Bitte um Begutachtung -Bildmaterial- | Posts 16+

That part must have come out again, right?

What causes such impacts, and how can they pass through the turbine without causing any problems?


'A piece of the piston has also broken off on my scooter (presumably).' 'Overheating), and the charger wasn't affected, even though it must have somehow discharged...'

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The engine came from a VW test vehicle and was one of the very first ARL engines ever produced (engine number 80)

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This engine number refers to a pre-production engine. It's quite possible that a mistake was made during the assembly process because the engine was new, and the assembly procedures weren't yet fully established.
That could be one possible explanation for how foreign objects got in there. However, the image of the piston and cylinder head doesn't seem to support that, as screws, nuts, or similar items would look different. I'm currently trying to figure out what else it could be.
The idea about the small stones isn't that far-fetched.

I'm leaning more towards metal; a stone would have likely ground it down, but this foreign object probably retained its shape for longer.

EDIT: I can already guess - while experimenting, they probably exceeded the injection times, and in one case, it caused the tip of a piezoelectric element to explode...

Okay, I'm going to search the entire area again and see if I can find anything else. I just took a look at the cat, but there's nothing there either. And given the intricate internal structure, it must have been very tiny to have escaped unnoticed.
As I said, I'm ruling out a turbo issue. Given the rotational and flow speeds, we should see signs of impact or at least some small marks on the impeller blades. The VTG blades are all present and in their correct positions.
The idea with the LLK (likely referring to a lightweight component) could be a possibility. If a piece breaks off from it (e.g., due to a rock impact), it might enter the combustion chamber without the turbocharger. However, I think the aluminum of the LLK is too soft to create such craters.
Okay, the PD engines are all still present and look very good visually (no signs of corrosion or deposits). Unfortunately, they seem to be absolute pre-production models. I couldn't identify the exact part number, as I don't need to remove them, but it ends in "073 G," which I can't find in either AKTE or ETOS, so they must be very old (then came the AA engines, which were later replaced by AL engines). I think that's also why the engine makes that loud, harsh noise.

What remains is the fact that the damage occurred at VW, because I still can't believe that the part causing the problem was located in two cylinders and could somehow bypass the turbo without leaving any traces...

I can only agree.

There aren't many options, as in my opinion, the LLK (likely referring to a specific piece of equipment) already acts as a "coarse filter," and anything larger than 2mm is unlikely to pass through it. And it looks like it might have been something bigger...

Best regards,

There's another possibility: The engine number suggests it might be one of the very first ARL engines ever produced. These engines are almost always tested on a dynamometer for several hours before they are (if at all) installed in a test vehicle. Perhaps the "mysterious" foreign objects damaged the turbocharger on the test bench, and because the cause wasn't properly diagnosed (e.g., only a drop in boost pressure occurred), a new turbocharger was installed and further testing was conducted...

@ Saurus

If VW is really testing so carelessly, it's quite ironic that the engines last so long. I can't even imagine that they would disassemble a motor on a test stand, then just slap on a new turbocharger and say, "Okay, that's good, it will work fine."

On the other hand, those workshops must have learned about those "exchange orgies" somewhere...

*Fear*
martin

So, with all the hypotheses, I also believe that this one is the most cautious. That's why there's a testing environment for it, and we can only learn from mistakes. Then the part from the test bench is taken apart, because even at VW, there are people who know what they're doing, and if they find half a turbocharger, they'll look for the rest of it.

However, Martin's theory about the swap meets isn't bad either: in such a case, wouldn't the workshop replace the entire engine? Check out our Audi; it got everything replaced because a connecting rod bearing was defective.

Who says that they saw the damage as a problem during the dynamometer test? Primarily, it did not impair its function.

'It's likely that the injection timing was pushed too far, which caused the high-pressure pump (PDE) to fail. After that, it was disassembled. There was no damage that would affect its function. A new high-pressure pump and a new injection pump were installed, and it's running again... Since this was just a test engine, I wouldn't be surprised if they did that. And I doubt it was sold with a warranty...'

They will continue running tests if they find a PDE (presumably a component) with a fractured tip at the head after a failure?

I'm switching to a Hyundai.














That was a joke, albeit a sad one.

Now, let's stop speculating.

"I can only speak from our experience. When we conduct test bench tests and damage occurs, the entire unit is disassembled, and the damaged areas are inspected to gather information for problem analysis and to document any potential sources of damage."
We don't manufacture engines, at least not engines for passenger cars.

Perhaps the truth about what it was will eventually come out. But guessing doesn't help anyone, especially since we can only make vague speculations.

I can try to show the picture to someone tomorrow who often deals with disassembling products like this; maybe they can give me a tip about what might be stuck inside.

However, the possibility of a dyno test still exists - because pre-production engines are generally locked and are not supposed to be sold, so you can test them (whether they are broken or not) as you wish. If it is obvious that the turbo is no longer producing pressure, it will be replaced and sometimes simply thrown away . If it is then installed in a test vehicle, and it still works, that is also acceptable.
The fact that this test car was then sold in individual parts is a whole different story...

I can't believe it.
What you're pointing out to an ISO-certified manufacturer about their sloppy work... :shaking head:
I just hope no one from VW is reading this... it borders on defamation.


Just to clarify. The engines that are disassembled (whether it's just a small part that they "swallow" or not ) are completely disassembled for analysis and then either repaired or destroyed. These engines are also not being sold (at least, not officially).
However, it often happens that such patterns disappear between the testing phase and the scrapping phase. Partially damaged engines are then "pieced together" and sold privately.

Based on my experience working with various manufacturers of fuel cells (and their testing procedures), which we collaborate with. VW is no exception.

Quote:

What you're throwing at an ISO-certified manufacturer for their sloppy work. .... :shaking head: I just hope that no one

is reading this and taking offense... that borders on defamation.

In this case, I agree with you. Who knows what, where, when, and how it got in there.

But, take a look at the junk that's been produced in recent years.

Crankshaft journals, defective cylinder heads in V6 or 2.0 TDI engines, undersized water pumps, control arms, door locks, camshafts requiring break-in, etc., etc...
I don't know what this has to do with ISO certification.
For me, it's simply rubbish.

The Japanese prove that there is another way to do things.

Perhaps the responsible manufacturers should use this forum to improve the quality of their products.

BM wrote:

... But, take a look at the junk that's been produced in recent years.

Do you really believe that VW is worse than other companies in this regard?
Sorry, but the others are only cooking with water too. Believe me.

Quote:

The Japanese prove that there is another way to do things.

... and will be ranked number one in the recall statistics for the year 2005... That's exactly how I imagine it!