Dannyuk

New Member
Hello all hope your well ? I have a 1988 defender 90 with the 2.5 petrol (17h I believe). engine. It runs fine but is slow and I would like something with a bit better sound and a bit better. My dad has just got a 3.9 v8 that runs perfect from his friend. I was just wondering how hard it would be to fit in my 90 to my existing gearbox any help greatly appreciate thank you dan
 
To do it properly you need a LT85 box from a 90/110 V8 or long stick lt77 from a Range Rover. The LT 77 you have had the wrong stud pattern for the V8, is too short for the engine to sit in the right position and has the wrong ratios (5th is only .83:1 where the V8 boxes are .77:1. Also your transfer box is too low 1.41:1 instead of 1.22:1. You could get conversion plate to get it to mate but it would be too revvy on the road. You could use a short stick LT77 from a Range Rover or a Discovery 1 but then the gearstick would be in the wrong place (at the front of the seatbox) It is possible to use a LT95 box from an early Range Rover but that only has 4 gears, overdrive are available but at a cost.
 
To do it properly you need a LT85 box from a 90/110 V8 or long stick lt77 from a Range Rover. The LT 77 you have had the wrong stud pattern for the V8, is too short for the engine to sit in the right position and has the wrong ratios (5th is only .83:1 where the V8 boxes are .77:1. Also your transfer box is too low 1.41:1 instead of 1.22:1. You could get conversion plate to get it to mate but it would be too revvy on the road. You could use a short stick LT77 from a Range Rover or a Discovery 1 but then the gearstick would be in the wrong place (at the front of the seatbox) It is possible to use a LT95 box from an early Range Rover but that only has 4 gears, overdrive are available but at a cost.
To do it properly you need a LT85 box from a 90/110 V8 or long stick lt77 from a Range Rover. The LT 77 you have had the wrong stud pattern for the V8, is too short for the engine to sit in the right position and has the wrong ratios (5th is only .83:1 where the V8 boxes are .77:1. Also your transfer box is too low 1.41:1 instead of 1.22:1. You could get conversion plate to get it to mate but it would be too revvy on the road. You could use a short stick LT77 from a Range Rover or a Discovery 1 but then the gearstick would be in the wrong place (at the front of the seatbox) It is possible to use a LT95 box from an early Range Rover but that only has 4 gears, overdrive are available but at a cost.

Hi so basically need a lt85 box
 
The 2.5 petrol engine isn’t the quickest but it’s a good engine. You can get upgrade kits from ACR which would give it a lot more poke and a sports exhaust is available from the same which would give it the sound you want.

Original landies are more sought after and hold their value better so think carefully before you get rid of the original engine. If you really want a V8, there are quite a few on eBay which means you could sell your current Landy to fund the purchase as there’s a market for such vehicles.
 
that or a v8 lt77 or v8 r380 with defender long stick ,to do as factory youd need different tunnel floor plates ,props as the whole lot sits further forward like the 300tdi defender do
Yes, I forgot about the V8 R380 long stick.
 
The easiest way would be to find a rotten V8 Discovery 1 and use the whole engine, transmission, gearbox crossmember, front prop, front section of exhaust, etc.
The front half of the Discovery 1 chassis is virtually identical to the 90/110 chassis other than the engine mounts, ideally to put the V8 engine in the standard position, you would use the matching Discovery crossmember, which would move the transfer box a couple of inches further forwards, the same as a 300tdi.
The problem is that most Discovery 1's have dissolved, so could be hard to find, a Discovery II is probably more available these days. I'm not sure how they compare to the Discovery 1's mechanically, the chassis is definitely different and more rusty, but they do use a similar transfer box. I imagine the ancillaries will be the issue here.
Alternatively you can use a V8 conversion plate from a Series 2/3 conversion, which will mate to your existing gearbox, but puts the engine way back in the engine bay, in the same position as the current engine, which creates its own problems. With a V8 conversion plate, you may have to chop the passenger footwell and you will have to fabricate the front section of the exhaust.
 
Sounds like a hell of a lot of work for achieving a car that won't be original, will probably not drive as well and one you will probably want to get rid of in a couple of years.

Col
Worth it for the sound alone, not to mention caning the b0llox off it, in in low-box 3rd in deep mud.
 

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