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flatplane8

JP/JK pulley

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Hi,

 

What size pulleys have people successfully fitted to JP/JKs? I'm looking at larger sizes to drive an alternator and possibly a 240v generator. This would be crankshaft mounted via a taperlock. I currently run our alternator from the flywheel rim via a belt, but this won't be a great option with our JK4, as the flywheel will be close coupled to a gearbox. I realise I could still use this method, but it would be nice to avoid breaking the coupling to change belts.

 

Large (400-630mm dia.) pulleys are readily available, but they are between 12-20kgs in weight and I my not sure if this would be an issue on the end of the crankshaft.

 

I've seen alternators driven by little rubber wheels from the rim of the flywheel, does anyone have any experience with such a setup?

 

Thanks,

 

Simon

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I didn't bother with a pulley I just ran the belt round the flywheel in the V made by the starter ring gear. Means there is a 45deg twist in the belt but it didn't matter. @frangar of this forum has the same setup.

There are belts that will allow you to break the belt to replace it (fenner)

Edited by Loddon

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Thanks, I use nutlink belting elsewhere. It won't work when run directly onto a flywheel, as the metal pins skate across the surface under load (ask me how I know...… :)

 

I currently run our alternator directly off the flywheel as you describe, but this won't be ideal with JK4.

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If there is a starter ring could you mount a cog on the alternator machined to match the ring gear?

 

ETA when I added a 12" pulley to the end of the crankshaft on the Ford in the barge it was aluminium and weighed very little. Cost a bit mind.

Edited by Loddon

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Size of pulley on the crank will depend on the size of the pulley on the alternator or vice versa (Depending on which you already have) to get the best speed match, not to slow, but equally doesnt overspeed the alternator at higher engine speeds. So to do the job properly first you need the output curve for your alternator model which will give you the max speed and the speed it excites.

 

We normally gear them so you are just short of max speed with the engine flat out which gives you the best possible output at tickover.

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20 hours ago, flatplane8 said:

Thanks, I use nutlink belting elsewhere. It won't work when run directly onto a flywheel, as the metal pins skate across the surface under load (ask me how I know...… :)

 

I currently run our alternator directly off the flywheel as you describe, but this won't be ideal with JK4.

I wonder if adhesive technology has come on enough to be able to cut then rejoin the belt?

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31 minutes ago, philjw said:

I wonder if adhesive technology has come on enough to be able to cut then rejoin the belt?

You can get round polyurethane belting which can either be welded or a connector fitted to form a complete loop in situ e.g. https://store.lathes.co.uk/belts/hollow-round-plastic-belting or 

https://www.stationaryengineparts.com/Polyurethane-Round-Belting/

  • Greenie 1

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2 hours ago, martyn 1 said:

Size of pulley on the crank will depend on the size of the pulley on the alternator or vice versa (Depending on which you already have) to get the best speed match, not to slow, but equally doesnt overspeed the alternator at higher engine speeds. So to do the job properly first you need the output curve for your alternator model which will give you the max speed and the speed it excites.

 

We normally gear them so you are just short of max speed with the engine flat out which gives you the best possible output at tickover.

Thanks, our current arrangement driven from the flywheel does this so we can go pretty large on any pulley. My question is more around adding 14-20kg of rotating mass on the crankshaft. But I guess that's tiny compared to a JP/JK flywheel. :)

 

Thanks for the other suggestions, I'm not sure round belting would suit alternator drives but will check it out.

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On 03/12/2018 at 18:18, Loddon said:

I didn't bother with a pulley I just ran the belt round the flywheel in the V made by the starter ring gear. Means there is a 45deg twist in the belt but it didn't matter. @frangar of this forum has the same setup.

There are belts that will allow you to break the belt to replace it (fenner)

My alternator belt just runs flat on the flywheel...it’s a standard vee belt powering a 70a 12v alternator....no machined groove or twist....worked just fine for the last 25 years...I do change the belt every couple of years just to be safe as it’s only driving on the bottom face on the flywheel..it can get a bit shiny but it doesn’t squeak or get warm...even though the wrap on the alternator pulley isn’t probably as great as it could be but even with a proper pulley on the flywheel you might need an idler pulley to achieve that.  

