Member Since: 09 Feb 2023
Location: Poznan
Posts: 4
I’m running Mahle filters and Castrol Edge Professional 5w30 C1.
23rd Mar 2023 9:03 am
Breg90
Member Since: 04 Feb 2017
Location: Falkirk
Posts: 348
Engines don't fail because of the oil IMHO.
They fail as the block creeps either side of the main bearing caps - this allows the main bearing caps to spread (they are in under tension/interference fit). The spreading of the main bearing cap reduces the bearing clearance until the oil film is too thin to prevent crank to bearing contact - bearing shells wear. If the bearing metal fatigues and fails the crank looses support at that bearing - the crank rapidly fails as it is not designed to take excessive radial deflection - crank snaps. But that is a symptom, not the cause.
The spreading of the main bearing caps also makes the main bearing clearance open up at the edges (3 and 9 o'clock). This will allow greater oil flow out of the edges of the bearings.
Only stripped and measured up two engines, so not extensive evidence, but I did go into a lot of detail. Blocks spread most at the front - there is the least external stiffening there. I believe that is why the cranks fail at the front. Not seen a block out of a Citroen - my suspicions is that the block is stiffer there for a engine mount or similar, hence lower reported engine failures.
LR in Korea were forced to do some thing. I think (my deduction and opinion) they put in the higher capacity oil pumps - 15mm rotor(with a higher relief valve setting) - to force in more oil to try and prolong the engine life. It wasn't a 'fix' as much as a band aid that they hoped would make them last long enough for LR to be off the hook.
Exception to the above - engine oil dilution with fuel.
If you get excessive fuel dilution then the engine oil viscosity drops - you will eventually wipe a main bearing. The engine might already be compromised by the creeping block, but low viscosity engine oil might then tip it over the edge.
You get excessive engine oil dilution with fuel from:
1/. Excessive numbers of cold starts. Broken glow plugs and block heaters don't help
2/. Repeated failed DPF regens
Make sure the glow plugs/heater etc work. React to failed DPF regens.Series one 1949 - in bits, chassis is strapped to the ceiling in my garage (beside the canoe)
LR 90 - In bits
Disco 3 - currently in bits
24th Mar 2023 12:05 am
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 13635
Follow on
26th Mar 2023 11:47 am
ClassikFan
Member Since: 02 Nov 2016
Location: Surrey
Posts: 1027
Lookingforward.to watching that A bit later.Just 'cause you got the power... that don't mean you got the right.
26th Mar 2023 12:54 pm
ratrunner
Member Since: 20 Nov 2015
Location: cotswolds
Posts: 194
Just in case you have never heard of Christian and Vera on u
Which of course you probably if not take a look .... have they have nailed why the crankshaft fails ?
This post has been merged by the site administration team
26th Mar 2023 1:18 pm
Dixie Dean
Member Since: 06 May 2006
Location: Halewood
Posts: 298
Murtovaara wrote:
... nobody has bought up the to me quite mysterious ZF 8HP oil change interval. This transmission is widely used in various cars, to my understanding, mechanically “same” (Chrysler is an exception), but with car specific operational variations.
ZF say oil & filter change 80 kkm – 120 kkm or 8 year, our Disco 4 service schedule say 234 kkm?
Wouldn’t you expect that the transmission manufacturer would have the best knowledge to say
when the unit need to be serviced?
I stupidly followed the Land Rover advice which cost me a small fortune to have my gearbox rebuilt when it failed. Nowhere did I read in the Land Rover literature that if I tow a heavy caravan should I change my oil and filter every 80K miles!
So, you can't believe everything that LR say!2008 D3 HSE Stornoway Grey with Ebony Leather, towing a Coachman VIP 575
5th Apr 2023 8:37 pm
Sidestick
Member Since: 22 Apr 2012
Location: Rome
Posts: 2288
Has anyone ever thought that the main cause of crankshaft failure is not due to lubrication?
As Christian & Vera have demonstrated, there is no sign of abrasion or friction inside that engine that could have caused the crankshaft to lock up, and this is the case with most engines that fail before 100K km. Does the weight of the car contribute to making the crankshaft work beyond its limits? I don't even believe in this hypothesis, just as the same crankshaft mounted on the recent RRSs supports well over 300 hp like the mapped engines on our D4...
So what changes compared to the engines installed by PSA?
The engine ECU, for example...
LR on the old D3 allowed via diagnosis to display the offset balance between the injectors and as well known in this forum, the parameter of each single injector should remain within a relatively narrow range.. .
But what exactly this value mean? Why when a cylinder has a very low offset value, the opposite one is greatly increased by the ECU? All this is the normal compensation procedure that the engine ECU implements in order to keep the engine running "round" and free from vibrations. How? Piloting the injectors for a longer time anticipating the "pilot injections".
