I'm pleased i've seen this thread as i have been meaning to post a similar topic on timing chains..
How do you know when one needs changing. The only reason i ask is that my diesel in my rover 75 has started to make a loud rattle between 3000 and 3500 revs and only at full throttle and not all of the time. At all other revs it is fine.
My first thought was the chain starting to rattle but never had to diagnose one before as just took previous cars in for cam belt change at intervals. The engine has now done 210,000 but oil changed every 5000.
I went to the local rover dealer (before they change to Renault!) and they quoted £1300 labour (23 hrs!!)plus the parts at about £250 inc. tensoiners etc.. They wanted the car in for diagnostics but were going to charge me £45 for the previlidge.
If it is the chain rattling how long is it likely to last before it snaps?? and will it get worse, i.e rattling throughout the rev range??
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That doesn't sound like chain rattle to me. Chain rattle is usually independent of load. I suspect it is something 'combustion related' - is your injection timing OK? It could even be the exhaust rattling - very hard to say without hearing it.
Chain rattle usually is first heard at start-up - a stretched chain takes longer to tension, so you hear a rattle for a short while after starting. As it gets worse you'll hear it rattling at idle. It'll go away when you rev the engine a bit.
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Would there be any other symptons if the injection timing is out??
Its very hard to explain other than it it sounds metallic and is intermittant and usually 2nd and 3rd gear, sometimes 4th but never 1st and 5th! Had new exhaust front pipe (including cat) but the noise was there before this was replaced!
Thinking back it has started making the noise since I put some injector cleaner through - maybe just coincidence.
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I don't know enough about Diesel engine timing to comment. Post it as a 'Diesel engine noise' query.
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Personally I suspect that a lot of the debate resolves around the quality of the design of the original installation, the qualities of materials used and the ease of access for repair (in case of belts).
In the case of Fiat 5 cylinder coupe, belt change is I believe = engine out (at 30,000 miles).
And as someone mentioned BL A series timing chains rattled after 20,000 miles : the design of tensioners was apalling (and were omitted once for costs savings!)
It's often a case as cars grow older maintenance is neglected. No oil chnages will kill a chain: and Nissan Micra chains wear quickly despite regular servicing.
Ford Zetec belts do last 100k miles (where specified) and have a good reputation.
On the other hand, Audi TDI tensioners last 70,000 miles and then you are in risk of them seizing...
A well designed and maintained chain system will beat belts 99% of the time. A badly designed or badly maintained one can be much more expensive to fix than a new cambelt.
As for driving water pumps from cambelts, that's muppet engineering imo...And look at Vauxhall design of moving water pumps to adjust cambelt tension. Designed for failure! No wonder GM are in the doldrums. With designs like that, they deserve it
madf
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As for driving water pumps from cambelts, that's muppet engineering imo...And look at Vauxhall design of moving water pumps to adjust cambelt tension. Designed for failure!
Vauxhalls haven't used that feature for quite some time - they have fitted a separate tensioner - which has caused its share of problems!
The original design wasn't as awful as you say. The only failures happened when people moved the water pump and didn't fit a new seal, i.e., muppet mechanics! If you did the job properly, they worked very well and reliably.
As for the engineering, I think it was very good. Managing to drive the cam, and the water pump, while using so few components none of which needed to be made to exacting tolerances is excellent engineering IMO. Money no object engineering doesn't impress me much, whereas the cunning use of few, cheap, components does.
number_cruncher
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Vauxhalls haven't used that feature for quite some time - they have fitted a separate tensioner - which has caused its share of problems! The original design wasn't as awful as you say. The only failures happened when people moved the water pump and didn't fit a new seal, i.e., muppet mechanics! If you did the job properly, they worked very well and reliably.
number_cruncher
Snag is the pumps sieze in place. I have had to 'smash them out' on occassions. Also the three silly little cap-head bolts tend to seize, and once the heads starts to round-off its one heck of a job to remove them. I once had to lift the engine out of a 2 litre Cavalier to extract them.
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Yes, seized pumps could be a problem!
Whenever possible, I would leave the pump in place, and slide the belt sideways out of the toothed pulleys. Upon putting the new belt in, if the tension was OK, then there was no need to touch the pump at all. I would say that on six or seven cars out of ten, changing the belt was a very quick and easy job indeed!
The socket headed cap screws were a silly feature I agree. From memory (I could be wrong here!), there were originally hex head screws in the early engines, but someone saw fit to 'improve' the specification by fitting the socket headed cap screws you mentioned to later engines.
