Komatsuengine(no series)

Komatsu NH-220-CI-1F(S/N 18566-UP)

Maintenance schedule, common problems & OEM parts breakdown

Search live NH-220-CI-1F(S/N 18566-UP) parts

The NH-220-CI-1F (S/N 18566-UP) is a Cummins-built, naturally aspirated inline-six diesel that Komatsu specified as factory power for its D60 and D65 dash-6 class crawler dozers built from the mid-1970s into the mid-1980s. It displaces roughly 12.2 L (743 cu in), runs a mechanical PT fuel system with a gear-driven oil pump and wet cylinder liners, and was fitted across straight-blade, angling-blade, power-angle-tilt, and LGP swamp-shoe configurations sold under the A, P, PL, E, and S model suffixes on the D60 and D65 lines. Gross output on these hosts ran roughly 140 hp (104 kW) to 155 hp (116 kW) depending on model and governed setting, with operating weights spanning about 12.8 to 18.3 tonnes (28,200 to 40,300 lb) across configurations. Earlier dozers in this size class also drew on Cummins NH power before this generation.

This particular 1F block, at engine S/N 18566-UP, sits in the early production run of the NH-220-CI family, the same serial series as the earliest -1B units. Komatsu later moved to a second production block of engine serials covering later dash-6 output and some dash-7 machines, largely running changes rather than a ground-up redesign. When the following D65-7/D65-8 generation arrived, Komatsu dropped Cummins sourcing for this size class in favor of its own 6D125-family diesel, ending the NH-220-CI's run as factory power. In today's used and parts market these are mechanical, pre-electronic diesels with no ECM or fault codes — valued for being straightforward to keep running and cheap to rebuild. Demand centers on gaskets, injectors, water pumps, dynamos/starters, and undercarriage wear parts on host machines that are now well past 40 years old.

Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.

Komatsu NH-220-CI-1F(S/N 18566-UP) specifications

Engine

Engine model	Cummins-built NH220-CI (Komatsu designation NH-220-CI), inline-6, mechanical fuel system, naturally aspirated. This 1F build variant carries S/N 18566-UP.
Gross power	Rated 104-134 kW (140-180 hp) at 1850 rpm, governed rating varies by host chassis and application within the NH220-CI family
Net power	Not published for this engine
Displacement	12.2 L (743 cu in)
Cylinders	6, inline
Emissions tier	Pre-emissions mechanical diesel; no emissions certification tier published

Weights

Operating weight (host chassis, varies by application)	Approx. 12,800 kg (28,220 lb) on lighter dozer applications up to approx. 15,730 kg (34,679 lb) on heavier applications; this engine family spans multiple dozer chassis, so weight tracks the host machine, not a fixed engine figure
Shipping weight	Not documented for this exact serial range - verify with your dealer
Ground pressure	Approx. 51 kPa (7.4 psi) on standard-shoe configurations; varies with shoe width

Dimensions

Overall length without blade	Approx. 4.0-4.2 m (13.1-13.7 ft), depending on host chassis
Overall length with blade	Approx. 5.1 m (16.85 ft) on longer-chassis applications
Width over tracks	Approx. 2.39 m (7.85 ft)
Height to top of cab	Approx. 3.0 m (9.9 ft)
Ground clearance	Approx. 0.40 m (1.32 ft)
Track length on ground	Approx. 2.4-2.5 m (7.9-8.0 ft)

Performance

Maximum forward travel speed	Approx. 10.3-10.8 km/h (6.4-6.7 mph), depending on transmission gearing (3-5 forward gears across host applications)
Maximum reverse travel speed	Approx. 9.1-13.7 km/h (5.7-8.5 mph), depending on host transmission
Drawbar/dig/lift performance	Not documented for this exact serial range - verify with your dealer

Service capacities (summary)

Fuel tank	Approx. 280 L (74 US gal), consistent across the D60/D65-class host chassis this engine powers
Cooling system	Approx. 55 L (14.6 US gal)
Engine oil	Not published for this exact engine build
Hydraulic system	Not documented for this exact serial range - varies by host machine and implement configuration

Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.

