Hi,
My other half has deceided she wants a 1.0 Nissan micra.
I've seen a 2003(53) 1.0 car for sale with 33k miiles and was wondering what the deal is with cam chains on them?
When do they require changing and are what are the symptoms of a car which has a stretched belt in need of replacement(I read somewhere that the stretch?)
Also how much does the chain replacement cost and is it something a home mechanic can do, I've done numerous cam belts but never a cam chain.
Thanks
Rob
I wouldn't worry - it'll more than likely do another 100k miles or more without needing attention.
If it's on its way out, it'll sound like a knackered Ford Fiesta.
chains have a fair life - belts on the other hand are critical and must be changed before the recommended intervals.
That's not really a full picture. Ford cam belts have had a
10year/100,000 mile change interval for more than a decade, and some models have now had that increased to 120,000 miles. They rarely fail early.Some cam chains can fail before 100,000 miles. Some VW models are prone to this. The cost of replacing the chain is usually significantly higher than changing a belt; for some models, when the chain rattles it's not cost effective to replace it.
Some Toyotas use plastic sprockets with a chain. The sprockets have been known to fail around three years/50,000 miles.
Both belts and chains are critical; failure of either on almost all modern engines will cause similar significant damage. On balance, there may be more damage done if a chain breaks, and the repair costs are likely to be higher due to the greater amount of dismantling required.
Over all, belts are a better solution from a number of points of view. If only owners had a better understanding of maintenance needs, and perhaps more importantly costs, belt driven cams would have continued as the preferred method.
Chris
Erm, I'd disagree with that.
Belts are the cheap solution to save the manufacturers a few quid - and are well known for early failure.
Ford may be confident in quoting 120k miles - but if your belt snaps outside of warranty at 100k miles, I very much doubt they'd pay for the damage.
One big advantage of chains is that you get plenty of warning before they let go.
Me too. I'd also take issue with "belt driven cams would have continued as the preferred method." Camshafts were driven by chains long before belts. And of course where it's really vital, they are gear driven.
Steve
Where it's really vital people follow the service schedule.
Well, I did say from a number of POV - not for every reason.
There have been some cases of early failure, yes. These were often VX, where they tried to keep up with Ford by doubling the change interval from 36k to 72k without making any improvement to the design. Needless to say, many failed around 40k, leading to a hasty retreat!
Other VX failures were caused by a large batch of faulty water pumps, which were prone to seizing. Some Renaults also did this. Driving the water pump from the belt is never going to be a good idea.
These failures were hardly the 'fault' of the use of a belt drive!
The other advantages of a belt are quietness, and the likelihood that valve timing will stay in spec over the belt's lifetime. Chain stretch is much more difficult to overcome.
Over the life of the vehicle, the cost to the owner *could* be less, as long as the design is right. For example, many cars are scrapped with less than 100k, and even 'high-milers' with 200k on them would have needed only one belt change at perhaps half the cost of changing a chain.
Nor Toyota when the plastic sprocket fails, or VW when chain replacement means engine/box splitting and a new crankshaft, of course.
Yes, you do. However, the sort of owner who ignores belt change intervals is most likely just to turn the radio up when the chain gets noisy...
Of course, the real reason for the debate actually is nothing to do with the way the cams are driven, but about how we demand more performance for less fuel costs. 25 years ago, a broken cam belt on my old Pinto-engined Transit took a garage 30 minutes to fix, and cost me 20UKP, including recovery!
Chris
On the K11 (99-54) we didnt have timing chain stretch, they just snapped and lunched the engine, wrapping around the crank sprocket and blowing the casing apart.
On the K12, stretching is very common, especially the earlier models. The chain AND the guides themselves are very prone to wear, espeically on low mileage cars that havent had regular enough servicing. Has the car in question had 6 monthly oil changes?
Anyhow, symptoms will be a rattle upon cold startup before oil pressure extends the tensioner, loss of power due to the timing being out, and when really bad EML light on with a crank / cam sync fault code and limp home mode.
If you remove the oil filler cap and look down at the tensioner and its more than a finger nail protruded the chain is fairly worn.
The larger 1.2, and 1.4 and 1.6 in the almera suffer in exactly the same way. You are looking at about £300 to replace the chain and guides.
Tim..
You will not get a better small car than a Micra.
En el artículo , Chris Whelan escribió:
They just don't learn, do they? Or is this a deliberate ploy to sell new engines when the sprockets fail?
Me too. I'd also take issue with "belt driven cams would have continued as the preferred method." Camshafts were driven by chains long before belts. And of course where it's really vital, they are gear driven.
Steve
Remember the Series 1 Morris Oxford. The fibre camshaft gear wheel used to strip their teeth?.
Mike
and revisited by Ford on their V4 and V6 engines
Ditto certain Volvo models..
Chris
yep but the side valves didn't clip the pistons when they failed :)
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