3.5 V8 Efi from an early Disco into 2.5P 90

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cappers

cappers

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Been offered a good running 3.5 V8 Efi from an early (K reg - 1992?) Disco, plus the LT77 box; not sure if it's a long stick or short stick - anyone know if/when they changed or were LS only used on early RRC?

I understand that if it's a long stick it'll fit a 90 without too much hassle as there are no tunnel modifications needed if using the existing 90 gearbox mounts. Prop-shafts remain the same as well, as does top hose, bottom hose, standard exhaust and V8 fan cowl.

A short stick will mean cutting the seatbox etc. and the gearstick ends up just at the front edge of the seat box.

If the box is no good should I just get the engine and hunt around for an appropriate box or get my squat bellhousing LT77 (4cyl 2.5 petrol) modified. I don't really want to bodge seat boxes etc and would like the V8 to drop in where the LR Godz designed it in a 90.

Any thoughts most appreciated please (yes I know there's probably 100s of posts about V8 conversions but I haven't time to search through what often appears to be conflicting opinions!).

capo
 
it will be short stick long stick is only early rrc and all defenders, apart from long or short stick there are 2 lengths of boxes all 4 cylinder defenders up to 300 tdi use a short box, with engine tight up to bulkhead,all rrc and discos and 300 tdi and v8 boxes are long with engine tight against rad in the defender, ,it also means from factory a 300 or a v8 has a different tunnel seat box floor plates etc as even though the box s long because the engine is tight against rad transmission sits about 2 inches further forward than short box vehicles
you could fit an adapter kit on the short sick and def long stick top if you can find one then fit the v8 further back in engine bay by 2 inches than standard, often done but a bodge job compared to fitting as factory would have done imo
 
Last edited:
Thanks for the reply James.
I'd rather not end up with a bodge so how would you do it? Would it be worth looking for a LT85 which would fit corrrectly or a LT380? I've been told an auto box would fit without hassle, is that so?
Jon
 
lt85 is the same length as disco box,just not as nice been a bit more agricultural, id sit engine forward against rad as landrover did ,auto is nice
 
This is what I have discovered so far...to me option #1 seems the easiest if not the cheapest route, whilst option #2 has potential....

1. Phone Mr Ashcroft and ask for a nice strong R380 (all the latest/greatest internals) with a V8 bellhousing/input and a Defender tailcasting/shifter.
Then it miraculously just all fits nicely with everything in the right place, with a proper V8 clutch and no mods to fit anything.
Yes it costs more money, but it cuts out a hell of a lot of pratting around both at build time and when servicing.

2. A LT77 gearbox from a circa. '85 R/R or an early V8 disco (the gear stickconfiguration is the same as a 90) there are no tunnel modifications needed if using the existing 90 gearbox mounts.
Propshafts remain the same as well, as does top hose, bottom hose, standard exhaust and V8 fan cowl.
Sit the R/R V8 engine mounts 1.5" further back than fitted on the R/R and the engine/ gearbox will drop in.
Don't use the "short stick" gearbox from Disco's and later R/R's unless you want to cut the seatbox etc. the gearstick ends up just at the front edge of the seat box.

3. A V8 Disco LT77 box will go in a 90 or 110 but the gearstick comes up through the front of the seat box.
Some people have suggested it's possible to cannibalise the 90/110 2.5 LT77 box and swap top housings/linkages etc - no idea how practical this is.

4. An auto box from a V8 auto Disco should just drop in - I once measured them and the Disco V8 auto, Disco V8 LT77, and 90/110 LT85 are all the same length. The Borg Warner chain drive transfer box that's usually mated to the auto box has a (IIRC) shorter front output flange so you need a different length drive shaft.

My query is you wrote:
jamesmartin said:
it will be short stick long stick is only early rrc and all defenders
Click to expand...
Yet #2 states: A LT77 gearbox from a circa. '85 R/R or an early V8 disco (the gear stickconfiguration is the same as a 90)...I assume a K-reg will be a late disco?

Apologies for all the Qs but if I'm going to do it I want to do it right, and you appear from your numerous posts to be the man who knows about these things.
 
capo said:
This is what I have discovered so far...to me option #1 seems the easiest if not the cheapest route, whilst option #2 has potential....

