LT230 input gear - respline advice please

[robertspark]

Hello,

I am in need of some technical advice please on resplining an LT230 input gear.

I am intending to install a non-standard gearbox / transmission into a landrover (never been done before as far as I know). [Tremec T-56 magnum mainshaft]

The output shaft of the gearbox will be a 31 spline (~34mm Major dia, ~31 mm Minor dia), involute profile. (I have the full spline profile specs, but it is essentially a yank transmission yoke spline profile for many different vehicles, very common on ford mustangs etc).

The problem I have is that the transfer input gears do not have much meat left on them if I was to remove (machine) the standard 10 spline arrangement.

The ten spline arrangement will not transfer the power (torque) that I'm looking at shunting around (engine output 505HP/470ftlb, to start with). Looking at the wear on my 3.5L + LT85 splines it's quite surprising they went with the 10 spline profile, albeit I am aware that a 1.222: 1 C suffix input gear is not crossdrilled, but can be replaced with the crossdrilled 26T/33mm variant)

Options are:

1) have a new LT230 input gear machined:

I've looked at the 1.222:1 input gear (suffix C) and the profile is very difficult to work out at it seems to have a very odd module (diametrical pitch) that the calcs just do not seem to work out for.

I've not got my 1.003:1 input gear (suffix B)out yet to establish / try to establish that gear profile.

I am able to use Autodesk inventor to provide a cad drawing to the gear manufacture, but these gear profiles seem to be proving to be above my intelligence.

2) interference fit a splined yoke within a machined input gear:

31 spline yokes are fairly common (imported from the US), it is possible to machine the input gear bore to provide an interference fit for a 31 spline cut down yoke.

But, the questions are:

a) what sort of force would be required to slide an interference fit yoke into an input gear (115mm long, interference bore 42.8mm)?

b) what sort of power (torque) will I be able to run through this arrangement?

Anyone know any good economical companies for this sort of work (yes, I know of rakeway, and they will be my fallback option, if I cannot do it by other means as they have not done this specific conversion / transmission before and seemed very busy at present with TKO500 / 600 conversions which appear to be of a very high standard, I just wanted a 6-speed box if I'm going to all this effort .... economically...), and no, I don't want a divorced setup, as I don't have the space in a 90....

Thanks in advance.

Rob

[ejparrott]

Take it to a gear manufacturers. I don't know where you are, but I have Sutton Gears in Coventry. They cut gears and splines, and very well too.

[sean f]

If you can get away with a bit of a gap between the gearbox and transfer box (wide adapter?) then it should be possible to join a standard yoke for the gearbox with an input shaft for the transfer box, the short conversion shaft used with a zf auto is generally the starting place. Getting the two machined and then heat shrunk together with a weld should be possible in any good machine shop, they should be capable of keeping it straight as well. The extra length will basically be the length of the shaft out the gearbox then about 1 to 2 inches. Not sure about the shape of a tremec gearbox but sometimes this will actually help with clearance for the front prop shaft.

This does mean you keep the 10 spline profile into the transfer box although most of the wear and trouble was on early gears with out the crossdrilling for oiling, once the wear starts the shaft in effect has a running start each time and the damage can be quite specacular. Provided you start with a new shaft and new cross drilled input gear (I believe these also have a longer spline length?) you should be ok although someone else would have to run the numbers to prove it as that is a bit beyond me.

[Mr Ian]

Hi Long way from the workshop but I'm sure when we used the TH350 the output was 31 spline? and we just 'wire EDM' the 31 spline into the gear. Be very careful if you are going to anneal a gear before machining as the helix can/will change slightly and then again as you re-case and harden, so you can very easily end up with a very noisy gear!!. Ian Ashcroft

[ejparrott]

I don't want a divorced setup, as I don't have the space in a 90....

Rob

[robertspark]

Gents,

Thanks for your posts, they are very much appreciated.

Ejparrott > That is is my second to last fallback option to go to a gear manufacturer, but I was hoping to go armed with a CAD file (3D Autodesk inventor model) which would be accurate, just the gear profile was being a PIA as it doesn't matter which way I look at the gear, I can't seem to get the dimensions to work out with standard gear profiles (DP's, modules and pressure angle calcs). I guess for all intense purposes I am trying to do a hack and avoid using Rakeway, not because there is anything wrong with them, I was just wondering if there was a cheaper way of doing it. The TKO's they do seem to be a nice bit of kit (good writeup on this link for those interested).

http://slroc2.co.uk/forum/index.php?topic=6768.0

There is also a good picture of the input gear they make, but to be honest the cost of the TKO was a bit high for what I was looking to do, but maybe I've underpriced my conversion as as the gearbox conversion is costing almost as much as I paid for an LS7 complete.

