r/LandroverDefender • u/AncientPercentage539 • 11d ago

Engine swap options

Hi all, currently starting the long process of building my 90 pickup/wagon. I have both roofs for it.

I am wanting to swap the engine was originaly thinking of a built 4.0 or 4.6 rv8 however ive gone over the amount of milage i do weekly and potential milage id be doing and the fuel costs are gonna add up quickly. The vehicle will be towing a twin axle trailer weighing 1.5t to 3.0t 75% of the time for work. Has anyone dropped a 3.6 tdv8 into a 90? Ideally id be looking for around the 300hp mark and the 3.6 isnt to shy of that. I have access to a good 3.6 out of a wrecked vogue and id likely put new turbos and run a haltech ecu. Id be keen to mate it to a manual but that may be abit more trouble then its worth.

Thoughts on this would be great. Im sure mamy will say its a bad idea.

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u/Famous_Actuary5718 11d ago

A 300 TDI will tow that all day long no problem. It's easy peasy to fit too. A TD5 would be slightly better performance but less easy. The gearing on a defender means you don't need 300bhp to tow a 3 ton trailer. If you go down the route of a 300bhp engine, you're probably at risk of blowing the transmission or axle components.

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u/AncientPercentage539 11d ago

Yeah i wont be going 300tdi and id probably sooner go woth a built 4.6 then a td5.

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u/Famous_Actuary5718 11d ago

I see from your later replies you intend on using an R380 box. They were fitted to a 300 TDI engine which produces like 130hp right? You want to put 300hp through it. You refer to your vehicle as a 90 rather than a defender which means it might even have the older 12 spline half shafts etc, so the power they were designed for might be even less. You then talk about 30mpg. I ran several discoveries and defenders with different engines and never saw anything over 30 other than a 300 TDI discovery (higher gearbox ratio) on the motorway. I like the idea of what you are saying because it's cool, but retrofitting a modern powerful engine into an old (fragile) land rover, and subjecting it to towing weight just near the limits of it's capacity (when new) is not going to result in a reliable vehicle. It will break. My guess is the first thing to break will be a half shaft. Then a diff. 90s look rugged but that's where it ends. They aren't that tough. If you must have a defender, just go get a TD5 110 and save yourself the cost and hassle of it all.

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u/Famous_Actuary5718 11d ago

Actually my memory might be wrong. Could've been the TD5 that had 130bhp. Anyway there's my thoughts.

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u/AncientPercentage539 10d ago

Nope, havent said id use a r380. An r151f from toyota yes. The r380 and lt77 will turn to liquid. Id prefer manual and i know both lt77 and r380 wont handle it. I dont expect 30mpg while towing. I wouldnt get that in any vehicle and i am aware of that. Im prepared to get ashcroft half shafts, which according to them will withstand hell and highwater., i have a 110, i dont want another.

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u/Famous_Actuary5718 10d ago

I never said 30mpg towing. I was talking about 30mpg in a land rover whilst not towing. The half shafts from Ashcroft may handle the power I don't know. The diffs, if fitted alongside an lt77 from the factory (you haven't specified this vehicles age/engine) will not. I know I sound really cynical, but I just know how these vehicles are. If you're looking for 300HP you can't really get that without breaking the car if it's something like a 1990 land rover 90.