want a good belt

[gaggle]

last winter during the coldest spell when we had the snow ect one ot the belts on my engine stripped the rubber from the inner part that is in contact with the pulley wheel,it came of the pully and an alarm alerted me i had a problem,alternater not working.

now after a couple of frosts the belt i put on to replace it has gone and done the same but snapped completely,the inner rubber had again stripped off.

would the belt be getting frozen to the pulley to cause this or do belts not last long anyway.

i had a new belt supplied by shire ready this time although the one i used as a replacement the first time was from halfords supposed to be the same in everything but name.

the play in the belt is as advised in the manual,about an inch up and down in the middle of the longest run between pullies.

[DHutch]

Is this just a standared (non-toothed) V-belt?

- What size alternator(s) is it driving, and i assume these are the stock alternators.

- Are the pulleys perfectly parrallel, and compleatly axially alined and true?

 

 

Daniel

[John Orentas]

Hi Gaggle.

 

There are a few elements to this, it is unlikely that the belt froze to the pulley but if the rubber was very cold it could conceivably have not been able to flex as it should, but on balance I suspect it was just co-incidence.

 

More than once on the forum it has been apparent that belts on boats have a much shorter life than similar applications on a car or van. My personal view is that:-

 

a. Alternators on boats work harder that those on road vehicles so for that reason alone it is not surprising they and their drive belts don't last as long.

 

b. On a road vehicle the alternator and it's drive belt are exposed to a constant stream of cold air. In the engine compartment of a narrowboat there is often much less ventilation, everything including the belt runs that much hotter and belt life may be reduced.

Edited November 7, 2006 by John Orentas

[gaggle]

the inner of the belt is ribbed like teeth and i dont know the size alternator,the engine is new fitted (12 moons) so it should be aligned,i can see no wobble while it is running and the engine is still solid on its fixings.

i kept the first belt to go and it looks like it has stripped off the inner rubber in much the same way as the second,about 4 inch space on belt teeth have come off the canvas in full,that is why i wondered if just a bit in direct contact with the pulley had frozen on to it.

back at the boat tomorrow morning and i will picture the belts.

[John Orentas]

That appearance of notches cut into the 'V' of the belt are just to allow the belt to flex more easily.

[Yoda]

the inner of the belt is ribbed like teeth and i dont know the size alternator,the engine is new fitted (12 moons) so it should be aligned,i can see no wobble while it is running and the engine is still solid on its fixings.

i kept the first belt to go and it looks like it has stripped off the inner rubber in much the same way as the second,about 4 inch space on belt teeth have come off the canvas in full,that is why i wondered if just a bit in direct contact with the pulley had frozen on to it.

back at the boat tomorrow morning and i will picture the belts.

 

Gaggle you need to check the pulleys to see if there are any rough bits inthe V section. Something probably mechanical is damaging these belts. When you look at the engine, side on are the belts running inline?

[DaveR]

The other thing to look at is the depth of the pulleys. Sometime if there is not enough depth for the belt to sit in the groove then the belt can belly out and wear from the side.

[Dr Bradley]

I have read somewhere recently, though having searched I cannot find it, (perhaps I read too much), that a certain engine - 43hp if I remeber right, has a problem with faulty pulleys destroying belts. Could this be the problem and can anyone else find the thread - I think it was on this forum. (Daniel - you seem able to find any thread needed - help).

[Mick and Pauline]

I have read somewhere recently, though having searched I cannot find it, (perhaps I read too much), that a certain engine - 43hp if I remeber right, has a problem with faulty pulleys destroying belts. Could this be the problem and can anyone else find the thread - I think it was on this forum. (Daniel - you seem able to find any thread needed - help).

 

Hi Doc,

 

I think you are refering to a batch of ISUZU engines that came on the market earier this year with drive pullies not machined properly and were chewing up belts.

[Crazy Scheme]

We have a yanmar barrus shire (just 5 y.o), had the engine serviced recently, but the last drive belts teeth lasted very little time. Had the boat 5 months and we are on our third drive belt! Haven't had the engine looked at again yet, it was impossible during the cruising season as everyone was too busy!

[Guest]

Our Vetus certainly hammers drive belts. I would question whether the belts fitted on many engines are up to powering 90Amp plus alternators. The Vetus has just one 3/8inch drive belt. I'll probably have Vetus on my case again for posting that

[DHutch]

Yeah, it seams fairly standard for the belts not to last very long.