Hence I am keen to explore other avenues.... like does anyone think it possible to interference fit a splined yoke (with the yoke cut off) into a machined LT230 input gear, then TIG weld both exposed edges of the LT230 input gear to provide additional strength, but will this provide enough strength for this monster engine?

Ian > Thans for the response, the TH350 appears to be commonly a 27 spline shaft, and less common 31 spline, hence you may have already done it (question is do you still do it?). How much torque and power were you putting out of the TH350? I would have thought that it was well below the Corvette / Crate engine LS7 at 500od HP + ~ 500 ft/lb of torque all the way up to 7000rpm.

Anyone hazard a guess on the cost of a resplined LT230 input gear? I am waiting for the T-56 magnum mainshaft to come in from the US... seems like a bought the last one on the planet, so am not in any hurry (I've also go to complete my defender build too) I am intending to use a T-56 magnum mainshaft within a TR-6060 transmission as this spline is shorter than a Z06 corvette TR6060 mainshaft, but has a much higher power rating than the "standard" Dodge Charger etc TR6060 which I need to look at modifying the tailhousing for the LT230 to mount onto (squarely).

Sean F > Not keen on the "normal" conversion route which is the ZF > LT230 spline adapter, cut down and welded to a cut down yoke splined output shaft + an adapter spacer (Marks Adapters does one, as do Advanced Adapters in the us, and www.MEz.co.uk has well documented making his own. I don't mind moving the engine forward, the LS7 is shorter than my 3.5 Rover V8, and the TR6060 is about the same length as the LT85 + 2 to 3 inches allowing for the adapter. The LT85 has a long belhousing (11" long, the TR6060 is about 5.5", the LT85 is 15" long (excluding the bell), the TR6060 is about 23-24" (excluding the bell).

Sorry for the waffle, but if you are interested (now or in the future there may be someone looking for if it can / has been done before) [before they end up with an LS7 in the garage....]

Thanks in advance again

Rob

[bishbosh]

Will the LT230 not self destruct with that much power and torque going through it?

[vulcan bomber]

Will the LT230 not self destruct with that much power and torque going through it?

Nah, the LT230's can handle Cummins 6bt's with tuned injector pumps, they probably stick out about as much torque.

[elbekko]

Will the LT230 not self destruct with that much power and torque going through it?

As long as you keep it in diff lock, apparently it's good up to 1000hp.

[sean f]

Didn't realise you where going to be wanting to put quite that much power through it!.

Not sure I would be to happy putting that much through a home made (all be it via an engineering firm but it would still have no testing) conversion shaft. I read the mez write up as well before I did mine although I think the friend I got to do mine had a bit more experience and better kit so hopefully better quality, we checked it was true to within a couple of thou, which when we did some other check was better that the mainshaft in a r380 gearbox stength I will only know once the vehicle is on the road and going.

If you want reliability I would suggest rakeway but as you have probable realised you are going to have to pay for it.

Surprisingly I found that the 4l80e gearbox was actually shorter than a zf24 autobox although by the time the transferbox adapter was made and added it was about the same as quite a long rear adapter is required for clearance for the front prop.

Out of interest what axles are you looking at, that is an aweful lot of power to go through rover axles even uprated ones.

[vulcan bomber]

As long as you keep it in diff lock, apparently it's good up to 1000hp.

Its torque that breaks stuff...

The week spot of a LT230 is the diff inside it, Ashcrofts make stronger bits for them.

[robertspark]

Hello all, sorry, been away on holiday...

The full plan is as follows:

LS7 complete with dry sump kit to be installed, dry sump to be positioned on the LHS front of the engine bay, dry sump hoses routed from the dry sump RHS outlet / inlet hose positions.

The LS7 has the full accessory kit, but I will remove the a/c compressor as its location is a little close to my power steering box.

I have the standard LS7 hydro-formed manifolds, I would prefer at this early stage to keep them if I can, as GM spent quite a bit of time, effort and development cost in developing the manifolds, so they may as well be worth a try, new exhaust obviously required from the manifold flanges, preferred option is to use a balance pipe between the two individual routed exhaust pipes, and no a common silencer box (such as the Rimmer Bros Sports Exhaust I have for my 3.5L), fall-back, follow the Rimmer Bros exhaust routing (not keen on this exhaust route because of the unequal "2" section, which creates an odd backpressure on the exhaust, which appears to be similar to a sticking exhaust valve in appearance of exhaust pulsations.... can't help engine power...