How and why manufacturers specify their fasteners is a long standing mystery to me. Tx45 for modern Vauxhall sump plugs - how does that keep the oil in better than the old hex head sump plug?
number_cruncher
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Also let us not forget that this design gave us clutch renewal without removing the gearbox,what a brilliant idea!
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With regards to Aprilia's comments, I remember doing a waterpump failure on my dads Cavalier, and it was quite frightening using a hammer to release the pump (as the pump was well and truly seized), as when you have started knocking it out of shape, you realise that if that if you don't crack the block hammering, it has to come out one way or another, and that there is then no way back.
The clutch seemed a good idea though, as far as I'm aware they don't have this system now. Does anybody know why?
Reggie
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The clutch seemed a good idea though, as far as I'm aware they don't have this system now. Does anybody know why? Reggie
It was only the early ones where the clutch was easy to change. On the later engines they went to the 'pot' type flywheel.
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Out of idle curiousity, can anyone tell me if the Ford Fiesta Mk III 1.1 engine was chain cam or belt cam?
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To clarify all Mondeos are now twin cam chain, TDCi and petrol, duplex on diesels and (I think) V6 petrols which of course have four camshafts, two per bank.
The Focus 1.8 TDCi is a single cam belt driven, the newer Ford/PSA 1.6 and 2.0 TDCi/HDi engines in the C-Max, Focus, 206, 407, C5, C4 etc are twin cam belt driven.
Chains are lubricated by the engine oil where as belts run outside of the engine (though under a cover), uniquely Honda have an internal oil lubricated belt driving the cam on their 135 and 160cc single cyl engines that are used in lawnmowers, generators etc. I have a 4.5 hp OHC 135cc Honda lawnmower, quite a neat little motor, very refined for what it is though, of course, max revs approx 3000 only.
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HJ's Telegraph column (11/06/2005) has the following account of chain failing without warning at a comparatively young age:
"My Vauxhall Zafira 2.2i 16v was first registered in February 2002 and belonged to a main dealership before I bought it almost two years ago. After 31,000 miles, it lost all power when I was driving on the M25. Apparently the timing chain had broken, destroying the engine. Vauxhall is prepared to meet 50 per cent of the cost but I still feel short-changed."
(HJ replied: "This is becoming uncomfortably common. The oil feed to this engine's timing chain tensioner gets blocked, leading to accelerated wear and failure. GM responded by improving the oil supply and fitting a larger filter, but extended service intervals allow the oil to degrade and contaminants to form - and it is these that block the flow. If oil and filter were changed every 5,000 miles, I doubt there would be any problem.")
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Good thread. Lots of good arguments. I'd say six of one... As for Hondas being well engineered, the cars seem to be great but the bikes from the 70's. It must have seemed a good idea to run the cam straight in the alloy head without 'proper' bearings. Anyhow my 405s ready for a belt change so I'm dreading that one, new belt, seals, tensioners, etc. I swapped from a chain to a vernier belt drive when I built up a fast A series engine, much quieter!
About chain changing, very short write up -
www.carmechanicsmag.co.uk/cgi-bin/tftt.cgi?q=050502
Steve.
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A related question, I have a 98 Mondeo 1.8 petrol with a "Silver top" engine with a cambelt replacement specification of 5 years/80k miles, however a "Black top" engine from 99 onwards quotes 10 years/100k miles.
Why the five year jump in time? Is it possibly because they see age as a much less likely killer than mileage?
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So I was wondering, the Toyota Camry turbo diesel built in 1986 ? would this be a chain or a belt driven engine?
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My Ford Duratech ST200 has a cam chain driving 4 cam shafts. I have seen a comment saying if chains are short they are ok. I guess my chain would be quite long.
What sort of mileage are the Duratech chains good for?
AdyBee...
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I forgot about the Vauxhall clutch design. I still have in my toolbox a slide hammer, Vauxhall F16 gearbox output shaft adaptor and set of clutch clips that I used on my old Cavalier mk2. Wonder if they'll ever see service again? G
Completely agree with Number Cruncher on the water pump design on these engines. When I did the cambelt on mine, I left the pump well alone. Slipped the old belt off, slipped the new one on and the tension looked fine. Didn't hum or squeal in use and did another 20k until I sold it with no problems.
As I see it, belt drive's advantages are manufacturing cost, and revenue for dealers at service time. I would go out of my way to buy a chain cam engine next time unless the belt was a doddle to change.
Cheers
DP
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All Ford 1.1 are chain cam(tho' for a few months there was a 1.1 CVH but not on a Mk. III).
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Thanks, jc2.
(I knew if I was patient, someone would answer my question.
And it only took one year, 2 months, 7 days, 10 hours and nine minutes.!)
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