No. 3376592 inch pound torque wrench and tighten the adjusting screw to 0.68 Nm [6 in-lb].
  3. Feel method: use a screwdriver and turn the adjusting screw only until the lever touches the feeler gauge.
  4. The adjusting screw must not turn when the locknut is tightened.
  5. Tighten the locknut to the value indicated.
  6. The feeler gauge must slide backward and forward with only a slight drag.
  7. Attempt to insert a feeler gauge 0.03 mm [0.001 in] thicker; the lash is not correct when the thicker gauge will fit.
  8. Repeat until clearance is correct on both intake and exhaust valves.
Air Cleaner Element Replacement - Single Heavy Duty Dry-Type maintenance

⚠ Holes, loose end seals, dented sealing surfaces and other damage require immediate element replacement.

⚠ Pull the cover and element straight out to avoid damage.

  1. Wipe dirt from the cover and upper portion of the air cleaner before disassembly.
  2. Loosen the wing bolt and band clamp securing the dust pan.
  3. Loosen the wing nut and remove the dust shield from the dust pan. Clean the dust pan and shield.
  4. Remove the wing nut securing the primary element and inspect the rubber sealing washer.
  5. Remove the dirty cleaner element and install the new primary element.
  6. Make sure the rubber sealing washer is in place under the wing nut before tightening.
  7. Assemble the dust shield and dust pan and secure with the band clamp.
Coolant Filter Replacement maintenance

⚠ Do NOT remove the radiator cap from a hot engine.

⚠ Do not allow oil to get in the filter; it will adversely affect the DCA.

  1. Remove the coolant system pressure cap and close the shutoff valve(s), if equipped, before removing the coolant filter.
  2. Push in the knob on the filter head or close the gate valve.
  3. Lubricate the seal on the new filter with engine oil.
  4. Install the new coolant filter. Turn the filter until the seal touches the filter head.
  5. Turn the filter an additional 1/2 to 3/4 of a turn after contact.
  6. Pull the knob on the filter head out or open the gate valve.
Cooling System Cleaning and Changing Antifreeze maintenance

⚠ Do not use caustic cleaners in the cooling system. Aluminum components will be damaged.

⚠ Wait until the temperature is below 50 C [120 F] before removing the coolant system pressure cap.

  1. Drain the cooling system. Do not allow the cooling system to dry out. Do not remove the coolant filter.
  2. Add 3.8 liters [1 U.S. gallon] of Fleetguard RESTORE (or equivalent) for each 38 to 57 liters [10 to 15 gallons] of cooling system capacity and fill with plain water.
  3. Turn the heater temperature switch to high to allow maximum coolant flow.
  4. Operate the engine at normal operating temperatures (at least 85 C [185 F]) for 1 to 1 1/2 hours.
  5. Shut the engine off and drain the cooling system.
  6. Fill with clean water to flush and operate at high idle for 5 minutes above 85 C [185 F].
  7. Shut the engine off and drain. Repeat flushing if the water is still dirty.
  8. Refill the system with new heavy duty coolant and SCA.
Fan Hub Inspection maintenance

Tools: dial indicator

  1. Remove the fan belt.
  2. Rotate the fan hub pulley to check for rough or damaged bearings.
  3. Inspect the pulley grooves for excessive wear.
  4. Check for grease leakage.
  5. Use a dial indicator to check the bearing end clearance.
  6. Replace with a new or rebuilt unit as necessary.
  7. Install the fan belt.
Fuel Filter(s) Replacement maintenance

Tools: 3375049 filter wrench

  1. Clean the area around the fuel filter head and replace the fuel filter(s).
  2. Use a filter wrench, Part No. 3375049, to remove the fuel filter.
  3. Clean the filter head gasket surface with a clean, lint-free towel.
  4. Apply a light film of clean engine oil to the filter gasket surface.
  5. Fill the filter with clean fuel.
  6. Install the filter on the filter head and tighten until the gasket contacts the filter head surface.
  7. Tighten the filter per the filter manufacturer's instructions.
Lubricating Oil and Oil Filter Changing/Replacement maintenance

⚠ Avoid direct contact of hot oil with your skin.

