LT77, LT85, R380 Which is where?

Diana,

I once looked at re-powering an S2B with a 3.9/LT85/230, but was advised that the UJ's in the front axles wouldn't last long with constant 4WD. They were really designed only to take power on the occasions when 4WD was engaged, not all the time.

This came from a website in Africa, where they do LOTS of things to Land Rovers as expedition vehicles.

I believe it would be possible to modify the transfer box so that the CDL became a 2WD/4WD selector.

Good luck, it is a nice project. BTW, I think you bought some S2B panels from me when I was in Lancefield, Vic. Hope they reached you okay.

Cheers,

Paul

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Originally Posted by Wilbur

Diana,

I once looked at re-powering an S2B with a 3.9/LT85/230, but was advised that the UJ's in the front axles wouldn't last long with constant 4WD. They were really designed only to take power on the occasions when 4WD was engaged, not all the time.

Paul

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I believe this applies to any series landie - couldn't the UJs and the associated axles etc be replaced with CVs out of later awd landrover products.

Gazzz

Or are HD axles/UJ's available for series axles?

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Originally Posted by Wilbur

... I once looked at re-powering an S2B with a 3.9/LT85/230, but was advised that the UJ's in the front axles wouldn't last long with constant 4WD. They were really designed only to take power on the occasions when 4WD was engaged, not all the time...

... I believe it would be possible to modify the transfer box so that the CDL became a 2WD/4WD selector...l

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Quote:

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Originally Posted by garrycol

I believe this applies to any series landie - couldn't the UJs and the associated axles etc be replaced with CVs out of later awd landrover products. ...

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Paul and Garry

Thanks for your concerns about my axles, however they are a little unfounded because of what I haven't told you.

This project will be motivated by Maxi-Drive halfshafts the front ones being hybrids that use Stage I V8 CV joints. Mal Story made them up for me in the final months before he retired. However I am lead to believe that Hi-Tough Axles (the successor company) will also make them up from my prototype designs should people require them.

Regarding the selectable 2WD design, some LT230s used by Santana have a selectable 2WD/4WD design and the gearsets can be retrofitted to UK manufactured LT230s. There is a mob in Adelaide who sell kits for the LT230.

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Originally Posted by Wilbur

Diana, ...
...Good luck, it is a nice project. BTW, I think you bought some S2B panels from me when I was in Lancefield, Vic. Hope they reached you okay.

Cheers,
Paul

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Paul

Yes t'was I who bought the panels and Jeff Sparks picked them up and delivered them to me at the LROCV Gathering in Melbourne last year. In fact you may know the chassis that is going to be used for this project. It was one that Ken West had although he sold it without the panels and doors. The Eaton truck rear end and that horrible tray have been removed and we are going to stretch the wheelbase to 130" (not 127")

https://www.aulro.com/afvb/images/im...010/06/756.jpg

They are your panels sitting on the vehicle in the pic - although I have swapped the bottom side panels for a couple in better condition from one of my other S2B's.

Do you still have an S2B? Do I have a couple of pics of it, grey ex-RAF excellent condition.

https://www.aulro.com/afvb/images/im...008/05/276.jpg

Cheers
Diana

Diana, if you are bunging in a V8 and most likely a "slightly improved" V8, then you will be playing with probably double or more the horsepower of the Rover 6. Assuming you keep the diffs at 4.7:1 then even with 9.00 x 16's you should have no problem pulling the fast ratio transfer case and get a reasonable engine speed for cruising. It is in low range for off road work that you need the deep reduction.

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Originally Posted by Brian Hjelm

Diana, if you are bunging in a V8 and most likely a "slightly improved" V8, then you will be playing with probably double or more the horsepower of the Rover 6. Assuming you keep the diffs at 4.7:1 then even with 9.00 x 16's you should have no problem pulling the fast ratio transfer case and get a reasonable engine speed for cruising. It is in low range for off road work that you need the deep reduction.

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Brian

Low range should not be a problem, the original FC helical box had a low ratio of 3.277:1 where all the LT230's have a low ratio of 3.321:1 so actually lower than the original t/f box.

What I don't seem to have at hand is the ratios within the R380 and LT85 gearbox. (I have the 4th O/D 5th but not 1st, 2nd, 3rd and rev ratios.)

