D4 3.0 SDV6 catastrophic failure

**Discodicky** · 28th April 2025, 09:19 PM

Originally Posted by Graeme

Now with bearings designed to handle some wear, the engine should be good for at least another 200-300K even with an imperfect crankshaft. At least these bearings won't destroy the crankshaft, allowing the crankshaft to be ground and undersize bearings fitted when they wear enough.

Might pay to replace the crankshaft. I just had a "flash re-call moment" in my 75yr old brain....

Just remembered that way back in 1974 ish when I was a factory trained Jaguar mechanic, I replaced two crankshafts in Jaguar XJ12 Series 1's. It was a well known problem; they'd run their conrod bearings. The cars didn't have huge mileage done.

Jaguar introduced an updated crankshaft.

Now, upon serious comparing of the new to old shafts, my colleagues and I came to the conclusion that in the new shafts Jaguar had changed the direction of the drilled oil holes which deliver the oil to the conrod and main bearing shells.

We concluded that in the old shafts, the direction of the drill passage thru the shaft caused the oil under pressure to enter the bearing shell in the opposite direction to the engine rotation.
Therefore, the oil pressure "fought" against the natural flow of the oil through the conrod caused by the rotation of the shaft. (am I making myself clear?)
This "phenomenon" (if you like) caused serious lack of lubrication to the bearing shells.

Why else would Jaguar have changed the direction of the oil passage drillings?

From memory, the Jaguar V12 engine did not have particularly high oil pressure, rather like the Disco engine.

My TDV6 has just clocked 220xxx klms and running sweetly. (touch wood!) I have used Wynns Professional engine oil additive since I bought the car at 102xxx klms.
Two bottles per oil change which is slight overkill given the sump oil capacity, but who cares?

I use Wynns because I believe that if my theory above is correct, then I am giving the bearings a greater chance of survival under those conditions.
Why use Wynns?
'cos after seeing them run a Wynns-treated 179 cu Holden engine on an engine stand without sump/oil at idle speed all day at the local AGFEST show I was very impressed.
Try doing that to your Disco or any other engine and see how long it lasts!

I also saw improved life from Jaguar 6 cyl XK engine camshafts bearings which are identical to conrod bearings but around dia of 50c piece. They can prematurely wear if engine not regularly used as the oil drains away from the overhead camshafts and takes a few seconds to get pressure up.

Would be worth comparing the latest 3.0 crankshaft to an old one to see of the oil passage drillings have changes direction!

**PeterOZ** · 13th May 2025, 07:20 AM

Originally Posted by PerthDisco

I’d say his methods are more stringent on tolerances than factory. He’s mixing the bearings between aftermarket and OEM to get a balanced tolerance on all main bearings in the mid range. You certainly learn a lot watching him.

It’s just madness there’s not a supply of new blocks and cranks available.

agree and you can not even get a 2.7 short or long engine and do not know of anyone in country rebuilding them. Given how critical they are of tolerances and the procedure of every bit I am not sure you would be comfortable with it being done correctly.

Low km Territory donks seems to be scarce now, only high km ones if you can find one.

**haydent** · 13th May 2025, 09:10 AM

Originally Posted by SimmAus

Interesting.
First I’ve heard of PM to this extent…what Kms is the general thinking on doing this.
Given you can’t buy a new engine nowadays would be interesting to hear of anyone who has done this.
I see Christian on LR time has rebuilt a few of these engines, not something I could undertake, has anyone heard of any AU based mechanics going this type of work?

I just found this listing on ebay https://www.ebay.com.au/itm/19443539...on=3000%7C2500
Capture.jpg

Originally Posted by PeterOZ

agree and you can not even get a 2.7 short or long engine and do not know of anyone in country rebuilding them. Given how critical they are of tolerances and the procedure of every bit I am not sure you would be comfortable with it being done correctly.

Low km Territory donks seems to be scarce now, only high km ones if you can find one.

Thank you so much for pointing this out, Here I was thinking a 2.7 was a great choice due to Territory engine availability, but did not know that you couldnt get rebuild parts for them (crank). There are engines on ebay with 140km on them, which is pretty low for the age, but i had thought that if i ever did need a swap over i would be able to rebuild the broken one, which may not be the case it seems.

**Graeme** · 13th May 2025, 12:04 PM

New Ford 3.0 cranks are available, as are after-market versions.

**haydent** · 13th May 2025, 12:15 PM

Originally Posted by Graeme

New Ford 3.0 cranks are available, as are after-market versions.

i know, and as hadnt looked into detail, just assumed also for 2.7, but thats not the case it seems

**PerthDisco** · 13th May 2025, 12:16 PM

New 2.7s are available also or were a few months back via Ford spares

**discomatt69** · 13th May 2025, 03:06 PM

Is the latest Ford crank a suitable replacement for the 3l or are there changes to the bearings

**Graeme** · 13th May 2025, 06:20 PM

The same crank fits both versions of the 3.0.
Ford changed the bearing material.

**Discodicky** · 22nd May 2025, 07:44 PM

Originally Posted by Graeme

The same crank fits both versions of the 3.0.
Ford changed the bearing material.

Further to my post #271, I'd like to view the oil gallery holes on the updated crankshaft to see if there is a 'lead in' /"scallop" for the oil to enter the conrod bearing in a different manner.

Coincidentally, the Jaguar V12 engine has very similar oil pump design configuration to the Ford/LR engine at the front of the crankshaft.

.... and that V12 engine always destroyed #2 conrod bearing shell (NOT #1) which as I gather, is what the LR engine does?

Jaguar modified the crankshaft.

**Graeme** · 22nd May 2025, 08:00 PM

Side by side pictures of a broken crank and a new LR crank in another thread show that at least some big-end oil holes were in different positions around the journal.
#2 main in my son's engine failed, with the top shell ending-up draped over the bearing cap with the lower shell gone. #3 big-end seized when the engine was switched off, after having idled for a couple of minutes without oil pressure.

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