The LS7 intake manifold will be installed backwards (same as used on a kit car, Utlima etc) which will avoid a tight bend on the intake before the radiator, also gives me an option to install two raised air intakes of decent bore at a later date if required (the LS7 uses 100mm bore intake hose, avoiding any suction pressure on the intake and (unnessesary) backpressure on the exhaust can only help power

Fuelling the LS7 will be via LPG (SGI)..... (preferred) + albeit I may use a single point / venturi to start with as I have a few vapourisrs around that will work fine, using the GMPP ECU with drive by wire throttle, GM spent enough developing this arrangement and it is sat on my LS7 at present. Need to check on the LPG comparability with the titanium valves, some say no problems, but nothing specific on the LS7 or LS9 which both have similar valves, albeit I don't think LPG is an option really pushed in the US....

I am trying to keep the LT230 transfer case mounting position, in order to reuse the propshafts and their standard geometry. (my base point).

The axles will be 90 HD axles, as standard with the factory fitted v8 90, albeit with both front and rear Detroit True Trac 24 spline LSD differentials. Speaking with Rakeway earlier, and with "corvette dave" on the slro2 forum, when I mentioned this conversion, both said the weak leak is likely to be the landrover axles, (Neale at Rakeway) mentioned that he would estimate the power rating of the landrover axles at about 300HP - 230HP each (torque rating not mentioned, but I would hazard a guess with gearing this would be quite high), and the problem that he saw was when dropping the clutch and the 90 sits on its back axle that would be the end of the rear crownwheel and pinion, and even the use of KAM differentials would not change this very much in his opinion. I am willing to keep an open mind and see what happens, the type of LSD I am using I am not too fussed by loosing a crownwheel or two through trial and error.

I am not intending to peg the diffs at present, but I may change my mind. I have looked at what is involved, and at getting it done, I have all the material, but am not convinced that it is the best solution... The problem that I see is that the phosphor bronze pressure plate is held in position with two dog bolts (basically a bolt with a rececced / turned down end) and two recesses in the phosphor bronze pressure plate. Reading ashcrofts welbsite, they recommend adjusting the bolts every few months... I am aware that the pressure plate is a close fit between the rear of the crownwheel, but if it is wearing down, at some point, and depending upon the wear rate (frequency & need of use) at some point there is the potential of the bronse pressure plate jumping the bolts and floating round the diff housing, which may cause the loss of crownwheel + pinion teeth (i.e. back where I started!). My solution that I am exploring after looking at my diff housing which appears to be a different casting with very little clearance between the CW & casing, is to build up the diff casing with a tig weld, (maybe weld a bronze lip), which will be in close proximity to the back of the CW, die ground and profiled to support much more of the rear of the CW exposed lip than the diff peg arrangement will provide. We will see how I get on with this solution.

I will also not be trying to pick the nose up and put all of the torque on the rear axle either...! Albeit trial and error required once its all together to see what its like.

The rear axle [standard "HD" v8 90 axle] has been converted to vented disk braked, using the well known sailsbury conversion route which does work on these "HD" axles. Braking will also be "trailed", both front an rear will be crossdrilled and grooved, with the front being vented and the rear using front sold disks and 110 rear calipers, albeit there is the question of brake bias effect. I did think about fitting ABS off a 90 complete, but am not going to go that route for various reasons and the 90 may become near un-insurable...in my opinion without going the SVA route + Q plate which I don't want to go unless unavoidable. Again, I would like to avoid custom bigger rotors, mounting brackets and bigger rims etc (intending to use my deep dish alloys).

The LT230 seems to be referred to as the only thing that Leyland designed and built that was done right and is fairly bulletproof (except for input gear splines, and the diff...). The plan is to install a Quaife TL230 LSD which should help spread the torque about between the front an rear axles, which will in turn spread their torque about using their LSD's.... that's the plan anyway. The use on the difflock is not really what I want to do in my road application (tarmac), albeit Neale from rakeway did mention that this was the standard racing approach albeit I suspect that this is on loose surfaces (high speed) and low speed applications only to prevent wind-up.

Insurance is going to be a whole other ball game on this one if I do too much to it, and I'd like to use it on the road.

