Nanni · Inboard diesel

Nanni N3.21, N3.30, N4.38 & N4.50

Nanni Industries of La Teste-de-Buch, France, marinises Kubota diesels; the N3.21, N3.30, N4.38 and N4.50 are its naturally aspirated, indirect-injection, heat-exchanger-cooled engines for sailing yachts and catamarans, rated 19.6, 29, 37.5 and 47.5 hp and sold with a Technodrive (Twin Disc) or ZF gearbox or with the SP60 saildrive. Nanni only says “Kubota base”, but bore, stroke and displacement match the Kubota D722 (N3.21), D1105 (N3.30), V1505 (N4.38) and V2203 (N4.50): the N3.30 and N4.38 are the three- and four-cylinder versions of one family and share oil filter, impeller and service kit, the N3.21 takes the parts of the two-cylinder N2.14, the N4.50 has its own, and fuel filter 970622350 fits all four. The first English owner’s manuals for these engines are dated August 2013, and all four are still current (manual revision C, September 2025). The N3.21 powers the one-design Figaro Bénéteau 3, and Bali’s 2024 builder sheets list Nanni as standard: the N3.21 in the Catspace, the N3.30 in the Bali 4.2 and the N4.38 in the Bali 4.4.

Manuals & documents

The links go to Nanni’s own documents — some as archived copies of pages the maker has since taken down. We host no manuals or drawings.

Wear parts & part numbers

PartOEM numberAlso fitsNote
Engine oil filter9703026971,2,3—N3.21; the same spin-on filter fits the N2.10, N2.14 and the older 2.45, 2.50HE and 3.75HE. About 69 mm across × 70 mm high. Dealers also list it as N302697 or 302697.
Engine oil filter9703027424,2,5—N3.30 and N4.38 (also the older 3.100HE, 3.110HE and 4.150HE). About 85 mm across × 100 mm high. Also listed as N302742 or 302742.
Engine oil filter9706030036,2,7—N4.50 (also N4.60, 4.220HE and several larger Kubota-based Nanni engines). About 95 mm across × 100 mm high. Also listed as N603003 or 603003.
Fuel filter (engine)9706223508,2—The same spin-on filter on the N3.21, N3.30, N4.38 and N4.50 (also N2.14, N4.40 and many older HE engines). Also listed as N622350 or 622350. The water-separating pre-filter is the boatbuilder’s, not Nanni’s.
Raw water pump impeller4340132,9—N3.21 (also N2.10, N2.14 and the older 2.45, 2.50HE, 3.75HE). Also listed as N434013.
Raw water pump impeller6045302,10—N3.30 and N4.38 (also 3.100HE, 4.150HE, N4.43). Also listed as N604530.
Raw water pump impeller5443102,11—N4.50 (dealers also list it for N4.60, N4.65, N4.80, N4.85, N4.100, N4.115 and 4.220HE). Also listed as N544310.
Impeller kit (with gasket)86002000112—Nanni kit with impeller and pump gasket; N2.10, N2.14 and N3.21.
Impeller kit (with gasket)86002000212—Impeller and pump gasket; N3.30, N4.38 and N4.40.
Impeller kit (with gasket)86002000312—Impeller and pump gasket; N4.50 only (the N4.65/N4.80 kit is 860020004).
Pump cover gasket5040282—N2.10, N2.14 and N3.21. One dealer source (Glasgow Engineering list).
Pump cover gasket6045292—N3.30 and N4.38. One dealer source (Glasgow Engineering list).
Pump cover gasket6146162—N4.50 (also N4.60 and N4.65). One dealer source (Glasgow Engineering list).
Pump seal kit4340312,13—Raw-water pump seal for the N2.10, N2.14 and N3.21; Nanni renews impeller and pump seals every 250 h or yearly. One dealer source (Glasgow Engineering list).
Pump seal kit6145162—Raw-water pump seal for the N3.30, N4.38 and N4.50. One dealer source (Glasgow Engineering list).
Service kit86002500212—250 h / yearly kit: oil filter, fuel filter, impeller, pump seal and zinc anode in one box; N2.14, N3.21, 2.50HE and 3.75HE (the N2.10 has its own kit).
Service kit86002500312—250 h / yearly kit with oil filter, fuel filter, impeller, pump seal and zinc anode; N3.30 and N4.38.
Service kit86002500512—The same contents for the N4.50 (also 4.220HE).
Anode (engine)4946352,12,13,14—Zinc in the heat exchanger, on the side opposite the alternator; a new one is 16 mm long. Nanni’s 2024 catalogue sells it as anode kit 970494635P with seal but names no engines; the fit for every Kubota-based N engine from N2.10 to N4.115 comes from one dealer (Glasgow Engineering list).
Saildrive anode9212001702—SP60 saildrive behind the N2.10 to N4.65 (the older SD10 saildrive takes 312810). Renew it separately from the engine zinc. One dealer source (Glasgow Engineering list).
Heat exchanger end-cap O-ring484181832,13—The same O-ring for the N2.10 to N4.65; Nanni renews the heat-exchanger O-rings every 500 h or 2 years. One dealer source (Glasgow Engineering list).
Alternator V-belt481081382,15—N2.14 and N3.21 with the 70 A alternator (the size on the current N3.21 data sheet). One dealer source (Glasgow Engineering list, 2020).
Alternator V-belt481081172,16—N3.30 and N4.38 with the 100 A alternator. Current data sheets give a 120 A alternator, which may take a different belt: compare with the markings on your old belt before ordering. One dealer source (Glasgow Engineering list, 2020).
Alternator V-belt481081332,17—N4.50 with the 100 A alternator. Current data sheets give a 120 A alternator, which may take a different belt: compare with the markings on your old belt before ordering. One dealer source (Glasgow Engineering list, 2020).
Raw water pump30780818—Complete Johnson-made pump for the N2.10, N2.14 and N3.21 (also 2.45, 2.50, 3.75), from Nanni’s 2016 accessory catalogue; compare with your pump before ordering.
Raw water pump30172518—N3.30 and N4.38 (also 3.100, 3.110, 4.150, 4.180, 4.190, 4.195), from Nanni’s 2016 accessory catalogue; compare with your pump before ordering.
Raw water pump30747418—N4.50 (also 4.220, 5.280), from Nanni’s 2016 accessory catalogue; compare with your pump before ordering.
Engine oil10635919—Motul Inboard 4T 15W-40, 4 × 5 l (101740 = bulk); Nanni recommends it for its N2, N3 and N4 engines in the 2024 Motul chart.
Coolant11262119—Motul Auto Cool Optimal −37 °C, 4 × 5 l (also 112620 = 12 × 1 l, 112622 = 20 l), from Nanni’s 2024 Motul chart.

