Wet Belt

[Cyril BonnettParticipant @cyrilbonnett24790]

This sheds some light on 'wet' cam belts.

**LINK**

[Peter G. ShawParticipant @peterg-shaw75338]

Chris Evans,

re: "Funny some on here do not like Fords".

My present and the previous two cars are:

Toyota Avensis 1.8 petrol, 41K from new, Bridgestone tyres which lasted on average 30K miles. Other than a headlight bulb, nothing else. 38.5 average mpg

Ford Focus 1.8 tdci. Bought at 2 years old with 27K on it, sold at 84K 4 years later. Tyre life with Bridgestone & later Michelin 14K all round with massive tram-lining whilst on the Bridgestones which disappeared once on the Michelins. Other problems: fuel filter at 30K, clutch at 56K, new engine at 59K, air mass flow sensor at some point. Other minor problems as well. 45.5 average mpg

Peugeot 405 td. Bought with 37K/2 years old, sold at 165K 10 years later. Tyre life with Pirelli 18K front, 30K rear, with Michelin 29K front, in excess of 45k rear. Cylinder head failure at 135K, clutch at guessing 80K, no other major failures. A few minor problems but considering it got to 12 years and 165k miles, a good reliable car. 42.5 average mpg.

All three cars have been used for exactly the same type of work – private motoring & towing the same caravan. And as you can see, in terms of mpg, there isn't that great a difference between the diesels and the petrol, yet the Focus proved to be by far and away the most unreliable and the heaviest in terms of tyre wear..

Ok, I may have got a "bad" one, but can you understand why I will never touch another Ford as long as I live? The real irony is that when I got the Ford, it was a toss-up between Japanese and Ford, and I got Ford because I thought spares might be cheaper, but I didn't bargain for a replacement engine!

Regards,

Peter G. Shaw

[Dave HalfordParticipant @davehalford22513]

Interesting link

Obsessing about engine noise

My lad got a Nissan leaf, all right he can fuel it for nothing currently :O) and it's deathly silent backing off the drive, but take it down the road at 30 and the tires put as much row as my Jeep does.

rubber cracks with age which is why cam belts have a life span of xx years OR 80K miles. Tires are worse because of UV damage as well. The tire might be 2 years old before it even goes on a new car.

[John FieldingParticipant @johnfielding34086]

I did some consulting work at the Toyota factory in Durban recently and took a look at the newest Corolla engines waiting to be fitted. I noticed that they didn't have the customary cambelts and asked the engineer what the story was.

I was told Toyota have gone back to using internal chains to drive the camshafts.

On enquiring if this was because they where troublesome I was told it wasn't the reason. By eliminating the cambelts, which stick out a fair bit on the front of the engine, Toyota managed to shave off about 80mm on the engine length. As they are front wheel drive cars with the engine mounted transversally it means they have more space in the engine compartments – to fit the stupid bl**dy plastic covers to hide the engine!

[KWILParticipant @kwil]

Interesting link to NGF Europe on VAG groups use of these in oil cambelts, seem to remember that VW has had wear problems on the belt guides in some engines. Not surprising when they are under pressure on both the tension and slack sides, apparently the pressure guide operating mechanism cannot stand the fluctuation.

Anyone here know better?

[Trev67Participant @trev67]

The Ford Ecoboost does indeed have a wet cambelt, it has a designed life of 160k miles. The belt is not designed to be replaced anyway, so it is a throwaway unit. This is all part of the effort to reduce emmissions, tiny engines, with all sorts off little tweaks to reduce internal losses, the wet cambelt being one of them, I think there is a Fiat or Nissan that even has an on demand oil pump!

The belt vs chain debate always makes me laugh, as the general perception is that belts are high maintenance and chains maintenance free. There are a good number of chain drive engines in which the chains probably have a shorter life than most belts, but are a lot more labour intensive to replace. Notable exambles being the small GM petrols that always rattle, the GM / Fiat 1.3 diesel, any chain drive VAG also some Mercedes. BMW messed up their 2 litre diesel when they redesigned it and put the chain on the back, but believe it or not it is actually now easier to replace, as long as you do it before it breaks and destroys the engine.

