gearbox advice please

[riprse]

ive got this with a 4in lift and the big wheels

but ive buggered the gearbox cos its got a 3.5 v8 in it , now what should i do rebuild the old box , buy a recon box , buy a different box, or buy a box of matches and set the bugger alite

[Andy]

give it to me i like that, its one nice looking motor.

seriously i believe series boxes cant really cope with V8s but im no expert.

[MECCANO]

give it to me i like that, its one nice looking motor.

seriously i believe series boxes cant really cope with V8s but im no expert.

well it depends how much cash you have to burn... the s2 box is ment to be stronger at holding the power and people tend to go for that. alternatively you can do silly thing slike lt77s to series transfer, but as the parts arent made any more its either a big hunt or alot of expensive one off jobs. Tonks the one to ask about this.

im interested, how did you achieve a 4 inch lift?

[bill van snorkle]

This question keeps cropping up but no one ever listens to the answer. Series boxes are carp. They were originally designed for the 80 inch landy of 1948 with 1.6 litre 11 hp engine and 28 inch diameter tyres, and were barely able to cope with that if any regular towing was involved. People fit bigger engines,that apply more input torque than the box was designed for. They find that the gearing is too low then fit higher ratio diffsand possibly larger diameter tyres. They are attacking the puny little gearbox from both ends, then they wonder why it won't stay together. I'll give an example of the effect of diff gearing and larger tyres on gearbox reliability. To keep the maths simple I will stick to even easily divided numbers.for the exercise I will disregard the transfercase reduction ratio and call it 1:1 . I will also disregard frictional losses

eg. If climbing a 20 degree slope requires 2000 lbs of tractive effort at the wheels and you have 2 ft (1ft radius)diameter tyres, then your differential output must be 2000 ft lbs of torque. If your differential has a ratio of 4:1 then your gearbox only has to multiply engine torque sufficiently to transmit 500 ft lbs of torque to the propshaft. If you fit 2:1 differentials then your gearbox has to multiply engine torque and transmit 1000 ft lbs of torque to the propshaft. That means the gearbox is under double the strain. Of course I have deliberately exaggerated the difference in diff ratios to make the explanation clearer, but you get the idea.

Bill.

[Andy]

good explination there Bill, i think i finally grasp what your regulary saying.

one question, was a 1.6 really 11hp? i thought they was a little bit more than that

[bill van snorkle]

good explination there Bill, i think i finally grasp what your regulary saying.

one question, was a 1.6 really 11hp? i thought they was a little bit more than that

That was their taxable horsepower.Small bore, long stroke engines had relatively low taxable HP ratings than large bore short stroke engines of similar cubic capacity. They actually developed about 53 bhp.

Bill.

[Tonk]

do iremember seeing that lr in a magazine somewhere?

series boxes, hmmm they're ok if you drive easy, but being made of toffee they dont last long if you use the landrover for rougher stuff.

i've blown loads, had enough and now i've got a lt77 in there.

[riprse]

thanks for the replys guys

but still no real ideas on how to overcome this problem,

tonk

ive got a lt77 with transfre box that came off a v8, apart from the floor work to get it in what else would need to be modified ?

[FridgeFreezer]

In an 88 it's tight but, as Tonk (and Jon W) prove, you can do it.

I think with the V8 you'll want to use an LT77 from a 4-pot and bolts the V8 adapter plate to it, otherwise the bellhousing is too long, the RR ones are about a foot of extra metal!

That said I had a 3.9 V8 in my 109 for years and it kept going (I've no idea how, it never sounded healthy from the day I bought it) got an R380 + LT230 going in now

[MECCANO]

In an 88 it's tight but, as Tonk (and Jon W) prove, you can do it.

I think with the V8 you'll want to use an LT77 from a 4-pot and bolts the V8 adapter plate to it, otherwise the bellhousing is too long, the RR ones are about a foot of extra metal!

That said I had a 3.9 V8 in my 109 for years and it kept going (I've no idea how, it never sounded healthy from the day I bought it) got an R380 + LT230 going in now

but a early 4 pot lt77 is ment to be almost as carp as a series box. you need a later suffix such as one from a 200tdi.