NH-220-CI-1F(S/N 18566-UP) fluids & capacities

System	Capacity	Recommended fluid
Engine crankcase, with filter	approx. 26.5 L (7.0 US gal) — single-source figure, unconfirmed for this exact serial range; oil-pan capacity can vary with sump configuration	API CF-4/CI-4 (or JASO DH-1) heavy-duty diesel engine oil meeting Cummins CES 20076/20078; Komatsu Genuine EO15W40-DH class multigrade for standard climates, shift to a lighter grade (10W-30) in sustained sub-zero cold per Komatsu's viscosity-by-ambient-temperature chart
Cooling system	65.1 L (17.2 US gal), reported at the dozer chassis level for this engine's host machine — treat as approximate for the exact 1F/18566-UP build	Komatsu Supercoolant AF-NAC, ethylene-glycol OAT type, 50/50 pre-diluted, meets ASTM D3306 / JIS K2234; do not mix with silicate-type antifreeze; change interval per Komatsu schedule (about every 2 years or 4,000 hours)
Fuel tank	approx. 420 L (111 US gal), host-machine chassis figure — varies by dozer configuration (D80A-12/D85A-12 class); not an engine-specific spec	No. 2-D diesel fuel per Cummins fuel spec; use winterized/No. 1-D blend or additive in cold climates to prevent gelling
Transmission/powertrain compartment	not applicable to this record — belongs to the host dozer's own OMM chapter, not the engine's fluid chart	not documented for this engine identity; consult the host machine's (D80A-12/D85A-12) service manual
Final drives (each side)	not applicable to this record — host-machine component	not documented for this engine identity; consult the host machine's service manual
Hydraulic system and tank	not applicable to this record — host-machine component	not documented for this engine identity; consult the host machine's service manual
Axles/differentials	not applicable — this engine model has no integral axle/differential assembly	n/a
Grease points (chassis/engine mounts, linkages)	spec only, no quantity given	NLGI No. 2 lithium-based multipurpose grease, typical for Komatsu-applied diesel engines of this era; not separately itemized in available sources for this exact serial range

Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.

Komatsu NH-220-CI-1F(S/N 18566-UP) maintenance schedule

Service interval	Tasks
Every 50 h	Check engine oil level daily and top off with the correct viscosity; never overfill above the full mark. Check coolant level in the radiator top tank only when the engine is cool; add pre-mixed coolant with corrosion inhibitor. Drain water and sediment from the primary fuel filter/water trap. Walk-around inspect for fuel, oil, and coolant leaks around the block, PT fuel pump, and water pump. Check the air cleaner restriction indicator weekly and service the primary element if it has tripped. Check dynamo (generator) and water pump drive belt tension and condition.
Every 250 h	Change engine oil and replace the full-flow oil filter element. Clean the crankcase breather. Inspect the fuel filter element and replace if restricted. Check battery electrolyte level and clean/tighten terminals. Grease external pressure-lubrication fittings on the water pump and linkage. Check torqflow transmission and steering clutch oil level, since the circuit shares the engine-mounted oil cooler.
Every 500 h	Replace primary and secondary fuel filter elements. Clean the radiator core externally and clear any packed debris from the fins. Inspect the dynamo, starter, and wiring harness for wear, chafing, or corrosion. Adjust or replace the water pump/dynamo drive belt if glazed or cracked. Inspect the exhaust manifold and muffler for leaks or cracks. Pull an engine oil sample for wear-metal trending if not already on a standing analysis program.
Every 1,000 h	Adjust valve (rocker) lash to factory clearance, checked cold and hot as specified. Check and reset PT fuel pump and injector timing per the factory setting procedure. Re-torque cylinder head bolts to factory sequence and value. Drain, flush, and refill the cooling system with fresh pre-mixed coolant and inhibitor. Check engine, dynamo, and starter mounting bolts for correct torque. Run a cylinder compression check on all six cylinders to trend wear.
Every 2,000 h	Perform a full injector calibration/reset across all six cylinders as a matched set. Inspect and recondition or replace the water pump. Service the oil cooler shared with the torqflow transmission and steering clutch circuit. Replace the thermostat. Inspect wet cylinder liners for cavitation pitting the next time the head is off; flag any pitted liner for replacement. Re-check governed engine speed against the factory rating and adjust if drifted.
Every 6,000 h	Pull the cylinder head for a top overhaul: recondition or replace valves, guides, and seats. Replace piston rings and inspect wet liners for cavitation damage, replacing any pitted bore. Recondition or replace all injectors as a matched set. Replace head, manifold, and oil pan gaskets on reassembly.
Every 10,000 h	Remove and disassemble the long block for a full in-frame rebuild: renew liners, pistons, and rod/main bearings. Inspect and recondition or replace the camshaft, gear train, and crankshaft as required. Rebuild or replace the PT fuel pump and injectors as a matched set to keep delivery balanced. Resurface the cylinder head, recondition the block, and replace all core plugs. Replace the water pump, dynamo, and starter as part of the rebuild.