⚠ Fill the oil filters with clean lubricating oil before installation.

Tools: 3375049 oil filter wrench

  1. Operate the engine until water temperature reaches 60 C [140 F]. Shut off the engine.
  2. Remove the oil drain plug and drain the oil immediately.
  3. Clean the area around the lubricating oil filter head and the gasket surface.
  4. Use an oil filter wrench, Part No. 3375049, or equivalent, to remove the oil filters.
  5. Apply a light film of lubricating oil to the gasket sealing surface before installing the new filters.
  6. Fill the oil filters with clean lubricating oil.
  7. Install the filters as specified by the filter manufacturer.
  8. Check and clean the oil drain plug threads and seal surface.
  9. Install and tighten the oil drain plug to 100 Nm [75 ft-lb].
  10. Fill the engine with clean oil to the correct level.
  11. Operate the engine at idle to inspect for leaks; shut off and check oil level again; add oil to the high H mark.
Short Term Storage Preparation (One Month to 6 Months) maintenance

⚠ Put a warning tag on the engine: The engine does NOT contain oil. Do NOT operate the engine.

  1. Operate the engine at HIGH IDLE until coolant temperature is 70 C [160 F]. Turn the engine OFF.
  2. Disconnect the fuel lines to the engine fuel filter and the injector return line.
  3. Put both fuel lines in a container of diesel fuel and START the engine.
  4. After the engine runs smoothly, transfer the fuel supply line to a container of preservative oil and operate until preservative oil flows out the injector return line.
  5. Turn the engine OFF and connect the fuel lines to the fuel filter and injector return line.
  6. Drain the oil pan sump, oil filters, and fuel filters.
  7. Disconnect the electrical wiring from the fuel pump solenoid; turn the fuel pump manual shutoff valve counterclockwise until it stops.
  8. Crank the engine slowly and spray lubricating oil into the intake manifold and air compressor inlet.
  9. Drain the coolant and put a warning tag on the engine.
  10. Store the engine in a dry area with uniform temperature and bar the crankshaft two or three revolutions every 3 to 4 weeks.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Voltage reconnection

VoltagePhaseConnectionLeadsNotes
110/190, 115/2003Code 31Reconnectible stator
120/2083Code 4460 Hz
120/208, 127/2203Code 519Reconnectible stator
120/2403Code 5D460 Hz
127/2203Code 8460 Hz
139/2403Code $ (99 on nameplate)4No Standard Voltage Code, number 99 is marked on the nameplate for reference information
200/3463Code 523Reconnectible stator
220/3803Code 7460 Hz
220/380, 230/4003Code 520Reconnectible stator
240/4163Code 7X460 Hz
240/416, 254/4403Code 521Reconnectible stator
240/416, 254/4403Code 522Reconnectible stator
240/4803Code 6D460 Hz
277/4803Code 4X460 Hz
347/6003Code 9X460 Hz

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Parts cataloged across the Cummins/Onan KTA38 family