Numbers checked against the sources below on 13 October 2026. Always confirm against your serial number and exact type before ordering.

Service intervals

TaskInterval
First serviceRun gently for the first 50 h; first service at 100 h or 90 days: engine oil and filter, fuel filter, gearbox oil and filter, and a check of anodes, belt, mounts, alignment and hoses. On a new or rebuilt engine the lubrication chapter also asks for an oil and filter change after 20 h.13
Engine oil changeEvery 250 h or yearly; halve the interval with biodiesel blends above B20 and shorten it with high-sulphur fuel13
Oil filterWith every oil change (250 h or yearly)13
Fuel filterEvery 250 h or yearly13
Fuel pre-filterCheck and drain the water daily13
Sea water strainerCheck and clean daily13
Raw water impellerReplace the impeller and the pump seals every 250 h or yearly13
AnodeCheck at the first service, then every 250 h or yearly; the 2013 manuals add a check every 3 months in the first year and replacement once more than half has gone13,14
Air filterCheck and clean every 250 h or yearly13
Exhaust elbow checkInspect every 250 h or yearly13
V-belt checkCheck the tension at the first service, then every 250 h or yearly13
Gearbox oil changeChange oil and filter at the first service, then every 250 h or yearly in Nanni’s table; the gearbox or saildrive maker’s manual has the final word13
Coolant changeReplace every 500 h or 2 years per the manual; Nanni’s 2024 Motul chart says every 500 h or yearly13,19
ThermostatReplace every 500 h or 2 years13
Cooling systemRenew the heat-exchanger pressure cap and O-rings every 500 h or 2 years13
Engine mountsInspect at the first service and every 250 h; replace every 1000 h or 4 years13
Engine alignmentCheck at the first service, then every 1000 h or 4 years13
Valve clearanceEvery 1000 h or every 4 years13
InjectorsInjectors checked every 1500 h, injection pump every 3000 h (emission-related; dealer work)13

From the maintenance table in Nanni’s owner’s manuals, revision C (09/2025), which is the same for the N3.21, N3.30, N4.38 and N4.50; hours or time, whichever comes first. It replaces the older table in the 2013 manuals. On coolant Nanni contradicts itself: the manual says every 2 years, the 2024 Motul chart every year.

