catastrophic diesel failures how many do we know of?

[MariusFourie]

Yes but when the motor is running and the housing is glowing the shaft is not at that temp, the shaft is still at normal operating temps and when you switch off the oil does not stop flowing immediately. Heat wants to travel in the direction of the largest temperature differential, outwards towards the housing and not inwards to the shaft. So the shaft never gets anywhere near the temp of the casing and a good clean synthetic oil will not burn off and leave deposits...if it did I would have gone through dozens of turbos.

Yes the shaft is not at that temp when running because it is constantly cooled by a fresh supply of oil.

Shut the engine down and the heat goes everywhere. The oil stops flowing very quickly as the oil line in a turbo has a constrictor to stop full oil pressure reaching the turbo that will push past the seals. Thermodynamics dictate that the heat will go through solids rather air (poor heat conductor) so the shaft will reach the housing temp very quickly.

This is the datasheet for a fully synthetic engine oil - http://www.farnell.com/datasheets/1718437.pdf

It's boiling point is a mere 250 celsius. If it boils it will leave deposits.

Please back up your arguments.

[VicC]

With a lot of 2so

Ah! There you go.

[BeachCat]

What Dirtshark said.

Your above statement is an indication of your lack of knowledge and/or understanding of the internal combustion engine, whether diesel, petrol or whatever.

Have you seen the start-up procedures for eg rally or racing engines?
Not to mention the capital spent on telemetry and the interpretation thereof.
Those are what you would call 'buts'.

I think you should have quit, when (you thought) you were ahead.

Yes but this is just a personal attack, AKA ad hominem....instead of attacking what I am saying you are attacking me, it just leads to everyone calling each other stupid and the discussion is as dead as a diesel

Racing engines are built with tolerances not seen in production vehicles....if they used the same tolerances in production motors then they would be very unreliable, which is why they don't.

A reliable vehicle, for me anyway, would be one you could give anyone the keys to without a word and know it would not fail. As soon as you have to give a long list of buts, it is no longer a reliable motor.

[Clint_Hemi]

Ah! There you go.

He was referring to the rotary, not a diesel. False alarm. Haha.

[Clint_Hemi]

if they used the same tolerances in production motors then they would be very unreliable, which is why they don't.

Um. No. Tighter tolerances would make an engine MORE reliable. Racing engines, if driven at 50%, would last a long time. They die because they're driven at 100%, otherwise they het a better driver.

Tighter tolerances cost more, which is why they're not used in production vehicles.

[albertvl]

Haha. You said Landy engine and bulletproof in the same sentence. Hahaha.

BMW M52 engine - not manufactured by Land Rover

[Clint_Hemi]

If every single production engine was built EXACTLY according to the design, with zero tolerance for deviation, they would all perform exactly the same, and cost ten times more. Which is why you don't hear of "built on a Friday" Ferraris.

[Clint_Hemi]

BMW M52 engine - not manufactured by Land Rover

Same same. But different.

All engines fail eventually. How close to perfect they're built, and how they're maintained, decides when.

Sorry to hear about your head, though.

[Clint_Hemi]

As for the "expensive maintenance", our D4D's services are either R1500 or R2500. Except for the timing belt at 150k, which, along with a major service, and a new clutch pedal assembly (the squeaking on the old one was driving me nuts), came to R6000. And all I do is drive it properly (idle a bit after driving fast and don't floor it at low revs), and put in 50ppm.

[BeachCat]

Yes the shaft is not at that temp when running because it is constantly cooled by a fresh supply of oil.

Shut the engine down and the heat goes everywhere. The oil stops flowing very quickly as the oil line in a turbo has a constrictor to stop full oil pressure reaching the turbo that will push past the seals. Thermodynamics dictate that the heat will go through solids rather air (poor heat conductor) so the shaft will reach the housing temp very quickly.

This is the datasheet for a fully synthetic engine oil - http://www.farnell.com/datasheets/1718437.pdf

It's boiling point is a mere 250 celsius. If it boils it will leave deposits.

Please back up your arguments.

If your shaft gets deposits then the turbo will fail, I don't have any failed turbos, I might open up one of my turbos and take some photos of the shaft if you can similarly prove your theory.

Please backup your heat transfer and boiling theory on turbo shafts with a published science paper.....I am not sure how you came to your conclusions as there is no way you could possibly have measured the temps you talk of.

But I'm up for some good science if you want to reciprocate.

[MariusFourie]

I've had my say

[BeachCat]

Um. No. Tighter tolerances would make an engine MORE reliable. Racing engines, if driven at 50%, would last a long time. They die because they're driven at 100%, otherwise they het a better driver.