- I think as catweasal has suggested, the belts, which where proberbly origanly spec'ed for somthing like a 35/40amp alternator used mainly for just toping up the start battery, are now less than totalty suitable for powering the 90/120/160amp alternators now fitted, espically with batterybank size and usage climbing all the time, and then often the use of alternator boosters ontop of that, and often also spining the origanal 'starter' alterntor too.

 

 

Daniel

[Tony Brooks]

We have a yanmar barrus shire (just 5 y.o), had the engine serviced recently, but the last drive belts teeth lasted very little time. Had the boat 5 months and we are on our third drive belt! Haven't had the engine looked at again yet, it was impossible during the cruising season as everyone was too busy!

 

I bet thsi is one of thir first twin alternator engines!

 

Only a prat (in my view) would try to run a V belt over 4 pulleys and expect no problems. Traditionally we expect to put a single V belt over about 1/3 of the pully for maximum drive. To try to drive 4 pulleys is asking for slip, wera and short belt life.

 

The other problem with these engines is with belt loading. Ford came unstuck when they fitted soem 90 amp alternators with singfle V belts to their cars. A short life an dfrequent adjustment ensued, especially with poorer quality belts. I expect these twin alternator engiens are using a 60 or 70 amp alternator for the domestic battery and about a 35 amp one for the engine battery. In my view thei sipushing your luck with just three pulleys, let alone four.

 

 

You could try finding an industrial supplier of V belts to factories and buy the best quality they offer. The only real "cure" is either to fit an additional crankshft pully and alter the position of one alternator to suit and drive it through another belt. If that sounds too expensive get a shorter belt and only drive the domestic alternator. Fit a split charge relay so both batteries are charged.

 

 

Sorry to be a pesimist

 

Tony Brooks

[Crazy Scheme]

Your comments are really interesting, I think you might be the first person to shed some light on our situation. Thanks!

 

After all, we had the engine serviced and they couldn't find anything wrong, in that nothing was misaligned.

 

Regarding these drive belts, do you have any pointers on how/where we'd be able to get an industrial quality v belt? Where does one start, what does one ask for? <scratches head>

[gaggle]

We have a yanmar barrus shire (just 5 y.o), had the engine serviced recently, but the last drive belts teeth lasted very little time. Had the boat 5 months and we are on our third drive belt! Haven't had the engine looked at again yet, it was impossible during the cruising season as everyone was too busy!

this is the name/type of engine i have , barrus yanmar 45 hp.

it has two belts on what must be two alternators one thicker than the other and it is the thin one that has give the problems.

[Yoda]

Your comments are really interesting, I think you might be the first person to shed some light on our situation. Thanks!

 

After all, we had the engine serviced and they couldn't find anything wrong, in that nothing was misaligned.

 

Regarding these drive belts, do you have any pointers on how/where we'd be able to get an industrial quality v belt? Where does one start, what does one ask for? <scratches head>

 

It is true that plain flat belts and V shape belts are no good at higher horse powers than drawn by a small alternator and water pump. The answer is to use square toothed belts which will not slip and will take the load of two alternators. These belts require toothed pullies and are available in industry. I haven't yet done a search. They are used on cars for such things as air con and superchargers.

[Crazy Scheme]

this is the name/type of engine i have , barrus yanmar 45 hp.

it has two belts on what must be two alternators one thicker than the other and it is the thin one that has give the problems.

 

Ours has one belt, two alternators and four pulleys, like Tony mentioned.

[Yoda]

Ours has one belt, two alternators and four pulleys, like Tony mentioned.

 

I personally would not have a one belt setup. Two belts can give you some redundantcy and share the total load as well.

[david and julie]

Regarding these drive belts, do you have any pointers on how/where we'd be able to get an industrial quality v belt? Where does one start, what does one ask for? <scratches head>

You could do a lot worse than having a chat to Fenner, you can search for a local branch here.

 

http://www.fptgroup.com/index/index.asp

[Split Pin]

Hi was pointed in the direction of this forum a few days ago so here my first contribution

 

Re Industrial Drive, belts from the info already give somewhere above the designation would either be a "Z" or "SPZ". The "Z" is 10mm top width and 6mm thick, the "SPZ" is 10mm top width and 8mm thick and as you might expect the "SPZ" can transmit more power. From memory the included angle of the Vee is 72 Deg. A single SPZ has a power rating of 2.8Kw at 5000 rpm when driving a 67mm PCD pulley. this drops to 1Kw at 1200 rpm these figures apply if the arc of contact between the belt and pulley is 180 deg, this drops to 70% if the arc is 90 deg. the minimum recommended is 120 deg.

