PGC Posted January 26, 2015 Share Posted January 26, 2015 Are you happy with the slow speed performance of your Lima Class 20? OK, I know this sounds like it might be a cheesy advert for some performance pills, but I promise you it's nothing of the sort! I have a Lima Class 20, and as my layout is a shunting plank, I need slow speed control. I've already replaced the standard Lima motor with a Mashima 1830 motor with a big flywheel on it, but it still doesn't give me the slow speed performance I need. Wondering what to do next, I took the gear tower apart and found a worm that has such coarse pitch that you could almost sling a hammock between the teeth. It it this that causes the problem, the Lima worm is a two start worm that gives a final drive ration of about 7:1 Earlier today I was with Ultrascale speaking about this, and theoretically they can produce a different worm and gear set which will give a final drive ration of 30:1, which will obviously be much better for slow speed running (but if you like your Class 20 emulating an HST, stop reading now!). The key word here is theoretically! Ultrascale don't produce this item as stock, but if there are enough people prepared to make a promise to purchase a set of these gears, they would be prepared to start looking at the project with a view to turning it from theoretically possible in to practically possible. To make this project viable for Ultrascale, however, we need to get at least 30 people promising to buy the gears, and until we get those 30, nothing will progress with Ultrascale. An approximate cost of a set of gears will be £25 plus postage. The worm will include a shaft to replace the existing Lima shaft and the gear will be a direct replacement for the existing Lima 1st stage gear, so the work to convert the loco will be very easy, I estimate 30 minutes. So, to the crux of the matter; are you interested enough to purchase a set of these gears? If you are, please PM me and I will create a list of people interested. I look forward to hearing from you. Phil Link to post Share on other sites More sharing options...
cobach47 Posted January 26, 2015 Share Posted January 26, 2015 i have two lima 20's both run very slowly i ran one the other day pulling seven heavy freightliner hoppers. it may seem like going back in time but have you thought of getting hold of a contoller with half wave rectification by Hornby or H& M i have a Hornby one and i can make any loco crawl. 1 Link to post Share on other sites More sharing options...
PGC Posted January 26, 2015 Author Share Posted January 26, 2015 i have two lima 20's both run very slowly i ran one the other day pulling seven heavy freightliner hoppers. it may seem like going back in time but have you thought of getting hold of a contoller with half wave rectification by Hornby or H& M i have a Hornby one and i can make any loco crawl. The controller I use on my test track is an H&M Clipper and even on half wave it doesn't make my class 20 crawl, well, not as I expect it to! In case you wonder what I'm after, this link will take you to a video of a Y7 0-4-0T that I've built, and this video was taken using the Clipper and before I'd run in the loco. Now it's run in, it's even slower, just as I like all my locos to run. Phil Link to post Share on other sites More sharing options...
tractor_37260 Posted January 27, 2015 Share Posted January 27, 2015 (edited) The controller I use on my test track is an H&M Clipper and even on half wave it doesn't make my class 20 crawl, well, not as I expect it to! In case you wonder what I'm after, this link will take you to a video of a Y7 0-4-0T that I've built, and this video was taken using the Clipper and before I'd run in the loco. Now it's run in, it's even slower, just as I like all my locos to run. Phil Another issue that affects slow speed running on Lima Class 20's, is the design of the pick up bars, these run in slots on the wheel backs. Depending on how well they are fitted/adjusted etc they can cause a lot of drag. Removing them and replacing with fine wire etc would help. The running quality of Lima 20's varied a lot between examples, some being a lot worse than others, especially at slow speeds. A Bachmann 20 - (with twin flywheels and 4 axle drive) would still outperform a modified drive gear Lima 20, it's a better model overall also. Perhaps borrow one to compare ? Edited January 27, 2015 by tractor_37260 Link to post Share on other sites More sharing options...
Simon Bale Posted January 27, 2015 Share Posted January 27, 2015 In the real world, shunting is not really a sedate activity. Best regards Simon Link to post Share on other sites More sharing options...
Alcanman Posted January 27, 2015 Share Posted January 27, 2015 I bought a Lima Class 20 when they were first released in the 1980s. The loco ran smoothly at speed but jumped along the track at low speed, useless for a small shunting layout. I returned the loco to the model shop and got a refund. I've never bought a Lima loco since. I now have a Bachmann 20 with a ESU dcc decoder and the slow speed control is incredible. At speed step 1, the loco movement is barely perceptible to the eye. There are Bachmann 20s on e-bay for reasonable prices. Link to post Share on other sites More sharing options...
