Discovery 3.9 v8 - rebuilds, reliability, options….

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If you are gonna run mega squirt then why not the 4.6?
But can see the rest of your points.


Yes.
But the main thing is it won’t move, which is the main problem in the first case.

J
I don’t know… I think it’s due to failure stories putting me off even though I know the failures are due to the liners 😂🤦‍♂️
 
Maybe you should ask how many “good” standard blocks could you get? And did you even consider rebuild cost?

J
I suppose it all comes down to what exactly you intend to do. If an engine you can see running from a breakers yard is £400, and you have the tools, space, etc to fit it yourself, and all youre doing is running a "sports" camshaft, a loud exhaust and a remap, and driving it on the road and through the occasional puddle, then its probably not worth spending thousands on expert engine rebuilds and top hat liners. On the other hand if youre building something with forced induction for a competitive offroad anvil dragging endurance race, or if youve got money to spend and you want the peace of mind that youll likely never need to take the engine out again, then sure, go for it.
 
I suppose it all comes down to what exactly you intend to do. If an engine you can see running from a breakers yard is £400, and you have the tools, space, etc to fit it yourself, and all youre doing is running a "sports" camshaft, a loud exhaust and a remap, and driving it on the road and through the occasional puddle, then its probably not worth spending thousands on expert engine rebuilds and top hat liners. On the other hand if youre building something with forced induction for a competitive offroad anvil dragging endurance race, or if youve got money to spend and you want the peace of mind that youll likely never need to take the engine out again, then sure, go for it.
If it was a Toyota Id agree. However, the rv8 block is a ticking time bomb for the liners to slip either way. You may get lucky but I don’t fancy chance after spending years building a solid shell. The cost is worth it to me as it will be the finishing touch to a project that got cancelled the first time and is finally coming to fruition. Without going doom and gloom I also want to have a v8 whilst I still can.
I’ve looked at other options vehicle wise I.e. getting a powerful non 4x4 estate….

It would cost me a lot less to build the 300tdi and throw that back in but I’ve got one of those already and a pure heart would be a good finish to the build.
 
the rv8 block is a ticking time bomb for the liners to slip
Thats not really true. Some slip liners, some crack blocks, some blow headgaskets, crankshafts wear out, etc etc. If I had to guess, most rover v8s that were ever made have either been recycled or still exist in a mechanically useable state but with crap electric components or a rusty car around them.

The cost is worth it to me as it will be the finishing touch to a project that got cancelled the first time and is finally coming to fruition
Thats more than fair enough
I’ve looked at other options vehicle wise I.e. getting a powerful non 4x4 estate….
Plenty of those to choose from, even with AWD, audis and subarus and so on. Ive got a subaru legacy 3.0R spec.b manual estate, I love it, but they arent for everyone.
would cost me a lot less to build the 300tdi
With the best will in the world, a 300tdi, or probably any of the land rover diesel engines, will never make the power of a V8 with a mild camshaft and a tune.
 
Thats not really true. Some slip liners, some crack blocks, some blow headgaskets, crankshafts wear out, etc etc. If I had to guess, most rover v8s that were ever made have either been recycled or still exist in a mechanically useable state but with crap electric components or a rusty car around them.


Thats more than fair enough

Plenty of those to choose from, even with AWD, audis and subarus and so on. Ive got a subaru legacy 3.0R spec.b manual estate, I love it, but they arent for everyone.

With the best will in the world, a 300tdi, or probably any of the land rover diesel engines, will never make the power of a V8 with a mild camshaft and a tune.
I think a lot of people would argue with that. It’s a fact that the machining was poor across most of them. I think even cosworth made some of their blocks to see if they could sort it.
They will slip liners due to block. They will blow hg due to block. Yeah they might be bang on if never get hot but it’s enough risk there to factor it in?
I had a legacy spec b wr Ltd twinscroll. One of best cars I’ve had. I’ve had bm’s, Audis, Toyotas, Hondas, Nissans. Have had a few fast cars just never a v8 (I don’t expect it to be fast by the way!).
 
