alternators

[Hawkmoth]

Can anyone help? I have a Vetus 4.17 engine in my boat. This drives a standard (?) alternator and a Travel Power 3.5 Kva unit. I would like to fit a 200 amp/h alternator which I have purchased in order to charge my second set of batteries. This alternator is of course larger than the standard one fitted at the moment, and also requires a poly V belt like the one used on the Travel Power. Is there anyone out there who has done this mod and could advise?

[Guest]

Can anyone help? I have a Vetus 4.17 engine in my boat. This drives a standard (?) alternator and a Travel Power 3.5 Kva unit. I would like to fit a 200 amp/h alternator which I have purchased in order to charge my second set of batteries. This alternator is of course larger than the standard one fitted at the moment, and also requires a poly V belt like the one used on the Travel Power. Is there anyone out there who has done this mod and could advise?

I can sort of offer some input on this as I got half way through doing this on a Vetus 415, but not finihed yet. I made a second crank pulley which bolts over the exisitng one using the tapped holes in the exisiting pulley. i have made some threaded "pillars" for the want of a better word, which will replace the main engine mounting nuts on the left hand side of the engine (same as existing alternator). A piece of box section will run along these with a second alternator mounted on it. I would suspect that a polybelt pulley off a car could be modified to fit onto the existing pulley n a similar manner. It is one of those jobs I cant seem to get finished

Please pm if you need any further details

[Timleech]

I can sort of offer some input on this as I got half way through doing this on a Vetus 415, but not finihed yet. I made a second crank pulley which bolts over the exisitng one using the tapped holes in the exisiting pulley. i have made some threaded "pillars" for the want of a better word, which will replace the main engine mounting nuts on the left hand side of the engine (same as existing alternator). A piece of box section will run along these with a second alternator mounted on it. I would suspect that a polybelt pulley off a car could be modified to fit onto the existing pulley n a similar manner. It is one of those jobs I cant seem to get finished

Please pm if you need any further details

 

What centres your second pulley to the crankshaft?

 

Tim

[Hawkmoth]

I can sort of offer some input on this as I got half way through doing this on a Vetus 415, but not finihed yet. I made a second crank pulley which bolts over the exisitng one using the tapped holes in the exisiting pulley. i have made some threaded "pillars" for the want of a better word, which will replace the main engine mounting nuts on the left hand side of the engine (same as existing alternator). A piece of box section will run along these with a second alternator mounted on it. I would suspect that a polybelt pulley off a car could be modified to fit onto the existing pulley n a similar manner. It is one of those jobs I cant seem to get finished

Please pm if you need any further details

Thanks Cat. That 's about where I was thinking. A car pulley may be a bit too small in diameter because the engine usually revs slowly so the Travel Power has a large drive wheel on the crank to turn the alternator faster. My prefrered option is to try to use the present polybelt drive pulley and fit some form of jockey wheels to ensure that the belt goes around both driven pulleys properly, and tightly.

[Guest]

What centres your second pulley to the crankshaft?

 

Tim

That was one of the first problems but I did some research. I noticed that other manufactures just used the bolts to centre the second pulley (three in total) so decided that would be OK. The holes are reamed, and were centred on my trusty lathe at work. i have fitted the pulley for trials, and using a DTI I had a runout of just under 2 thou IIRC.

Comments welcome!

 

Thanks Cat. That 's about where I was thinking. A car pulley may be a bit too small in diameter because the engine usually revs slowly so the Travel Power has a large drive wheel on the crank to turn the alternator faster. My prefrered option is to try to use the present polybelt drive pulley and fit some form of jockey wheels to ensure that the belt goes around both driven pulleys properly, and tightly.

I see. How is the polybelt pulley fastened to the crank pulley on your engine presently?

[charles123]

I undertstand that vetus now offer a second alternator set up though I have not yet seen one, you could try Kings Lock Chandlery at Middlewich for advice

 

Charles

[Guest]

This issomething like the pulley I have made

 

[Timleech]

This issomething like the pulley I have made

 

I hope you've got a better pulley ratio than that, otherwise you might struggle to get much out of your alternator.

