Serpentine belt

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Mr Cassandra

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I have just bought a yacht with a Perkins T80 engine the previous owner said that the belt was changed 4 years ago and according to the specification needs changing. This is not an easy job on this engine and as its only done about 120 hours and looks in VGC .
Would you wait until the end of the season to replace when wintering the boat?
 
Assuming you mean the Perkins M80T and further assuming you mean the timing belt, it really isn't that hard to change. If it breaks, damage can be expensive, up to the engine being a write off.
 
rtboss1 said:
I have just bought a yacht with a Perkins T80 engine the previous owner said that the belt was changed 4 years ago and according to the specification needs changing. This is not an easy job on this engine and as its only done about 120 hours and looks in VGC .
Would you wait until the end of the season to replace when wintering the boat?
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Assuming it is a true serpentine belt (aka "polyvee" on this side of The Pond), I'd be in no rush at all. The first one I had on a boat I changed after 2000 hours, and only out of caution. After initial bedding-in it had required no adjustment, and never shedded dust (a good sign that it's on the wane.) That (and subsequent ones) was on a Beta. To the best of my knowledge Beta suggest no specific replacement intervals.

Incidentally, if the reason for the "not easy" changing is having to remove lots of other bits to do so, you might consider fitting two when you do replace it, the second tied out of the way. This is practical on some Betas where engine pipework gets in the way.

P.S. (prompted by Paul's post) if it's the timing belt it's not a polyvee/serpentine. So ignore everything I wrote.
 
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Referring to car engines here, but if it is a serpentine polyvee belt then just inspect it. No need to worry about tiny cracks in the ridges but if there are any ridge sections missing or any splits, cracks or perforations in the solid, non-ridged, part of the belt then it needs changing.

If it's a toothed cam belt then it should be changed according to the service schedule although if there are no cracks in it then it is not in danger of failing. However, inspection of the toothed belt normally needs sufficient dismantling that you might as well simply replace it.

Richard
 
Not disagreeing with any of the above, regarding serpentine belts, but i don't think the OPs engine has one.

There is no such thing as a Perkins T80, so i assume he means M80T. Of course, he might have meant a Thorneycroft T80 :) Perhaps he'll clarify that ?

If it is the Perkins M80T it has a toothed cam belt, if that breaks it's a big bill. The belt is not hard to change and the whole kit only costs £24.75 ! The alternator belt is just a "toothed" V belt.

OP : parts are available here : https://www.parts4engines.com/perkins-prima-m50-m60-m80t-500-series/?sort=featured&page=1
 
rtboss1 said:
I have just bought a yacht with a Perkins T80 engine the previous owner said that the belt was changed 4 years ago and according to the specification needs changing. This is not an easy job on this engine and as its only done about 120 hours and looks in VGC .
Would you wait until the end of the season to replace when wintering the boat?
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I certainly would not panic!

Compare with the cam belt on my car, for which the recommendation is 36k miles or 10 years ( now well past 10 years but sill under 36k and will cost more than the value of the car to replace!)


If you gan see it inspect the roots of the teeth for cracks where it flexes backwards over the tensioner or an idler.
 
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VicS said:
I certainly would not panic!

Compare with the cam belt on my car, for which the recommendation is 36k miles or 10 years ( now well past 10 years but sill under 36k and will cost more than the value of the car to replace!)


If you gan see it inspect the roots of the teeth for cracks where it flexes backwards over the tensioner or an idler.
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If the belt breaks or one of the roller lets go, will you buy him a new engine ?
 
rtboss1 said:
I have just bought a yacht with a Perkins T80 engine the previous owner said that the belt was changed 4 years ago and according to the specification needs changing. This is not an easy job on this engine and as its only done about 120 hours and looks in VGC .
Would you wait until the end of the season to replace when wintering the boat?
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It is the same base engine as the MD22 with a turbo fitted. An old design and fitted to boats in the late 90s and early 00s so its getting on a bit now. Seems strange to have such low engine hours? However, to the question. The belt is 30mm wide, bullet proof according to some of the Landrover guys who used to use the engines out of Maestros to improve fuel economy etc. Mine was 10 years old when I bought my boat, had never been changed looking at the green VP paint on the fastenings. Since then Ive changed it twice. 4 years seems a good time interval! Ive seen various VP recommendations. However none of the belts have been in need of change, one of the rollers had a little grease seepage. So peace of mind if you dont have any documentation of changes. Easy enough to do, if the OP wants to contact me I can send him a pdf of what I did.
PS take the little plastic cover off the cam belt cover and twist the belt to inspect it, end of the season should be OK.
 