93
Part #DescriptionCategory
UC224CAlternator Modelalternator
UC274FAlternator Modelalternator
052045Lead Acid Battery - Dry (Export)battery
011261Battery Lead (-VE)battery_lead
011262Battery Lead (+VE)battery_lead
011270Battery Lead, +vebattery_lead
035095Clamp Boltbolt
427560Battery Boot, Single Outletboot
427561Battery Boot, Copper Linkboot
035090Battery Clampclamp
049001Clipclip
010156Heater Hose Connectionconnection
0101591” NPT x 16 I/D Hose Connectorconnector
0300-4623-26DFJD (600V)current_transformer
0300-4623-51DFJD BR (0-480V)current_transformer
149-1689Element (Dual Fuel/Water Separator)fuel_filter
FF202Fuel, Spin-Onfuel_filter
FS1216Fuel/Water Sep Spin-Onfuel_filter
155-0675Gasket (Water Outlet)gasket
155-1030Gasket (Exhaust Header)gasket
415-0486Gasket (Fuel Tank - Overhead/Underground Supply)gasket
526-0063Gasket (Fuel Tank)gasket
M-4352580Upper Gasket Setgasket
503-0359Hose (Cooling System - Standpipe)hose
503-0788Hose (Cooling System - Standpipe)hose
3822575Injector and valve adjustment kitinjector
011281STR/STR - STR/Earth Lead (-VE)lead
011250Battery Linklink
05086111/4’’ NPT x 1’’ NPT Hex Nipplenipple
715250M8 Steel Wing Nutsnut
151-0399Controller (Electric Governor)other_service
151-0419Actuator (Electric Governor)other_service
159-0020Cap, Tankother_service
307-0839Valve, Solenoid (Cooling System - Standpipe)other_service
307-1861Valve, Solenoid (Overhead Supply)other_service
309-0407Valve, Float (Overhead Supply)other_service
3096680Piston STC 13.8:1 Ratioother_service
3096681Piston KT Series 15.5:1 Ratioother_service
3096682Piston KTA Series 14.5:1 Ratioother_service
3096683Piston 13.5:1 Ratioother_service
3096684Piston KTA 15.7:1 Ratioother_service
3096685Piston STC 13.9:1 Ratioother_service
331-0027Switch, Thermostaticother_service
332-2634Clamp, Retainer 4 Prior To December 1996 Production (Mounted On Top And Side Of Control Box Wrapper)other_service
3628731Piston STC Kitother_service
3630913Piston KTA-50-G7other_service
3631241Piston Kit STC 13.9:1 Ratioother_service
3631242Piston Kit 13.5:1 Ratioother_service
3631243Piston Kit KTA 15.7:1 Ratioother_service
3631244Piston Kit KTA Series 14.5:1 Ratioother_service
3631245Piston Kit KT Series 15.5:1 Ratioother_service
3631246Piston Kit STC 13.8:1 Ratioother_service
3803530Piston Assembly STCother_service
3804747Piston Kit KTA-50-G7other_service
3804885Piston KTA-50-G8/G9other_service
4089847Piston Kit GTA38/19other_service
4090013Piston Kit KTA-38-M2other_service
4090029Piston Kit QSK19CEother_service
4090181Piston GTA38/19other_service
4097889Piston KTA-38-M2other_service
4910463Piston QSK19R/Mother_service
4910465Piston QSK Seriesother_service
4916177Piston GTA/GQSK19other_service
4918058Piston QSK19CEother_service
4922319Piston QSK19Cother_service
4955233Piston Kit QSK19R/Mother_service
4955235Piston Kit QSK Seriesother_service
4955236Piston Kit QSK19Cother_service
4955238Piston Kit GTA/GQSK19other_service
508-0018Washer, Insulating (1/4" ID)other_service
518-0548-24Clamp, Retainer Begin December 1996 Production (Mounted On Top And Side Of Control Box Wrapper On The Side Towards The Control Box Cover)other_service
518-0548-42Clamp, Retainer 4 Prior To December 1996 Production (Mounted On Top And Side Of Control Box Wrapper)other_service
960-0104other_service
960-0142other_service
960-0263other_service
960-0606other_service
960-0609other_service
M-3804747Piston Kitother_service
V2403-M-E3BGEngine Modelother_service
05050151Reducer, 1/2” x 1/8” NPTreducer
706187M4 x 12 mm Steel Cheesehead Screwscrew
01930388Sender, Oil Temperaturesensor
150-0717Switch Assembly, Overspeedsensor
151-0411Pickup, Magneticsensor
960-0504PCC Control Service Manualservice_manual
960-0507Detector Control Service Manualservice_manual
010167Heater Supportsupport
03090269Switch, Low Engine Temperature (LET)switch
418520Battery Terminal, On Lineterminal
010112Thermostatthermostat
309-0243Valve, Control - Temperature Regulatingthermostat
035105Battery Traytray
716007M4 Plain Washer, Thick, Steel, Form Awasher

Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.

Common questions

What is the displacement of the Cummins/Onan KTA38-M1?

The Cummins/Onan KTA38-M1 has a displacement of 37.7 liters with 12 cylinders.

Which generators use the Cummins/Onan KTA38-M1 engine?

The Cummins/Onan KTA38-M1 powers 1 generator set(s), including Cummins/Onan KTA38.