Alternator alignment .

MontyMariner said:
Not sure what alloy you have in mind, but my inclination would be to use steel tube.
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Why ?

The sleeve is just to centre the bolt - it has no structural use at all ... you could use plastic tube and it would still do the job ...

Once the bolts are tightened up - the mount will not move.... the sleeve has done its job.
 
IanCC said:
I am up in Scotland. Yes done all the straight edge stuff. The alternator pulley is slightly twisted otherwise it's correct. I have shim washers down to 0.1mm but not really needed until i can get it straight.
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Twisted on the alternator - or twisted against the straight edge ?

Shims can be used on one or more bolts to alter the 'twist' of the alternator

Are you sure there is not a washer / shim / sleeve missing from your installation ? Or maybe mount arm (if it has such) is not bent ?
 
I must be misunderstanding the issue, the way I'm looking at it I still can't see how a sleeve will alter the twist.
Btw, I can make you a sleeve to your dimensions and prefered material in a couple of minutes and send it to you FOC. Im just confused as to how this is the issue 🙂
 
Refueler said:
Twisted on the alternator - or twisted against the straight edge ?

Shims can be used on one or more bolts to alter the 'twist' of the alternator

Are you sure there is not a washer / shim / sleeve missing from your installation ? Or maybe mount arm (if it has such) is not bent ?
Click to expand...
Thanks for all your input.
colhel said:
I must be misunderstanding the issue, the way I'm looking at it I still can't see how a sleeve will alter the twist.
Btw, I can make you a sleeve to your dimensions and prefered material in a couple of minutes and send it to you FOC. Im just confused as to how this is the issue 🙂
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Very kind thought. Ok. This is a saddle mount alternator so alternator mounting lugs go astride a chunk of the thermostat housing and a long m8 bolt goes through the lot. Two places where there is slack in the system.
First, and biggest, the holes through the alternator lugs, for the m8 bolt are m10. So, as the bolt needs to be slack whilst tensioning the belt, the alternator twists on the bolt to take up the slack between the m8 and the m10. Second and similarly there is some slack in the mount through which the bolt passes. Thus again the alternator has to twist or turn to take up that slack before the belt is tight.
It could be argued that tightening the bolt will true it all up again but it doesn't, i can see the pulleys are not paralell. When i put a straight edge across there is a difference of about 1mm between one side of the pulley and the other.
 
IanCC said:
Thanks for all your input.
Very kind thought. Ok. This is a saddle mount alternator so alternator mounting lugs go astride a chunk of the thermostat housing and a long m8 bolt goes through the lot. Two places where there is slack in the system.
First, and biggest, the holes through the alternator lugs, for the m8 bolt are m10. So, as the bolt needs to be slack whilst tensioning the belt, the alternator twists on the bolt to take up the slack between the m8 and the m10. Second and similarly there is some slack in the mount through which the bolt passes. Thus again the alternator has to twist or turn to take up that slack before the belt is tight.
It could be argued that tightening the bolt will true it all up again but it doesn't, i can see the pulleys are not paralell. When i put a straight edge across there is a difference of about 1mm between one side of the pulley and the other.
Click to expand...
If you put tubes in the holes it will not twist. 10mm copper pipe is 8mm bore, 2 bits of this easy to find material will sort it out.
 
I have a 2GM20F with a recently upgraded alternator and a chronic problem of belt dust. In upgrading the alternator I also noticed it twisting, but I thought the mounting bracket with the slotted hole was out of true. Next time I'm at the boat I'll take a closer look to see if we might have the same issue. So at the moment I'm unable to comment directly on your post.

Many Yanmar owners with similar engines have been reporting belt dust issues. Alternator alignment is one of the causes. Another cause is rust/pitting on the belt pulleys, particularly the fresh water pump, which can be resolved with emery cloth. Regardless, some users have voiced dissatisfaction with the quality of the belts provided by Yanmar. If my notes are correct, the Yanmar belt is actually a Mitsubishi Remf6370. Having upgraded my alternator to an 80A model, I felt it prudent to upgrade the belt as well to ensure that it will cope with the higher loads. I went for the Gates 9380HD, which seems to be the Rolls Royce of engine belts, and priced accordingly. Size-wise the 9380HD is fine, though in my case the 9385HD might've been a slightly better fit due to the larger dimensions of the alternator. There are reports on the internet that moving to the Gates belts eliminates the dust, though it obviously won't fix any alignment problem (which, apart from producing dust, will cause wear to the bearings). I don't have enough engine hours on mine to be able to comment on this personally.
 
sailoppopotamus said:
I have a 2GM20F with a recently upgraded alternator and a chronic problem of belt dust. In upgrading the alternator I also noticed it twisting, but I thought the mounting bracket with the slotted hole was out of true. Next time I'm at the boat I'll take a closer look to see if we might have the same issue. So at the moment I'm unable to comment directly on your post.

