We recently received into the workshop an F1AE0481D Iveco engine that lately resided in a Fiat Ducato van. The engine was removed by the owner’s mechanic in Mittagong and sent to us for repair. Advice from the mechanic was that the engine would turn over partway in one direction and then stop, and then partway in the other direction and also stop. Both owner and mechanic were thinking “timing belt failure”.
We stripped the engine down when it arrived into our shop, and this is what we found:
The timing belt and chain were in good operating order. The engine is a DOHC setup with one camshaft driven by the timing belt and the other camshaft driven by a small chain at the back of the head.
The head wasn’t in very good shape from a previous “repair” job. The retaining bolts for two of the injector retainers had broken off in the head and instead of removing the broken bolts, the previous repairer had just ground the bolts off flush with the head and used the valve cover holes instead. These are much shorter than the injector retainer holes, so there’re not really suitable for this purpose. One of the injector retainers had broken free, probably because of being hit by the piston.
The real problem then became obvious…. One of the valves had broken off at the end of the stem, breaking one of the rocker arms at the same time.
So, it was off with the head to discover the real extent of the damage. And that valve really had made quite a mess! It had hammered itself into the piston and left deep marks in the head as well.
To make matters worse, bits of metal had broken off the head and the piston and made their way into neighboring cylinders, becoming stuck under valves and coming to rest inside the cylinders. When we removed the manifolds from the turbocharger, a metallic “sand” poured out from the exhaust side, basically spelling the end of the turbo as well. Even the bottom end didn’t escape unscathed, with both the main bearings and big end bearings damaged from the excessive forces. But, crankshaft measured up within tolerance and a crack test confirmed it was OK.
In the end, this failed valve resulted in a new head, reconditioned turbo, a new set of injectors and new pistons, rings, bearings and a complete set of valves, as well as the usual bits and pieces like timing belt, pump etc. We had to import most of the parts from Europe as these aren’t the most common engines in Australia.
So, what caused the valve failure? Hard to say exactly, but our best guess is over-revving.