ZF S5-42 to LT 230.

Read up the post I put on the modified section LT230 Perspective then tell me how you are golng to beef up the rest of the TC as I am very interested:o.
Shortly we will have people making tailshafts out off solid 4140 as to avoid the weld to the yoke 2.5"x .100" if you are lucky:o .One way to insure the shaft will never break is to build 2 off The second will still be in the spares locker in 2050:D
AM

Hi AM.
Apart from altering the center diff with Ashcroft goodies I'm not planning to touch the LT.. The only failures I've seen/had with those boxes are the center diff, and that's only because the guy had a 4 pot Nissan turbo up front and never engaged the CDL until it was too late! The output shafts share the load, and driver care comes into it with an engine like I'm planning.. There won't be any 'Brain in pocket foot on floor' moments in first and second low as there's little point. Other than the LT I'm limited in choice with an offset full time four wheel drive compact transfer case.. The Americans talk of the LT being comparable with an Atlas transfer box (which I've never seen and know little about), so I've gone with what I know... What I will be doing is fitting a large oil sump in it, and between that sump and the case I'll be fitting a plate with spars across from each face of the case, so as to minimise the case trying to spread under load. Not only that, I want to use this engine in 'stock' form, so apart from an intercooler and a decent 4" exhaust (purely for 'that' sound) it will remain standard. With the resources I have available to me, the 'tubed' input gear idea seems to be the best approach/idea. Time will tell.. The tail shaft of ZF box has to be bolted (as Nick discovered last week). and I don't fancy a long M12 socket head bolts chances for long at the torque setting in the ZF book. Thanks for the input and link to the other thread tho.. We'll see how it goes! Cheers!

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Originally Posted by DasLandRoverMan

A 4BD1T will fit a 101, it's been done.

Smart idea with the tensioner nut, looks tidy.

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Thanks.

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Originally Posted by Sitec

Ha! Love it! That conversion all looks very neat. I hear you re welded shafts, but still not convinced that the original input shaft (same size as the old RR/Disco 10 spline axle shafts) will withstand 400-500 nm of torque. Time will tell I guess. :) Length is also an issue with my conversion.. I have to get the transfer case as close to that ZF box as possible or I'll have a 300mm long rear shaft!!

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I did the calcs on this when I designed that above shaft back in 06/07. I dug them up recently:

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Originally Posted by Dougal

I don't believe your shafts will stand up if not hardened. I forget the exact hardness mine was done to, but I was looking for a material with at least 1000 MPa yeild, the concern being stress concentration causing fatigue at the start of the splines.

The final material I received had a yeild when hardened of almost 2000MPa. Overkill, but it boasted minimal distortion in heat-treatment and the cost difference was minimal.
I received quotes from $NZ350-750 to make my shaft, in the end the workshop that started didn't finish it, I had to do the final machining and heat-treatment. Total cost around $NZ600.

I'll see if I can dig up my original calculations, but the FEA study I ran at the time shows 650 MPa bulk stress with 1450MPa max stress concentration at the start of the splines. The computer simulations tend to exaggerate stress concentration as computer modelled geometry tends to have sharper transitions than actual manufacturered parts.
This is with 2000Nm applied to the shaft. 2000Nm was the shaft torque required to light up wheels on tarmac. It represents 345Nm applied by the engine in first gear or 666 Nm applied in second gear.

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Shaft needs to withstand about 2000Nm worst case in my application. If you are heavier for the same gearing then your worst case torque should be higher.

Of course Engineers can easily tell when something is plenty strong enough and also when it's not strong enough. In between there's a huge range that depends on a huge number of uncontrolled factors (like who is driving). My design and material spec is well into the "plenty strong enough" bracket. The previous welded shaft also held up for years but the engine didn't have the same torque then.

