2015 TDV6 Snapped Crank

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Originally Posted by BradC

There have been a few on the disco3 UK forum where even a gentle “piston meet valve” event has seen the top end repaired only to be followed later by a bottom end failure. It’s always a risk. If you whack a valve hard enough to damage the valve and/or supporting infrastructure you are bound to introduce a pretty severe shock load to the spinny bits.

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Which is why i can't understand why Ford / JLR didnt design it as a non interference engine.

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Originally Posted by Eric SDV6SE

Which is why i can't understand why Ford / JLR didnt design it as a non interference engine.

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Engineers don’t design an engine around limiting damage when a key component fails. They would have a reasonable assumption the crank won’t fail and that timing belts are serviced at the correct interval, hence no need to compromise the engine design for unlikely failures.

Plus non-interference engines has a either/both tall combustion chamber and/or shallow cam throw. They aren’t designing the engine with the plan for a failure - they design the engine for maximum efficiency which means designing an efficient combustion chamber/head design.

I should add it’s all a compromise and a list of design priorities, but with government regs and customer expectations on fuel consumption, efficiency wins every time.

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Originally Posted by Tote

My 2.7 failed after 270,000KM of being serviced religiously at the scheduled interval, although I will concede that oil breakdown may have had something to do with it. The vehicle had just completed two 800KM round trips with a sheep trailer on the back when it failed, and it was close to needing a service from memory. No, the oil wasn't low [bigsmile1]

Regards,
Tote

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I'm sorry to hear that.
Do you know what has happened?
When you say "the scheduled interval", what was the interval klms?
Assume you are using correct spec Full synthetic oil?

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Originally Posted by Discodicky

I'm sorry to hear that.
Do you know what has happened?
When you say "the scheduled interval", what was the interval klms?
Assume you are using correct spec Full synthetic oil?

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It was in 2015 so I'm over it now [smilebigeye] Service intervals were by the book, from memory around 20K and the oil was bought in 20 lt drums of magnatec professional, same as the dealers use.

Linky to post about its demise here, seems I was even better with the services than I thought I was Bye Bye Permagrin

Regards,
Tote

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Originally Posted by Tote

It was in 2015 so I'm over it now [smilebigeye] Service intervals were by the book, from memory around 20K and the oil was bought in 20 lt drums of magnatec professional, same as the dealers use.

Linky to post about its demise here, seems I was even better with the services than I thought I was Bye Bye Permagrin

Regards,
Tote

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In hindsight, 10,000 between services might have been better.
PS: I wouldn't mind your RRS!! (Envy)

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Originally Posted by Eric SDV6SE

Which is why i can't understand why Ford / JLR didnt design it as a non interference engine.

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Being that the valves are vertical in the head it would mean large recesses in the pistons where the combustion chamber is, that would likely mean a heavier and taller casting for the pistons.

A diesel engine will always be interference due to required compression ratio, unless it's a 2 stroke .

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Originally Posted by Discodicky

.... and why can't the case of excessive klms between oil changes be the ONLY cause??? It's quite feasible.

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But for that to be the cause the oil will have to have totally sheared (lost all viscosity) and be totally depleted of all AW additives.

We are talking a premium engine oil developed with the manufacturer to last that distance.
I'd love to see an oil sample at 26,000km.

I've taken TD42T Patrols past 20,000km back when we didn't have ULS fuel and the oil samples were stellar.
Over the road transport regularly exceed 100,000km on oil changes, but they regularly take samples, the sump capacities are large and top ups keep additive depletion to a minimal.

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Originally Posted by M005

Got someone looking at it next Friday, but trying to move the process on a bit quicker given Christmas is looming.

How could service / oil filter affect it, assuming genuine parts & sufficient oil ?

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M005 Has there been any result from last Friday?