Servicing the NH-220-CI-1F(S/N 18566-UP) beyond the schedule

Predictive Maintenance & Fluid Analysis

No ECM or fault codes exist on the NH-220-CI-1F, so oil sampling is the main predictive tool available. Pull samples at every filter change and trend wear metals — a rising iron or copper count usually flags a wearing wet cylinder liner or main bearing before it fails outright. Watch coolant condition closely too, since the mechanical water pump and cast-iron block are prone to cavitation pitting if corrosion-inhibitor levels drop; test and replenish additive between full coolant flushes rather than waiting for the next scheduled change.

Corrective & Common Repairs

Common failure points center on this engine's 1970s-era electrical and cooling components: the dynamo (a DC generator, not an alternator) and starter wear out and are frequent swap items, as is the water pump shaft seal. The PT fuel pump and injectors drift out of calibration with age, causing rough running or smoke; recalibrate as a set rather than chasing individual cylinders. On the dozer side, check the oil cooler shared with the torqflow transmission and steering clutches whenever engine oil turns milky or the transmission runs hot.

Overhaul & Rebuild Points

Because the NH-220-CI-1F uses wet cylinder liners, a top overhaul should always include liner inspection for cavitation pitting on the coolant side, not just ring and valve work. Replace liners as a full set if any bore shows pitting rather than mixing new and used liners. At a full in-frame rebuild, renew the camshaft bushings, gear train, and rod/main bearings together, and rebuild the PT pump and injectors as a matched set so fuel delivery stays balanced across all six cylinders after reassembly.

Seasonal & Environment Servicing

This engine has no turbocharger or electronics to protect, but its mechanical PT fuel system and dynamo charging setup are sensitive to cold starts; use an ether-free starting aid and keep batteries fully charged in winter, since a slow-cranking dynamo-charged system struggles below freezing. In hot, dusty dozing environments, service the air cleaner element more often than the standard interval and keep the radiator core clear of packed debris — the mechanical water pump has no electric backup if the engine runs hot under sustained blade load.

NH-220-CI-1F(S/N 18566-UP) common service parts

Part number	Part	Notes
6631-71-8000	Fuel Filter Ass'Y	Fuel system service	Check fitment →
6631-71-8001	Fuel Filter Ass'Y	Fuel system service	Check fitment →
6631-71-8002	Fuel Filter Ass'Y	Fuel system service	Check fitment →
07000-02075	O-Ring,Steering Oil Filter	Lubrication service	Check fitment →
6631-51-5000	Oil Filter Ass'Y	Lubrication service	Check fitment →

Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.