http://www.aulro.com/afvb/attachment...-230-image.jpg

Perhaps I'm missing something but what do you propose to do for a front bearing

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Originally Posted by Sitec

Hi AM.
Apart from altering the center diff with Ashcroft goodies I'm not planning to touch the LT.. The only failures I've seen/had with those boxes are the center diff, and that's only because the guy had a 4 pot Nissan turbo up front and never engaged the CDL until it was too late! The output shafts share the load, and driver care comes into it with an engine like I'm planning.. There won't be any 'Brain in pocket foot on floor' moments in first and second low as there's little point. Other than the LT I'm limited in choice with an offset full time four wheel drive compact transfer case.. The Americans talk of the LT being comparable with an Atlas transfer box (which I've never seen and know little about), so I've gone with what I know... What I will be doing is fitting a large oil sump in it, and between that sump and the case I'll be fitting a plate with spars across from each face of the case, so as to minimise the case trying to spread under load. Not only that, I want to use this engine in 'stock' form, so apart from an intercooler and a decent 4" exhaust (purely for 'that' sound) it will remain standard. With the resources I have available to me, the 'tubed' input gear idea seems to be the best approach/idea. Time will tell.. The tail shaft of ZF box has to be bolted (as Nick discovered last week). and I don't fancy a long M12 socket head bolts chances for long at the torque setting in the ZF book. Thanks for the input and link to the other thread tho.. We'll see how it goes! Cheers!

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You should re-think the statement that the output shafts share the load :eek:

The way I see it the GB rear bearing will be used as the front support for the TC imput gear which unfortunately puts the weld in the poorest position:(
Probably wrong but just my 2 cents worth

AM

The front bearing will stay exactly where it is. The output shaft of the ZF is a fraction smaller than the bearing carrier on the LT230.... so it'll still be fully supported..
Did a little more work to the plate this eve before beer got in the way. I took a paper print of the holes on the transfer box then transposed it onto the plate. Hole drilling tomorrow!! :)

Like John I'm struggling to see how this is going to work.

Taper roller bearings are almost always mounted in opposing pairs which have a method of finely setting the preload (threads or shims) so they can run with the necessary small clearance for free running without the shaft dropping off-line.
Whatever you've welded to the front of the LT230 input shaft (a modified drive yoke?) prevents you from installing the front opposed bearing. So the rear taper roller is running alone.

It may be possible to pair the gearbox and transfer and then set the preload on the rear taper using the main gearbox bearings to oppose it. But it will be extremely difficult and rely on everything being perfectly straight and concentric. Which is damn near impossible without shafts being welded.

Can you explain this plan a bit better?

Ok, here's a pic of what I'm going to try... The transfer case input gear will remain supported as it was by the two taper roller bearings. It will have the PTO output drive lugs machined off to give me a flat bolting face, and it will also have the original 10 splines machined out of the center to give me a set size up its guts. The ZF (branded spicer) output prop flange has had its lugs cut off, and will be machined down to the seal track face (approx 50mm o/d). This (luckily) is marginally smaller than the i/d of the LT230's taper roller bearings. It will be vee'd out and welded to the nose of the LT's input gear and checked for alignment. It will also have the drill run down the center again to make sure its clear of burrs. A large dia (to suit the hole where the splines were) bolt will then be machined/made with an internal thread to suit the ZF output shaft (poss using the ZF nut). The modified gear will then be refitted into the transfer case (now with a 50mm tube poking out of the input hole). Once set up with no play, the mating face to tube face will be measured and checked against the conversion plate and ZF internal spacer/mating face. It will be machined if too long, or shimmed if too short. The transfer box can then be fitted to the gearbox, and bolted tight. The new 'Bolt' can then be inserted through the PTO cover and tightened. Holding the ZF shaft tight as it needs to be. Cover on and job done! The bolt will also support the gear as it will be a close fit inside it. Hope this all makes sense.

The only thing that might change from the drawing, will be the front taper roller bearing size in the LT. If I can find a 'slim' bearing with the same o/d as the original, it will allow my welded join/boss to be nearer 60mm in dia rather than the drawn 50mm. Still working on that bit. Either way, there has to be two bearings carrying that gear so none of the sideways loading caused by the helical gear gets to the ZF box, but in the same breath the ZF has to have that output ring bolted tight to it to keep its internal gears tight on its output shaft.... I figure that a shaft size of 50+ mm has to be as strong if not stronger than the original 10 spline input shaft at its thinnest point......

That makes a lot more sense.

But are you sure the steel on the LT230 input is even weldable? It may be too high in carbon content and simply crack on cooling unless you've got your weld proceedure down (including post heat and potentially rehardening).

I would still be very concerned about alignment. Nothing in that setup has the ability to float and align, your tensioner arrangement will also cause the LT230 bearings to fight the gearbox bearings and indeed both cases and adapter plates for axial tension.