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18 hours ago, flatplane8 said:

I'm not sure round belting would suit alternator drives but will check it out.

It should be fine in a standard  V pulley. My father uses one to drive a lathe.

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40 minutes ago, David Mack said:

It should be fine in a standard  V pulley. My father uses one to drive a lathe.

Thanks, I'll check it out, it would be a solution if it worked ok driving an alternator.

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14 inch pulley gives max output (240 amps) from my two alternators @ 650 engine rpm.

Tested and proven using 3kW kettle as load via 3500 watt inverter whilst monitoring just a few amps drain from batteries and confirmed via clamp on ammeter. 

 

"A" groove pulley used with twin belts to larger alternator. Hm7STEY.jpg

Edited by by'eck

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before adding a rotating weight to the crank,you should calculate if you are going to cause a critical vibration period in the operating range.......The  flywheel at opposite ends is generally frowned on ,but may be ok if the revs are low enough.....A belt drive will provide some dampening effect.

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An Ally pulley will be lighter, a skeleton one even lighter.

Or fabricate with a center, a turned "v" rim and steel spokes/drilled disc welded together.

It only needs to cope with about 5 HP

Running rubber wheels on the rim of a flywheel is a poor solution, I've seen a few engineering odds and sods like that and they all have severe limitations.

Edited by Boater Sam
added more

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18 hours ago, by'eck said:

14 inch pulley gives max output (240 amps) from my two alternators @ 650 engine rpm.

Tested and proven using 3kW kettle as load via 3500 watt inverter whilst monitoring just a few amps drain from batteries and confirmed via clamp on ammeter. 

 

"A" groove pulley used with twin belts to larger alternator. Hm7STEY.jpg

How do you attach a pulley to the front of the flywheel? Mine is at the back, meaning i have to use link belting and is also prone to any oil leakage. 

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one of the major loads on a belt drive is the motor accelerating rapidly,this is highly unlikely with a JP Lister,so a steady load rating belt will be OK.........2 x A section belts being sufficient........if you go to three belts,you generally have trouble with two versus one......Ive found the polygroove belt used on trucks runs very well on a large smooth pulley as the driver,grooves to the inside.,and allows a smaller driven pulley,as the flat poly belt is very flexible,and is often reverse bent in automotive drives.

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I can find you an alloy pulley for a JP the same as Steve Hudson used on their boats

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5 hours ago, RLWP said:

I can find you an alloy pulley for a JP the same as Steve Hudson used on their boats

How, and to which side of the flywheel does it attach?

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6 minutes ago, BWM said:

How, and to which side of the flywheel does it attach?

Is yours a marine JP?

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9 hours ago, RLWP said:

Is yours a marine JP?

Yes, 3 cylinder hand start. 

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1 hour ago, BWM said:

Yes, 3 cylinder hand start. 

Ahh. Then we would need to do some dimension checking. Hudsons generally have industrial JPs

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Fitting a drive pulley to a marine JP is easy peasy. We use a drive shaft adaptor that replaces the large flywheel nut. To this we fit a taper lock pulley and boss sized for the speed and alternator type.  In fact, By Ecks engine shown in an earlier response has such a set up. We have fitted dozens of them over the years. Standard on our marine JPs and  converted JPs

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1 hour ago, steamraiser2 said:

Fitting a drive pulley to a marine JP is easy peasy. We use a drive shaft adaptor that replaces the large flywheel nut. To this we fit a taper lock pulley and boss sized for the speed and alternator type.  In fact, By Ecks engine shown in an earlier response has such a set up. We have fitted dozens of them over the years. Standard on our marine JPs and  converted JPs

That sounds interesting. Would it be capable of taking drive to a gearbox? I need to make an adaptor for my JK and was going to use the three threaded studs that would have connected it to the generator, but something like that could be another option. My gut feeling is that its fine for pulley loads, but might not be great with a whole 62hp going through it. :)

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