W3526602 Posted July 8, 2010 Share Posted July 8, 2010 Hi, Was it here that somebody reported a broken cam-belt? I was looking at Jap double-cabs on Ebay, saw one that looked interesting, so sent vendor a question. Q - When was cam belt last changed? A - It hasn't been changed, there's nothing wrong with it! 602 Link to comment Share on other sites More sharing options...
takeaflight Posted July 8, 2010 Share Posted July 8, 2010 "It hasn't been changed, there's nothing wrong with it!" How does he know ? I know when we had a Fiat based m/h the handbook said something like, 50000 miles or 5years I believe cam belts can expire with age just as much with mileage. Roy Link to comment Share on other sites More sharing options...
colin Posted July 8, 2010 Share Posted July 8, 2010 Gf's father brought a Mitsubushi, I asked him if belts had been changed, it had no servive history so I told him to replace ALL the drive belts, he didn't bother, 12 months later it's sat in the yard with a buggered engine. Link to comment Share on other sites More sharing options...
hallii Posted July 8, 2010 Share Posted July 8, 2010 I hate cam belts, whilst I have never had one snap I HAVE spent an inordinate amount of money to have them changed regularly for my peace of mind. I have heard of belts snapping for no reason at very low mileages, It's a good job Aircraft engines don't use them! I have three vehicles and each one has a chain cam. I will not buy another vehicle with a cam belt, the quicker manufacturers realise that they are costing sales the better. They fit them because they are quiet running they say. Chains run quiet as well but they cost a bit more to engineer. So it's cost again. Cheap to make and expensive to change, but that's OK because the customer pays and it keeps their franchises in business. Hallii Link to comment Share on other sites More sharing options...
euroserv Posted July 8, 2010 Share Posted July 8, 2010 Hallii, I hate cam belts as much as the next guy! BUT..... The 2.8JTD Ducato has a cam belt and high pressure fuel pump that is driven by gears directly from the crankshaft and when one fails it is a doddle to change one. The Ford 2.4 engine has a timing chain and the fuel pump is driven off this even on the later common rail engines. To change this pump is a pain in the backside and very time consuming. Never had a Fiat JTD cam belt fail but have fixed several 2.4 Ford timing chains that have failed. The bottom line is that only VW have ever come up with a better solution; this being a gear driven camshaft on the LT but even this was poorly executed because it was at the back of the engine and there was no way of telling what position the gears were in once you started lowering the head back onto the block. I am pinning my hopes for the future on Fiat's new multi-air system which does away with cam belts, chains and gears. Do a search on youtube for it and be prepared to be impressed. This system will be used for everything in the years to come, probably licenced to everyone by Fiat in the same way that it was them that invented common rail injection. Fiat frustrate me more every day, but they do have some clever ideas that define the progress of the motor industry, and for that I am grateful. Bottom line? Change cam belts on time. Don't assume that a cam chain is always going to be more reliable than a belt. If you hear any abnormal squeaks or rattles either when starting or driving get someone to check that your tensioners, idlers or whatever other devices you have on your belt or chain are in good order because it is considerably more likely that one of these will fail long before the belt or chain will. It might be something on the auxiliary belt that is making the noise but that can be almost as serious if you have water pumps and power steering pulleys driven by that. Nick Link to comment Share on other sites More sharing options...
Brian Kirby Posted July 8, 2010 Share Posted July 8, 2010 euroserv - 2010-07-08 5:37 PM ...... I am pinning my hopes for the future on Fiat's new multi-air system which does away with cam belts, chains and gears. Do a search on youtube for it and be prepared to be impressed. This system will be used for everything in the years to come, probably licenced to everyone by Fiat in the same way that it was them that invented common rail injection. Fiat frustrate me more every day, but they do have some clever ideas that define the progress of the motor industry, and for that I am grateful. ........... Nick Fascinating Nick. However, the bit of film I found shows a camshaft actuating the exhaust valves directly, while being used to pressurise computer controlled hydraulic actuators for the inlet valves. That seemed a bit cumbersome, since it requires retention of the camshaft, and therefore, some means to rotate it. It made me wonder if I had found the right clip.Why have they not eliminated the cam etc, and used a high pressure pump to actuate all the valves through computer controlled solenoid actuators. That way, they'd get the ultimate "elastic" cam, capable of assuming whatever profile engine demand requires. This is so obvious it must have ocurred to everyone involved on day one, so why have they retained the mechanically driven rotating camshaft? What I saw was undoubtedly clever, but it didn't look what I would call "elegant" engineering. Link to comment Share on other sites More sharing options...