1. Phone Mr Ashcroft and ask for a nice strong R380 (all the latest/greatest internals) with a V8 bellhousing/input and a Defender tailcasting/shifter.
Then it miraculously just all fits nicely with everything in the right place, with a proper V8 clutch and no mods to fit anything.
Yes it costs more money, but it cuts out a hell of a lot of pratting around both at build time and when servicing.

2. A LT77 gearbox from a circa. '85 R/R or an early V8 disco (the gear stickconfiguration is the same as a 90) there are no tunnel modifications needed if using the existing 90 gearbox mounts.
Propshafts remain the same as well, as does top hose, bottom hose, standard exhaust and V8 fan cowl.
Sit the R/R V8 engine mounts 1.5" further back than fitted on the R/R and the engine/ gearbox will drop in.
Don't use the "short stick" gearbox from Disco's and later R/R's unless you want to cut the seatbox etc. the gearstick ends up just at the front edge of the seat box.

3. A V8 Disco LT77 box will go in a 90 or 110 but the gearstick comes up through the front of the seat box.
Some people have suggested it's possible to cannibalise the 90/110 2.5 LT77 box and swap top housings/linkages etc - no idea how practical this is.

4. An auto box from a V8 auto Disco should just drop in - I once measured them and the Disco V8 auto, Disco V8 LT77, and 90/110 LT85 are all the same length. The Borg Warner chain drive transfer box that's usually mated to the auto box has a (IIRC) shorter front output flange so you need a different length drive shaft.

My query is you wrote:
Yet #2 states: A LT77 gearbox from a circa. '85 R/R or an early V8 disco (the gear stickconfiguration is the same as a 90)...I assume a K-reg will be a late disco?

Apologies for all the Qs but if I'm going to do it I want to do it right, and you appear from your numerous posts to be the man who knows about these things.
Click to expand...
if you buy ashcroft or use another box you have to decide how you fit it, as lr did or in the 2.5 transmission place
as i posted earlier only early rrc used a long stick lt77 which is a long bell housing box and is same length as lt85 and r380 or auto all disco boxes are short stick,defender long stick as in 4 cylinder models use a long stick short bell housing box, if you had a v8 landrover defender with factory fit v8 they were fitted with a long stick long bell housing box at one time
 
jamesmartin said:
if you buy ashcroft or use another box you have to decide how you fit it, as lr did or in the 2.5 transmission place
Click to expand...
Ideally as LR did it in the V8 90! My former V8 90 & 110 were long stick, long bell housing LT85s.

So I need to find a RRC/Defender long stick, long bell housing LT77 or the Ashcroft 'modded' R380 with V8 bellhousing/input and a Defender tailcasting/shifter?
 
capo said:
Ideally as LR did it in the V8 90! My former V8 90 & 110 were long stick, long bell housing LT85s.

So I need to find a RRC/Defender long stick, long bell housing LT77 or the Ashcroft 'modded' R380 with V8 bellhousing/input and a Defender tailcasting/shifter?
Click to expand...
why modded r380 ?any std defender v8 box or disco/rrc with an adapter to change to long stick
 
jamesmartin said:
why modded r380 ?any std defender v8 box or disco/rrc with an adapter to change to long stick
Click to expand...
Doesn't need to be a modded R380, it just seems from various threads that is a possible option.
The simplest would be, as you say, a Defender V8 box or Disco/RRC and L/S adaptor.
You don't happen to have any lying around by any chance?!
Thanks for all your advice.
 
you have a 4 cylinder 90 and theres no way of fitting a v8 as lr did without moving transmission which means tunnel and props etc or by fitting v8 engine further back wich means non std exhaust ,coolant hoses etc
 
So, not as straightforward as I had hoped.
Of the two choices above I'd rather mod the tunnel and get the appropriate length props.
jamesmartin said:
you have a 4 cylinder 90 and theres no way of fitting a v8 as lr did without moving transmission which means tunnel and props etc
Click to expand...
From that I take it you disagree with the above advice I found? : LT77 gearbox from a circa. '85 R/R or an early V8 disco (the gear stickconfiguration is the same as a 90) there are no tunnel modifications needed if using the existing 90 gearbox mounts. Propshafts remain the same as well, as does top hose, bottom hose, standard exhaust and V8 fan cowl. Sit the R/R V8 engine mounts 1.5" further back than fitted on the R/R and the engine/ gearbox will drop in.
 
capo said:
So, not as straightforward as I had hoped.
Of the two choices above I'd rather mod the tunnel and get the appropriate length props.