 

Tim

[Guest]

I hope you've got a better pulley ratio than that, otherwise you might struggle to get much out of your alternator.

 

Tim

Agreed. I have made the pulley larger in dia than the original (6" I think). That one in the picture is way too small I believe. I was demonstrating the bolting method, and would be interested in comments from anyone who has more engineering background than I. It was a Beta engine upon which they had bolted the second pulley in this fashion that first gave me the idea.

 

 

 

More like it!

 

Edited August 29, 2008 by Guest

[Timleech]

Agreed. I have made the pulley larger in dia than the original (6" I think). That one in the picture is way too small I believe. I was demonstrating the bolting method, and would be interested in comments from anyone who has more engineering background than I. It was a Beta engine upon which they had bolted the second pulley in this fashion that first gave me the idea.

 

 

 

More like it!

 

 

 

I wonder why they have gone for such large pulleys?

One of the great things about polyvee is that it will run OK over much smaller pulleys than will an ordinary Vee belt, yet they have stuck to 'ordinary vee belt' diameters. I can't see why, unless it's a very high output alternator. I also wonder whether they (whoever they may be) have checked with the engine manufacturers about hanging all that undamped inertia on the front of the crankshaft, that style of solid pulley is quite heavy?

 

Edited to add that the crankshaft pulley could be aluminium in which case I wouldn't be quite so concerned, pulleys like that bought over the counter are generally cast iron.

 

Tim

Edited August 29, 2008 by Timleech

[Justme]

Edited to add that the crankshaft pulley could be aluminium in which case I wouldn't be quite so concerned, pulleys like that bought over the counter are generally cast iron.

 

Tim

 

 

Could also be machined out on the reverse side to reduce weight.

If not would not take long to drill it full of holes on a bench drill press. Or even use a hole cutter.

 

Justme

[PeterF]

Hi,

 

I increased the 80A domestic alternator on my Barrus Shire 40 to a Sterling 140A unit (Stelring rebadged AC Delco). Rather than using the poly Vee pulley on the alt they also supplied a twin V belt. Thorneycroft sell a twin V belt pulley about 200mm diamete so with standard 65mm pulley on the alt you get a 3:1 drive ratio and the full 140A out of the alt with engine at 1000rpm. I had to get a local machine shop to alter the rear of the Thorneycroft pulley so it fitted. The existing pulley on my engine had the 3 threaded holes but also had a small boss so I got the rear of the new pulley machiend to sit over the boss.

 

I have put together some info for another person on the forum to do the same to his Shire engine, I know the Vetus will not be the same as a lot is engine specific but if you want some general info them PM me your email address and I will email you the info on my mods.

 

Link to earlier post about my mods. Large alternator on Shire engine

 

Some pictures below. First shows general view of the new alt. "nd one shows the new pulley from Thorneycroft machined to fit onto the existing pulley and you can see new pulley much larger. FInal one shows side view of the new belt runs.

 

 

 

 

Best of luck with any mods,

 

Peterf

[bottle]

I wonder why they have gone for such large pulleys?

One of the great things about polyvee is that it will run OK over much smaller pulleys than will an ordinary Vee belt, yet they have stuck to 'ordinary vee belt' diameters. I can't see why, unless it's a very high output alternator. I also wonder whether they (whoever they may be) have checked with the engine manufacturers about hanging all that undamped inertia on the front of the crankshaft, that style of solid pulley is quite heavy?

 

Edited to add that the crankshaft pulley could be aluminium in which case I wouldn't be quite so concerned, pulleys like that bought over the counter are generally cast iron.

 

Tim

 

Hi Tim

 

The engine is a Beta Marine and they fit as standard a 45amp and a 150amp alternators.

[Timleech]

Hi Tim

 

The engine is a Beta Marine and they fit as standard a 45amp and a 150amp alternators.

 

OK, if it's an outfit of the size of Beta I'm sure they will have checked the inertia question. I still wonder whether they could have used smaller diameter polyvee pulleys without any detriment.

 

Tim

[bottle]

Not qualified to be able to comment but a thought if it is 'over engineered' it may make it better on belt and bearing wear.

