This series of exceptionally light and compact engines, features very high reliability in every condition; furthermore, this specific project has been carried out in order to optimize durability and low fuel consumption without reducing the performance of the engine.

4 stroke marine diesel engines, fresh water cooled via heat exchanger with zinc anode protection; cast-iron engine block; one piece cast-iron cylinder head, reborable liners; indirect injection; gear driven single shaft with push rod valve operation; hydraulic tappet; crankshaft mounted vane type lubrication pump; water injected stainless steel exhaust elbow; self-priming sea water pump; air filter. Special anti-corrosion treatment.


The camshaft is located in the upper part of the crankcase to allow a reduced width in the lower area of the engine.

The innovative design of the gear train, the injection system design and location, and the reduced cylinder pitch, shorten the engine length.

The special crankshaft balancing gives exceptional low vibrations and ensures an excellent operational performance during use.

The innovative design of the fuel injection system, as well as the utilization of hypereutectic pistons which reduce piston slap, and the utilization of a heavy-duty block, assist in greatly reducing noise levels that are normally associated with diesel engines.

The QLC pump, offers high performances on all engine speed. Compared to the conventional injection pump, QLC features a one way flow and a unique delivery fuel system that prevents unwanted variations on injection pressure and timing, eliminating gas bubbles.

This line of engines, due to their advanced design of the injection and combustion systems results in improved environmental behaviour in conformity with expected pollution limits.

These exhaust emissions and the engines performances are checked with dedicated test rigs on 100% of the Lombardini Marine production.

All maintenance operations are made easier due to the simple construction of the product. Also for maintenance of the QLC pump it is not strictly necessary to involve the services of a pump specialist, but the servicing of parts can be completed by any qualified workshop.

The Lombardini Marine S-Drive transmission have been developed from our experience gained from years of sailboat racing. This experience in collaboration with many professional skippers helped us to devise two transmissions featuring the essential requirements of sturdiness and reliability whilst, at the same time, offering the minimum water resistance during sailing.

The shape of the submerged part of drive has been evolved to incorporate an excellent hydrodynamic profile with an extremely low drag coefficient, where the drive’s section and chord are reduced to the minimum, for optimum boat speeds between 4 and 12 knots.

The axial thrust is handled by a special conical bearing arrangement.

To make the installation easier, the drive has its own built-in sea water inlet and is supplied with a sea cock.

The clutch assembly has been developed to ensure soft and precise gear engagement. A technologically advanced metal-spray surface treatment on the bronze clutch cone allows the oil to drain quickly from the clutch when maneuvering, ensuring smooth, positive shifts.

Particular attention has been paid to the design of the gear teeth since mechanical noise mostly depends on the profile of the gears adopted. Conical gears with helical teeth incorporating a special involute shape, which allows continuous contact between the gear tooth surfaces, reduce gear noise. The GLEASON method is used during manufacture to guarantee minimum tolerances on the special alloy steel teeth, which are carburized and hardened for maximum life.

Lubrication throughout both the upper gear mechanism and the lower part of the drive is assured by utilizing a single oil path.

The oil is circulated by the pumping effect of the special gear profile.

The large capacity of the oil sump in the drive allows longer intervals between servicing.

Oil cooling is assured by the contact of the drive with the sea water.

The drive is protected against corrosion by the use of a special aluminium alloy with a reduced copper content and stainless steel is employed for all shafts, nuts and bolts. Two electrochemical treatments, before and after machining, followed by an electro-deposition paint process and two coats of special marine paint protect the external surfaces. An extra large zinc, directly mounted on the drive provides protection against galvanic corrosion.

The sealing gasket is made from a special rubber resistant to both hydrocarbons and sea water. Its special shape in combination with the strength of the rubber ensure maximum life and durability and allows the drive to move independently from the hull, which promotes a pleasant sailing with no vibration being transmitted to the boat.

Particular attention has been taken with regard to weight reduction, in anticipation of applications on board racing boats; reinforcement ribs have been employed to increase the mechanical strength of the drive housing without reducing reliability.