Thread: Why do 2.7 cranks break?

Originally Posted by DiscoJeffster

There is a Chinese seal that you can find online for the internal unit. The external seals are readily available.

I also used the Nissen and it’s was seemingly fine quality.

Yes, Gravy alerted me to that Chinese seal, but its an awful lot of trouble to go to and find its quality is suspect.....may as well buy a new Nissens complete assy and be done with it I guess.
It would appear that LR don't supply an internal seal; I'll check with the Hobart Dealer next week.

Originally Posted by Discodicky

Yes, Gravy alerted me to that Chinese seal, but its an awful lot of trouble to go to and find its quality is suspect.....may as well buy a new Nissens complete assy and be done with it I guess.
It would appear that LR don't supply an internal seal; I'll check with the Hobart Dealer next week.

You’re correct. They don’t because they don’t manufacture the unit or service them.

Originally Posted by Discodicky

On another post a coupla months ago, GRAVY replaced his 3.0 litre cooler with a Nissen and said the quality was excellent.
Does anyone know if it is possible to buy a seal kit as such for a cooler?
All "O" rings and the middle seal?

Pretty sure Nissen is OEM supplier to LR? It’s the only brand AF sell. They are like the worlds biggest oil cooler and similar supplier to many manufacturers.

Originally Posted by Bulletman

I mentioned this to a mechanic i know that works at a Ford dealership and he just laughed and said it was another myth probaly started by hi lux owners...

Certainly not saying he knows more than anyone else but he does work on them most days he tells me.

Bulletman

Your mechanic friend is obviously a very patriotic FORD fan.
This problem is very well known and documented and has on many occasions caused extreme problems with mechanics if they take a smidgen too long to change the engine oil. Common fix is to add roughly 20 litres engine oil, get the pressure back, then quickly drain off the excess!. However I recently read of all that being done and more, yet still no oil pressure! Not sure what he did or if he ever overcame the problem. Also on Mazda BT50 with the same engine.

An interesting observation from the LR Time crankshaft assembly video which gives us more clues as to why the 2.7 is prone to spinning bearings.

In the video Christian notes that the main bearing clearance should be between 0.038mm-0.050mm and this is what he achieved with the new bearings.

So this is equivalent to 1.5-2 thou clearance on 2.75inch journal. That is a tight tolerance. Old school rule of thumb is 1 thou clearance per 1 inch journal - so more like 2.75 thou or 0.07mm clearance minimum.

To run tighter clearances you need a couple of things in your favour - such as near perfect crank and engine block geometry and perfectly balanced crankshafts.

You also need to run a lower viscosity oil.

This is typically seen in modern engines which are chasing better fuel economy. The tighter tolerances allow you to run thinner oils and the reduced drag improves fuel economy. Furthermore, the thinner the oil, the smaller the hydrodynamic wedge, less oil flow is needed, and more fuel savings by running a smaller oil pump.

The downside is heat. The thinner the film of oil, the bearing runs hotter, wear can increase, and you make it all easier to spin a bearing. This probably explains why the oil pump flow capacity was updated - to improve bearing cooling.

Implications of this (other than just something to read on a lazy Tuesday).

For new engines, due to the tight clearance tolerances used, the 5W-30 was probably the right oil to start with if changed regularly. But a thinner oil with a bit of fuel dilution from extended oil change intervals and if the engine gets too hot, the oil thins out too much and you can get metal on metal contact which if you are unlucky can spin a bearing.

For worn in motors (outside of warranty), well if we have more bearing clearance it is because we have less bearing metal left and so the thicker 5W-40 oil with more wear protection additives (such as zinc) should be better.

But we just need to be aware that when the oil is cold, the flow rate will be lower, it takes longer to get oil flow and pressure up when you start the engine, this leads to greater wear on cold starts, plus we will also have a lot more drag on the bearing surface as the oil is potentially too thick (when cold) for the tighter bearing clearance, and theoretically this too could all cause a bearing to spin (if you are really unlucky). So keep the revs and engine load low until the oil is warm (should go without saying).

And it is not just the Ford/PSA TDV6 with the problem. The Fiat/Chrysler/VM Motori 3.0 V6 Turbo diesel found in the RAM 1500 also has a “spun bearing club”. Read some of the forums debating why these fail and you would think you are on a Land Rover forum.

Originally Posted by Discodicky

Also on Mazda BT50 with the same engine.

Probably why the BT50 nows runs Isuzu gear.

Originally Posted by Tins

Probably why the BT50 nows runs Isuzu gear.

A re-badged isuzu.

I was on a drive on Sunday, 3 x TDV6 D3's and 1 x D4 3.0ltr. mine was the only car with its original motor - not a good average.