Tighter tolerances cost more, which is why they're not used in production vehicles.

Apart from the fact that different types of metals expand and contract differently with heat, a tight tolerance might be better in a world where metals don't expand but a disaster in a world where they do.

A tight tolerance is just a measurement when making the part, it doesn't cost more, what cost's more is the selection of materials so that nothing seizes.

[albertvl]

Same same. But different.

All engines fail eventually. How close to perfect they're built, and how they're maintained, decides when.

Sorry to hear about your head, though.

No stress, it happened years ago. My point is that petrol isn't a guarantee that the engine is unbreakable. What I do know is that the M52 head was a lot cheaper to repair than a td5 head (according to the workshop).

[bushwacka]

FAiled diesels , sure. But also great ones. Peugeot 306 Diesel had her in France, 350000km not a single problem. Sold her to a friend and he reports she is still going strong used daily along rough rural roads

Nuff said.

[MariusFourie]

The different materials expand to a known percentage. Hence why you get hot and cold values for solid lash adjusters/tappets. Tighter tolerances are always better. Formula 1 is a prime example. The tolerances are so tight that the engine oil and coolant is heated before the car is started.

But perhaps I'm wrong again. It looks like I clearly know nothing about engines......

[kevjones]

I have just sent a letter to Volvo (know the people there) and told them the forum thinks they are complete idiots for doing R&D on diesels and the forum recommends strongly that they switch to petrol which is far more reliable (well some members say so). Some members think this torque thing is just that, talk talk. I have asked my buddies at Volvo to copy these letters to GE and get them to start making petrol trains as well for the same reasons.

When you have between 500-800 NM of torque at 2000 rpm going to a petrol engine is like kissing your sister.

[Bekker Snr]

The different materials expand to a known percentage. Hence why you get hot and cold values for solid lash adjusters/tappets. Tighter tolerances are always better. Formula 1 is a prime example. The tolerances are so tight that the engine oil and coolant is heated before the car is started.

But perhaps I'm wrong again. It looks like I clearly know nothing about engines......

Marius, Leave this argument you would not persuade BeachCat. Since the mid 60th all agriculture engines, truck,trains you name it are diesel. If I remember correctly 60+% of all European cars sold are diesel. I owend both and love the torque of a diesel.

[EttiennedK]

Exactly they have to be pampered and treated like an old lady.

NOT!!!!!

My 2 Defenders drag 4,5tons of digger-laden trailer around on a daily basis. 90% of all km's done are on dirt- and farm roads. The Tdi is heading for 500 000 and the Td5 for 300 000k's.

I do an oil change every 5000, full service every 10 000k's, give the turbo enough time to wind down before I switch off and that's IT.

My dad of 85yrs old is a mechanical terrorist of note who will quite happily use a vineyard pole as a braking aid. His '84 Hilux's body therefore has as many bumps and dents as a granadilla. The 2.4 diesel motor, notwithstanding the fact that it probably got a service (read that as oil change) every 30 000k's is still going strong after nearly 400 000k's.

The only catastrophic engine failure I've ever experienced was about 2 months ago when a petrol engine decided to turn its no3 combustion chamber into a blowtorch (due to the intake manifold nuts coming loose) and burned a hole in the piston.

[BeachCat]

I built a photography studio with a glass retracting roof, I decided to be clever and instead of using normal building tolerances of 5mm I built the thing using lasers to be within a millimeter, it was such a mission I had to use blocks and chains working at night so I could see the laser beams to pull everything to the extreme tolerances I wanted.

The result was that the sliding roof would jam on a hot day because of the expansion of the beams. I learned a big lesson, that extreme tolerances are only possible when nothing expands or contracts with heat OR you use the exact same materials so everything expands and contracts together.

This is why a racing motor needs to be preheated with blankets or an extreme startup procedure because when the motor is outside normal design temperatures then parts can either rattle and slap or seize.

The correct tolerance for a RELIABLE motor would be the one where no matter the temperature all parts remain free to move without any leaks.

The correct tolerance for a Performance motor would be the one where at normal operating temperature there is minimum freeplay of parts and maximum sealing.

Therefore a performance motor does not necessarily mean a reliable motor.

[sweeper]

Nothing wrong with a maintained diesel or petrol, also one must compare apples with apples, comparing a old v8 repair bill with a modern day diesel is silly, just as comparing a modern day petrol with an old 250 isuzu... Maintenance is key, i concede a petrol is more forgiving if abused and neglegted, but thats not the diesels fault.... Rather the operator. My diesel is maintained well, for not a lot of moola and its not letting me down..