Chaps,

I have R V8/LT77 and 3.92 diff.

I pulled away (quite quickly) in 3rd gear today. Never use 1st.

Now I know that once I get a 3.14 diff things will improve, but will it be enough. Can box ratios be changed - I've looked at the R380 and the only difference was the 3rd decimal, so insignificant.

Any suggestions for alternative - easyish fit boxes with better ratios

Thanks

ATB

Simon

not sure if this is gonna help you, but Land Rover gearbox rations are: (formatting may be off!)

LT77 90/110 LT77 V8 Disco LT77 TDI Disco LT95
1st 3.585 3.321 3.692 4.0691
2nd 2.3008 2.132 2.132 2.448
3rd 1.5074 1.397 1.397 1.5049
4th 1 1 1 1
5th 0.8314 0.77 0.77
Rev 3.7007 3.429 3.429 3.6643

I had rv8 & 3.14 diff in my mx5 & it worked very well with the T5 box - 2nd did ~65, 3rd in the 90s. 3krpm was 80 in 5th. Later I put the 0.63:1 5th gear in & that was too high, something like 0.75:1 would have been better, I was getting about 34mph per 1000revs, which , though excellent on the motorway, was too high a gear to use below 40odd when pottering. OK re your question, the T5 is a bombproof box, goes on with an auto bellhousing and a 12mm adapter plate on the gearbox end if you use a cossie 'box. The spline on the cossie box fits a rover driven plate but you'll need to turn an annular adapter to fit the ford (neeedle roller) spigot bearing.
cheers
Bob

quote:

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Originally posted by Bob C
.............but you'll need to turn an annular adapter to fit the ford (neeedle roller) spigot bearing.
cheers
Bob

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ive got a 3.15 7" sierra diff from classic conversions which cost just under 500quid fitted. cost wise a t5 might be cheaper but without the taller diff you wont gain much .the yanks use an 8.8 ford diff in some cars which il bet have good ratios ,i seem to remember they went into south african xr4i s with a big v8 in.

ive got the same problem with mine and as i cant use the 3.15 diffs im stuck with 3.62 so il keep looking for another gear at 70mph

there are companies in LR magazines that will change all the internals over to change ratios completely not particularly cheap but you can have pretty much whatever you want iirc

OK spigot bearing: the cossie 'box input shaft has to spin in a wee bearing in th middle of the flywheel (at least it does when you press the clutch) The wee bearing (or spigot bush) in a rover flywheel doesn't wotk with the bearing part on the end of the 'box inpu shaft so you have to adapt them to fit. I first tried a phosphor bronze bush but that wore out so I replaced it with the ford part (which is a needle roller bearing) and that worked fine. As I said, I had to turn a 'ring' which went round the ford part and into the hole in tha flywheel (actually the end of he crank if memory serves correctly).
The auto bellhousing (don't know which one....) had a hole enlarged in the side for the release arm - though if doing it again I'd just use a concentric slave cylinder e.g. saab. I can post a picture later on tonight if you want.
The other possibility is to get a TVR bellhousing - they sell 'em as spare parts - to bolt a T5 to a RV8 + all the clutch release gubbins.
cheers
Bob

PS - you need to turn down the cosworth box input bearing housing for it to fit in the TVR bellhousing (10 minute job if you have a lathe)
plus I suspect you may be rather old before you see high ratio diffs from Kammdiffs - I looked into this myself 2 years ago & it was being talked about then.... I got lucky & found a scrap 3.14:
maybe the freelander option is worth pursuing?
Bob

Thanks very much chaps.

For the mo, I'll keep my eyes peeled for a 3.14 diff - one may well be sitting on someone I know's driveway - better ask

Cheers again.

ATB

Simon

Sorry to drag this back up, but found this, and thought it may be of use to some:

http://www.gearboxman.co.uk/psbellhousings.html

ATB

Simon

Simon,

One thing to think about if you're considering the T5 is that its external dimensions are quite different to an LT77. From memory its wider, so you may have to mod your tranny tunnel. I have all the dimensions (including a nice SolidWorks model) but I'm out of the country at the mo so cant get hold of them for you.

If you do get anywhere with new internals/freelander diffs or you come across a hidden stash of 3.14 diffs, be sure to let me know as I'll be facing the same problems eventually.

Cheers,
Adam

[Edited on 24/4/06 by AdamR]

quote:

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Originally posted by Bob C
PS - you need to turn down the cosworth box input bearing housing for it to fit in the TVR bellhousing (10 minute job if you have a lathe)
Bob

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Sorry Adam, I finally got shut of all my V8 stuff a while back: I remember considering making the thing by wrapping some 1.6mm or 1.2mm steel plate round something, so it's quite a thin ring (BTW it was shite - don't even think about it... get it turned properly!)
I'm sure you'll feel safer if you've bought the bearing and measured it and the hole in the crankshaft yourself!
cheers
Bob

FYI I believe these to be the ratios of a v8 mustang in the US.

first transmission gear ratio =3.35
second transmission gear ratio =1.93
third transmission gear ratio =1.33
fourth transmission gear ratio =1
fifth transmission gear ratio =.68


My 93 Cobra does 2000 at 70 mps with 3.08:1

[Edited on 30/6/06 by locostv8]