Hi guys anyone know how hard it is to down size a disco 1 3.9 L petrol engine to something smaller preferably around 2.5L .

 

It should be pretty easy. Rover offered a inline 4 cylinder engine for the DI.
It should be a bolt right up thing since you already have a petrol engine and transmission.
Are your taxes to high on the truck with the larger engine?

 

If you think you're going to get better mileage... Well, You're probably not going to realize enough of a difference to offset the price of admission for quite a while...

John

 

I think he wants to do it for tax reasons, in some countries they tax each car every year based on engine size.
We pay a registration fee every year for our licence plate, they pay based on engine size.
Land Rover offered a 4-cylinder engine specifically for this reason.

 

I certainly don't know how that would work. Here if that was the case, It would be taken from the VIN and it wouldn't matter if you changed out the engine or not... Like some worker at the DMV would know a 2l 4cyl from a 4l 6cyl...


So, What I did was took this 4.0l V8 and lenghthend the rods and changed out the crank. Now it's only a 2.6L

I mean why not go ahead and tell them some story like that ?

John

 

its for consumption reasons. dont think there is a tax issue. im a student and cant afford the 4.0L. would the change make a difference?

 

No swapping to a smaller engine will not make a difference in fuel consumption.
A smaller engine has to work harder so it uses more fuel.
You want a diesel engine, you will get almost 30mpg with a Rover TDI compared to the V8's 15mpg.
But the cost of the conversion, although cheap in Europe, will still cost more than a years worth of petrol.

 

Not really sure how much of a change it would make as far as consumption. Its a lit of truck for a little engine and god for bid you have to climb a steep hill. In general to me i think you will end up overworking that poor little motor.

 

Here is something we have all forgotten to mention, there are ways to make the 3.9 more fuel efficient.
New spark plugs and leads, new dizzy cap and rotor, increase tire pressure, use 80w-90 gear oil in both diffs and the t-case, make sure the air filter is clean, keep all windows closed when driving, dont have a roof rack, remove all extra weight out of the truck, use the cruise control, drive slower, accelerate slow, anticipate your stops, so instead of stopping at a stop light coast up to it so you dont actually have to use the brakes.
If it is a 5-speed "dog" the engine, in other words up shift sooner than you normally would so you keep the engine RPM's lower.
Replace your from oxygen sensors if you have them.

 

Man this thing hardly has enough power with a 4.0, I could t imagine less engine in there. I'd love a diesel though, I do work on diesel equipment for a living so it'd be appropriate haha.