NH-220-CI-1F(S/N 18566-UP) fault codes & troubleshooting

Code	Meaning	Likely cause	What to do
No CID/FMI/SPN diagnostic code system	This engine is a mechanical PT (Pressure-Time) fuel system diesel with a mechanical flyweight governor and no engine control module, so it does not generate alphanumeric or numeric diagnostic fault codes of any kind.	Not applicable - engine predates electronic engine management.	Diagnose with mechanical test tools (fuel pressure gauge at the pump quick-disconnect, injector pop tester, compression test) rather than a code reader or scan tool.
Low Oil Pressure warning lamp (red)	Engine oil pressure has dropped below the safe minimum threshold monitored by the mechanical oil pressure sender.	Low oil level, worn oil pump, clogged oil filter, or a failing pressure sender/switch.	Stop the engine immediately, check crankcase oil level, inspect the oil filter and confirm actual pressure with a mechanical test gauge before restarting.
High Coolant Temperature warning lamp (red)	Engine coolant temperature has exceeded the safe operating range.	Low coolant level, slipping or broken fan belt, blocked radiator core, or a failed thermostat.	Reduce load and idle down, let the engine cool, check coolant level and belt condition, inspect the radiator and cooling fan.
Charge (alternator/generator) warning lamp	The charging circuit is not producing adequate output to the battery.	Broken or slipping drive belt, faulty alternator or generator, or a bad voltage regulator.	Check belt tension and condition first, then test charging output and regulator with a multimeter.
Air Cleaner Restriction indicator	Intake air filter restriction has reached the service limit.	Dust and debris loading on the air filter element, common in dozer/earthmoving duty.	Inspect and service or replace the air filter element, then reset the restriction indicator.
Torque Converter Oil Temperature warning lamp	Power-train (torque converter/transmission) oil temperature is above the safe operating range.	Low torque converter oil level, sustained high-load operation, or a blocked torque converter oil cooler.	Reduce load, check torque converter oil level, and inspect the oil cooler for restriction or leaks.
Fuel Level Low indicator	Fuel tank level has dropped to the reserve threshold.	Normal fuel consumption approaching empty, or a fuel gauge sender fault.	Refuel and check for water or sediment contamination when the tank runs low.

Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.

NH-220-CI-1F(S/N 18566-UP) attachments & work tools

Dozer blades

This engine powers the Cummins NH220-equipped Komatsu crawler dozer class (D60-D85 range). Blade choices for that class include straight blade, semi-U blade, and angle (power-angle power-tilt) blade. Blade width runs roughly 3.6 m (11.9 ft) with capacity around 6 cu m (7.8 cu yd) and cutting depth near 540 mm (21 in), varying by exact model and blade type.

Ripper

Rear-mounted parallelogram ripper is the standard work tool for this dozer class, offered as single-shank (giant ripper) or multi-shank (typically three-shank) configurations. Multi-shank units in this size class run roughly 2-2.3 m wide and 1400-2600 kg depending on shank count and cylinder arrangement; hydraulically actuated via a dedicated ripper cylinder circuit.

Blade mounting / coupling

Blades mount on a C-frame and trunnion arrangement with lift cylinders bolted to the tractor frame; there is no universal quick-coupler on this vintage mechanical dozer class, so blade changes are a frame-level swap rather than a pin-grab attachment change.

Ripper mounting

The ripper frame bolts/pins to the rear of the tractor main frame in place of (or alongside) the drawbar, using its own lift and tilt cylinders. It is not interchangeable with the blade hydraulics and requires the tractor's rear ripper linkage provision.

Hydraulic kit requirements

Angle/tilt blade operation (PAT) needs additional angle and tilt cylinders plus a dedicated control valve beyond the base straight-blade hydraulics. Ripper operation likewise needs its own ripper valve and cylinder circuit; not all base machines in this class ship with these circuits pre-plumbed.

