Easy- you dont have the emotional investment. You may say thats a good thing- its not when you consider somethings have significant emotional value and if you dont have the same mindset as the vested, you are essentially making a unfair argument- based on your lack of skin in the game.

 

Come on Q&C. I'm on your side with the argument here and thank you for your persistence and subsequent enlightenment here it is a value to all of us whether today or tomorrow so readers should take heed but that last paragraph is a BIG stretch. Of course EVERY company is going to take the "safe" way out when they can, they have no reason to do otherwise as again it was not prevalent nor would it help them stoking a fire under this own butts thus creating problems where so very few are. I have yet to see a single car mfg do otherwise sadly even with major issues that have caused deaths they won't take the route you mention. There is an issue, there is thankfully a likely cause and effect brought forth with your attention to this but that last sentence or two is reading heavily into it with a slant. I can point out MANY problems with most every mfg that are handled the same way without regard to previous customer problems being acknowledged but are changed in the next iteration.

 

Well, you're wrong on all counts, but that's never stopped you before. I'm not sure that having a condescending attitude to all that aren't members of your fan club will gain you much support.

 

Leeper, we are in complete agreement categorically.

You did not realize I am saying what you are. And that is the point, its standard operating procedure with all mfgs. Thats why the onus is on us to do the digging. Moreover, as early adopters we have to be particularly open to have not been the beneficiaries of all the revisions.

 

Which one of is is going out of our way, me the guy thats posting scientific documents, laws and experiences of others. Or you the guy that is only here to put some protein in the punch bowl. But you wont see that as condescension. You cant be wrong friend, to do that you have to post some substance.

 

Certainly everyone may have an interest, and presumably they are reading this thread to learn about the issue. However some seem more interested in denying that a problem may exist then they are in having a meaningful discussion based on facts.

 

You seem to be shooting the messenger when it would make more sense to listen to the message to determine if it is important to you.

 

So this is supposedly happening in many DI engines, is there any clarity as to why? Is it due to the better and more complete burning of the fuel? I can't imagine it would have anything to do with the extreme pressures needed to get the fuel into the chamber though the injection pumps seem to be unhappy in several BMW models showing a high and expensive failure occurance. Perhaps a change in fuel itself might benefit/address this issue if it is due to the additive instead of the petroleum itself?

 

For me, trying to assess how likely it would be that such an engine goes massively wrong so as to decide whether to avoid buying a car with one.

I recall horror stories about a number of engines / gearboxes over the years, none of which were really justified overall. Don't know whether this is similar.

I'm particularly surprised - very - to hear that (allegedly) engines are no longer tested as they were.

 

Does anyone know if there were any plastic parts used in the 5.0L engines, such as with the tensioners, guides or rails, etc.?

 

Bingo.

Key word allegedly.

 

Yes it is important to me. Very. Might be a deal breaker for a pending purchase in fact. It is also important to sort fact from fiction. Also important to keep egos and emotions in check.

 

Spare us your arrogance as a self appointed "keeper of egos in check".

 

First let me state that I have no GDI engines, but I do have engines with timing chains.

I have read the above reference and it is obvious that there is no real qualitative difference between soot produced in GDI,PI and Diesel engines. There are significant quantitative differences both in tail pipes and and some increase in engine oil contamination.

I also followed up a reference provided by that paper--"Timing Chain Wear Assessment with different Types of Oils" published by SAE International in Paper#2009-01-0198.

Basically they tested various oils under constant conditions in a diesel engine and then measured timing chain elongation and metallographic inspection of chain rollers.

If I understood their conclusions, the elongation of the timing chains was up to 0.02% for mineral oils and semi-synthetic oils after 300hrs of operation and half that for synthetic oils. Also the depth of scratches on pins and bushes was much less with synthetic oil.

The threshold of elongation for engine timing error is said to be 0.5% and therefore implies that in the tested engines, using synthetic oil, it would take about 15,000 hrs of operation, or 7500hrs with conventional oil, to reach that level of elongation.


They also state that typical maximum recommended oil contamination for soot is 3%,ie make your oil change before 3% soot contamination level.

Now since I have no data on how your 5.0l engine was driven, I can only estimate that it operated for somewhere between 1500 and 3000 hours before your timing chain elongated by 0.05%. This based on achieving an average speed of 13.3 mph and 26.6 mph

It is also unlikely that your oil had anything near 3% soot in it if you followed the recommended oil change interval.

I would conclude that if there is a problem with timing chain wear on the 5.0l engine it is not due to the extra soot created by PDI.

Early oil change is not indicated but it is cheap peace of mind until the timing chain stretches again (or maybe Jaguar used better parts when they replaced them).

 

I'm not an engineer, but I find your input interesting. Since we know there is a problem with timing chain stretching, do you have any concept of why this is occurring?

 

The sum total of my thoughts and concerns on this entire thread.......


*yawn*

.

 

The soot in GDI is different and a new animal- because it is smaller than what we have designed stuff to deal with. We cant filter out of oil, like we can diesel soot etc.

The particles are also more abrasive, the breakdown oil faster.

The way it affects timing chains is that it allows the links to wear faster, because they are concentrated in the nooks and crannies of the chain. Then what we call stack-up tolerances occurs. i.e if each link wears by 0.1mm (a tenth of a millimeter, very little) and you have 250 links in the chain, you will get 25mm (one inch) elongation in the chain.

Even the oil industry has OPENLY acknowledged that timing chain elongation is the main drawback of GDI. While you visit the link, note how long the timing chain is on a GDI, that itself makes it more prone to wear. From the example above if you had 500 links instead or 250, you would get 2 inches of deflection, with just .0039 inches of wear on each link. ILSAC To Add Timing Chain Wear Test To GF-6 | Passenger Car Engine Oil

"Another challenge related to GDI soot formation is that carbon particulates can hide in crevices and get washed down cylinder walls or enter the crankcase via blow-by, causing problems with lube oil. The active surfaces of these carbon particles readily absorb key additives in lube oil that minimize oxidation and wear, compromising lube performance. These carbonaceous particles also tend to be abrasive increasing wear on critical engine parts such as cams and valve lifters. Such suspended carbon particles can reach 1% to 3% of the total lube oil mass. Lube oil blenders and lube additive suppliers, such as Lubrizol, are developing measures to offset these GDI side effects."

 

You cant have metal guides mate, that would wear the daylights out of a metal chain. And the effing noise would drive the crickets mad.

Perhaps some pundit here can debate to the contrary.

 

That answer is simple- Even Ferrari switched to GDI because the performance gains are astronomical and outweigh the inconveniences. Its not just more power, but more power and mileage. Its also explosive power in the Jaguar, 50-70 in 1.9 seconds- thats warp drive and twice as fast the Lambo Gallardo and faster than the new Lambo Huran! 2015 Lamborghini Huracán LP610-4 Tested ? Review ? Car and Driver

Its not that engines are not tested as before, its that they are not made like engines of yore. So the Jag engine prior has had technology and components that have been around for 50 years. The 5 liter has technologies never used by the world before. Do you expect them to have caught all the bugs from day one.

Besides you are confusing the issue- its not about if an engine was tested, consumer maintenance and best practices can only be established after it is in the market for a good while.

 

I do expect them to have caught the kind of very serious fault(s) alleged before the engine was fitted to road cars, yes. That's hardly from day one. Wear of the size posted on this thread ought to be detected and had it occurred (which I doubt) probably would have been.

OTOH liberties have been taken by some car makers such as VW, though that wasn't an engine wear issue I believe.

I'm not in a rush to buy a 5.0, either way.