From that I take it you disagree with the above advice I found? : LT77 gearbox from a circa. '85 R/R or an early V8 disco (the gear stickconfiguration is the same as a 90) there are no tunnel modifications needed if using the existing 90 gearbox mounts. Propshafts remain the same as well, as does top hose, bottom hose, standard exhaust and V8 fan cowl. Sit the R/R V8 engine mounts 1.5" further back than fitted on the R/R and the engine/ gearbox will drop in.
Click to expand...
the above must mean sitting the engine in a further back position than lr did ,engine will be sitting back 2 inches so engine fittings like hoses are are going to either stretched or non stock parts
if you fit a v8 as landrover did then rrc or disco front prop then fit
 
jamesmartin said:
the above must mean sitting the engine in a further back position than lr did ,engine will be sitting back 2 inches so engine fittings like hoses are are going to either stretched or non stock parts
Click to expand...
I defer to your knowledge and experience, but what I quoted above does say that props, top hose, bottom hose, exhaust and V8 fan cowl are in the correct place, so why is the engine not? Isn't the RRC chassis longer than the 90 so 1.5-2" further back on the 90 chassis would still site it 'correctly'?
Sorry :) not arguing, just want to get the facts clear before I make any decisions. The main message - correct me if I'm wrong - is that there's no point getting the box from the disco on offer, I need a LS LB/H LT77. or an auto.
Again, thanks for the help.
 
capo said:
I defer to your knowledge and experience, but what I quoted above does say that props, top hose, bottom hose, exhaust and V8 fan cowl are in the correct place, so why is the engine not? Isn't the RRC chassis longer than the 90 so 1.5-2" further back on the 90 chassis would still site it 'correctly'?
Sorry :) not arguing, just want to get the facts clear before I make any decisions. The main message - correct me if I'm wrong - is that there's no point getting the box from the disco on offer, I need a LS LB/H LT77. or an auto.
Again, thanks for the help.
Click to expand...
its a fact 300tdi and v8 use a long box which does sit further forward than the 4 cylinder with short box so as the need to alter tunnel and swap props, if you fit a v8 or a 300 with the longer box in the short box position the engine itself wont be fitted as lr did it will be 2 inches further back so in non std position all the exhausts and top hoses are made to fit the v8 in lrs position not one further back,
when it comes to chassis a v8 or 300 tdi when fitted as lr did ,engine and box fit as they do in rrc or disco hence disco front prop fitting
theres no point in getting a short stick box unless you can alter the top to long stick if you can id suggest fitting in lr std position which is 2 further forward than your transmission sits now,i know because ive done about every conversion there is going some quite a few times
 
Have a look at my ongoing thread in the defender forum. I removed my 200tdi (same engine location as 2.5 petrol i think) and am installing a v8 with mounts that i have fabricated. Everything apart from the mounts and exhaust+manifold will be standard and in the land rover position.
 
Mikewilliams said:
Have a look at my ongoing thread in the defender forum. I removed my 200tdi (same engine location as 2.5 petrol i think) and am installing a v8 with mounts that i have fabricated. Everything apart from the mounts and exhaust+manifold will be standard and in the land rover position.
Click to expand...
Cheers just what I want!
Doing an open day so read later.
 
Fuelling for 3.5 efi.....I have an in tank pump on the 2.5p carb but I doubt the pressure is right for efi.
So should I add a Facet pump inline after the in-tank pump or get an efi rated in-tank pump? I think the latter would be less noisy, my old Pacet whined!
 
3.5EFi fuel pressure tested at the fuel rail should be between 34 & 37psi.
Fuel from the tank goes to the pressure regulator at the engine (varies pressure according to manifold depression) then around the rail & unused fuel goes back to the tank so you'll need delivery & return lines.
 
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