I had a legacy spec b wr Ltd twinscroll
Lovely. I was tempted by a twinscroll but the cost of a 6 speed manual was 3 times what I paid for my 3.0 one. Also tempted by BMWs and Audis, but only for the 6-pot diesel engines, and I dont do enough miles to part with my Legacy at the moment.
On that note, have you considered non-land rover engine options? (BMW M51 and M57, Mercedes OM605/606, etc?
Honestly, if you're starting with a diesel already, then an M57 might actually be cheaper, and itll probably be more powerful, although it wont sound anywhere near as good.
 
Another interesting specialist video just watched….

Builder seems confident that once out of the emissions and lean running scenario that if a block hasn’t cracked, and is then installed on a richer and cooler run, there’s no reason it should/will. Interesting how peoples views and thoughts differ. Problem is, and don’t mean this rudely, but anyone selling products or services will have a biased view. Said people are generally the experts though!
 
it is true that lean running is one of the main reasons for a rv8's block issues.

up there with a neglected cooling system, but as for running it rich never seen the reason for swaying from one extreme to another, just getting it running correctly isn't that difficult and the best scenario for any engine. :)
 
Problem is, and don’t mean this rudely, but anyone selling products or services will have a biased view.
Theres generally a good way to tell. If the person selling it to you can tell you how and why it works in a way that makes logical sence, then its probably correct.
Top hat liners definately work - theres no question about that. Really what you're asking is, "is there anything wrong with the standard one?" - and Id argue not, unless you intend on doing something extream. Having said that, you pays your money, you makes your choice.
 
it is true that lean running is one of the main reasons for a rv8's block issues.

up there with a neglected cooling system, but as for running it rich never seen the reason for swaying from one extreme to another, just getting it running correctly isn't that difficult and the best scenario for any engine. :)
Yeah that was what I meant mate - bad choice of words. Correct fuelling rather than lean
 
Hi again all, am I right in assuming all variants use the same chassis mount locations? I’d assume they made the 3.9 disco engine to fit the same as the 3.5 to avoid chassis differences and then all the blocks are the same anyway?

Cheers
 
Hi again all, am I right in assuming all variants use the same chassis mount locations? I’d assume they made the 3.9 disco engine to fit the same as the 3.5 to avoid chassis differences and then all the blocks are the same anyway?

Cheers
Never notice any changes with the mounts on
3.5/3.9

If you purchasing a new galv chassis they should know.
 
Hi again all, am I right in assuming all variants use the same chassis mount locations? I’d assume they made the 3.9 disco engine to fit the same as the 3.5 to avoid chassis differences and then all the blocks are the same anyway?

Cheers
Id be very supprised if they changed them, although they might be different depending on the gearbox?
Blocks are identical, just bored out for the 3.9s
 
Id be very supprised if they changed them, although they might be different depending on the gearbox?
Blocks are identical, just bored out for the 3.9s
Without running off on a tangent on this thread, as I know you got yours, what have you got that’s working and not working and that you want rid of?
 
Without running off on a tangent on this thread, as I know you got yours, what have you got that’s working and not working and that you want rid of?
Currently, nothing starts. Both have dead batteries, and with a jump, one turns over, and the other starts if you fiddle with the starter motor wire, at least that was the case when I looked last, which was last year.
The manual one had MoT and was driven daily until the end of 2022, everything worked, except the cruise control and the passanger door lock sometimes a bit sticky, other than that it was perfect. The auto drove up the road and onto a trailer last year, other than that, I assume its all broken.
The plan currently is probably to get the seats and door cards from the manual one, either to keep for a future disco, or to turn into some mancave furnature. I might also keep the gearbox and transfer box for a future Landy, but the syncro on 2nd wasnt the best (it worked fine 99% of the time, but if you tried to rush it at high RPMs it would crunch, I suspect the majority of R380s are like this) but if a diesel R380 can be rebuilt with the taller 5th gear, and the parts to do so are readily available at a sensible price, then its not worth keeping. As for the transfer box, if I end up buying a 110 or RRC, Ill want it.
What do I want rid of? Both of them, in exchange for some money. Or just the auto one, in exchange for getting the manual one to run. Or Ill pinch the few bits that I want to keep, and start breaking them.
Currently, its costing me nothing to keep them, and in my head one day Ill build my idealistic dream landy out of it, but in reality, my Land Rover plans require a budget, skillset, workplace and tools that I simply dont have, and possibly may never have.
 
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