Drawbar

A rear mechanical drawbar/towing pintle is available for this dozer class for towing scrapers, trailers, or compaction rollers, typically fitted in place of or alongside the ripper mount depending on job configuration.

Guarding and cab/canopy options

Factory options for this dozer class include ROPS/FOPS canopy or enclosed cab, underside/screen guarding for rock work, and rear grille or counterweight guarding to protect the ripper linkage and engine compartment in heavy ripping or forestry duty.

All NH-220-CI-1F(S/N 18566-UP) assemblies by section

Every catalogued assembly group for the Komatsu NH-220-CI-1F(S/N 18566-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Cooling And Electrical Systems

Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cooling And Electrical Systems : Air Cleaner

01***08	Nut,R.H. Thread	6
01***30	Washer,Spring(Sandy?Dusty Terrain S.)	6
01***16	Washer,(With Water Separator)	6
60***60	Nut,Wing	2

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cooling And Electrical Systems : Cooling Fan

02***38	Capscrew	6
02***57	Bolt,(Cold Weather Spec.)	6
02***76	Bolt,(Cold Weather Spec.)	6
02***24	Washer,Radio Controlled Slag Handling	6

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cooling And Electrical Systems : Corrosion Resistor

01***40	Bolt,(Dust And Dirt Protection)	2
01***36	Washer,Radio Controlled Slag Handling	2
01***23	Washer, Flat	2
02***32	Bolt	2

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cooling And Electrical Systems : Dynamo

66***10	Dynamo Ass'Y (12a),(0.3kw)	1
KD***20	Brush Ass'Y	4
KD***30	Rear Bracket Ass'Y	1
KD***00	Band	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cooling And Electrical Systems : Dynamo And Mounting

01***30	Bolt,Radio Controlled Slag Handling	1
01***35	Bolt - Torque Converter Totransmission Mounting	1
01***25	Bolt	4
01***10	Nut,(Dust?Drip Proof? Trimming S.)	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cooling And Electrical Systems : Staring Motor And Mounting

01***45	Bolt	3
01***45	Screw	3
01***48	Washer,Spring? Single Flange	3
60***11	Starting Motor A.,(7.4kw)	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cooling And Electrical Systems : Starting Motor(#18566-30046)

66***10	Starting Motor Ass'Y,(7.4kw)	1
KD***01	Spring,Brush	4
KD***05	Washer,Lock	21
KD***02	Metal	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cooling And Electrical Systems : Starting Motor(#30047-)

KD***50	Field Coil Ass'Y	1
KD***80	Metal	1
KD***60	Center Bracket A	1
KD***10	Stopper,(Not Shown)	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cooling And Electrical Systems : Thermostat And Water Connection

02***25	Bolt,(Europe Spec.)	2
02***89	Bolt	2
02***95	Bolt	2
02***24	Washer,Radio Controlled Slag Handling	6

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cooling And Electrical Systems : Voltage Regulator And Safety Relay

60***00	Regulator Ass'Y	1
66***10	Safety Relay Ass'Y,Safety	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cooling And Electrical Systems : Water Pump And Pulley

01***40	Bolt	3
01***16	Bolt (Welded)	4
01***20	Bolt,(Used When Towing Winch)	2
01***30	Bolt,Radio Controlled Slag Handling	6

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Cylinder Block

Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Block : Cam Follower And Push Rod

02***25	Bolt	16
02***70	Bolt	2
02***20	Washer	18
02***24	Washer,Radio Controlled Slag Handling	18

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Block : Camshaft

02***25	Key	1
02***04	Plug,(Not Shown)	1
66***10	Gear,Camshaft	1
66***30	Washer,Thrust	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Block : Crankshaft And Vibration Damper

01***35	Bolt,(Cold Weather Spec.)	6
01***40	Bolt,(Cold Weather Spec.)	6
02***38	Bolt	6
02***04	Plug,(For Shipping)	6