Specifications

TypeKubota base (Nanni names no model). Bore, stroke and displacement match Kubota’s published figures for the D722 (N3.21), D1105 (N3.30), V1505 (N4.38) and V2203 (N4.50)20,21,22,23,24
CylindersN3.21, N3.30: 3 in line · N4.38, N4.50: 4 in line; four-stroke with gear-driven valve train16,25
AspirationNaturally aspirated (all four)16
DisplacementN3.21 0.719 l · N3.30 1.123 l · N4.38 1.498 l · N4.50 2.197 l20
Bore × strokeN3.21 67 × 68 mm · N3.30 and N4.38 78 × 78.4 mm · N4.50 87 × 92.4 mm (2013 manual, matches the Kubota V2203). The current N4.50 data sheet prints 83 mm, which is the N4.40’s bore and would not give 2.197 l.26,14,27,17
Compression ratioCurrent data sheets: N3.21 23.5:1 · N3.30 24:1 · N4.38 23:1 · N4.50 22:1 (the 2013 manuals give 22.6:1 for the N3.30 and N4.38)15,16,25,17,14
InjectionIndirect injection (Kubota E-TVCS swirl chamber), cam-driven in-line injection pump, mechanical governor, lift pump with hand primer15
PowerN3.21 14.61 kW (19.6 hp) at 3600 rpm · N3.30 21.3 kW (29 hp) at 3600 rpm · N4.38 27.6 kW (37.5 hp) at 3000 rpm · N4.50 35.42 kW (47.5 hp) at 2800 rpm (ISO 8665, current data sheets). Older Nanni documents and the 2024 oil chart give 15.4 kW (21 hp) for the N3.21 and 36.8 kW (50 hp) for the N4.50. Duty class M5 (up to 1000 h a year) for the N3.21 and N3.30, M4 (up to 3000 h a year) for the N4.38 and N4.50.20,15,25,19,26,27
Maximum torqueN3.21 44.1 Nm at 2450 rpm · N3.30 64 Nm at 2600 rpm · N4.38 94.8 Nm at 2200 rpm · N4.50 146 Nm at 1800 rpm15,16,25,17
Rated speedN3.21 and N3.30 3600 rpm · N4.38 3000 rpm · N4.50 2800 rpm. Recommended cruising range (2013 manuals): N3.21 and N3.30 2880–3240 rpm, N4.38 2400–2700 rpm, N4.50 2240–2520 rpm20,14
Full-throttle rangeMaximum at full throttle (2013 manuals): N3.21 and N3.30 3820 rpm · N4.38 3220 rpm · N4.50 3020 rpm26,14,27
Idle speedN3.21 1050 rpm · N3.30 930 rpm · N4.38 850 rpm · N4.50 840 rpm (data sheets; the 2013 manual gives 850 rpm for the N4.50)15,16,25,17,27
Injection pressure137.3 bar, all four (2013 manuals)26,14,27
Injection timingN3.21 21° · N3.30 18° · N4.38 17° · N4.50 16.25° BTDC (2013 manuals)26,14,27
Valve clearance (cold)Intake and exhaust 0.145–0.185 mm on the N3.21, N3.30 and N4.38; 0.18–0.22 mm on the N4.50 (2013 manuals)26,14,27
CoolingClosed fresh-water circuit with heat exchanger (keel cooling optional), gear-driven self-priming raw-water pump, water-cooled exhaust manifold and elbow; zinc anode in the heat exchanger13
Engine oil capacityNanni/Motul chart 2024: N3.21 3.0 l · N3.30 4.5 l · N4.38 5.0 l · N4.50 7.5 l (varies with the sump option). 2013 manuals: N3.21 3.3 l · N3.30 4.5 l · N4.38 5.5 l (with filter) · N4.50 7.5 l. Fill to the dipstick.19,26,14,27
Engine oil gradeCurrent manual: API CK-4, CJ-4, CI-4 PLUS or CI-4, or ACEA E9/E7/E6/E5/E4, multigrade preferred, viscosity to suit the air temperature. Nanni’s 2024 Motul chart: SAE 15W-40, at least API CF (Motul Inboard 4T 15W-40)13,19
Oil pressureAt least 3.5 bar at rated speed (2013 manuals)14
Coolant capacityN3.21 4.0 l · N3.30 5.0 l · N4.38 5.0 l · N4.50 9.0 l (Nanni/Motul chart 2024, heat-exchanger versions; the 2013 manual gives 4 l for the N3.30)19,14
Coolant50 % ethylene- or propylene-glycol antifreeze with 50 % deionised water, all year; nitrite-free, to ASTM D6210; never mix ethylene- and propylene-glycol coolants13
FuelDiesel to EN 590, ASTM D975, BS 2869 A1 or JIS K2204; paraffinic diesel to EN 15940 (HVO, GTL) is approved13
Alternator12 V; N3.21 70 A · N3.30, N4.38, N4.50 120 A (current data sheets). The 2013 manuals list 100 A for the three larger engines.15,16,14
Starter motorN3.21 1.0 kW · N3.30, N4.38, N4.50 1.4 kW26,14,27
BatteryStarter battery: N3.21 and N3.30 35–50 Ah, 350–400 A cold cranking · N4.38 65–75 Ah, 450–500 A · N4.50 100–120 Ah, 650–700 A (2025 owner’s manuals)13,28,29,30
Belt tension7–9 mm deflection when pressed (current manuals); the 2013 manuals said 8–10 mm with the belt warm13,14
Dry weightEngine only: N3.21 97 kg · N3.30 136 kg · N4.38 139 kg · N4.50 216 kg. With transmission: N3.21 106 kg (TMC40) or 142 kg (SP60) · N3.30 145 kg (TMC40) or 181 kg (SP60) · N4.38 153 kg (TMC60) or 184 kg (SP60) · N4.50 229 kg (TTMC35A)15,16,25,17
GearboxN3.21: TMC40, TTMC35A · N3.30: TMC40, TTMC35A/P, ZF10M · N4.38: TMC40 (TMC60 on the dimension sheet), TTMC35A/P, ZF12/ZF12M, ZF25A · N4.50: TTM345A/TM345H, TMC260, TMC60, TTMC35A/P, ZF25/ZF25M. TMC/TTMC are Technodrive (Twin Disc) gearboxes. The N3.21, N3.30 and N4.38 are also offered with the SP60 saildrive, the N4.50 with a saildrive whose model Nanni does not name.15,16,25,17,18
SaildriveSP60 (Technodrive / Twin Disc SeaProp60): ratio 2.15:1 or 2.38:1, about 2.8 l oil, 43 kg, according to Twin Disc’s 2011 bulletin; check your own drive’s plate and manual. Nanni: the SP60 is electrically isolated from the engine and must not be bonded to the boat’s ground.31,32,26
Direction of rotationCounter-clockwise seen from the flywheel14
Max. installation angle15° bow down, 15° bow up15
EmissionsRCD 2013/53/EU, EPA Marine Tier 3, BSO 215