I was getting everything drawn up whilst on leave, and think I have a plan on the adapter plate which will reduce the work required. It will be a month or so before I am at the stage of tail putting the transmission and engine all together so I'll park this for a moment, the consensus seems to be speak to Rakeway for the input gear.

[Hybrid_From_Hell]

Pictures will always be good

Sounds a nutty lunactic plan, bordering on excentric and barking = very very interesting for me

Good luck, looking forward to updates

The Phosphor Bronze pads take more abuse than you would think, but another "Odd" pegging option I saw when with Steve at KAM was a suzuki unit

and this had a seriously odd and Bodgey feel to it - BUT WAS FACTORY really we said in a enthusiast did it everyone would scream "Nasty Bodge " !!

Drilled casing with BIG F O Bolt screwed in with what I can only describe as a Ball bearing welded on the end of the bolt as the "Hold it all in place"

stylee but I did think that 2 x maybe 3 x of these mounted in the diff would give wider spread of protecvtion / hold, but the noises could be interesting !

you'd prob get a audible "its Working Eeek" sort of warning

Nige

Nige

[robertspark]

Nige there are a few posts about using the lone bolt head solution: http://www.lro.com/forum3/viewtopic.php?f=2&t=50255

I did think about using a few of these ball headed set screws: http://www.ondrives.com/fasteners-set-screws-m4-m16-2.html, they do teflon ones too and other tipped ones, albeit I was not keen for the chance that the ball may come off the end and end up floating around the inside of my axle tube in close proximity to a turbulent CW, and may (like a stray phosphor bronze backing plate) end up in a CW&P and do a whole lot of un-nessesary damage, hence the consideration to weld / braze a support rim in close proximity to the rear of the CW to serve the same purpose.

Pictures----

I am hoping to use a Tremec TR6060 suitable for a camero (420 lbf ft torque rated albeit there seems to be an approch that these are suitable for all LS engines albeit this is probalby expecting a bit of tyre slip to handle the higher torque motors....).

The "weak point" of these transmissions in the mainshaft, it uses a flanged yoke, with a very nice groove around the mainshaft, just before the short splined section that the yoke secures to (in my opinion acting similar to a fusible spline (KAM use something similar), if you look at the failed mainshafts, you will notice a clean break around this groove....

The best solution to this also aligns with what I'm trying to do, change the mainshaft for a Tremec T56 Magnum Mainshaft....

T56 Magnum Mainshaft on the LHS, TR6060 Camero Mainshaft (flanged yoke) shown on the RHS above,

This conversion is suppose to be good for in excess of 700 lbf ft of torque, albeit there is mention of up to 1000 lbf ft..... either way it fits in with what I want / need to do, because the Tremec T56 Magnum Mainshaft has a long splined (31 teeth, near 1.4" diameter, exact machine spec's I managed to get direct from Tremec, very helpful co).

With a longer mainshaft, if gives me the opertunity to align the transmission better with a fully splined LT230 input gear...

Thats the plan anyway.

I did look at using a T56 transmission (essentially the same as the TR6060, albeit there are many internal advances / improvements in the TR6060 / T56 Magnum so the internal components are not interchangeable.

The conversion also now does offer the opertunity for electronic shifting via either flappy paddle, or sequential type shifter....

. but I'd like to get it working first before exploring this conversion option.

[Gazzar]

W643d Tre0ec c4st60 0a2e a 0a5nshaft f6r y64/

Arrgh! Number lock on a laptop! WILL PRY OFF KEY.

Anyway - what I was trying to say is

"would Tremec custom make a mainshaft for you?

G.

[bishbosh]

That made me laugh! Thanks

[robertspark]

Don't think that Tremec are too interested in one offs (from the feedback I got on their forums, they are helpful though), besides I don't think that the 10 spline landrover gearbox output shaft is particularly strong being 10 spline....

Stronger spline arrangement seems to be the 31 spline output shaft (larger diameter shaft, smaller teeth (less eroded material + larger contact surface area). Looking at my LT85 output spline wear and the odd wear profile (suspect it was due to LT230 input gear bearing wear + movement under load), I'm not impressed, also the LT85 output shaft seems to load the rear of the LT230 input gear because of the way the LT85 mainshaft is machined, whoever thought of that makes me wonder?

My T-56 Magnum 31 spline mainshaft arrives in a few weeks, albeit I don't think that I will getting heavily into the TR6060 --> LT230 conversion for a little while as I am still doing axle rebuilding + strengthening work (couple of hours every night arrangement).