[Guest]

Hi,

 

I increased the 80A domestic alternator on my Barrus Shire 40 to a Sterling 140A unit (Stelring rebadged AC Delco). Rather than using the poly Vee pulley on the alt they also supplied a twin V belt. Thorneycroft sell a twin V belt pulley about 200mm diamete so with standard 65mm pulley on the alt you get a 3:1 drive ratio and the full 140A out of the alt with engine at 1000rpm. I had to get a local machine shop to alter the rear of the Thorneycroft pulley so it fitted. The existing pulley on my engine had the 3 threaded holes but also had a small boss so I got the rear of the new pulley machiend to sit over the boss.

 

I have put together some info for another person on the forum to do the same to his Shire engine, I know the Vetus will not be the same as a lot is engine specific but if you want some general info them PM me your email address and I will email you the info on my mods.

 

Link to earlier post about my mods. Large alternator on Shire engine

 

Some pictures below. First shows general view of the new alt. "nd one shows the new pulley from Thorneycroft machined to fit onto the existing pulley and you can see new pulley much larger. FInal one shows side view of the new belt runs.

 

 

 

 

Best of luck with any mods,

 

Peterf

I am interested in the way you fitted the new pulley over the existing one, and how there was a boss on the pulley. I dont believe I can do that on mine. Am I pushing my luck by elying on 3 x 10mm shouldered bolts inside reamed holes to "clamp" the new pulley to the existing one? I likened it to car wheels where some do have to be centred on a boss on the hub, but some dont and rely on just the bolts. I would be interestd in any comments.

[Timleech]

I am interested in the way you fitted the new pulley over the existing one, and how there was a boss on the pulley. I dont believe I can do that on mine. Am I pushing my luck by elying on 3 x 10mm shouldered bolts inside reamed holes to "clamp" the new pulley to the existing one? I likened it to car wheels where some do have to be centred on a boss on the hub, but some dont and rely on just the bolts. I would be interestd in any comments.

 

If it runs true, and if it's clamped solidly against something which won't 'give' or distort under load, I should think you will be OK. Much better if you can arrange some sort of a register, though. Could you use the OD of the existing pulley, if that runs true and has a clean enough edge? There might be enough of a land on the edge of the pulley that your second pulley could overlap this enough to give a register function without interfering with the original belt.

 

Tim

[PeterF]

I am interested in the way you fitted the new pulley over the existing one, and how there was a boss on the pulley. I dont believe I can do that on mine. Am I pushing my luck by elying on 3 x 10mm shouldered bolts inside reamed holes to "clamp" the new pulley to the existing one? I likened it to car wheels where some do have to be centred on a boss on the hub, but some dont and rely on just the bolts. I would be interestd in any comments.

I hope this drawing helps. The original pulley on the engine had a boss about 90mm diameter on the front. The 3 threaded holes were within this boss. The pulley I bought from Thornycroft had a large boss on the back which did not fit my engine, so I had that machined off so the new pulley sat the right distance in front of the original pulley, then I had a recess machined into the boss that was a clearance fit above the 90mm. So the new pulley actually sits over the boss as the centre. The pulley is cast aluminium so it would not be as bad as a steel pulley if it was not fully true. If you look closley in the middle picture of my instalaltion you will see that the new pulley does not sit hard against the old pulley at the outer edge, this is because the face os the recesss is sitting hard against the face of the boss and I had the recess machined shallower than the boss because I used the face of the boss as my datum.

 

Edited August 30, 2008 by PeterF

[Guest]

Thanks Timleech and PeterF. That all amkes sense and I think I have a cunning plan for registering it

[Eeyore]

Thanks Timleech and PeterF. That all amkes sense and I think I have a cunning plan for registering it

Just thinking out loud - If the pully came from Thorneycroft it probably fits a Mitsubishi, and the Vetus is a Mitsubishi. Or did I miss that in between all the pictures.

Steve

[John Orentas]

I have a new spare crankshaft pulley if anyone can make use of it:

 

Overall diameter.................. 162mm

Max 'V' width ........................ 12

4 x fixing holes ...................... 9 dia

PCD .....................................40

Centre hole ..........................25 dia

 

Fits the standard 'V' belts which I used to describe as 13mm width.

 

Free to good home.