D4 SDV6 Engine Failure

Ford have pretty much said they have changed the metallurgical processes for the crank with the redesign for the F-150. Changing the heat treatment and stress relieving process would be one of many tweaks they say they made to both the design and manufacturing process to make the crank more durable.

The other change they most likely made to the design is to improve the stress relief around the web to journal interface by making small adjustments to the dimensions around the undercut at the corner fillet. This is the highest stress point in the design and would have been subject to a lot of modelling and finite element analysis to get right.

And given the new crank seems to still fit the old motor, there is not much else they could do to the design of the crank.

Hopefully they will show some better close up pictures of the failure. The propagation point will normally have some beach marks.

The other good point they made - the new crank they have was manufactured in 2023. So would have all the design and process changes made by Ford incorporated.

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Originally Posted by Tombie

although with retrospec it does demonstrate his previous hypothesis on "poor gallery design" was, as further above in this post, incorrect.

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Incorrect? Or seperate? I guess the new F#50 cranks might provide an answer.

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Originally Posted by Tombie

Exactly... and this is the key problem - there seems to be metalurgical / manufacturing issues, not lubrication issues.

This is one of their good videos, although with retrospec it does demonstrate his previous hypothesis on "poor gallery design" was, as further above in this post, incorrect.


If they do get the crank tested, that will provided quite a few answers..

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I'm not convinced the "poor gallery design" is incorrect. I'll wager a good bottle of red that the drilling for the gallery is implicated in the break, even if it's not the source of the crack. I reckon my bottle is pretty safe because it'll never actually get properly investigated, but machining a hole through that web without causing stress would be nigh on impossible.

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Originally Posted by BradC

I'm not convinced the "poor gallery design" is incorrect. I'll wager a good bottle of red that the drilling for the gallery is implicated in the break, even if it's not the source of the crack. I reckon my bottle is pretty safe because it'll never actually get properly investigated, but machining a hole through that web without causing stress would be nigh on impossible.

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I’m glad that someone (Christian) a lot more qualified than me is looking at this. Even if it’s a “YouTuber” (which I personally hold no grudge against).

My simple brain says…of the cranks I’ve seen / heard of broken…most of them have split in the same area…too much coincidence to not be design/process failure

Would be great if they do get some more detailed analysis done.

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Originally Posted by SimmAus

I’m glad that someone (Christian) a lot more qualified than me is looking at this.

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Well, yes and no. It's interesting, but regardless of the actual outcome of any further investigation it's not going to make any different to either Land Rover or the lives of those that drive with a crank-grenade up front.
Sure, it might settle a few internet arguments, but unless someone magically uncovers a reliable source of "less failure prone" cranks it remains entirely academic.

Any design has its limits and that usually relates to hp.

This is a 4 bearing crank that’s been souped up for performance with capacity increases and sequential turbos.

In marine terms a NA version of engine X would run at 180hp forever but the Turbocharged Aftercooled 550hp version of same engine was a hand grenade. TBO of NA was 10,000 hours.

TBO of 550hp 2,000 hours if it made it that far. The trade off was duty cycle. 180hp was almost 24/7 and 550hp intermittent or recreational use where 100 hours a year might be the norm.

What IS interesting though, is that on the face of it, at least with the 3.0 litre engine, it would seem that the problem is much more prevalent in a D4 than a Jaguar or for that matter, a R/Rover?

If this is the case, then why?

I can't subscribe to the fact that towing is a contributor, nor the Kw output, as the problem would seem to happen regardless of TDV6 or SDV6 power, and RRS has been up around 210Kw for a number if years (I think).

Is it simply due to an occasional problem during manufacturing of the c/shaft treatment processes?
And quality control not being good enough?
Bad enough to have the problem recurring over some years?

Do Jaguar drivers drive slower and never take the engine over say, 1500-1800 rpm, which is quite easy to do given their great torque and gearing, and does the lower rpm determine crankshaft life to some extent?

Of course we'll never know LR's manufacturing processes with regard to what engines are built when and in what "batches" etc etc.

I'd be interested to read people's opinions on this matter.

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Originally Posted by Discodicky

What IS interesting though, is that on the face of it, at least with the 3.0 litre engine, it would seem that the problem is much more prevalent in a D4 than a Jaguar or for that matter, a R/Rover?

If this is the case, then why?

I can't subscribe to the fact that towing is a contributor, nor the Kw output, as the problem would seem to happen regardless of TDV6 or SDV6 power, and RRS has been up around 210Kw for a number if years (I think).

Is it simply due to an occasional problem during manufacturing of the c/shaft treatment processes?
And quality control not being good enough?
Bad enough to have the problem recurring over some years?

Do Jaguar drivers drive slower and never take the engine over say, 1500-1800 rpm, which is quite easy to do given their great torque and gearing, and does the lower rpm determine crankshaft life to some extent?

Of course we'll never know LR's manufacturing processes with regard to what engines are built when and in what "batches" etc etc.

I'd be interested to read people's opinions on this matter.

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It is likely the vehicle weight and possibly all wheel drive load the crank more. Meaning the heavier D4 puts more strain on the componentry.

One of Ford’s Engine Supervisors involved in the original Lion engine design and later on the redesign team for the 3.0 Powestroke noted the original design may be OK for how a Range Rover is used, but not suitable for the duty cycle of the F-150 without being redesigned.

Basically he was saying OK if used like a Toorak Tractor, but not for anything more heavy duty.

Putting aside towing capacity for the moment, the 2018 F-150 weighs less than a D3/D4, and whilst it has a higher payload, in most configurations the GVM is still less than a D4. Let’s be honest here - the D3/D4 has a weight problem. The only area the F-150 is truly more heavy duty is its towing capacity.

So reading between the lines he was admitting the original Lion engine was not truly suitable for use in something as heavy as a D3/D4.

Interestingly - Ford US consider moderate to heavy loading use, or moderate to heavy towing, or operating in off road conditions, or extended idling, or extended hot condition usage, as all being considered as “Severe” usage, and they drop the service intervals for the F-150 from a maximum of 10,000 miles (16,000 kms) to 7,500 miles (12,000 kms).

They also recommend changing the oil from 5W-30 to 5W-40 in these conditions.

The usage of most D3/D4’s in Australia would probably meet one of these conditions of being considered “severe” usage (even just based on the vehicles weight alone).

Would the vehicle's popularity not be the main reason - there are more 3.0L D4s than RRS or jaguar, so there are more failures.