PGC Posted January 27, 2015 Author Share Posted January 27, 2015 (edited) Another issue that affects slow speed running on Lima Class 20's, is the design of the pick up bars, these run in slots on the wheel backs. Depending on how well they are fitted/adjusted etc they can cause a lot of drag. Removing them and replacing with fine wire etc would help. The running quality of Lima 20's varied a lot between examples, some being a lot worse than others, especially at slow speeds. A Bachmann 20 - (with twin flywheels and 4 axle drive) would still outperform a modified drive gear Lima 20, it's a better model overall also. Perhaps borrow one to compare ? I agree about the pickups - that's why I've taken the bars off completely and replaced them with .35mm PB wire on both bogies. Makes a dramatic difference to the haulage ability as well. I know the Bachmann is good, but I've got the Lima one that I've had for 15 years or so, and I want to use that rather than sell it and have to try and find a Bachmann unit in green In the real world, shunting is not really a sedate activity. Best regards Simon Agreed - but all locos have to run slowly at times, and my class 20 doesn't at present. Phil Edited January 27, 2015 by PGC Link to post Share on other sites More sharing options...
stewartingram Posted January 28, 2015 Share Posted January 28, 2015 I added extra pickups to mine (since replaced by a Bachmann). I found that in one direction the bogie ws lifting slightly in one direction, leading to poor pickup, made worse by traction tyres if I remember correctly. Once modified, and with a "tlc service" (that has been mentioned elsewhere as vital for Lima), it became a very impressive runner. Stewart 1 Link to post Share on other sites More sharing options...
PGC Posted January 28, 2015 Author Share Posted January 28, 2015 I added extra pickups to mine (since replaced by a Bachmann). I found that in one direction the bogie ws lifting slightly in one direction, leading to poor pickup, made worse by traction tyres if I remember correctly. Once modified, and with a "tlc service" (that has been mentioned elsewhere as vital for Lima), it became a very impressive runner. Stewart I'm more than a little reluctant to replace mine - I model in EM and have an Ultrascale conversion. With the revised pickups and Mashima motor it runs far better than the standard model, but still not good enough for me! As I've received no messages with interest in the gears, I suspect I will have to go it alone. Ultrascale can provide me with the necessary gear and worm to convert my loco, but as a one off it's not the simple drop in job that the conversion offered in my original posting would be. When I get the gears and convert the loco, I will put a video on here so people can see what I've been aiming for. Phil Link to post Share on other sites More sharing options...
royaloak Posted January 29, 2015 Share Posted January 29, 2015 (edited) You have given us a mere 3 days to respond, blimey! I would have been interested in a couple of sets (possibly 4) but I am obviously a bit too slow for the OP, some of us dont visit this site every day and when we do visit we might only go through 10% of the new posts, give us a chance! Edited January 29, 2015 by royaloak Link to post Share on other sites More sharing options...
thaddeus Posted February 5, 2015 Share Posted February 5, 2015 while I agree that the gearing is to low on the Lima 20, I feel that 30:1 on the initial gearing maybe a tad high. Wouldnt conversion of the two start worm to a single start give you 14:1 and halving the speed? you could also use the same worm wheel and save a bit on the machining cost. Link to post Share on other sites More sharing options...
PGC Posted February 6, 2015 Author Share Posted February 6, 2015 while I agree that the gearing is to low on the Lima 20, I feel that 30:1 on the initial gearing maybe a tad high. Wouldnt conversion of the two start worm to a single start give you 14:1 and halving the speed? you could also use the same worm wheel and save a bit on the machining cost. This was something that I spoke with Ultrascale about, as it seems an easy solution to me. Their response was that with a single start worm, the helix angle is different to that of a double start worm so a new worm wheel needs to be cut that matches the helix of the single start worm, which is just as much work as the route they're investigating. When I was originally discussing with Ultrascale the options for changing the gearing, we settled on two options. The first option, and the one I was offering to RM Webbers, is an easy to undertake complete conversion, as in my original post, but for this Ultrascale need to know they will sell 30 sets, and so far I have had interest in three sets, so a fair way short of the minimum requirement. The alternative option is production of a single worm and gear that will give about 30:1 ratio, but once produced, the old worm wheel needs to be modified, which I will be having to do myself. Ultrascale are currently working on this and tell me they may have some development news next week - I will let you know what the outcome is once I know. Phil Link to post Share on other sites More sharing options...