Anyway there seems to be plenty on things on cars nowadays that will make them uneconomic to repair, besides throwaway engines. Apparantly Renaults have a designed life of 5 years, after which they go in the shredder to be recycled!

Regards

Trevor

[martin perman 1Participant @martinperman1]

Gentlemen,

Going off topic slightly but still in the same vain, I currently drive, for work, a 61 plate Vauxhall Vivaro which has a 2.0 litre diesel turbo of approx 100 hp and its soon, in a couple of weeks, to be replaced by a Renault Trafic, the same vehicle made by Vauxhall in Luton, which has given me a small shock, the new van has only a 1.6 litre diesel with two turbo's producing similar hp, the same towing capabilities and more mpg, we seem to be going backwards and screwing the last ounce of horsepower out of smaller engines.

Martin P

[KWILParticipant @kwil]

Martin,

Small engines used lightly give "good" MPG, ie seen to be efficient. Small engines with turbos, give greater HP on demand with an equally greater use of fuel, nothing is for free.

If you use the engine at its upper end longer you will loose the much publicised efficient engine, all to do with meeting the rules set by politicians and the green lobby.

Some savings with lower loses from newer engine design, but overall a "con"

[martin perman 1Participant @martinperman1]

KWIL,

I will be interested to see how it performs, I can easily do a 1000 miles plus every week with my job as a service engineer and currently have no difficulty managing just about 40 mpg with my current van and I use the van at weekends towing a trailer carrying my hobby to vintage rally's etc.

At times technology seems to be done for the sake of doing it rather than sticking with something that works.

Martin P

[Michael GilliganParticipant @michaelgilligan61133]

Posted by KWIL on 21/02/2016 09:48:30:

… nothing is for free.

If you use the engine at its upper end longer you will loose the much publicised efficient engine, all to do with meeting the rules set by politicians and the green lobby.

.

Right in one, Sir !!

As a not-proven rule of thumb; I have always believed that an engine is running at its most efficient when delivering peak torque [as opposed to peak power] … On this grey Sunday morning; would anyone care to support or contradict that notion?

MichaelG.

[Tony Pratt 1Participant @tonypratt1]

Posted by Dave Halford on 17/02/2016 21:21:39:

Interesting link

Obsessing about engine noise

My lad got a Nissan leaf, all right he can fuel it for nothing currently :O) and it's deathly silent backing off the drive, but take it down the road at 30 and the tires put as much row as my Jeep does.

Just bought an 11 plate Fiesta, nice car but fitted with nearly new Chinese tyres & the noise from them is horrendous.

Loads of tread but I am tempted to change to hopefully something quieter

Tony

[Neil WyattModerator @neilwyatt]

Not sure about that. Proportionately the 139 BHP from 2 litres of my turbo diesel Mondeo is higher power per cc, and the MPG is very good and achievable over a very wide range of driving conditions, from motorway to free-flowing urban traffic. Yes if I floor it, it slurps fuel, but that's true of any engine.

Neil

[Clive HartlandParticipant @clivehartland94829]

The peak of the Torque curve usually equates to a road speed of between 59- 62 mph, so keeping a steady 60 mph gives the best performance against Mpg. Go over that speed and fuel is used in greater quantity, but then at lower speeds in town plus more use of the gears uses more fuel.

One comment from my recent VW escapade was that over use of the clutch was one of the reasons why it failed. As I heard that I was speechless as one of the things about a hi-speed diesel is that the torque curve is narrow so gears are arranged to to widen that gap. Thats why cars now sometimes have up to 6 gears.

