FridgeFreezer Posted November 22, 2011 Share Posted November 22, 2011 Chatting today about the lack of gearing in the 109, the idea occurred that it may be viable to build an LT230 which is over-driven in high range. Currently I run a 1:1 ratio LT230, my axles are 5.99:1 and my tyres are only 37's as I don't want to chop the bodywork about. Low range is great, but in high-range the V8 is doing far more revs than it needs to. Looking at the workings of the LT230 it looks like it may be possible with some basic machining to reverse the high-range gearset on a 1.222:1 ratio box to give 0.8:1 ratio. Before anyone says it, no I don't want an overdrive for various reasons, including the fact that I have a hydraulic PTO I'm quite keen to fit to the box. So, the plan would be something approximately like this: I will abbreviate high range intermediate gear to HRIG and high range output gear to HROG otherwise I'm going to be typing forever - Take HROG, machine the dogs off - Take intermediate gear set, machine HRIG bit down to ID of HROG - Slide HROG onto intermediate gear set & weld up - Take another HROG, machine its teeth off to make it a carrier with the appropriate dogs on - Take another intermediate gear set, machine the HRIG off, bore the centre out to slip over the HROG-based carrier and weld it up. - Tea & medals. A few unknowns: - Just how hard the gears are, if they can be machined without the aid of NASA - I have assumed the HROG has a bigger ID than the intermediate gear set as the parts book seems to back this up, but I don't know 100%. - If the new and potentially smaller HROG will still fit over the output shaft. - If welding gears together will knacker the alignment / strength / hardening - If there's an easier way of doing this / off-the-shelf bits, etc. - When the hell I'd get the time to do it So - discuss! Quote Link to comment Share on other sites More sharing options...
zoltan Posted November 22, 2011 Share Posted November 22, 2011 The gears are probably about 58-60 Rockwell which will machine with CBN tips (-ish). Your main issue will be getting through the case hardening, hence the CBN tips. Once through the case they should machine with ordinary carbide tips OK. Electron beam welding should give you a reliable enough joint but that isn't something you'll be doing in your shed, it is more NASA's territory. Plenty of companies who do this though Quote Link to comment Share on other sites More sharing options...
Landy-Novice Posted November 22, 2011 Share Posted November 22, 2011 would it not just be easier to get one of these'? http://ashcroft-transmissions.co.uk/index.php?act=viewCat&catId=70 or a permanent over drive? http://ashcroft-transmissions.co.uk/index.php?act=viewProd&productId=43 Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted November 22, 2011 Share Posted November 22, 2011 Should certainly be doable, lots of Zuki guys do it to get a lower low range. Just get at it! Quote Link to comment Share on other sites More sharing options...
ejparrott Posted November 22, 2011 Share Posted November 22, 2011 What about mechanical joining methods instead of welding? Dowels, keys.... I'd imagine a H13A tip will get through the gears no problem, I've done some pretty tough stuff with them before now. Quote Link to comment Share on other sites More sharing options...
B reg 90 Posted November 22, 2011 Share Posted November 22, 2011 Interesting idea and thread. Definately out of the box stuff for LR forums! My imeadiate thoughts were avoid welding. Leads to all kind of distortion issues, expecially with gears that are toleranced in microns. Bore out your gears then either key or spline to fit to the appropriate hubs?? Alternatively get new gears made. Tad more expensive... but not unrealistic. Try some one like 'Lamond and Murray'. They are based in central Scotland. I use then through work to make gears for gearboxes and other stuff. They are excellent and have technical support agreement with David Brown Gears, hence can get the right advice for gear heat treatment etc. Their CNC gear grinder is amazing to watch. It grinds a gear profile, measures what is has ground and if necessary automatically reprofiles the grinding wheel to maintain accuracy. The machine that deals with the grinding debri in the coolant is the size of a double garage on it's own! Despite this they will make one off's Adrian Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted November 22, 2011 Share Posted November 22, 2011 Interference fit + mig Quote Link to comment Share on other sites More sharing options...
landroversforever Posted November 22, 2011 Share Posted November 22, 2011 would it not just be easier to get one of these'? http://ashcroft-tran...iewCat&catId=70 or a permanent over drive? http://ashcroft-tran...od&productId=43 None of the ashcroft ratios give an overdrive high range And the other link is for a series box which fridge doesnt have. I think machinging out the centres and then EB welding them would be a good bet. EB has a very small HAZ around the weld (relative to the size/power) and is capable of VERY deep welds . Shouldnt be much, if any, distortion! Quote Link to comment Share on other sites More sharing options...
kiwi_110 Posted November 23, 2011 Share Posted November 23, 2011 Someone with a Series truck has done something very similar, I was reading a post the other day that included a link to his site. He ground the dogs and hardened areas off with an angle grinder and then machined and MIGed things back together. He weld-filled the intermediate shaft holes and bored new ones to relocate the intermediate shaft once the gears were swapped around. It was pretty ambitious stuff and very well done. Here's the link: http://www.goatpark....transferbox.htm Ray. Quote Link to comment Share on other sites More sharing options...
