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Cambelt or chain? Vetus M4.14


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7 minutes ago, cuthound said:

I do wonder if frequent cambelt changing is a "rip off Britain" thing. 

 

I had a 2005 Ford Focus 2.0 diesel, and the recommended cambelt change interval was 10 years or 100,000 miles. It got to 100,000 without an issue.

 

My current VAG 2.0 diesel requires a cambelt change every 5 years or 140,000 miles according to VAG UK, but a German friend has an identical engine in his car and VAG Germany say 10 years or 100,000 miles.

Something to do with the lack of speed limits on the Autobahn?

Edited by Machpoint005
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So nothing to worry about then :)

 

Here's the pic I found:

 

https://www.ajsutton.co.uk/genuineparts/25878/2-11/vetus-m4-14-marine-diesel-engine-/timing-parts?uID=0

 

Presumably the 4 gears do the same job as a belt or chain.

 

Begs the question, why would anyone design a belt or chain into an engine?

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2 hours ago, David Schweizer said:

 

I didn't change the belt on my first Passat until after the (then) recommended 80,000 miles, my garage then suggested that I changed the belt on the next two at 60,000 miles, and then on my fourth Passat it had been reduced to 40,000, but apparently this had very little to do with the belt but the belt tensioner, which had been changed from metal to plastic, and it simply wore out. As there is almost the same amount of labour involved with a tensioner change as there is with a belt change, it was sensible to change the belt at the same time. By the time I got my last Passat,  the tensioner had been re-designed and was made of metal, so the belt change interval was longer, and I got it changed at 78,000 miles. Unfortunately not long after the new cam belt had been fitted, the car was written of by a careless "White Van Man", by which time VW were no longer importing petrol Passats, so I got a Golf 1.4TSI estate (as rare as hen's teeth!) which is very economical and very lively, but it isn't a Passat!??

My Passat requires a cambelt change at 140,000 miles.

 

I bit the bullet at only 120,000 on the basis that I would exceed 140,000 - but not 240,000.  So I was going to pay for one change (and never two) in any event and might as well bring it forward rather than take it to the wire.

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18 hours ago, Tony Brooks said:

 

18 hours ago, Tony Brooks said:

many petrol engines will suffer no damage if the belt snaps, they just stop.

My wife didn't want the car to "just stop" when the cam belt on her Rover 214 failed in the fast lane of the M6!

But she had the presence of mind to depress the clutch and coast to the hard shoulder. And all that was needed was a new belt to get the car back on the road.

Unlike my experience with a timing chain failure on a (petrol) Zafira, which wrote the vehicle off.

Edited by David Mack
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2 minutes ago, David Mack said:

My wife didn't want the car to "just stop" when the cam belt on her Rover 214 failed in the fast lane of the M6!

But she had the presence of mind to depress the clutch and coast to the hard shoulder. And all that was needed was a new belt to get the car back on the road.

Ditto with my petrol Mondeo. The 4 lane bit of the M6 just before Corley. 

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I agree that one really should try to avoid having an engine just stop and that is why I change my cam belt as recommended - plus the other bits that nowadays seem mandatory. However some on here seem to be trying to say that there is no problem with exceeding the manufacturer's recommendations. The point I was trying to make was that on a "safe" petrol engine doing so is a fair risk for the individual to take but on a diesel it is completely different and if one broke it could easily be new engine time. It is one thing deciding to take a degree of risk yourself but I feel totally irresponsible in giving potentially less knowledgeable people operating engines in a  very different environment the idea that regular cam belt changes on diesels can be avoided.

23 hours ago, David Schweizer said:

Some VW turbo engined car owners may not agree with that statement. The problem is that the timing chain is much longer and of lighter construction on the OHC engines than on the older OHV engines. The consequence is that they are more prone to stretching, and in the worst cases juming a tooth on the cam cog. Furthermore the cost of replacing a cam chain is almost double that for a cam belt.  The belts fitted to earlier engines were prone to premature failure, prompting the introduction of chains. However, technology has moved on and the new belts are far more reliable, and some manufactures have returned to using belts, particularly in their higher performance engines (they are also a lot quieter.)

 

On this point I bet that chain was a single link width chain and very long where as those on the diesels I know of are at least twin link (duplex) or three link wide chains so the point does not seem to have any bearing on the advisability of accepting a cam belt in marine use.

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58 minutes ago, Tony Brooks said:

I agree that one really should try to avoid having an engine just stop and that is why I change my cam belt as recommended - plus the other bits that nowadays seem mandatory. However some on here seem to be trying to say that there is no problem with exceeding the manufacturer's recommendations. The point I was trying to make was that on a "safe" petrol engine doing so is a fair risk for the individual to take but on a diesel it is completely different and if one broke it could easily be new engine time. It is one thing deciding to take a degree of risk yourself but I feel totally irresponsible in giving potentially less knowledgeable people operating engines in a  very different environment the idea that regular cam belt changes on diesels can be avoided.

 

On this point I bet that chain was a single link width chain and very long where as those on the diesels I know of are at least twin link (duplex) or three link wide chains so the point does not seem to have any bearing on the advisability of accepting a cam belt in marine use.

 

I broke the timing chain on my 2.5L OHC diesel Mitsubishi many years ago. It was definitely duplex, possibly triplex. Wrecked the cylinder head but bottom end was fine. We fitted a £300 chinese copy from ebay (which worked fine!) and sold the car quick. 

