It will definitely come as a surprise if anyone would come to know that Fiat is in the process of testing two of its excellent cars, which were launched in January 2012. Testing was done somewhere near Ranjangaon, where Fiat also has its manufacturing facility. The two vehicles that are being tested include the 2012 Grande Punto and the Linea. 2012 Fiat Grande Punto is a hatchback and 2012 Fiat Linea is a luxury sedan, both of these vehicles have diesel engine variants. Now there has to be an element of curiosity as well sincethese have been launched already and it’s the diesel variants which arecomparativelycheaper in India against petrol. Moreover, these two were launched with some minor refreshed features and the ground clearance was also increased.
It was indeed a tough task to find out the reason on why the two diesel variants were doing intensive test rounds near their manufacturing facility, but finally we got the inside scoop. The discovery was done and it was found that Grand Punto and Linea diesel engine based cars were being tested with an-all-new timing chain. Now then, the sole reason for this test was obviously because of the failures of the smooth functioning of the timing chain on the Grand Punto and Linea 90 hp models since past one year and so. This may just look like only the snapping of timing chain in the engine but this is not “only” a problem, this is a disastrous problem. When the timing chain fails to work because of skipping a tooth or two, or even at times it snaps in two, it could cause a catastrophic level of engine failure with bent valves. At an event of the timing chain failure or it getting completely broken in two, since the Fiat has a multijet diesel engine which is an interference type engine as well, the piston motioning upwards at an incredible speed will meet the valves which are coming downwards. In this situation, the piston will hit the valves and bend them.The crown of the piston will also get damaged due to the contact with valve.
There is also a very reasonable possibility of the head itself getting damaged. At the time of the valve getting stroked by the piston against the engine head, when the timing chain snaps, the head is also at a risk of being damaged exponentially. This would result in a very expensive work on repair to retrieve the engine to its original condition and shape. Although the diesel engine of Fiat is multijet type interference and there is an excellent safety design worked up into the engine with the rocker arms giving in to stop the piston from contacting the valves in the event of a breakage in the timing chain. The breakage in the timing chain could still stall the engine by seizing-up, which will definitely result in a major breakdown.
This particular problem is coming mostly in the 1.3 liter Multijet engines of Fiat cars, which have a variable geometry turbocharger that pumps out 90 hp. Another 1.3 multijet diesel engine with the fixed geometry turbocharger pumping out 75 bhp seems to be working fine. Now there is a question which arises in our mind with this information and that is will there be a recall of the previous versions of Grand Punto and Linea diesel cars which have already been bought and are plying in the Indian roads. If a recall is done ithas to be done ideally for the existing owners of Grande Punto and Linea. They have a 90 bhp multijet diesel engine so they may not suffer the consequences of the manufacturing defect done by the company.It is to observe if the Tata Manza 90 bhp Quadrajet diesel could get affected by the same problem of timing chain snapping since this engine is supplied by Fiat India to Tata Motors.