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Block : Cylinder Block

02***16	Bolt,Water Bypass	1
02***19	Bolt	12
02***25	Bolt,(Europe Spec.)	4
02***25	Bolt	2

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Block : Flywheel? Pto And Rear Support

01***20	Bolt	6
01***12	Bolt,(Without R.P.C.U.)	4
01***20	Bolt,(Sandy? Dusty Terrain Spec.)	6
01***25	Bolt,(Sandy? Dusty Terrain Spec.)	4

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Block : Gear Case Cover And Front Support

02***19	Bolt	2
02***51	Bolt	15
02***64	Bolt	1
02***20	Washer	2

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Block : Oil Pan And Oil Filler Bracket

01***30	Bolt	1
01***12	Bolt,(Without R.P.C.U.)	4
01***30	Bolt,(Cold Terrain Spec.)	1
01***30	Bolt,Radio Controlled Slag Handling	2

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Block : Piston And Connecting Rod

66***30	Ring,Snap	2
66***40	Crank Pin Metal A	6
66***41	Crank Pin Metal A	6
66***10	Bolt	2

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Block : Rear Cover

02***16	Bolt	4
02***25	Bolt	2
02***32	Bolt	2
02***38	Bolt	2

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Cylinder Head

Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Head : Air Intake Manifold And Connection

01***30	Bolt	4
01***30	Bolt,(Cold Terrain Spec.)	4
01***25	Bolt,(Sandy? Dusty Terrain Spec.)	8
01***30	Bolt,(For France Noise Suppression)	4

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Head : Compression Release

01***40	Bolt,(Dust And Dirt Protection)	1
01***36	Washer,Radio Controlled Slag Handling	1
02***16	Bolt	1
02***20	Washer	2

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Head : Cylinder Head

02***16	Plug	6
66***20	Nut	12
66***10	Collet,Half? Valve	16
66***00	Cylinder Head Ass'Y,With Valve	3

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Head : Exhaust Manifold And Muffler

01***15	Bolt	1
01***20	Bolt,(Large Capacity Type) (Std)	4
01***30	Bolt,(For France Noise Suppression)	2
01***20	Bolt	2

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Head : Rocker Arm And Housing

02***89	Bolt	19
02***32	Washer,Spring	19
66***10	Nut	1
66***20	Housing Ass'Y,Rocker Arm	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Head : Rocker Arm Housing Cover

02***32	Bolt	9
02***20	Washer	9
02***24	Washer,Radio Controlled Slag Handling	9
66***10	Cover,Rocker Housing	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Cylinder Head : Water Manifold

02***22	Bolt	12
02***20	Washer,Spring	12
02***04	Plug,(For Shipping)	1
02***10	Plug (Heater Not Installed)	1

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Fuel System

Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Fuel System : Accessory Drive

02***44	Bolt	3
02***25	Bolt	2
02***07	Nut	4
02***20	Washer	4

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Fuel System : Fuel Filter

01***12	Bolt	1
01***40	Bolt	2
01***12	Bolt (M8-1.25x12)	1
01***40	Bolt,(For Position Fixing)	2

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Fuel System : Fuel Tubing

01***18	Nut	1
01***68	Washer,(Not Shown)	1
02***16	Bolt	3
02***16	Bolt	2

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Fuel System : Injector And Fuel Connection

66***21	Body Ass'Y	1
66***20	O-Ring	1
66***30	Gasket? 0.40mm,Classes 0 To 8	1
66***40	Gasket? 0.51mm,Classes 10 To 19	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Fuel System : Pt Fuel Pump (1/3)

02***32	Bolt	6
02***44	Bolt	3
02***38	Bolt	1
02***19	Bolt	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Fuel System : Pt Fuel Pump (2/3)

02***32	Bolt	6
02***44	Bolt	3
02***38	Bolt	1
02***19	Bolt	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Fuel System : Pt Fuel Pump (3/3)