[riprse]

That said I had a 3.9 V8 in my 109 for years and it kept going (I've no idea how, it never sounded healthy from the day I bought it) got an R380 + LT230 going in now

how easy/hard would the r380+lt230 b to fit

[bill van snorkle]

That said I had a 3.9 V8 in my 109 for years and it kept going (I've no idea how, it never sounded healthy from the day I bought it) got an R380 + LT230 going in now

how easy/hard would the r380+lt230 b to fit

If you don't mind cutting sheetmetal you could move the rear axle back to accomodate the extra length.

A 200 tdi gearbox/transfercase is a about 110mm longer than your series transmission and will bolt up to your existing V8 adaptor. If you want an R380 you could have the input shaft shortened (cut and shut ) to match the length of the LT77.

Bill.

[FridgeFreezer]

but a early 4 pot lt77 is ment to be almost as carp as a series box. you need a later suffix such as one from a 200tdi.

I wasn't advocating finding one in a hedge and bolting it in - whatever the box I'd say either buy it from or have it reconned by Ashcrofts, they will put the latest spec internals into it and should be able to sort you out the right input shaft / bellhousing should you need that done.

Gearboxes are something I have no desire to mess about with - for the money it's not worth the hassle IMHO.

how easy/hard would the r380+lt230 b to fit

Well, you dangle it in place and then weld the mounts in - you need to weld tubes into the chassis for the bolts and if you haven't got them you need the mounts to go with them - mine are from a Range Rover, they're all the same as the chassis rails are all the same distance apart and the whole lot is supported by the LT230 not the gearbox so you can cannibalise a dead RR for the mountings. Aparrently Defender mounts are somewhat uglier than the RR ones, go figure

Some 109-in-build piccies for you showing the mounting:

Obviously in a vehicle of inferior wheelbase you'll be a bit pressed for space, my engine is a fair way back as well. Oh and the Series Gbox crossmember has gone since that photo was taken

[riprse]

fridgefreezer

the gear boxcross members not needed then or just in the way

[FridgeFreezer]

The old mounts on it were doing nothing so I chopped it out and put in a bolt-in one from a RR which did end up in a slightly different position - procedure very similar to doing the gearbox mounts really.

[jericho]

''Well, you dangle it in place and then weld the mounts in - you need to weld tubes into the chassis for the bolts''

What diameter and wall thickness tube?

[FridgeFreezer]

What diameter and wall thickness tube?

Errr, I think it was about 16mm diameter which would make the walls about 3mm - really all you need is a bit of tube that is maybe 1mm bigger ID than the bolts to allow a little bit of tolerance, wall thickness is not critical just as long as it's not a bit of copper heating pipe

The important bit is lots of measuring to get the holes though the chassis straight, otherwise it's a lot of messing round with a carbide burr, or if you're a masochist, a file

I held a bit of card against the cross member and cut out a template of the shape/bolt pattern so I could hold it against the chassis and know that the bolt holes would all be in the same relative positions, then all you have to do is make sure the template is in the same position both sides. I measured backwards from the bulkhead outriggers as they should be a reasonable datum, you could always leave the old x-member in and measure to that instead. To check the tubes were going straight through, I found a bit of 10mm bar and stuck it through the holes inside the tube, then measured the squareness to the chassis with a square.

[istruggle2gate11]

In an 88 it's tight but, as Tonk (and Jon W) prove, you can do it.

I think with the V8 you'll want to use an LT77 from a 4-pot and bolts the V8 adapter plate to it, otherwise the bellhousing is too long, the RR ones are about a foot of extra metal!

Im guilty of this conversion too in a series 1 86" V8, same as fridge mentioned, 4 pot lt77 bolted to the adaptor plate, rear prop shortend (seemed happy enough) I also opted for the borg warner viscous at the same time, I used the later 300tdi gearbox mounts as these only required very simple brackets to be fabricated (from 2" angle IIRC).

Its worth the effort to go for the LT, for some reason my series gearbox stayed good, but Dirtydiesel blew loads of em (especialy reverse).

[Tonk]

the LT is worth going for, i've blown reverse gears in series boxes just driving out the garage before