Good to know

  • Buy by engine family, not by horsepower: the N3.30 and N4.38 take the same oil filter, impeller, impeller kit and service kit, while the N3.21 shares its oil filter, impeller and service kit with the two-cylinder N2.14. The N4.50 needs its own; fuel filter 970622350 fits all four.2,12
  • Nanni’s parts catalogues and workshop manuals for these engines are not public, so this page lists no numbers for the air filter, thermostat, glow plugs, injectors, gaskets or exhaust elbow. Order those from a Nanni dealer with the type and serial number from the engine plate (TYP and NR), and trust the plate rather than a boat brochure, as builders have changed engine make between model years.2,33,13
  • Fill oil to the dipstick marks rather than to a book figure: Nanni’s own documents disagree (3.0 or 3.3 l on the N3.21, 5.0 or 5.5 l on the N4.38), and the sump option and installation angle change what goes in.19,26,14
  • Keep a spare impeller and a spare alternator belt aboard. If a removed impeller has vanes missing, find the pieces (usually in the heat-exchanger inlet) before running the engine again.13
  • Under sail above about 8 knots, close the engine’s raw-water seacock so water is not forced into the exhaust, and open it again before starting. Never sail with the stopped engine in forward gear; in neutral, Nanni wants the engine run for 15 minutes at least every 6 hours to lubricate the gearbox, and the gearbox or saildrive maker may have its own rules.13
  • The SP60 saildrive is electrically isolated from the engine: do not bond it to the boat’s ground or other metal fittings, and renew its own anode (921200170 in the Glasgow Engineering list) separately from the engine zinc.26,2