PGC Posted February 20, 2015 Author Share Posted February 20, 2015 As people will see here, this thread is one of two concerning making my Lima Class 20 run as best it can. Why do I want to do this when I could buy a Bachmann Cl 20? Well, I bought the loco many years ago and spent quite a bit of money on an Ultrascale conversion, a Craftsman detailing kit (which I've yet to add to the loco!) and a SE Finecast flush glaze pack, and I don't want to waste them. In the other thread, it can be seen I've asked about limited haulage capabilities and when I was told about the Lima pick ups causing problems, I replaced the Lima pick ups with .35mm phosphor bronze wire and suddenly the loco started pulling 15 wagons where before it couldn't pull 5! However, my criteria for a good running loco is one that will crawl well rather than shoot off lice an Apollo space rocket the moment a hand goes anywhere near the controller. In trying to sort out the slow speed running, I took the drive bogie apart and discovered a twin start worm which gives a reduction ratio of 7:1. I wondered what to do about this, and spoke with Ultrascale - this is covered in the earlier part of this thread. So, an update. Yesterday I collected a new worm and worm gear cluster from Ultrascale. When I got home, I spent about 20 minutes putting these in to the Lima bogie (it's a very easy job to do) put power to the bogie and watched in awe as the loco just crawls along. The final reduction ratio of this worm set is 30:1 so the loco now has what I believe to be nearer to a realistic high speed, but in addition when power is applied, the loco moves off in a very smooth fashion rather than shooting off like a startled rabbit. I can't as yet put a video of the running qualities on there, as I have a little bit more work to do that isn't related to the Ultrascale conversion. I bought a Branchlines conversion pack so now have a Mashima 1830 motor and flywheel driving the loco. Unfortunately, the flywheel is rubbing on the chassis block when I put the body on, so I need to do a small bit of carving to rectify this and then I will take some video and more pictures and put them on the website. When I was at Ultrascale, they showed me their Cl. 20 running with the standard Lime motor and it runs so much better than the standard loco, so I know mine will as well when I've finished. If anyone is interested in purchasing a set of these gears, Ultrascale can supply them but as they are a non production item the price is yet to be determined as it depends on how many people are interested. If you would like to find out more, please PM me. In addition, the loco will be running on the Blackwells Brewery layout at the St. Neots show on 14/15 March, so if you're there, come and say hello and ask to see the loco running so you can determine for yourself just how good the change is. Phil 1 Link to post Share on other sites More sharing options...
plarailfan Posted February 20, 2015 Share Posted February 20, 2015 I haven't seen this post until now. I reckon these gears would sell quite well on ebay, as there will be quite a few folks who purchased and then, lovingly detailed, Lima 20's, back in the day when the only alternative was Wrenn / Dublo. Well done for your initiative ! Link to post Share on other sites More sharing options...
John of York61 Posted February 20, 2015 Share Posted February 20, 2015 I fitted my Lima 20 with a Mashima motor connected to High Level cardan shaft. Still too fast. I then scratchbuilt a 2:1 gearbox to the Lima final drive. Better now, runs like a Bachmann one. Since fitted a Zimo decoder with sound.....better still! Link to post Share on other sites More sharing options...
PGC Posted February 20, 2015 Author Share Posted February 20, 2015 I fitted my Lima 20 with a Mashima motor connected to High Level cardan shaft. Still too fast. I then scratchbuilt a 2:1 gearbox to the Lima final drive. Better now, runs like a Bachmann one. Since fitted a Zimo decoder with sound.....better still! My preferred option would be to replace the two start worm with a single start, giving the same reduction as yours, but Untrascale couldn't help there. What they have done is produce a new cluster gear to replace the original Lima one that matches with a worm they already produce and hey presto. Any easy conversion that works well. I'm happy! Phil Link to post Share on other sites More sharing options...
PGC Posted March 6, 2015 Author Share Posted March 6, 2015 As I'm writing another entry to my blog and adding a bit about my Lima Class 20, I've looked at my last post on this thread and realised I didn't write it particularly well. Now that Ultrascale have produced the worm and final drive gear, they are prepared to offer these items for sale to modellers who want them. At the moment, the price is unknown but won't be desperately expensive, if you're interested, please either let me know or contact Ultrascale direct and they will know what you're talking about. I will be spending today at my workbench and one of the jobs will be adding detailing and flush glazing to the Cl so, so while the body is off I will take some photos to show how easy this conversion is. I may also try and take some video of it running, but I can't promise that, although I have to say that when running the loco on the club layout last night, the smoothness and slow speed ability are very impressive. Just what I originally wanted! Phil Link to post Share on other sites More sharing options...
