D90mitch

D90mitch

Well-Known Member
After having a good read over many pages, it would seem that a fair few have suffered this problem. But is it REALLY that common? Engine I am looking at is a from a 2000 reg disco 2 and is the 4.0 . Engine would be going in an off roader so won't be used that often. It's got about 125k on the clock.....

Would I be better off with a 3.5 or 3.9 in all honesty?

The vehicle may be based on a disco 2 anyway.
 
jamesmartin said:
3,5 would be bullet proof 3.9 no better as it shares the same liner and too thin bore walls
Click to expand...

Unless a 3.5 service engine seen couple of rovers factory service replacement slip liners.

I agree though that 3.5 v8 generally good bar tipped heads and cam wear
 
I thought as much - I lied, I don't actually know how many miles are on it, I don't know where i got that figure from, been looking at so many. Do you reckon the 4.0 would not be worth even if it was lower miles (say 80k or so) and dirt cheap? Also, this engine is likely to do less than 1000 miles a year

Thanks.
 
D90mitch said:
I thought as much - I lied, I don't actually know how many miles are on it, I don't know where i got that figure from, been looking at so many. Do you reckon the 4.0 would not be worth even if it was lower miles (say 80k or so) and dirt cheap?

Thanks.
Click to expand...

who can say, any 94mm bore v8 still running will do so unless its cooling system allows it to get too hot ,those that couldnt manage running temps have long since died
 
Ok thanks for that. If i can secure a decent deal on it I will see. Only thing is, he says he's seen it running but not necessarily up to temperature / water loss / pressure in the tank etc. Then again that applies to buying most engines i guess. If in the morning i still seem as stupid, I will give him a ring and see if i can squeeze out some more info :D

V8's :rolleyes:

Cheers, again.
 
Dr_evil said:
buy a small block and the adaptor plate :p
Click to expand...

perhaps for a future project :p

The engine 4.0 is much further away than I thought so not bothering with it now. Probably for the best. going to hold out for a 3.5 or a seemingly good 3.9, I heard that they are less prone to the slipping than the 4.0 onwards.

Will probably buy a disco or rrc with it in anyway as a base vehicle. Funny how when you want to find one, you can't. Normally there's loads of MOT failure vehicles around to get cheap. Not today at the moment :p I will be patient.
 
the reason they feck up is they can get too hot..

the fueling maps on the p38 were set to get good (ish)mpg and get though emmisions..(in usa)

this causes too high combustion temps that causes severe problems in an otherwise poorly maintained (MOST) vehicle..
so..there is no reason why a 94mm bore engine cannot last for many many miles if WELL serviced and espically cooling system looked after..
even better if run richer than stock, but that will mean aftermarket ecu or carb conversion..(POOH)
i have just boosted and nitrosed a 4.6...i expect it to survive bar maybe headgaskets...uprated rad and aftermarket ecu though..
 
3.9 and 4.0 are the same engine, same capacity, just a rebadge.

Most problems stem from the wrong coolant and subsequent internal corrosion.

If the external steel water pipes are rusty inside it will be a problem sooner or later.

OAT keeps the inside of the cooling system clean.

Peter
 
true OAT i use...though if there is a dodgy component anywhere you will soon know..ie if your heater rad is porus...etc..
but as peter says ...no internal corrosion again..
 
147K on my 4.6 (LPG'd) & running sweet. Headgaskets done 30' miles ago. Cooling system kept in prime condition.
Liner slip is always a concern whether 3.9 (4.0) or 4.6.
 
zen said:
the reason they feck up is they can get too hot..

the fueling maps on the p38 were set to get good (ish)mpg and get though emmisions..(in usa)

this causes too high combustion temps that causes severe problems in an otherwise poorly maintained (MOST) vehicle..
so..there is no reason why a 94mm bore engine cannot last for many many miles if WELL serviced and espically cooling system looked after..
even better if run richer than stock, but that will mean aftermarket ecu or carb conversion..(POOH)
i have just boosted and nitrosed a 4.6...i expect it to survive bar maybe headgaskets...uprated rad and aftermarket ecu though..
Click to expand...

Absolute rubbish about the fuel maps,its just a crap engine.The story was put around by companies like RPI,its easy to disprove.
 
eightinavee said:
Absolute rubbish about the fuel maps,its just a crap engine.The story was put around by companies like RPI,its easy to disprove.
Click to expand...

well then we need to see this disproved then:p, must admit rpi do have a load of bull on their site as they are looking to sell rebuilt top hat linered engines and at a premium, I have just rebuilt a 4.0 that is run with megasquirt in my 90, first block was had cracked /sliped liner and failed preasure test, second block passed preasure test at 90deg so that got rebuilt, would like to see,and sure other here would also like to see evidence that its not the fuel maps that caused the problem.
 
wangie46 said:
would like to see,and sure other here would also like to see evidence that its not the fuel maps that caused the problem.
Click to expand...

