Review: Nanni Diesel N3.30

By: Andrew Norton


This Nanni Diesel N3.30 engine performs admirably on a 12m sailing catamaran moored in Far North Queensland.

Review: Nanni Diesel N3.30
This Nanni Diesel N3.30 saildrive has no problem handling coral dust ingestion even though this saildrive operates in Far North Queensland.

Recently my youngest cousin Gary and I were discussing the best diesel engines for sailing yachts. Like me, his moored boats have only ever been yachts, so we’re both on another planet compared to cruiser owners.

After a while Gary was raving about the twin Nanni N3.30 diesel engine he had in a 12m sailing cat, driving through Technodrive SP saildrive legs. He said that apart from clutch linkage problems in the legs, the engine-drive packages from were very good.

A key factor in his enthusiasm is the Kubota base engine which Nanni Diesel marinises in France to become the Nanni N3.30. Like all smaller Kubota engines it is heat exchanger cooled to maintain even running temperatures which combined with the indirect injection, means the Nanni Diesel N3.30 complies with all current exhaust emission regulations. Direct injection in these small engines would prevent them from meeting the regulations, simply because the air-fuel mix isn’t burnt thoroughly enough.

 

NANNI N3.30

The Nanni N3.30 engine is of all cast iron construction, with gear-driven pushrods operating the overhead valves. The engine is almost ‘square’, reducing piston speed when the engine is worked hard. A simple inline fuel injection system reduces servicing costs and glow plug preheating makes for quick starts in cold climates.

A 100amp voltage-regulated alternator is standard, mounted alongside the cylinder head, but additional pulleys can be fitted for another alternator or running refrigeration equipment. Like all small Nanni Diesel Kubota-based engines, there’s no provision for hand starting, so you’ll never be embarrassed in front of passengers trying to manually overcome the 23:1 compression ratio. In any case the starter motor is mounted well up the cylinder block, so unless the engine is half under water or the starter battery is low on charge it should always start when the ignition key is turned.

The standard A4 instrument panel cleverly includes an analogue tachometer with digital hour meter display plus the usual warning alarms for low oil pressure, water in fuel, high coolant temperature and battery charge. And of course the glow plug ‘on’ warning.

On its fibreglass mounting base the saildrive model is 1016.5mm long, 594.1mm wide and 742.5mm high. Though frankly overkill for an engine of this output, the Italian-made Technodrive SP60 leg used for all Nanni Diesel saildrive models from 9.9 to 59.2bhp at the flywheel (approximately 9.5 to 56bhp at the prop) is rated to 170Nm, so it should have a long service life. The reduction ratio is a usefully low 2.38:1 and the cooling water intake is just above the gear case torpedo, with a seacock above the leg diaphragm.

 Only a short hose is needed to connect the seacock to the gear-driven raw (sea) water cooling pump. The freshwater pump is driven by the same vee-belt that drives the alternator.

To give an idea of the saildrive dimensions compared to the shaftdrive model, this is 744.8mm long, 467.2mm wide and 589.2mm high with a dry weight of 145kg, driving through a mechanical TMC40 gearbox. So while the mounting base adds significantly to the engine’s footprint, this is compensated for by the absence of stern gear and not having to align the gearbox end flange and propeller shaft.

Access to the engine oil dipstick and canister oil filter is very good, with recommended servicing intervals at 20 hours, then every 200 hours or annually. As the engine would be mounted parallel to the water surface, all the old sump oil can easily be removed from the forward drain plug. This is connected to a brass sump pump for rapid evacuation. Nanni Diesel recommends using API CD SAE 15W40 diesel engine oil in all climates.

 

ENGINE PERFORMANCE

Too interested in sailing, Gary never got around to recording speed versus rpm figures but in a 12m sailing catamaran, twins should be able to cruise at 6 to 6.5kts at 2600 to 2800rpm and run out to better than 8kts driving through three-bladed 15 x 12in props. Maximum torque is produced at 2600rpm and with its fixed fuel injection timing the N3.30 should be run continuously at or above this rpm to prevent possible cylinder bore glazing from fuel over-supply below 2600.

Note (in the torque and fuel consumption chart) how flat the torque curve is with 90 per cent of maximum torque available at just 1600rpm. Even at wide open throttle the drop off from maximum is only 11 per cent. This is why tractor and industrial diesels make such good yacht auxiliaries.

 

THE VERDICT

With its excellent service network around Australia, it’s logical to consider Nanni Diesel when buying a saildrive auxiliary. The Nanni N3.30 diesel engine is well designed and engineered, and with regular maintenance and a little TLC should provide countless years of reliable motoring.

Even though Gary lives in Far North Queensland he said coral dust ingestion didn’t affect the cooling system and a quick burst in ahead and astern quickly cleared growth from his folding props. For Gary, Nanni Diesel rules!

For more on this engine-drive package, visit NanniDiesel.co.nz

 

NANNI DIESEL N3.30 PERFORMANCE

Torque and fuel consumption

RPM

MAX TORQUE (NM)

BHP (ABSORBED BY PROP)

FUEL BURN (LT/H)

1600

59

1.8

0.9

1800

61

2

1.1

2000

62

3.5

1.5

2200

63

4.1

1.9

2400

64

6.5

2.4

2600

65

9.5

3

2800

64

12

3.6

3000

62

15.9

4.3

3200

60

19.8

5

3400

59

23.9

5.8

3600

58

28.6

6.4

 

NANNI DIESEL N3.30 SPECIFICATIONS

TYPE Inline three-cylinder diesel engine

RATED HP 28.6 at 3600rpm

DISPLACEMENT 1123cc

BORE x STROKE 78 x 78.4mm

DRY WEIGHT 178kg w/ saildrive

 

See the full version of this review in Trade-A-Boat #249, January / February 2015. Why not subscribe today?

Keep up to date with news from Trade-A-boat or like us on Facebook!