Hi techies - been looking at the diesel powered Mazda MPV. I understand this has a cam chain rather than a belt. Other than this being, hopefully, more robust are there any major negative cost implications with such a set up (e.g cost of replacement etc.)?
Also, do diesels require catalytic converters?
Thanks in anticipation from a grateful technophobe :)
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Mazda diesels are not made by Mazda but sourced through their Ford parent company, some of which are chain cam (130 bhp), but the 115 bhp is not only belt driven but is the result of a joint Ford/Peugeot co-operative venture, which I personally would`nt touch with a barge pole.
Nearly all the petrol engines in the Mazda range are genuine Mazda (except the Mazda 2) and they are absolutely superbly engineered, - at tick-over for example, they are totally inaudible and one has to rely on the rev counter to see if the engine is still running.
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I had a look at the Mazda web site - seems the MPV is only available with Mazda's own engine, and the website doesn't give any clue as to whether it's chain or belt, but going on what Dude says it's probably chain. Replacing a chain will probably cost (a lot?) more than a belt, but it should never need doing in the normal life of the engine as long as good oils are used and changed when specified. Chains are slightly heavier, might be a bit more noisy, but unlikely to just snap one day with no warning.
The diesel is probably fitted with a 'cat' of sorts, but it is nothing like a petrol cat - it just converts NOx back to Nitrogen using the excess air that is always present in a diesel engine - none of those lambda sensors to go wrong here. The diesel doesn't appear to meet Euro IV (as it says the petrol does, assume the diesel doesn't) so there probably isn't a particulate trap (again no mention of this, so almost certainly not). Because of the different combustion, diesel engine exhausts typically last 8-10 years or more anyway.
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RichardW
Is it illogical? It must be Citroen....
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HJ mentioned that the new Focus C Max petrol had a cam chain, any body know if the Diesel has a chain or belt? I quite like the look of the 1.6 TDCI.
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Actually the diesel engine 'cat' converts un-burned diesel fuel into water and carbon dioxide. This device cannot convert NOx to nitrogen as this would require a reduction reaction to occur to strip away the oxygen from the nitrogen - not possible in lean running diesels.
NOx control is achieved by retarding injection timing and re-burning exhaust gas. Interesting stuff!
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Thanks Dude, Richard and Dieselhead - very interesting if slightly confusing. Interestingly I've just noticed that the technical brochure I was given is dated Mar 2003 and refers to the 2.3l MZR petrol & 2.0l MZR-CD engines. I don't know if these are the engies you refer to but IIRC correctly HJ's CBC breakdown referred to a revamp for 2004 models so I'll need to check whether the engines have been changed at all.
Why can't these manufacturers just stop fiddling with things? :)
Going to test drive a 2.0l diesel Hyundai Trajet this morning so it'll be interesting to see how it compares with the Mazda and whether it is cam belt or chain.
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Dude what in your opinion is wrong with Peugeot/Ford HDI engines?
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I know there has been much written on earlier threads on this forum about car reliability surveys and their variable conclusions.
There is a consistency however with the vehicles at the bottom of all these surveys, where you will find Renault, Peugeot and Citroen languishing.
Profitability amonst manufacturers is being constantly squeezed with ever tighter margins, but surely Ford should have encouraged their Mazda subsidiary, whose reliability is second to none and whose reputation is very much in the ascendancy, to design and build their diesel engines rather than forge a commercial link with Peugeot/Citroen.
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PSA and Renault diesels are excellent, the reliability reports are not engined induced, it other parts of the cars
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I think you are scare-mongering, ever so slightly! I agree that Mazda make exceptional engines and have been increasingly impressed by their developing car range. However, I've heard nothing but optimism from this Ford/PSA project. Surely its only a good thing that 2 large car firms (who make unusual soulmates)combine their thinking and produce some engines...
Lets see and judge the products before we start knocking this venture.
Splodgeface
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