INTRODUCTION - PISTONS AND CONNECTING RODS

3.2 JTS

Specifications

The pistons are produced through aluminium alloy fusion, whilst the connecting rods are made from steel.

The gudgeon pin is the floating type and works inside the bush inserted in the small end and is kept in place by two circlips.

The pistons have impressions for the valves and the combustion chamber in the crown; they are cooled at the bottom by an oil jet.

The compression seal is ensured by two bands, whilst there is a third band with three seals for the oil seal, one upper seal and one lower seal with an oil scraper ring in between.

1. connecting rod and cap

2. bolts fixing connecting rod cap

3. small end bush

4. upper connecting rod half-bearing

5. lower connecting rod half-bearing

6. piston

7. gudgeon pin

8. circlip

9. upper band (compression)

10. lower band (compression)

11. oil seals

12. oil scraper ring

2.2 JTS

SPECIFICATIONS

The pistons are produced by aluminium alloy casting; the connecting rods are made from hardened and tempered steel, produced by hot pressing.

This engine type has impressions for the valves and the combustion chamber and is cooled by an oil jet. The piston has a seat on the skirt to prevent interference with the jet nozzle.

The connecting rod caps are the fracture type joined by pressure using bolts, together with the half-bearings. The pistons and small ends are connected by means of a bush and pin kept in place by two circlips.

Since the connecting rod caps are produced by facture, each cap matches perfectly with the connecting rod that it comes from. When refitting the connecting rod caps, each cap must be matched with the connecting rod to which it belongs in order to prevent damage due to the imperfect matching of the surfaces.

1. Piston rings

2. Oil scaper ring

3. Gudgeon pin

4. Piston

5. Piston rings

6. Bush

7. Connecting rod

2.4 JTD 20v

CONNECTING RODS

Specifications

Type

The connecting rods are in hardened and tempered steel with a copper bush (1) fitted for matching with the piston gudgeon pin (2).

The floating pins are held in place by two expansion rings (3) that are housed in grooves on the piston hubs.

PISTONS

Specifications

Type

The silicon light alloy pistons with autothermic inserts are subdivided into three size categories

An OMEGA-shaped combustion chamber in the piston crown improves combustion efficiency.

There is a channel inside the piston through which the oil, sent by the jet, flows, ensuring improved piston cooling.

The piston is coupled to the pin by means of two copper alloy bushes.

• 1 Piston
• 2 Injector
• 3 Heater plugs
• 4 Air intake
• 5 Exhaust gas outlet