If the timing belt fails on the 2.8 Fiat/Iveco diesel (1999 etc) the pistons and valves will collide. Is it nescessary to exchange te whole motor due to the risk of cracks in the pistons, or will it be suficcient to just exchange the top? I know this is different for different motors, the larger and sturdier valves the worse, sculpted piston tops also makes things worse.
Technical 2.8 diesel. Replace top or motor after cambelt failure?
- Thread starter Octagon
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Technical 2.8 diesel. Replace top or motor after cambelt failure?
There is probably no definite answer to this, as each failure might have the valves in different positions.
What matters is the damage to the pistons.
If valves have hit when only partly open, and have bent easily, piston damage will most likely be just surface, and can be polished out. The harder it hits the valves, the more likely the piston will suffer damage.
The piston is strongest, and most resistant to damage a few mm in from the edge. At the edge, there is a risk that the piston ring grooves get squeezed, then the rings will not hold tension against the bores, so loss of compression and oil burning. Too far in and the piston crown could distort downwards, and become weaker, leading to failure later as a hole appears.
If several valves have hit hard, and resisted bending out of the way, there is a risk of the conrod becoming bent. This is rare, especially with diesels, as conrods are very strong due the high pressures in the combustion chamber. This can be checked initially by checking that all pistons are the same level at TDC.
Damage to the head could be just the valves, or valve guides might break. Rockers are often sacrificial on modern diesels, saving other parts.
A used head will come from a used engine, often swapping the whole thing is easier than just the head.
What matters is the damage to the pistons.
If valves have hit when only partly open, and have bent easily, piston damage will most likely be just surface, and can be polished out. The harder it hits the valves, the more likely the piston will suffer damage.
The piston is strongest, and most resistant to damage a few mm in from the edge. At the edge, there is a risk that the piston ring grooves get squeezed, then the rings will not hold tension against the bores, so loss of compression and oil burning. Too far in and the piston crown could distort downwards, and become weaker, leading to failure later as a hole appears.
If several valves have hit hard, and resisted bending out of the way, there is a risk of the conrod becoming bent. This is rare, especially with diesels, as conrods are very strong due the high pressures in the combustion chamber. This can be checked initially by checking that all pistons are the same level at TDC.
Damage to the head could be just the valves, or valve guides might break. Rockers are often sacrificial on modern diesels, saving other parts.
A used head will come from a used engine, often swapping the whole thing is easier than just the head.
Thanks for your answer. I've been looking for a complete engine for a while now without any luck. There are loads of the common rail type engine 2.8 litre 8140.43S I found at least 10, but my Fiat have the mechanical injection 8140.43. The only motor I found is a refurbished one, but the refurbisher is listing the 43 and 43S using the same item number, which is wrong, can't trust a company like that. Reviews aren't too good either.
The car is at a shop 500 km away, so I can't open it and have a look. I just assumed the motor was toast and had no time to check it, but as time goes and I don't find any motors, maybe it's the only reasonable option.
The car is at a shop 500 km away, so I can't open it and have a look. I just assumed the motor was toast and had no time to check it, but as time goes and I don't find any motors, maybe it's the only reasonable option.
I have no knowledge of these engines, or the van really, but some general information may help. With many modern diesels, differing power outputs are achieved with changes to turbo and fuelling, and the mechanical parts of the engine are standard. A diesel engine always runs with excess air in the cylinder, so changes to camshaft and valves is rare. A bigger turbo stuffs more air in, and the fuel pump adds more fuel to give more power.
This could be why the engine supplier lists the same engine for both models.
Whilst reviews may not all be favourable, they need to be read carefully. Purchasers are already unhappy, having to buy an engine, and can be over critical, and blame the engine supplier for issues that may have contributed to the original failure. Sometimes of course, the 'new' engine is not well made. I'd be reading the reviews with an open mind, and looking at what warranty the supplier offers. The way any warranty issues are dealt with is often more important that initial impressions of the engine. At this time, their engine is better than yours.