Discovery 3.9 v8 - rebuilds, reliability, options….

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marjon said:
Won’t be a straight ex though as V8 is different bellhousing. So extra surcharge probably.

Diesel to petrol, exhaust system. Lots of little things, donor car here we come.

You sure? That’s all that need changing?
Thought cam and a few other things need changing to.

But at the end of the day I wouldn’t discourage anybody from having a V8 in their life :)

J
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Well it would have to have a new exhaust anyway wouldnt it just to make it worth it 😂
 
Henry_b said:
Sump - Oil pickup - front cover - oil pump - from memory, not too difficult.
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Keeping distributor for the simple 3.9 efi wiring? which would be the wrong tune for a 4.6 ?

Yes they are all mix n match with the right bits and money.

J
 
resto_d1 said:
I wonder if the top hat liner fitment is included within that v8 developments build cost
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I would hope so.
I have just taken a 4.6 engine out of the spare P38 it’s worth more than the rest of the car.

You need to think how deep are your pockets cos it can be easy with money.

4.0 is the same engine as the 3.9 with engine control difference
4.6 is a stroked 4.0.
Thor and gems are a huge electronic “advance?” From the simple early 3.9 efi.

So you can see the minefield for mods. A basic 3.9efi in good nick would do,
 
marjon said:
I would hope so.
I have just taken a 4.6 engine out of the spare P38 it’s worth more than the rest of the car.

You need to think how deep are your pockets cos it can be easy with money.

4.0 is the same engine as the 3.9 with engine control difference
4.6 is a stroked 4.0.
Thor and gems are a huge electronic “advance?” From the simple early 3.9 efi.

So you can see the minefield for mods. A basic 3.9efi in good nick would do,
Click to expand...
There’s one with box for sale at the moment on the bay. Problem is, as always, you don’t know if it’s been overheated etc before!
 
Okay - V8 D1 owner here. Mines a 3.9 manual, but anyway.
Power - excellent. Will blow any 300tdi out of the water, even a modified one, and even if you fill your boot with lead. And it makes more torque than a 300tdi, and the clutch is much lighter. Also because of the gearing etc, its a much easier and more relaxing car to drive, it hits 50mph in 2nd gear, but has ample power from about 35mph in 5th. Even the steepest hill with the heaviest trailer, 60mph will be maintained, even if it takes 3rd gear to do it. Obviously the auto isnt as good.
Fuel consmption - awful. I would average about 14.5mpg over a tank. On a long run, if I didnt use my right foot too much, Id get almost 18mpg, almost. Around town, I got 12mpg. Over a whole 20 gallon tank.
Reliability - generally, they are quite mechanically reliable. If you overheat them, theyll go wrong, but then thats the case for most engines. The problems come when the computer says no. Mine broke ages ago, it went to 2 garages, neither of whom could fix it, and Ive lost all motivation. Its basically a giant paperweight, but its not worth much as scrap, so theres no point in selling it, I might get round to it yet!
A few other things, depending on when your particular car was registered - if its 1993 or newer, it needs catalytic converters to pass an MoT, and that means you cant run carbs, which means you need the EFI, you can use LRs original one, or you can change to a megasquirt or whatever.
Differences between the engines are minor, but basically, the original engine was a 3.5, and to go up to 3.9 the bore size was increased, and that leaves the block a little weaker, so it can crack, and/or the cylinder liners can drop, but from what I understand, this normally only happens when it overheats. The bores for all the engines bigger than 3.5L are the same (afaik) so the only difference is the stroke, which is determined by the crankshaft. I dont think you can put a 4.6 crank in a 3.9 block, but I could well be wrong.

I have an interesting proposition for you. I bought a 1999 3.9L V8 auto D1 as a running, driving parts car for my manual one. I think its on 155k miles, the bodywork is awful, the interior is pretty grim, and Ive not even bothered looking for rust, but theres probably plenty. Now, currently it doesnt start, because the battery is flat and the wire to the starter is buggered, its also sat for a fair few months, as I won it on ebay sometime last year, and it hasnt moved since. So here is my offer, should you choose to accept it - if you can fix my manual disco (i.e, get it started and running for a sufficiently long period of time, such that it is definately fixed), you can have the auto one for free. Now that may seem like a great deal, free car for some tinkering, or it may seem like a **** deal, several hours of your time for something thats worth a few hundered quid, thats up to you to decide. Also, it goes without saying, if you cant fix it, youve wasted your time and you dont get the other one.
 