euroserv Posted July 9, 2010 Share Posted July 9, 2010 Hi Brian, This is the first generation of multi-air and so that people do not worry too much, the cam has been retained in order to ensure that in the case of hydraulic failure, the valves cannot be in the 'wrong' position and cause damage to the pistons. The lobes act as limit-stops as well as providing lift......for now anyway. The next stage, once the public and typically cynical motoring journalists accept the system is to do away with the cam completely. I agree that it does not seem very elegant at this moment but remember that it will work with Diesel as well as petrol engines and can be 'bolted' on to the majority of Fiat's petrol engine range right now. Improvements of 15% fuel economy, 10% more power and 10% lower emissions are hard to come by these days so it is regarded as something of a break through. Take a look at the twin-air 900cc 85hp 2 cylinder engine they are launching next. Forget the rev-happy Fiat 500 that it is destined for (and will be very entertaining) for a minute; This engine could sit under the bonnet of a medium sized electric car and tick over at 1000 rpm while charging batteries only; not powering the car, so that you need never plug in to the mains. 100+ mpg and lower emissions than plug in electric or conventional hybrid. Pretty exciting stuff, I think. Fiat ! Sort your transmissions out and you could lead the world! Nick Link to comment Share on other sites More sharing options...
Basil Posted July 11, 2010 Share Posted July 11, 2010 euroserv - 2010-07-08 5:37 PM ........................... probably licenced to everyone by Fiat in the same way that it was them that invented common rail injection.................... Not sure that you are correct with that part of your statement, as my understanding is that the CRD (Common Rail Diesel) injection was invented and patented back in the 1940's by Clessie Cummins well known for Cummins Diesel engines. The Fiat development of this system was sold to Bosch in 1993 as they did not have the expertise to manufacture the system. Bas Link to comment Share on other sites More sharing options...
euroserv Posted July 12, 2010 Share Posted July 12, 2010 Hello Bas, If it was only a development of the system, it would have been hard to register patents and 'sell' the system to Bosch! It was not a lack of expertise but a lack of funds at the time that led to the licencing agreement. I actually think that Bosch demonstrated a lack of expertise because the packages that were sold to early adopters of the system were absolutely rubbish, and Bosch accepted no responsibility for this for nearly 10 years while we struggled on with flawed injectors and pumps on many vehicles. The latest generations are better and at least now they have some competition. Not everything that is written in Wiki or Google is completely correct. Nick Link to comment Share on other sites More sharing options...
Basil Posted July 12, 2010 Share Posted July 12, 2010 Hi Nick, I don't doubt your knowledge and expertise, however as I understand it (not that I suppose it matters other than for accuracy) and without the aid of Wiki (which I never use, or Google which has its uses) it was not CRD that Fiat/ Bosch patented but the development and patent was the electronic side. CRD was invented by Cummins in 1943 and it was incorporated into their L10 engine, which was for heavy truck use, during 1970, a modified CRD system was used under license from Cummins by Cooper-Bessemer on their GN-8 (circa 1942). These engines (L10 and GN8) were all pushrod design on a straight six engine with two valves per cylinder but using 18 pushrods the other six operating the injectors which were fed by the Common Rail system from a remote pump. The Fiat prototype was a collaborative development between Magneti Marelli, Centro Ricerche Fiat and Elasis. The completion and final development was by Robert Bosch GmbH who purchased it as a whole and made the system suitable for mass production on commercial vehicles by the mid 90's and finally suitable for passenger cars in 1997. Bas P.S. Only making this post for historical accuracy no other reason. Link to comment Share on other sites More sharing options...
euroserv Posted July 13, 2010 Share Posted July 13, 2010 Bas, So the original design that was called Common Rail was absolutely nothing like what we now know as common rail. Thanks. Very interesting. Fiat invented the common rail injection system that we now all use. You know, the electronic stuff that precisely meters the fuel and turned diesels from slow and smelly to fast and clean. Nick Link to comment Share on other sites More sharing options...
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