Fitted in

Boats whose builder lists it as standard or optional equipment:

  • Bali 4.2 — Nanni N3.30 × 2 (Standard from the A-2024 spec sheet (December 2023), also on A-2025: 29 hp)
  • Bali Catspace — Nanni N3.21 × 2 (Standard from the A-2024 spec sheet (May 2024), also on A-2025: 19.6 hp each, saildrives; option: 2 × 37.5 hp)
  • Outremer 45 — Nanni N4.38 × 2 (Barreau/Neuman 45 built in Lorient: the yard’s sales listings name the N4.38 for hull 94 (October 2024) and hull 102 (2025), and its page has given 2 × 38 hp since 2026)

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Sources

  1. sheridanmarine.com/product/nanni-diesel-970-302697-oil-filter
  2. glasgowengineering.com.au/uploads/general/Service-Parts-N-Engines-GE.pdf
  3. web.archive.org/web/20250326085800/https://www.salmarine.com/nanni-oil-filter---n302697-n…
  4. sheridanmarine.com/product/nanni-diesel-970302742-oil-filter
  5. web.archive.org/web/20250425094301/https://www.salmarine.com/nanni-oil-filter---n302742-n…
  6. sheridanmarine.com/product/nanni-diesel-970603003-oil-filter
  7. web.archive.org/web/20241208211823/https://www.salmarine.com/nanni-oil-filter---n603003-n…
  8. sheridanmarine.com/product/nanni-diesel-970-622350-fuel-filter
  9. web.archive.org/web/20251213200008/https://www.salmarine.com/nanni-impeller-kit-n434013-n…
  10. web.archive.org/web/20250812180617/https://www.salmarine.com/nanni-impeller---n604530-n60…
  11. web.archive.org/web/20250907054758/https://www.salmarine.com/nanni-impeller---n544310-n54…
  12. nannienergy.com/wp-content/uploads/2024/06/GB_CatalogueAccessoire_2024.pdf
  13. nannienergy.com/wp-content/uploads/2025/10/DGBXXT09002C-N3.21.pdf
  14. web.archive.org/web/20181222170949/http://www.nannidiesel.com:80/downloads/manuals/N3.30-…
  15. nannienergy.com/wp-content/uploads/2023/11/DGBXXC01003B_N3.21-2.pdf
  16. nannienergy.com/wp-content/uploads/2023/11/DGBXXC01004B_N3.30-2.pdf
  17. nannienergy.com/wp-content/uploads/2023/11/DGBXXC01007B_N4.50-2.pdf
  18. web.archive.org/web/20160508154232/http://www.nannidiesel.com:80/downloads/catalogue/Acce…
  19. nannienergy.com/wp-content/uploads/2024/12/Preco-OIL-Engine-EN.pdf
  20. nannienergy.com/wp-content/uploads/2024/10/Nanni_Brochure_10_2024_ENG.pdf
  21. engine.kubota.com/en/products/product_pdf/8_pdf_1.pdf
  22. engine.kubota.com/en/products/product_pdf/22_pdf_1.pdf
  23. engine.kubota.com/en/products/product_pdf/33_pdf_1.pdf
  24. engine.kubota.com/en/products/product_pdf/55_pdf_1.pdf
  25. nannienergy.com/wp-content/uploads/2023/11/DGBXXC01005B_N4.38-2.pdf
  26. web.archive.org/web/20140327075031/http://www.nannidiesel.com:80/downloads/manuals/N2.10-…
  27. web.archive.org/web/20190610053249/https://www.nannidiesel.com/downloads/manuals/N4.40-N4…
  28. nannienergy.com/wp-content/uploads/2025/10/DGBXXT09003C-N3.30.pdf
  29. nannienergy.com/wp-content/uploads/2025/10/DGBXXT09004C-N4.38.pdf
  30. nannienergy.com/wp-content/uploads/2025/10/DGBXXT09006C-N4.50.pdf
  31. twindisc.com/downloads/SeaProp60_bulletin.pdf
  32. tradeaboat.co.nz/reviews/1502/nanni-diesel-n438-marine-engine-review
  33. nannienergy.com/service/spare-parts/

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