02***32	Bolt	6
02***44	Bolt	3
02***38	Bolt	1
02***19	Bolt	1

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Lubricating Oil System

Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Lubricating Oil System : Lubricating Oil Bypass Filter

02***32	Bolt	2
02***20	Washer,Spring	2
02***01	O-Ring (Kit)	1
09***20	Plate? Instruction,(Japanese-English)	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Lubricating Oil System : Lubricating Oil Cooler

02***32	Bolt	5
02***24	Washer,Radio Controlled Slag Handling	5
02***06	Plug,(Not Shown)	1
66***11	Gasket (K4)	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Lubricating Oil System : Lubricating Oil Fullflow Filter And Mounting

01***36	Washer,Radio Controlled Slag Handling	4
02***51	Bolt	2
02***20	Washer	4
02***28	Washer,Spring	4

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Lubricating Oil System : Lubricating Oil Pipe And Connection

01***25	Bolt	1
01***45	Bolt	6
01***25	Bolt,(Without Auto Priming System)	1
01***45	Bolt,(S6d155-4b)	6

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Lubricating Oil System : Lubricating Oil Pump

02***64	Bolt	2
02***22	Bolt	1
02***76	Bolt,(Cold Weather Spec.)	6
02***25	Bolt	2

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Lubricating Oil System : Pto Lubrication Oil Piping

01***30	Bolt,(For France Noise Suppression)	2
01***30	Washer,Spring(Sandy?Dusty Terrain S.)	2
07***12	O-Ring, Between Valve And Pump	22
66***10	Flange	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Lubricating Oil System : Torque Converter Oil Cooler

01***45	Bolt	2
01***45	Bolt,(S6d155-4b)	2
01***30	Bolt,(For France Noise Suppression)	6
01***60	Bolt (M10-1.50x60)	2

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Tool And Kit

Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Tool And Kit : Gasket Kit

01***12	Washer,Lock (K5)	8
01***33	Washer	3
02***16	O-Ring (K2)	4
02***18	O-Ring (K7)	1

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Komatsu : Nh-220-Ci-1f(S/N 18566-Up) : Tool And Kit : Tool

09***00	Wrench,(Except Japan)	1
09***11	Wrench	1
09***14	Wrench	1
66***80	Wrench	1

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Frequently asked questions

What is the Komatsu NH-220-CI-1F engine?

It's a Cummins-built NH-220-CI, a naturally aspirated inline-six diesel displacing about 12.2 L (743 cu in) with a mechanical PT fuel system and wet cylinder liners. Komatsu used this serial block (S/N 18566-UP) as factory power on its D60/D65 dash-6 class crawler dozers.

What is the operating weight of machines built on this engine?

Host dozers using this engine range from roughly 12.8 to 18.3 tonnes (28,200 to 40,300 lb) operating weight, depending on configuration — straight blade, angling blade, power-angle-tilt, or LGP swamp-shoe.

What replaced the NH-220-CI-1F?

Within the same engine family, Komatsu later moved to a second, later engine-serial block covering further dash-6 and some dash-7 production. The following D65-7/D65-8 generation then dropped Cummins power for this size class in favor of Komatsu's own 6D125-family diesel.

What NH-220-CI-1F(S/N 18566-UP) owners discuss

What engine is actually under the hood on machines carrying the NH-220-CI-1F tag, and is it Komatsu-built?

No. NH-220-CI is a Cummins mechanical inline-six, factory-fitted to Komatsu dozers of this era (D80A-12 class and related D65/D75/D80 machines). It is a naturally aspirated, roughly 12-liter six running a Cummins PT (Pressure-Time) fuel system, not an electronic engine. Owners searching for a Komatsu-branded overhaul kit or ECM diagnostic routine are chasing the wrong parts catalog — everything downstream (fuel pump, injectors, timing gear) is Cummins PT-series and shared with on-highway NH applications of the same period.

The engine cranks fine but won't fire evenly on all cylinders after a rebuild — what do techs check first?