The original LT95 Range Rover 4 speed had a 1st gear of 4.069:1 which would compensate for a 1:1 t/f reduction however if the R380/LT85 have shorter gear ratios then the lower 1.222 or 1.41 t/f ratio may be preferable and less strain on gearbox.

As an aside, I was also considering dropping the tyre size to 8.25 16, because of better availability and reduced cost. I think that works out at 34". (8.25 16 are a common truck size still in production.) this would mean that the selection would be either the 1.003:1 or 1.222:1 LT230 ratios.

My thoughts last week (before this thread) were to look for a manual SI Discovery with the 1.222:1 ratio. Which works out at 2600 RPM @ 100KPH (being the max torque on the 4.6, but I don't have the numbers for the 3.9). The reason for the disco, is that it is likely the best compromise available at the cheapest cost. RR's being LT77's and Defenders holding their value better.

Diana

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Originally Posted by Lotz-A-Landies

SB

Just to clarify where I'm coming from. The final drives in high range on 4.7:1 ratio diffs and (KPH/1K RPM 9.00 16 tyres) are as follows:
Forward Control helical t/f = 7.19:1 (22.64 KPH)
F/C Helical + Farey OD = 5.61 (27.58 KPH) (combination not available)
Regular Series t/f = 5.4:1 (30.15 KPH)
Series + Farey OD = 4.21 (36.72 KPH)
LT230 1.003:1 5th = 4.7:1 (34.64 KPH)#
LT230 1.003:1 4th = 3.43:1 (47.45 KPH)#
LT230 1.222:1 4th = 5.74:1 (28.35 KPH)
LT230 1.222:1 5th = 4.19:1 (38.83 KPH)
LT230 1.41:1 4th = 6.63:1 (24.57 KPH) *
LT230 1.41:1 5th = 4.84:1 (33.65 KPH) *

* Probably the best options when you think about it!

Diana

Out of interest: Regular series vehicle 7.50 16 tyres = (27.49 KPH/1K RPM) + O/D = (33.48 KPH/1K RPM)

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Hi Diana, I agree with your asterisked selections,( a final drive of around 1.3:1 would be good if it existed! )The 1.222 would be too high, as fourth gear would be used mostly then, 3rd into a headwind or hilly country. The 1.41 is the best solution, as a 3.5 or 3.9 needs to be at around 3000rpm to be in its 'happy place' pushing a FC through the air at 100kmhr. This then gives you the use of 4th gear, the strongest one, to tow and lug with.
Sounds like a nice project, well done thinking it through properly before starting. More people should do that, ESPECIALLY with reference to gearing selections!!!

JC

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This project will be motivated by Maxi-Drive halfshafts the front ones being hybrids that use Stage I V8 CV joints.

Do you still have an S2B? Do I have a couple of pics of it, grey ex-RAF excellent condition.

Cheers
Diana

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Hi Diana,

You are really doing things properly, this will be some vehicle. Do you have a particular use in mind? You mentioned the Canning....

Yes, that was my S2B, in ripper condition. It had only done 50,000 miles from new, and drove like it. It wasn't RAAF, it had been used by the Dept of Ag for a few years and then privately owned with a camper on the back until I bought it. I sold it and many others when I moved from Lancefield to the South coast of NSW - too b----- cold in Central Victoria. The logistics of moving too many vehicles up here defeated me, but now I really do regret selling that S2B. Irreplaceable, but it went to a nice guy.

Cheers,

Paul

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As an aside, I was also considering dropping the tyre size to 8.25 16, because of better availability and reduced cost. I think that works out at 34". (8.25 16 are a common truck size still in production.)
Diana

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FWIW I put 8.25x 16's on my S2B because I couldn't get any decent 9.00x16's at any price. The marginal drop in final drive ratio suited the LR 6 very well, and I could cruise at higher speeds than with the 9.00's.

Sigh, dearly departed S2B....named Wilbur, by the way.

Cheers,

Paul

LT85 box ratios are:-
1st - 3.649:1
2nd - 2.180:1
3rd - 1.436:1
4th - 1.000:1
5th - 0.795:1

LT95 are :-
1st - 4.069:1
2nd - 2.448:1
3rd - 1.505:1
4th - 1.000:1