In addition to these conditions we need to add two more service factors one for a speed increase and the other for the type of prime mover, so as a general calculation we have an alternator nominal output of 100amp at 14v. So Watts=VxI in this case 14x100 = 1.4kW. this is the output from the alternator, allow some for mechanical efficiency and you could be looking at an input power requirement of 1.6kW as this is a speed increasing drive a typical value is 1.05 we are now at 1.68kW The prime mover factor would typically be 1.2 this gets us to 2.016kW So depending on pulley contact areas I would be inclined to say that this drive belt is a little marginal on size especially if it is driving other things as well. If I had calculated it I would have either fitted 2 "SPZ" belts or an "SPA" section (next size up 13x10). You may find that the belt that you have fitted is already a "Z" type section but with an automotive part No, I doubt that you will find an industrial belt to be any better made or last longer, a point to note is that engine manufactures sometimes use different belt widths and angles so check carefully.

Toothed Vee belts can generally be used to drive smaller pulleys. They also generate less heat due to bending as they pass round the pulleys. If you observe the wall angles when bent in a small arc you will see that the side angles change due to the compressed material at the bottom and the stretched matl at the top

Obviously with the toothed belt this doesn’t start to happen until very small radiuses are encountered

 

Whilst alignment of pulleys is often given as a major problem for belt life I find that provided that the belt has been sized with some spare capacity they are quite tolerant of misalignment and will continue to work under very poor conditions

Probably the biggest single factor affecting belt life is heat, an overloaded belt may well be slipping (creep)in the pulleys without you being able to detect it so generating heat and fatiguing the core leading to premature failure

 

If you have an alternator management system on as well this will affect the belt life

I have read some where that some engine manufactures will not warranty ther units if a controller is fitted due to belt life problems, this to me indicates that the calculations have been carried out using the wrong criteria as a drive should be able to work at its maximum capacity for at least 16hrs per day

From my 30+ years of working with drives in industry I would say that the belt is undersized for the application

 

Whilst Timing belts as reffered to in a earlier post will transmit more power they are generally wider and the pulleys more difficult to adapt, my own preference is to use Multivee belts, most car manufactures are switching to them and the pulleys are relativley easy to make and adapt

 

Apologies for having gone on a bit hopefully it will make some sense

 

Steve

Edited November 17, 2006 by Split Pin

[PeterF]

Ours has one belt, two alternators and four pulleys, like Tony mentioned.

 

The boat we have just bought has a 4yr old Barrus Shire (Yanmar) 2000 40hp engine using a single drive belt with 50Amp + 80Amp alternators. When I inspected the boat before purchase the belt on the drive had no teeth left and there was loads of rubber powder around the alternators. I thought what a shoddy owner leaving the belt to get into that state but reading this it could easily have caught someone unawares with rapid wear. I am now forwarned and will watch this routinely.

 

Has anybody tried to remedy this at all although as one alternator has no adjustment it would be more difficult to change to 2 indepedent belts - suppose could try and add 2nd pulleys.

 

Joining this forum is reaping benefits, glad I found it.

 

Peter.

 

Ours has one belt, two alternators and four pulleys, like Tony mentioned.

 

The boat we have just bought has a 4yr old Barrus Shire (Yanmar) 2000 40hp engine using a single drive belt with 50Amp + 80Amp alternators. When I inspected the boat before purchase the belt on the drive had no teeth left and there was loads of rubber powder around the alternators. I thought what a shoddy owner leaving the belt to get into that state but reading this it could easily have caught someone unawares with rapid wear. I am now forwarned and will watch this routinely.

 

Has anybody tried to remedy this at all although as one alternator has no adjustment it would be more difficult to change to 2 indepedent belts - suppose could try and add 2nd pulleys.

 

Joining this forum is reaping benefits, glad I found it.

 

Peter.