PGC Posted March 6, 2015 Author Share Posted March 6, 2015 Well, now the loco runs as I want it to, I've started detailing it, firstly with SE Finecast flush glazing. So far I've spent an hour and get three pieces of glazing to my satisfaction. Just as well I've got lots of hair, it won't notice so much as I pull bits out! However, the real reason for this update is that, as I mentioned in the last post, I've had the body off and taken some pictures to show what's involved in the conversion. This picture shows my loco chassis with the conversion in place and gear box lid removed. Please note, as well as using the Ultrascale conversion, I have changed the standard Lima motor (seen behind the chassis) for a Mashima 1830 with flywheel. This was in an attempt to improve the slow running, which didn't work as well as I'd hoped. There is no need, with the Ultrascale conversion, to change the motor. (Oh, and if you're wondering what all the wires are, I've taken the Lima pick ups off, replaced them with ,35mm PB wire ones and added them to the drive bogie - the loco runs far better for it) This picture shows inside the gear tower and the Ultrascale worm, while the last picture just shows more detail inside the gear tower. To do the conversion, the power bogie needs to be taken out of the loco (it just unclips) then two of the gears inside the tower need to be taken out (the sides of the tower need to be eased apart and the gears fall out) after which the shaft of the top gear (the one the Ultrascale gear replaces) need to be pushed out through the gear tower, after which the top gear can be replaced. To change the worm shaft, the front bearing just pulls off of the shaft and put on the Ultrascale replacement while the universal joint end on the original shaft needs to be eased off (I gently levered mine off with a screwdriver) after which the rear bearing can be pulled off the original shaft, replaced on the Ultrascale shaft, then the universal joint housing gets replaced, the whol lot reassembled and all of a sudden you have a very slow and smooth running Class 20. All in all, I reckon the conversion would take about 30 minutes maximum and gives simply wonderful running qualities. As I said before, if you're interested in getting some of these conversions, either contact me or Ultrascale direct. I'd recommend them, but I would! :-) Phil Link to post Share on other sites More sharing options...
thaddeus Posted March 6, 2015 Share Posted March 6, 2015 your power bogie is back to front... at least the side frame any way. Looks most impressive, I will be interested but I am a bit strapped for cash a the mo (as usual). As to pickups, I replaced my Lima bogies with Hornbys variety, as you say the difference is remarkable. Link to post Share on other sites More sharing options...
RMweb Premium ELTEL Posted July 8, 2015 RMweb Premium Share Posted July 8, 2015 Looking to add a class 20 in a distressed form with side missing showing the locomotive engine. However I am struggling to find photographs showing the inner workings of a class 20 When complete the model will be shedded awaiting work/refurbishment on my DRS TMD layout Oil Drum Lane Thanks Terry Link to post Share on other sites More sharing options...
RMweb Premium HillsideDepot Posted July 8, 2015 RMweb Premium Share Posted July 8, 2015 How about 20008 at Thornaby? http://www.the-siding.co.uk/class20/pages/2x20.htm Not my photo, but remembering it standing there a quick Google came up with several, of which that is probably the best. Link to post Share on other sites More sharing options...
RMweb Premium ELTEL Posted July 8, 2015 RMweb Premium Share Posted July 8, 2015 How about 20008 at Thornaby? http://www.the-siding.co.uk/class20/pages/2x20.htm Not my photo, but remembering it standing there a quick Google came up with several, of which that is probably the best. Thanks if you find any more let me know Terry Link to post Share on other sites More sharing options...
deltic79 Posted July 9, 2015 Share Posted July 9, 2015 I know the OP is looking for an upgrade to the existing Lima drive etc rather than replace with a Bachmann but just in case anyone isn't aware, the Bachmann class 20 chassis sits underneath the Lima body with ease. I have a pair of detailed Lima 20s in BRT livery that I didn't want to part with but I did want improved running. I picked up a couple of Bachmann 20s on eBay that had suffered a shocking repaint so were very reasonable (can't remember how much I paid now, around £25-£30 each I guess plus I then sold the bodies on again for a few pounds). The underframe tank sides on the Lima 20 are molded as part of the body but are also included on the Bachmann chassis so they need to be simply cut away from the Lima body with a razor saw. Then the body is a snug fit over the Bachmann chassis without needing any body screws etc to keep it in place. Link to post Share on other sites More sharing options...
crompton 33 Posted July 9, 2015 Share Posted July 9, 2015 Hi Eltel look this up http://www.wnxx.com/Then click on the Stored Loco Galleries . Link to post Share on other sites More sharing options...
RMweb Premium ELTEL Posted July 9, 2015 RMweb Premium Share Posted July 9, 2015 Hi Eltel look this up http://www.wnxx.com/Then click on the Stored Loco Galleries . Many thanks - what a find Regards Eltel Link to post Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now