wiggy
Well-known member
Why does my belt need constant adjusting?
VP2020D Alternator Belt Wear
- Thread starter wiggy
- Start date
SaltyC
Well-known member
Hmmm, thinking alignment? any black dust?
I ran a 2020 for 11 years and never needed to adjust the belt tension.
Subsequently have a Yanmar 4J4E and it needs adjusting 4 times a year and distributes black particles everywhere eating a belt every year.
I am advised by a Yanmar agent 'normal for that engine'???!!!!
I ran a 2020 for 11 years and never needed to adjust the belt tension.
Subsequently have a Yanmar 4J4E and it needs adjusting 4 times a year and distributes black particles everywhere eating a belt every year.
I am advised by a Yanmar agent 'normal for that engine'???!!!!
wiggy
Well-known member
I do get lots of black dust.
SaltyC
Well-known member
I have not yet found the solution with the Yanmar.
SaltyC
Well-known member
Sorry, not very helpful. The 2020 DID not wear belts. The Yanmar does, I have checked alignment and seems OK, my boat was one of the first with an uprated Alternator Circa 70 to 120 Amp. Hence a lot more load. My assumption is there is insufficient friction on the belts for the load giving slippage and black dust.
Seemingly I can get new pulleys for flat high torque belts (still researching), however, if MD2020 is standard fit would check alignment first.
Seemingly I can get new pulleys for flat high torque belts (still researching), however, if MD2020 is standard fit would check alignment first.
penfold
Well-known member
As already noted; check the basics, alignment of pulleys, burrs or damage to pulleys that will wear the belt, quality of belt, is it a spare that's been stored incorrectly. Are you tensioning it properly? Describe the method you use.
Some installations just seem to eat belts, smaller Beta Marine engines went through a phase of that in the 90s and eventually Beta offered a polyvee belt/pulley conversion kit. Some find that changing to a cogged belt helps in marginal installations as they are more flexible than plain vee belts which helps with resisting slip.
Some installations just seem to eat belts, smaller Beta Marine engines went through a phase of that in the 90s and eventually Beta offered a polyvee belt/pulley conversion kit. Some find that changing to a cogged belt helps in marginal installations as they are more flexible than plain vee belts which helps with resisting slip.
Seastoke
Well-known member
If your tensioner pully is plastic it might need replacing .
scottie
Well-known member
At this time of year Christmas puddings?
PeterWright
Well-known member
Many possible answers:
Insufficiently tensioned, so it slips
Alignment - are any of the pulleys out of line?
Rusty pulleys - rust on the working surfaces of the lulley work like a grindstone on the belt
Asking the belt to deliver more torque than it is designed for. The most common cause of this is fitting a bigger alternator or fitting a smart regulator to the existing alternator. A standard alternator only delivers its rated output at leak revs. A smart controller will cause it to produce nearr peak output at all revs, making your battery charge faster at tickover and cruising revs. Now power = torque x revs, so to get the rated alternator power at 800 rlm tickover requires 3.5 times the torque nneeded to get the same power from the a,ternatir at 2800 rlm max rated engine power. No wonder the belt slips and produces black dust, usually screaming in pain as it does so.
Of course, it could just be that the engine designer asked the belt to take on more than it can - that, in my view, makes the engine not of merchantable quality!
Peter
Insufficiently tensioned, so it slips
Alignment - are any of the pulleys out of line?
Rusty pulleys - rust on the working surfaces of the lulley work like a grindstone on the belt
Asking the belt to deliver more torque than it is designed for. The most common cause of this is fitting a bigger alternator or fitting a smart regulator to the existing alternator. A standard alternator only delivers its rated output at leak revs. A smart controller will cause it to produce nearr peak output at all revs, making your battery charge faster at tickover and cruising revs. Now power = torque x revs, so to get the rated alternator power at 800 rlm tickover requires 3.5 times the torque nneeded to get the same power from the a,ternatir at 2800 rlm max rated engine power. No wonder the belt slips and produces black dust, usually screaming in pain as it does so.
Of course, it could just be that the engine designer asked the belt to take on more than it can - that, in my view, makes the engine not of merchantable quality!
Peter
kippers26
Member
Changed my alternator belt at the start of the season and after the initial adjustment it has been reset at least 4 times. Replacement belt is a cogged PIX branded belt. Are there superior makes of belt and if so which Brands should I look for ?
Boater Sam
Well-known member
Running an alternator bigger than 90A @12v on a single Vee belt is always going to over stress the belt even if it is cogged and on clean pulleys. The slightest misalignment in any plane of even one pulley will make it much worse.
