Generalities

GENERALITIES

The engine is of the 4 cylinder in line type in light alloy with a double on-head camshaft, timing variator and double static ignition and injection controlled by a single BOSCH MOTRONIC M1.7 control unit.

The clutch - gearbox - differential group is connected behind the engine and forms an integral part of the engine unit.

The engine itself is front mounted and set transversally with a 13° inclination forwards.

It is installed on the frame by suspension type mounts and fixed by two elastic damping supports. A third support of the compass type secures it to the suspension crossmember.

A rod between the engine and the body prevents excessive shaking of the engine.

The engines described below conform to the "USA 83" exhaust emissions regulations.

STRUCTURE

Engine block:

this is a single block in light alluminium and silicon with a high mechanical resistance and heat dissipation. The crankshaft is supported by five main supports. Grooving in the walls of the engine block permit the circulation of engine coolant and lubricating oil. For AR67202 (1995 c.c.) engines only, oil spray jets which cool the pistons are located at the base of the cylinders.

Cylinder liners:

these are in cast iron and are of the low resting type and directly lapped on the outside by the cooling liquid for a more rational heat dissipation (wet). The size of the cam is such that it is not deformed and is thus able to contain the gasses

Front cover:

this is in die-cast in aluminium alloy and completing the forward part of the engine block, protects the timing chain. The oil pump body is located in the lower part and the volute for the installation of the water pump rotor is located on the upper part.

Cylinder head:

this is of the monolith type, compact and chill-cast in aluminium and silicium alloy with a double camshaft with direct action valves arranged in a "V" of 46°. There are two ignition spark plugs for each cylinder. The conformation of the combustion chambers is optimal due to the position of the valves; at the same time the rectilinear intake ducts have a contained loading loss and permit maximum exploitation of the resonance, a distinct advantage with regard to volumetric performance.

Oil sump:

this is a structural part of the engine with mechanical functions in addition to that of containing the engine oil. It is made of die-cast aluminium with liquid silicone sealing.

The cylinder liners are supplied already coupled with their relative pistons and are divided into three dimensional classes.