Community reports on this exact symptom point first at the PT fuel system, not the injectors themselves. Air trapped in the fuel supply line or a restricted/incorrectly plumbed fuel filter housing is the most common culprit — one documented case cleared a dead cylinder simply by bypassing a bad float-tank connection and running the filter straight off the tank. If bleeding the system doesn't resolve it, move to individual injector cups next; push tubes bent during teardown are a repeat offender and get replaced along with a full injector recheck, not just torqued back down.

Injector adjustment on this engine seems to use different numbers than a standard Cummins NH — is that normal?

Yes, and it trips up mechanics who set injectors to the on-highway truck spec from memory. The Komatsu-application version of this engine is down-rated versus the standard NH220, so injector plunger torque is set lower than the typical cast-iron/aluminum rocker-housing figures. Timing reference marks are stamped on the outer edge of the accessory drive pulley (readings such as 1-6, 2-5, 3-4 paired with a TC/VS designation) and line up with a fixed pointer on the front cover. Setting injectors too tight makes the engine hard to start; too loose and it smokes heavily at idle. Because this is a bottoming-torque adjustment on the injector cup, an inaccurate inch-pound torque wrench will throw the whole engine off — have your dealer or a shop with a verified Cummins PT torque wrench confirm the setting before returning the machine to service.

After shutdown the engine keeps running or spluttering for several seconds instead of stopping clean — what causes that?

This shows up after PT pump or injector rebuilds and is reported as fuel vapor spitting from the return line rather than a solid fuel stream at shutoff. It traces back to the fuel shutoff solenoid on the pump not seating fully — backing out the adjustment screw on top of the solenoid a full turn is the fix mentioned in the field. Because this is fuel shutoff/injection timing hardware and a mis-adjustment here can lead to overrun or hydraulic lock, have your dealer verify the fix on this specific pump before relying on it.

Undercarriage wear seems fast for a dozer this size — is that typical for this class of Komatsu?

Yes, undercarriage is the recurring complaint on Komatsu crawler dozers in this weight class generally, not a defect specific to one serial range. Field reports describe going through multiple undercarriage sets over a machine's working life even with reasonable maintenance, and some contractors order one size up from factory-standard track components to cope with heavier duty cycles. Watch for pointed (rather than flat-tipped) drive sprocket teeth and uneven roller wear as the practical wear markers — both mean the undercarriage is past its useful limit regardless of hour-meter reading.

There's no ECM on this engine — what electrical issues actually come up on machines this old?

Because the fuel and governing system is entirely mechanical, reported electrical complaints are basic charging-system and cold-start-aid issues rather than sensor faults: corroded gauge sender wiring, weak charging output, and cold-start ether/starting-fluid metering valves that stick or over-dose. The ether-injection metering chamber (feeding starting fluid into the intake ahead of the cylinders) is the one electrical-adjacent system worth checking on a used unit — a stuck or leaking valve can over-fuel a cold start and cause detonation. Have your dealer verify the starting-aid metering valve condition if the machine will see cold-weather service.

What should I check before buying a used NH-220-CI-1F(S/N 18566-UP) powered machine?

Confirm the engine serial and application code matches this specific range before assuming parts interchange with other NH-220-CI suffixes — Cummins ratings and injector settings varied by suffix even on the same base engine. Pull oil samples from engine, hydraulics, and final drives rather than trusting appearance alone. Walk the undercarriage first: sprocket tooth profile (pointed = worn out, flat-tipped = usable) and even roller wear tell you more than hour meter readings on a machine this age. Check for fuel or coolant weeping at the water pump and around injector cups — both are common leak points on rebuilt units. Start the engine cold if possible and watch for excess white smoke at idle (points to loose injector settings) and confirm it shuts down cleanly without run-on or spluttering at the fuel return line. Have your dealer or an independent Cummins PT-familiar shop verify injector timing and fuel shutoff solenoid condition before final purchase.

Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.

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