I find the modern single swivel bolt mounted alternators are often out of line when under load even if tight. I have had multiple bolt fractures with these flexing under load.
Gates belts seem better than most. The old Fenner belts were good but seem to be unavailable now.
I find the modern single swivel bolt mounted alternators are often out of line when under load even if tight. I have had multiple bolt fractures with these flexing under load.
Gates belts seem better than most. The old Fenner belts were good but seem to be unavailable now.
coopec
N/A
Well that was my understanding too "Running an alternator bigger than 90A @12v on a single Vee belt is always going to over stress the belt" . I believed that so I mounted twin "V" belt pulleys.
An experienced guy on the forum said he had never had problems and he had a 100A (12V) alternator. After some discussion we decided he could get away with it because he had a lot of "wrap" on his alternator pulley.
If the alternator belt also powers the water pump maybe there is insufficient "wrap".
How much "wrap" here?
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Porthandbuoy
Well-known member
Last year was my first season on the new boat with a Yanmar 4J3E engine. Lots of black dust and belt adjustment required. Alignment is good, pulley condition good and alternator mounts aren’t slackening off. It has a Balmer alternator. If memory serves it is 80A, only 10A more than standard but with a smart controller that allows it to charge the batteries quicker. Next season I’m going to try a cogged belt, and if that doesn’t help I’ll convert all the pulleys and fit a multi-v belt.
coopec
N/A
Beneteau381
Well-known member
I had a similar issue with a 2030. I swopped it for a Gates "toothed" belt and it solved the problem.
Porthandbuoy
Well-known member
All things are possible if you have the engineering expertise and tooling. I don’t have much of the former and very little of the latter. Worth considering though.
penfold
Well-known member
Another option is double vee belts, although this is dependent on there being room for the longer pulleys; it does have the advantage of using vee belts which are generally easier to obtain if you are somewhere less well connected.
coopec
N/A
An idler pulley might be the simplest way of solving the problem. ( I'd look at doing that first) Can you talk to the Yanmar people to see if they have a solution?
When you talk of changing to multi "V" pulleys that can be a big job. Boring the pulley blanks, cutting the keyways? (?) (Been there, done that)
You would need a double "V" pulley on the crankshaft, water pump(?) and the alternator. You are no doubt looking at $500+++ to get someone to do it for you and fit it.
V belt tensioner for sale | eBay
PetiteFleur
Well-known member
Definitely try a Gates CRE Belt (Cogged Raw Edge) as they transmit more horse power than a standard vee belt. Years ago I had this on a different non boat related problem and they solved the problem of belts not working.
Daydream believer
Well-known member
I have the same engine & the same problem initially. Standard alternator. Just basic electrics.The tension arm has to be adjusted fairly hard & I used to do this with the aid of a small crow bar inserted between engine & alternator. Then do the bolt up tight. After 80 hours ( which would be a couple of times a year) the belt would slip & I would hear it squeal on start up. I had to throttle back & rev slowly after starting so it gripped better.
I determined that what was happening was that the standard belt was bottoming on the "V" of the pulley. This stopped the belt from gaining friction on the sides of the belt. It slipped & wore more of the side & the issue just got worse.
My solution was to buy a wider pattern belt. We have a belt supplier near us so I was able to drop in & chat to the assistant. (Who just happens to sail a Phantom like my son & I) He sorted me the belt & being wider it was a bit of a job to force over the pulley. But once on it fitted OK . It initially rode up on the outer circumfrence of the pullies.
It grips well & I only have to adjust at the start of each season. I motor a lot so that is about 200 hours PAnnum by the time I have been up the Dutch canals etc.( much less in covid time)
I am pretty sure that the belt I bought is AVX13X800 & I fitted it April 2018 & it is still in use.
I determined that what was happening was that the standard belt was bottoming on the "V" of the pulley. This stopped the belt from gaining friction on the sides of the belt. It slipped & wore more of the side & the issue just got worse.
My solution was to buy a wider pattern belt. We have a belt supplier near us so I was able to drop in & chat to the assistant. (Who just happens to sail a Phantom like my son & I) He sorted me the belt & being wider it was a bit of a job to force over the pulley. But once on it fitted OK . It initially rode up on the outer circumfrence of the pullies.
It grips well & I only have to adjust at the start of each season. I motor a lot so that is about 200 hours PAnnum by the time I have been up the Dutch canals etc.( much less in covid time)
I am pretty sure that the belt I bought is AVX13X800 & I fitted it April 2018 & it is still in use.