 

 

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Just now, Mike the Boilerman said:

 

I broke the timing chain on my 2.5L OHC diesel Mitsubishi many years ago. It was definitely duplex, possibly triplex. Wrecked the cylinder head but bottom end was fine. We fitted a £300 chinese copy from ebay (which worked fine!) and sold the car quick. 

 

 

Note both this and the VW are OHC with very long chains so opulently of opportunity to whip. I have a feeling the lombardini with the belt is also OHC.

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Timing belts mostly strip the teeth rather than actually snap often when the engine is idling or when the vehicle is being manouvered slowly, especially if the tick over is a bit rough which gives bigger tugs on the belt.  When they snap they are usually thread bare and in tatters anyway.

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1 hour ago, Tony Brooks said:

I agree that one really should try to avoid having an engine just stop and that is why I change my cam belt as recommended - plus the other bits that nowadays seem mandatory. However some on here seem to be trying to say that there is no problem with exceeding the manufacturer's recommendations. The point I was trying to make was that on a "safe" petrol engine doing so is a fair risk for the individual to take but on a diesel it is completely different and if one broke it could easily be new engine time. It is one thing deciding to take a degree of risk yourself but I feel totally irresponsible in giving potentially less knowledgeable people operating engines in a  very different environment the idea that regular cam belt changes on diesels can be avoided.

 

On this point I bet that chain was a single link width chain and very long where as those on the diesels I know of are at least twin link (duplex) or three link wide chains so the point does not seem to have any bearing on the advisability of accepting a cam belt in marine use.

That's always my strategy; on my vehicle/ boat I follow the service schedule to the letter even though some aspects may seem OTT. 

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16 hours ago, WotEver said:

Because the camshaft is a long way from the crankshaft on an OHC engine.

That^^
The Manx Norton motorcycle was an example of an OHC engine driven by a vertical shaft via bevel gears. Few others attempted this AFAIAW.

a friend of mine had a belt driven OHC engine (poss. Lombardini) let go in spectacular style following the failure of the alternator belt. This in turn somehow got between the cam belt and the pulley, and bang! Wrecked the engine for the sake of a V belt. 

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5 minutes ago, catweasel said:

That^^
The Manx Norton motorcycle was an example of an OHC engine driven by a vertical shaft via bevel gears. Few others attempted this AFAIAW.

a friend of mine had a belt driven OHC engine (poss. Lombardini) let go in spectacular style following the failure of the alternator belt. This in turn somehow got between the cam belt and the pulley, and bang! Wrecked the engine for the sake of a V belt. 

I can't see how this could be possible on my Lombardini engine as the cambelt is behind a secure protective cover, whilst the alternator belt is external to this. Other versions may be available though.

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16 minutes ago, catweasel said:

That^^
The Manx Norton motorcycle was an example of an OHC engine driven by a vertical shaft via bevel gears. Few others attempted this AFAIAW.

a friend of mine had a belt driven OHC engine (poss. Lombardini) let go in spectacular style following the failure of the alternator belt. This in turn somehow got between the cam belt and the pulley, and bang! Wrecked the engine for the sake of a V belt. 

I think an early MG did similar but  used the dynamo as the vertical shaft. I think they had constant upper oil seal troubles that caused charging failures.

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The BMC 1.8 has a much longer chain than the 1.5 and it is more prone to failure.

I had one that was so slack that it thrashed the tensioner into submission and then picked up on the back tooth on the crankshaft sprocket. Ripped all the teeth off the sprocket.

Piston smacked a valve, bent the pushrod a bit.

But being a tough old engine it was back in action with a new chain, copy sprocket, slipper and tensioner, I straightened the valve and pushrod.

Incidentally, on these diesels the chain tensioner & slipper and the cam & crank sprockets are the same as the 1.8 petrol "B" series used in the MGB.

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21 hours ago, Machpoint005 said:

 

Something to do with the lack of speed limits on the Autobahn?

 

Shouldn't think so, after all the manufacturer cannot know how buyers intend to use their cars.

 

I wouldn't think the average private user in Germany, France, Spain etc would use his car much differently than someone in the UK.

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6 hours ago, rgreg said:

I can't see how this could be possible on my Lombardini engine as the cambelt is behind a secure protective cover, whilst the alternator belt is external to this. Other versions may be available though.

Not sure sorry, but am fairly certain it was a Lombardini engine of some sort. He couldn't have been further away from home when it let go, and had to have a new engine fitted. Expensive holiday.

6 hours ago, Tony Brooks said:

I think an early MG did similar but  used the dynamo as the vertical shaft. I think they had constant upper oil seal troubles that caused charging failures.

Interesting. I believe the Manx Norton also suffered oil seal problems in this area. It always looked beautifully engineered though.

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7 hours ago, Tony Brooks said:

Note both this and the VW are OHC with very long chains so opulently of opportunity to whip. I have a feeling the lombardini with the belt is also OHC.

Some may have, but the 1.4 TSI petrol engine has two shorter ones with a double sprocket between the the crankshaft and the twin cam sprockets, Probably helps to explain why it is such a noisy engine.

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14 hours ago, David Schweizer said:

Some may have, but the 1.4 TSI petrol engine has two shorter ones with a double sprocket between the the crankshaft and the twin cam sprockets, Probably helps to explain why it is such a noisy engine.

 

Below is a drawing demonstrating the twin chain system. However the longer chain is still apparently prone to stretching, particularly if the advised regular service intervals are  ignored.

 

timing-chain-on-VW-1.4-TSI.png

Edited by David Schweizer
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