[Crazy Scheme]

The boat we have just bought has a 4yr old Barrus Shire (Yanmar) 2000 40hp engine using a single drive belt with 50Amp + 80Amp alternators. When I inspected the boat before purchase the belt on the drive had no teeth left and there was loads of rubber powder around the alternators. I thought what a shoddy owner leaving the belt to get into that state but reading this it could easily have caught someone unawares with rapid wear. I am now forwarned and will watch this routinely.

 

Has anybody tried to remedy this at all although as one alternator has no adjustment it would be more difficult to change to 2 indepedent belts - suppose could try and add 2nd pulleys.

 

Joining this forum is reaping benefits, glad I found it.

 

Peter.

The boat we have just bought has a 4yr old Barrus Shire (Yanmar) 2000 40hp engine using a single drive belt with 50Amp + 80Amp alternators. When I inspected the boat before purchase the belt on the drive had no teeth left and there was loads of rubber powder around the alternators. I thought what a shoddy owner leaving the belt to get into that state but reading this it could easily have caught someone unawares with rapid wear. I am now forwarned and will watch this routinely.

 

Has anybody tried to remedy this at all although as one alternator has no adjustment it would be more difficult to change to 2 indepedent belts - suppose could try and add 2nd pulleys.

 

Joining this forum is reaping benefits, glad I found it.

 

Peter.

 

 

Ha! When we bought our boat the drive belt was in EXACTLY the same condition We thought the same as you!

 

After only about 5 hours running, it starts to slip, which is pretty bad. According to our log book, the last belt lasted for 56 hours, about half of that we were cruising, the rest in neutral. It's still usable, but we took it off, the teeth wore off and we were burning diesel and getting hardly any battery charge, so we've put a new one on. Before the engine service, we could wear all the teeth off a drive belt in about 10 hours! I also remember comnig back from central London to North London barely over tickover, which was as fast as we could go without the drive belt slipping! It took us 11 hours!

 

It is such a pain in the ar*e, but at least I know what we can do now, I'm gonna get our engineer to read this thread and we will make a decision on what to change. On the other hand now cruising season is over and people actually have the time to talk to you, I might call the enigne people and see what they say.

 

Hmm.

[John Orentas]

Ha! When we bought our boat the drive belt was in EXACTLY the same condition We thought the same as you!

 

After only about 5 hours running, it starts to slip, which is pretty bad. According to our log book, the last belt lasted for 56 hours, about half of that we were cruising, the rest in neutral. It's still usable, but we took it off, the teeth wore off and we were burning diesel and getting hardly any battery charge, so we've put a new one on. Before the engine service, we could wear all the teeth off a drive belt in about 10 hours! I also remember coming back from central London to North London barely over tickover, which was as fast as we could go without the drive belt slipping! It took us 11 hours!

 

It is such a pain in the ar*e, but at least I know what we can do now, I'm gonna get our engineer to read this thread and we will make a decision on what to change. On the other hand now cruising season is over and people actually have the time to talk to you, I might call the enigne people and see what they say.

 

Hmm.

 

 

Hi Crazy.

 

In your case tightening the belt would help, nothing wears a belt faster that it slipping on it's pulley. When this topic last came up several people said buying good quality belts from Halfords partially cured their problems. Make sure you get the correct width too, the correct size belt should sit a little above the pulley flanges.

 

Also take a look at my previous post re-overheating I am certain that is a major factor.

[chris w]

John

 

the correct size belt should sit a little above the pulley flanges

 

I'm definitely not an expert on belts, but my understanding was that a properly fitted V belt had to sit just below the pulley flanges.

 

Am I wrong in my understanding?

 

Chris

[PeterF]

Hi Crazy.

 

In your case tightening the belt would help, nothing wears a belt faster that it slipping on it's pulley. When this topic last came up several people said buying good quality belts from Halfords partially cured their problems. Make sure you get the correct width too, the correct size belt should sit a little above the pulley flanges.

 

Also take a look at my previous post re-overheating I am certain that is a major factor.

 

John and Chris,

 

I take this to mean that the forces should be borne totally on the sides of the belt and the teeth should be kept clear of the pulley and they should not bear any load on their inner surfaces. The belt on the boat when we got it was quite narrow and I repleced it with like for like but from Halfords and it was sitting deeply in the pulleys - the new one is better but looking at the earlier link to an industrial supplier a wider belt may help to at lengthen belt lives by keeping the teeth away from the pulley but perhaps not cure the problem.

 

Will see what sort of temperature develops in the engine bay on next lengthy cruise.

 

Thanks,

 

peter.