Tranona said:
Do you have any evidence that the belt breaks after only 120 hours?

Scaremongering at its best.
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I'd have thought better of you.

Do you have any evidence that a 20-30 year old engine has only done 120 hours ? Any evidence that it has ever been changed ? Even if it has only done 120 hours the belt and the rollers could be anything up to 30 years old.

£24.75 for the kit to do it and it's a simple job that any half competent person should be able to do, offset against the chance of ruining the engine, seems like a no-brainer to me.
 
PaulRainbow said:
I'd have thought better of you.

Do you have any evidence that a 20-30 year old engine has only done 120 hours ? Any evidence that it has ever been changed ? Even if it has only done 120 hours the belt and the rollers could be anything up to 30 years old.

£24.75 for the kit to do it and it's a simple job that any half competent person should be able to do, offset against the chance of ruining the engine, seems like a no-brainer to me.
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Suggest you read the original post - as I did before jumping to conclusions. Just re-confirmed by the OP.

My diesel C Max has done 90k miles on its original belt and I am sure there were thousands of Montegos and LDV vans etc that did similar mileages on the same engine that the OP has.

Of course the damage can be catastrophic if the belt does fail which is why I had the one in my Morgan's Zetec engine replaced after only 13 years and under 20k miles. Needless to say it was perfect.

Would guess the failure rate of belts on Perkins engines is similar to that of saildrive seals.
 
I have had the misfortune of having a cambelt snap whilst 200 miles away from home. I managed to get a lift to a Vauxhall dealer who had the belt in stock and I had enough tools with me to replace the cambelt parked on a very busy main road in Warrington. Luckily it was not an interference engine so ran perfectly once I'd re-set the valve timing and put on the new belt.

However, I should add that this was the first car with a cambelt that I had owned so, although the engine had given me plenty of warning that the cambelt was going snap, I misinterpreted those warnings and did not act on them. I will not make that mistake again ..... but it confirms my long held view that mechanical devices very often give you a warning that they are heading for failure but you have to listen/feel/smell those warnings and, more importantly, understand what they are telling you. :o

Richard
 
Tranona said:
Suggest you read the original post - as I did before jumping to conclusions. Just re-confirmed by the OP.
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I did read it and i have jumped to no conclusions.

He said
I have just bought a yacht with a Perkins T80 engine the previous owner said that the belt was changed 4 years ago and according to the specification needs changing.
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So according to the specification, it needs changing now. That's assuming the belt was actually changed four years ago and further assuming the rollers were also changed at the same time. As he's just bought it he has no guarantee either of those assumptions are correct.

This is not an easy job on this engine and as its only done
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about 120 hours and looks in VGC .
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About 120 hours ? I know exactly how many hours mine has run. He's only just bought the boat. My advice is to change the belt. You can advise what you like, it isn't your engine and you don't have to risk anything by giving advice to ignore it.

 
The M80 looks very similar to my MD22, aka M50. Our boat and engine were launched in 2001 and the timing belt never changed until I've done it last winter. Unknown engine hours, but quite a few. Belt was in good condition, but like on skipper_stu's engine, the idler pulley (changed along with the belt and the tensioner pulley) was seeping grease. Wouldn't worry unduly, and you can inspect the pulley condition visually by only removing a few bits - should give you a hint of the engine hours too.

Doing it is a few hours of work. The Haynes manual has useful advice, as has this article, and probably skipper_stu :)

Since I couldn't lay my hands on a belt tension gauge in Portugal, I did some measuring, counting and a bit of math and acoustically checked/adjusted the timing belt tension with the help of a free guitar tuning app on my phone. This was fun and worked very well. Apparently that's how it's done in workshops these days.
 
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