Small engines running like the clappers must use more fuel than a big car/engine running at lower revs.at the same speed.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Clive Hartland on 21/02/2016 10:44:47:

The peak of the Torque curve usually equates to a road speed of between 59- 62 mph, so keeping a steady 60 mph gives the best performance against Mpg. Go over that speed and fuel is used in greater quantity, but then at lower speeds in town plus more use of the gears uses more fuel.

.

['though of course the optimum speed ^^^ is a design choice]

MichaelG.

[Peter G. ShawParticipant @peterg-shaw75338]

My Avensis, non-turbo 1.8 petrol, apparently has a peak power of 140bhp at 4500 rpm, and a 6-speed box. This equates to something like 45 in 2nd, 50+ in 3rd, etc up to 124 in 6th. What it means is that in general we can never legally use this power in this country so most of the time it runs between 2k & 3k rpm, not the fastest off the mark, but satisfactory all the same.

What has surprised me is that when towing, it's performance is very similar to the two diesels, something which did initially concern me, all three vehicles (see my earlier post) being around 25-27mpg on motorways and 30-35 on slow country roads. Even more surprising is it's hill climbing ability – 2nd up a 30% hill (no caravan & 2 up), and having to slow down on a steep hill because I was doing over 10mph more than the recommended speed for a rather nasty bend in the middle (2 up and towing).

What this tells me is that this engine is running well within it's limits even when towing and at lowish rpm's. And, it doesn't have a DMF, turbo, or DPF.

From which you will gather that I rather like this car.

Regards

Peter G. Shaw

[Neil WyattModerator @neilwyatt]

Posted by Peter G. Shaw on 21/02/2016 11:30:55:

What this tells me is that this engine is running well within it's limits even when towing and at lowish rpm's. And, it doesn't have a DMF, turbo, or DPF.

It seems that the engine in your car does have variable valve timing: en.wikipedia.org/wiki/VVT-i which is meant to achieve just that – a very flat torque curve.

Neil

[JAParticipant @ja]

My observations from riding bikes are that engines with their peak torque at low revs are nicer to use than those with the peak at high revs. However having the peak at high revs gives more power and thus top speed. I will leave you to think of examples.

Other than my present car all the cars I have owned have tended to have their peak torque at higher revs. This gives one the typical pulling away problem with a small engine, quite a bit of revs, a low first gear and clutch wear. My present car has turbocharged 1.4 litre petrol engine that produces a flat torque curve from about 1800 to 4500 rpm. There is no pulling away problem even in second gear. It has six gears and one is encouraged to keep the revs below 2500 rpm. As revs increase the force needed to pump of air around the crankcase also increases (theoretically to the square of the engine speed). This moves the efficient running of the engine towards lower revs although, obviously, there are also many other factors. Back to reality, Honda claim that my car has a better fuel consumption than their 1.4 litre Jazz which like the Triumph twins of old has its peak torque at maximum engine revs. Finally, in this case not from manufactures' figures, the car returns an overall average fuel consumption of around 43 miles/gallon.

JA

[Peter G. ShawParticipant @peterg-shaw75338]

Neil,

Mine's actually the Valvematic engine although I suppose it does the same as the VVT.

Peter

Editted to add one word.

Edited By Peter G. Shaw on 21/02/2016 14:14:23

[Neil WyattModerator @neilwyatt]

Posted by Peter G. Shaw on 21/02/2016 14:13:20:

Neil,

Mine's actually the Valvematic engine although I suppose it does the same as the VVT.

Peter

Editted to add one word.

Edited By Peter G. Shaw on 21/02/2016 14:14:23

"The Valvematic system offers continuous adjustment to lift volume and timing, and improves fuel efficiency by controlling the fuel/air mixture using valve control rather than conventional throttle plate control"

Sounds a nightmare for DIY maintenance!

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Neil,

Also available in a German version:

**LINK**

MichaelG.

[Peter G. ShawParticipant @peterg-shaw75338]

Neil,

Gave up on DIY maintenance some 17 years ago when I exchanged a Montego 1.6L petrol for a Pug 405 1.9L diesel.

Peter

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