Many Yanmar owners with similar engines have been reporting belt dust issues. Alternator alignment is one of the causes. Another cause is rust/pitting on the belt pulleys, particularly the fresh water pump, which can be resolved with emery cloth. Regardless, some users have voiced dissatisfaction with the quality of the belts provided by Yanmar. If my notes are correct, the Yanmar belt is actually a Mitsubishi Remf6370. Having upgraded my alternator to an 80A model, I felt it prudent to upgrade the belt as well to ensure that it will cope with the higher loads. I went for the Gates 9380HD, which seems to be the Rolls Royce of engine belts, and priced accordingly. Size-wise the 9380HD is fine, though in my case the 9385HD might've been a slightly better fit due to the larger dimensions of the alternator. There are reports on the internet that moving to the Gates belts eliminates the dust, though it obviously won't fix any alignment problem (which, apart from producing dust, will cause wear to the bearings). I don't have enough engine hours on mine to be able to comment on this personally.
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Seems to me best to start by getting the pivot correct and shim the adjustor arm after. Shim washers are easy to get hold of.
 
IanCC said:
Seems to me best to start by getting the pivot correct and shim the adjustor arm after. Shim washers are easy to get hold of.
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To be honest I think that I don't have an alignment problem and that the slotted arm bends to meet the alternator without twisting it out of position. But I have to check this when I'm next at the boat. I don't want to hijack your thread with what might be an unrelated non-problem, but I did want to draw your attention to the existence of non-Yanmar belts which might help with any belt dust issue that remains after you have sorted out your alignment issue.
 
sailoppopotamus said:
I have a 2GM20F with a recently upgraded alternator and a chronic problem of belt dust. In upgrading the alternator I also noticed it twisting, but I thought the mounting bracket with the slotted hole was out of true. Next time I'm at the boat I'll take a closer look to see if we might have the same issue. So at the moment I'm unable to comment directly on your post.

Many Yanmar owners with similar engines have been reporting belt dust issues. Alternator alignment is one of the causes. Another cause is rust/pitting on the belt pulleys, particularly the fresh water pump, which can be resolved with emery cloth. Regardless, some users have voiced dissatisfaction with the quality of the belts provided by Yanmar. If my notes are correct, the Yanmar belt is actually a Mitsubishi Remf6370. Having upgraded my alternator to an 80A model, I felt it prudent to upgrade the belt as well to ensure that it will cope with the higher loads. I went for the Gates 9380HD, which seems to be the Rolls Royce of engine belts, and priced accordingly. Size-wise the 9380HD is fine, though in my case the 9385HD might've been a slightly better fit due to the larger dimensions of the alternator. There are reports on the internet that moving to the Gates belts eliminates the dust, though it obviously won't fix any alignment problem (which, apart from producing dust, will cause wear to the bearings). I don't have enough engine hours on mine to be able to comment on this personally.
Click to expand...

I have same engine but raw water cooled and no dust ... runs true and sweet .... nothing mod'd ...

dApSjBpl.jpg
 
Refueler said:
Why ?

The sleeve is just to centre the bolt - it has no structural use at all ... you could use plastic tube and it would still do the job ...

Once the bolts are tightened up - the mount will not move.... the sleeve has done its job.
Click to expand...
You are probably right, as my experience was from a D reduction tube on the pivot side of the alternator and over time the hole through the tube became oval, probably due to vibration and a torque load on the bolt.
It's just made me a bit cautious so I tend to over engineer.
 
DinghyMan said:
Alternator Replaces Yanmar 2GM20 2GMF 2GMFL 2GMFY 2GML 2GMYEwith W Terminal shows a nice dimension picture of the alternator

And it shows the bush in one side of the alternator mounting
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D of the hole and an I.D of the bolt would do the job. The OP does seem not to understand as he claims not to be an engineer but its a simple fit requiring little engineering skill IMHO

Here is a post about and alternator pivot bush alignment

Alternator Pivot Bolt Bushing

Here's another about alternator alignment and bushing

Alternator Alignment - Trawler Forum

The OPs other thread posted about oval holes and I told him have to open the holes up to cllow bushing as described above
 
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