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 (LDW 502 M, LDW 702 M, LDW 1003 M, LDW 1404 M), fresh water cooled via heat exchanger, complete with zinc anode protection; cast-iron engine block (aluminium for LDW 502 M); reborable liners; one piece aluminium cylinder head; indirect injection with unit injector pump in the cylinder head; overhead camshaft with timing belt; vane type lubrication pump on crankshaft; fresh water cooling pump in the engine block; stainless steel water injected exhaust elbow; self-priming sea water pump; air filter; anti-corrosion surface treatment.


The original design concept as the pearlitic grey cast iron cylinder head with integral reborable “twin” arranged liners, with cross flow intake and exhaust pipes, has allowed the reduction of the engine length assuring at the same time an exceptional sturdiness. The LDW 502 M, which has been built with an aluminium engine block and reborable liners is the lightest of the FOCS series.

Excellent results have been obtained in reducing noise emission thanks to the location of the injection system in the cylinder head, to a ribbing system along all the engine structure and to the complete absence of gears.

The overhead camshaft is driven through a cogged belt, especially designed for heavy duty applications to ensure longevity of belt life.

The utilization of newly developed and “Lombardini patented” pump-injector units, in place of a conventional system, incorporating separate fuel injection pumps and injectors, allows the elimination of fuel pipes and consequently provides a better injection timing with the result of great performance advantages.

The “Lombardini patented” injection system has been tested for exhaust emission levels to the lowest limits. FOCS engines achieved high acclaim with regard to exhaust emissions being well below the EEC requirements.

The very accurate balancing of the moving components together with optimum combustion allows low vibration levels at all engine speeds.

Components subject more frequent checking are located in the upper part of the engine, just under the cover. This allows easy and low cost equipment maintenance.

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.