So would I...

But... it's quite simple I think? The cracks in metal or slipped liners are caused by too much heat. Couple of ways about that, lean mixtures which run hotter or a cooling system which isn't good enough (through lack of care, maintenance or just bad to begin with) causing an engine to run hot or over heat.

Take your pick I guess... Or both.


At the end of the day, the bad design is the fact that the Rover V8 block wasn't designed to have a 94mm bore, the walls of the aluminium between the liner and the water jacket were reduced to a thickness where they crack and or the liners slip from the heat. And that's why the best Rover V8 is the 3.5L! :D (Slightly unrelated, but if you can get hold of one, the 3.5L blocks made after 1995 proper casting for cross bolted bottom end for total over kill:cool:)
 
Its quite simple,either scope or use a scanner to monitor the oxygen sensors whilst driving.I've done this loads of times both to diagnose faults and to use the feedback to tune LPG systems.
Even the first closed loop Rover v8's on 14CUX ran better than anything before them.All the other have done the same, sensors cycling nicely at idle and cruise to get as near Stoich as possible.(14.7/1 - Air to fuel) This is not lean - its perfectly normal,and then stick your foot down and they will happily go open loop and get back down to about 12/1 - best for power. I've seen this using wideband sensors and AFR gauges.Its all what you would expect of a closed loop system running narrow band Titania or Zirconia oxy sensors.The only way the map could be made leaner is for them to stay closed loop under wide throttle/heavy load conditions - Which they don't.
The engine is just bored out too much,with not enough material supporting the liners.Probably variable quality control and then poor maintenance after a few years and they give up.
They never got the investment they needed to either make a bigger block with wider bore centres - or to go the whole hog and develop a new quad cam 32v 5 litre unit which was what they really needed.Shame, cos they have the clever minds to do it - always have... Just never given funding.
 
So
How come the 4.6 gets better mpg than the efi 3.5 giving the fact that they both run 14.7

Seems strange

Now i run afr wb on all my motors.. The stock 4.6 on gems was lean too lean on cruise
Not to bad on wot and lean on idle..ecu and lamdas were good etc

So why these readings?? Cos thats what lr set them at to get decent mpg??
Also talking in depth to various tuners .no nameszbut NOT RPI
But people who know their stuff and work for lr ovetfinch etc reason for talking to them iwas making gearbox ecu for zf 24 hpeh and needed info

Now conversation went to linersAND YES YOU ARE CORRECT in that block is too thin
But the fact that engine runs too hot ( internally) REALLY dont help..

Hense in running better afr and cooling can make issue dissappear..

However i suggest only real curecis top hat liners,one dont havecto buy from rpi!!

Or prehaps as a bodge liner bolts

So please dont slag me off for my input as aint guessing here but done my homework..



Also i agree its a shame lr didnt get funding, if only ..
Sally my 1971 rrc runs supercharged lpg toyota quad can v8
Ruby runs supercharged nitrosed lpg rv8 4.6
Sally is sooooooo much more refined!!guess which i take to europe??lol
Guess which i take to europe??lol

Back to figures..prehaps notvall rv8's arevthevsame

SORRY FOR SPELLING AND GRAMMER using my bloody phone as interpoohbdown
I hate phone but reallyvrecomend otter iphone cases!!as using same phone i just threw as hard as i could against wall,bouncing off telly standcand fire place cos it ate all above!!
Phone still wirks!!or works even

Simon
 
My fecking phone wont sllow me to efit or fecking edit

So i need to add

I use aftermarket ecu's to control lpg too as well as engine and gearbox
Seems to work much better than judt the lpg ecu edpically on boost.
Rvu doesxyake into account lpg temp?pressure and uses gas law
 
You must log in or register to reply here.

Similar threads

Becks Bear
Defender V8 3.9EFI manual to automatic
Replies
6
Views
1K
discool
discool
oakey
P38A Interested in a P38?
2 3
Replies
47
Views
3K
oakey
oakey
F
P38A Starting issues.
Replies
7
Views
667
kermit_rr
kermit_rr
J
2003 Disco 2 4.0 Thor Auto - strange accelerator behaviour - fixed
Replies
1
Views
668
JohnKeane
J
K
Disco 2 ACE Fault
Replies
7
Views
469
kingy08
K