Daan Posted November 23, 2011 Share Posted November 23, 2011 Easy! hmm maybe not that easy. Anyway, is the ratio not a product of 2 gearsets and therefore by flipping the 2ns gearset round, this doesnt give you the result you want? Maybe worth to count teeth and see what you get. There is plenty more to choose from out of the 4 ratios and flip em round, I have a 1.2 box in bits that I can count the teeth of if you like? Daan Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted November 23, 2011 Author Share Posted November 23, 2011 Some good info coming up already, cool. Getting gears made is certainly an option, my initial thought was that a couple of scrap LT230's would be the cheapest way to prove the concept even if the "final" version involved spending proper money. There are various options on joining the bits - interference fit and MIG/TIG, drill some holes & plug weld, have the machining done in a "keyed" shape rather than round, then weld just to hold the bits together, etc... again the proof-of-concept can probably afford to be less than perfect. Ray - I saw that guy's site, he did a hell of a lot of work there and I'm hoping not to have to do stuff like move the intermediate shaft within the casting, fingers crossed this would be a straightforward gear swapping exercise (if it's not I probably don't have the time/patience for it!) Daan - you're right, there is the ratio of input gear to intermediate, if you fancied counting the teeth in your box that would be handy. I was working under the assumption that reversing the intermediate-to-final gear would give *some* overdrive, even if the specific ratio wasn't bang on. Quote Link to comment Share on other sites More sharing options...
Andy Posted November 23, 2011 Share Posted November 23, 2011 I've known zook guys who've done this sort of thing for a lower low range. I know they weld two gears together without issues when it's done properly. I can't see why a LR gearbox shouldn't be weldable in the same way. It's been a few years but I seem to recall the names 'Rob Storr' & 'Rocklobster' for the zook mod. Could well be worth a google as they'll have had much the same issues I'd have thought. Quote Link to comment Share on other sites More sharing options...
Quagmire Posted November 23, 2011 Share Posted November 23, 2011 The gearcutting company I used to work for would sometimes make propshaft yokes for GKN and others, the yoke and tube were splined and then electron beam welded around the top. The spline took the force, the weld held it all in place with minimal effort. You could do that with your HROG/Intermediate bit. I would recommend the work that my company did, the stuff the guys turned out was stunning, however the owner was a bit dodgy and if your job was not deemed "important" (i.e. not a huge order) then you could be left waiting for months and months....So for that reason I will not hand out their details. Quote Link to comment Share on other sites More sharing options...
simonr Posted November 23, 2011 Share Posted November 23, 2011 Good project Fridge. It's got to be worth a go, cannibalising LT230s. Machining is difficult, but you can take the case hardening off with a grinder / sander then it's pretty easy. Gears are perfectly possible to weld back together. They are weaker, but by an amount that may not be a problem. I would try it. If it breaks, get another one made. If you need one making, I'll put you in touch with someone decent and good value. Si Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted November 27, 2011 Author Share Posted November 27, 2011 Well, after a fair bit of looking & thinking and some maths from TSD we've worked out that it's not easily possible to make a useful ratio change by faffing with the gearsets in this way. The ratio is set by the input:intermediate as well as the intermediate:output which complicates things. Even TSD's idea of making an input gear that drives on the high-range gear directly didn't work out well, the size/tooth count maths screws the pooch and again you end up with ratios which aren't particularly different to what's already available - I think one possibility came out as ~1.5:1 which is between two easily available ratios anyway. The idea of having custom gears made is potentially doable, but it's a bit beyond my enthusiasm/wallet at the moment. So, for the time being the idea is shelved Quote Link to comment Share on other sites More sharing options...
discomikey Posted November 27, 2011 Share Posted November 27, 2011 what about turning the transfer box backwards/upside down? i.e output is input and input is now output. this may/may not be feasable but just another angle on it. Quote Link to comment Share on other sites More sharing options...
Astro_Al Posted November 29, 2011 Share Posted November 29, 2011 Ranger overdrive? Quote Link to comment Share on other sites More sharing options...
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