Inside the Fiat 500 1.4 EVO Flex engine

The NAFTA Fiat 500 produced in Toluco Mexico is sold all over South America. The Fiat 500 for the southern hemisphere is similar, but there are some differences. One is there is 1.4 liter flex-fuel engine available that has 8 valves and conventional variable valve timing. The 1.4 EVO Flex, as the engine is called, is a single overhead cam design and is from the FIRE engine family. It produces 85 hp on gasoline and 88 hp on ethanol.

For our friends in South America, here is a little more about this interesting engine, courtesy of Chrysler.

The four cylinder in-line engine displaces 1368 cubic centimeters (83 cubic inches) and features eight valves operated by a single overhead camshaft with variable valve timing (VVT). Valve lash is maintained by mechanical tappets.

Ignition timing, valve timing and fuel delivery are controlled by the powertrain control module (PCM).

To reduce polluting emission levels, the engine is equipped with:

• Oxidizing catalytic converter and two oxygen sensors.
• Fuel vapor evaporative emission system.
• Crankcase blowby gas recirculation system.

Cylinder Head
The one-piece 1.4L 8V aluminum alloy cylinder head features two valves per cylinder with pressed in metal valve guides. The valves are actuated directly by the camshaft through bucket style mechanical tappets using selectable shims to adjust valve clearance. The head gasket is made of an aramidic fiber and the head does not require retightening throughout the life of the engine.

The "variable turbulence" combustion chamber design offers maximum performance and efficiency with reduced emissions. The variable turbulence is achieved through the inclusion of a calibrated deflector near the exhaust valve head (3) and special curvature of the intake manifold (1). This allows a consistent amount of the exhaust gases (about 25%) to be recirculated in the combustion chamber (2) reducing fuel consumption and exhaust emissions when driving in partial load conditions.

Variable Valve Timing
The 1.4 8V engine is equipped with Variable Valve Timing (VVT). This system is capable of continuously modifying the position of the camshaft in relation to the crankshaft. In this way the engine is operating with optimum timing under all driving conditions to improve engine performance, mid-range torque, idle quality, fuel economy, and reduce emissions. The camshaft pulley (1) is integrated with the VVT assembly and is serviced as an assembly. The VVT assembly is sometimes referred to as a camshaft phaser. The camshaft phaser is managed entirely by the powertrain control module (PCM) which:

• monitors the camshaft position with the camshaft position (CMP) sensor.
• alters this position according to engine operation on the basis of a calibrated map.
• keeps the camshaft position under control.

Engine Block
The engine block (1) is made from cast iron. The crankshaft is supported by five main bearings. The thrust bearings are attached to the center upper main bearing. The cylinder block has four piston cooling jets located under the main bearing shells. The cylinders are formed directly into the engine block and are divided into three size categories. Special channels formed in the crankcase walls allow the passage of coolant and lubrication oil. A knock sensor is located on the left side of the block.

The bedplate (2) is made from die-cast aluminium alloy and has cast iron cast-in bearing caps. The supports and main bearing caps are machined while assembled together with the engine block. Bolts and locating dowels are used to assure precision assembly of the bedplate and engine block. There is a bead of sealant between the bedplate and engine block to prevent oil leaks.

The function of the bedplate is to:

• form the load carrying structure with the engine block
• support the crankshaft
• allow return of the engine lubrication oil to the pan
• support the engine oil pan

Crankshaft
The crankshaft is made from induction hardened forged steel. Eight counterweights at 180° balance the crankshaft rotary mass. The main journals are crossed drilled for rod bearing lubrication. The crankshaft is supported by five select fit main bearings with the center bearing serving as the thrust washer location. Both the front and rear seals are a single piece design and are mounted to the oil pump and cylinder block.

Pistons
The pistons are a lightweight design made of a high strength silicon aluminium alloy with low tension piston rings. The piston pin is a press fit into the rod. The connecting rod cap is bolted to the connecting rod. The connecting rod bolts are not reusable. Pistons are available in three different diameters. The piston rings have a dot or a mark that must face the top of the piston. The pistons have an arrow stamped on the crown to indicate assembly orientation.

You can read more about the different Fiat 500 models sold in South America here.

 

 

Description courtesy of Chrysler