This compensation occurs when one or more injectors fail to guarantee the correct quantity and flow rate in the unit of time due to blockages, old age or fuel contamination.
The problem is that JLR has programmed its ECUs with compensation parameters that are too broad for the type of architecture of our engine (for more information, the difference that V60° engines have with the rest of the architectures should be investigated), causing in fact pre-ignitions even before the pistons reach their top dead centre. This determines a knocking on the piston, opposite to the crankshaft rotation via the the connecting rod, generating (above all at low rpm) anomalous and large torques to the engine crankshaft.
Curiously, JLR has eliminated the possibility of reading the offset balance of the injectors from the D4 onwards (who knows why) ...
Racing garages,(who use picoscopes) know this problem well, as the engine control units usually used in racing allow exaggerated compensations which, if not well calibrated, lead sooner or later to the mechanical failure of the moving parts of the engine.
The above is what I have been able to ascertain in these years of ownership of Discovery and it remains my personal opinion on premature failure of the crankshafts, but try to think about it, it seems to me a more than plausible reason...- Easy-Lift suspension module 4.0
- GoodWinch 9500 lb
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6th Apr 2023 2:44 pm
jenseneverest
Member Since: 12 Jun 2017
Location: somewhere
Posts: 765
Breg90 wrote:
Engines don't fail because of the oil IMHO.
They fail as the block creeps either side of the main bearing caps - this allows the main bearing caps to spread (they are in under tension/interference fit). The spreading of the main bearing cap reduces the bearing clearance until the oil film is too thin to prevent crank to bearing contact - bearing shells wear. If the bearing metal fatigues and fails the crank looses support at that bearing - the crank rapidly fails as it is not designed to take excessive radial deflection - crank snaps. But that is a symptom, not the cause.
The spreading of the main bearing caps also makes the main bearing clearance open up at the edges (3 and 9 o'clock). This will allow greater oil flow out of the edges of the bearings.
Only stripped and measured up two engines, so not extensive evidence, but I did go into a lot of detail. Blocks spread most at the front - there is the least external stiffening there. I believe that is why the cranks fail at the front. Not seen a block out of a Citroen - my suspicions is that the block is stiffer there for a engine mount or similar, hence lower reported engine failures.
Are you saying that the engines you stripped had insufficient interference on the bearing caps, or do you mean the block itself is flexing under loads ?
6th Apr 2023 7:03 pm
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 13635
Part 3 , was interesting with regards to the shell oil hole sizing where one shell was bigger than the other , not knowing I would have fitted the same size as the block but see that’s not correct with him mentioning it will upset the oil distribution
9th Apr 2023 11:57 am
LR4_NO
Member Since: 26 Feb 2023
Location: Buskerud
Posts: 20
...yet another entertaining video, these to crack me up
What me fascinates the most is that there is a 12 pages long discussion about 2 youtubers being right or wrong.
What you should take away from this videos is the "can do attitude" and showing people that it is possible to work on there one cars.
For me this is encouraging since I'am in my own engine rebuild nightmare right now.
What this series although points out is that there are bad parts out there that people unknowingly buy for a lot of money.
I would encourage everybody to watch there videos for entertainment or information ->what YOU take away from a youtube video is your own business
Last edited by LR4_NO on 10th Apr 2023 5:52 pm. Edited 1 time in total
10th Apr 2023 1:47 pm
HairyFool
Member Since: 04 Jan 2023
Location: Essex
Posts: 523
I am quite impressed with his attenion to detail, the section on the use of plastigauge is better than when I did my apprenticeship.
There are a few videos of modern engine assembly plants and I didn't see anyone scouring the back of the bearing shells . The process is based on absolute precision of the manufacturing stages involved. Mercedes set some store on the AMG engines being hand built but if you watch it the assembler is supplied a kit of parts, no actual egineering is involved.A visitor from the dark side, my other vehicle is an MG5 EV
10th Apr 2023 4:22 pm
Alwaysthirsty
Member Since: 16 Jan 2023
Location: Cape Town
Posts: 26
Its definitely a good cop bad cop show, I crack up every time he uses the Toyota comparison, I'm in the entertainment camp because Ill never have time to carry out projects like this, I dont see any malice in their approach just a bit of Taking Ex D3 2008 HSE owner in UK, a part of the family let go to the Autotrader orphanage
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...
. The process is based on absolute precision of the manufacturing stages involved. Mercedes set some store on the AMG engines being hand built but if you watch it the assembler is supplied a kit of parts, no actual egineering is involved.
Taking 
