flatplane8 Posted December 3, 2018 Report Share Posted December 3, 2018 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 Link to comment Share on other sites More sharing options...
GUMPY Posted December 3, 2018 Report Share Posted December 3, 2018 (edited) 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 December 3, 2018 by Loddon Link to comment Share on other sites More sharing options...
flatplane8 Posted December 3, 2018 Author Report Share Posted December 3, 2018 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. Link to comment Share on other sites More sharing options...
GUMPY Posted December 3, 2018 Report Share Posted December 3, 2018 (edited) 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 December 3, 2018 by Loddon Link to comment Share on other sites More sharing options...
Boater Sam Posted December 3, 2018 Report Share Posted December 3, 2018 Run on the ring gear? Never! The noise and wear would be 'orrible Link to comment Share on other sites More sharing options...
TheBiscuits Posted December 4, 2018 Report Share Posted December 4, 2018 3 hours ago, Boater Sam said: Run on the ring gear? Never! The noise and wear would be 'orrible Rubber cog .... Link to comment Share on other sites More sharing options...
martyn 1 Posted December 4, 2018 Report Share Posted December 4, 2018 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. Link to comment Share on other sites More sharing options...
philjw Posted December 4, 2018 Report Share Posted December 4, 2018 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? Link to comment Share on other sites More sharing options...
David Mack Posted December 4, 2018 Report Share Posted December 4, 2018 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/ 1 Link to comment Share on other sites More sharing options...
flatplane8 Posted December 4, 2018 Author Report Share Posted December 4, 2018 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. Link to comment Share on other sites More sharing options...
frangar Posted December 4, 2018 Report Share Posted December 4, 2018 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. Link to comment Share on other sites More sharing options...
David Mack Posted December 5, 2018 Report Share Posted December 5, 2018 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. Link to comment Share on other sites More sharing options...
flatplane8 Posted December 5, 2018 Author Report Share Posted December 5, 2018 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. Link to comment Share on other sites More sharing options...
by'eck Posted December 5, 2018 Report Share Posted December 5, 2018 (edited) 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. Edited December 5, 2018 by by'eck Link to comment Share on other sites More sharing options...
john.k Posted December 6, 2018 Report Share Posted December 6, 2018 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. Link to comment Share on other sites More sharing options...
Boater Sam Posted December 6, 2018 Report Share Posted December 6, 2018 (edited) 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 December 6, 2018 by Boater Sam added more Link to comment Share on other sites More sharing options...
BWM Posted December 6, 2018 Report Share Posted December 6, 2018 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. 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. Link to comment Share on other sites More sharing options...
john.k Posted December 6, 2018 Report Share Posted December 6, 2018 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. Link to comment Share on other sites More sharing options...
RLWP Posted December 6, 2018 Report Share Posted December 6, 2018 I can find you an alloy pulley for a JP the same as Steve Hudson used on their boats Link to comment Share on other sites More sharing options...
BWM Posted December 6, 2018 Report Share Posted December 6, 2018 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? Link to comment Share on other sites More sharing options...
RLWP Posted December 6, 2018 Report Share Posted December 6, 2018 6 minutes ago, BWM said: How, and to which side of the flywheel does it attach? Is yours a marine JP? Link to comment Share on other sites More sharing options...
BWM Posted December 7, 2018 Report Share Posted December 7, 2018 9 hours ago, RLWP said: Is yours a marine JP? Yes, 3 cylinder hand start. Link to comment Share on other sites More sharing options...
RLWP Posted December 7, 2018 Report Share Posted December 7, 2018 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 Link to comment Share on other sites More sharing options...
steamraiser2 Posted December 7, 2018 Report Share Posted December 7, 2018 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 Link to comment Share on other sites More sharing options...
flatplane8 Posted December 7, 2018 Author Report Share Posted December 7, 2018 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. Link to comment Share on other sites More sharing options...
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