Hicap phill said:
If it’s not the daily drive don’t worry about it.
The fun factor outweighs MPG

Also fuel pump needed as pressure difference .
Most things can be swapped/used off the diesel
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This is true. I use my pickup for everything anyway with the dogs etc and it’s set up for the off-roading I do.
My vision for the D1 is making it as 90s premium as I can - hence getting an ES then collecting up all the optional bits and re-doing all the walnut. I want it to stink of leather and not diesel really. 300tdi is an excellent machine no doubt but a v8 just seems such a nice idea. I’ve rebuilt petrol engines before and would be happy to refresh a v8 but sounds like if I do that I want to get someone to get liners fitted
 
lynall said:
Whenever I see a discovery one or discovery two or an older range Rover going down the motorway at 55/60 miles an hour I always know it's a V8!
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Even in my new truck I rarely go over 70 lol. My driving has changed with age. I’d rather chill out with a podcast now than rush 😂
 
LetsHopeItFits said:
Okay - V8 D1 owner here. Mines a 3.9 manual, but anyway.
Power - excellent. Will blow any 300tdi out of the water, even a modified one, and even if you fill your boot with lead. And it makes more torque than a 300tdi, and the clutch is much lighter. Also because of the gearing etc, its a much easier and more relaxing car to drive, it hits 50mph in 2nd gear, but has ample power from about 35mph in 5th. Even the steepest hill with the heaviest trailer, 60mph will be maintained, even if it takes 3rd gear to do it. Obviously the auto isnt as good.
Fuel consmption - awful. I would average about 14.5mpg over a tank. On a long run, if I didnt use my right foot too much, Id get almost 18mpg, almost. Around town, I got 12mpg. Over a whole 20 gallon tank.
Reliability - generally, they are quite mechanically reliable. If you overheat them, theyll go wrong, but then thats the case for most engines. The problems come when the computer says no. Mine broke ages ago, it went to 2 garages, neither of whom could fix it, and Ive lost all motivation. Its basically a giant paperweight, but its not worth much as scrap, so theres no point in selling it, I might get round to it yet!
A few other things, depending on when your particular car was registered - if its 1993 or newer, it needs catalytic converters to pass an MoT, and that means you cant run carbs, which means you need the EFI, you can use LRs original one, or you can change to a megasquirt or whatever.
Differences between the engines are minor, but basically, the original engine was a 3.5, and to go up to 3.9 the bore size was increased, and that leaves the block a little weaker, so it can crack, and/or the cylinder liners can drop, but from what I understand, this normally only happens when it overheats. The bores for all the engines bigger than 3.5L are the same (afaik) so the only difference is the stroke, which is determined by the crankshaft. I dont think you can put a 4.6 crank in a 3.9 block, but I could well be wrong.

I have an interesting proposition for you. I bought a 1999 3.9L V8 auto D1 as a running, driving parts car for my manual one. I think its on 155k miles, the bodywork is awful, the interior is pretty grim, and Ive not even bothered looking for rust, but theres probably plenty. Now, currently it doesnt start, because the battery is flat and the wire to the starter is buggered, its also sat for a fair few months, as I won it on ebay sometime last year, and it hasnt moved since. So here is my offer, should you choose to accept it - if you can fix my manual disco (i.e, get it started and running for a sufficiently long period of time, such that it is definately fixed), you can have the auto one for free. Now that may seem like a great deal, free car for some tinkering, or it may seem like a **** deal, several hours of your time for something thats worth a few hundered quid, thats up to you to decide. Also, it goes without saying, if you cant fix it, youve wasted your time and you dont get the other one.
Click to expand...

Sorry mate, I didn’t see your reply - thanks for taking the time to share your experiences and thoughts so clearly! I can deal with 14 or 18 on a run. I’d maybe use it once or twice a week or just when I want a smile. Like Phil said - I guess it doesn’t even matter when it’s a toy.
In regards to your broken one - I’m always open to try and help others on here where and when I can as over the years people have helped me and the first time I met Phil he handed me the keys to his defender and I had my first day laning driving his truck!!!
Problem is, I know very little about these engines and systems hence this thread. I’ve cash in the bank should you want to sell your ‘spare D1’ and would be interested in discussing further. I could certainly try and aid you with fixing yours but my experience lies with DOHC jap engines and not these old relics!
I’m quite close with my local specialist so things that are beyond me electrickery wise or EM wise I could call in to him or invite him round for s coffee!
 
resto_d1 said:
Do we reckon classic and disco EFI setup is near identical?
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Yes identical. Think even the looms are the same on the earlier models. May have changed on 300 type disco.
All have short stick gear boxes & long bell houses.
Unsure about the gear box cross members
 
Hicap phill said:
Yes identical. Think even the looms are the same on the earlier models. May have changed on 300 type disco.
All have short stick gear boxes & long bell houses.
Unsure about the gear box cross members
Click to expand...
Cheers. I’ve got one sorted with loom. Engine mounts - have to relocate/weld new brackets on to suit v8 I assume. Welders not happy over 3mm with the 13a plug on it!
 
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