Bitte um Begutachtung -Bildmaterial- | Posts 32+

Bertil wrote:

I just hope that no one from VW is reading this

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I think so...

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... and will be ranked first in the recall statistics for the year 2005

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As far as I know, it was a Mercedes.

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Do you really believe that VW is worse than other companies in this regard?

Of course not, otherwise I wouldn't own a car from this manufacturer. I can personally handle these shortcomings quite well, but I'm sure it doesn't contribute much to customer satisfaction, does it?

Sometimes you wonder if the designers were drunk - for example, the design of the KW (Kupplungs Wellen) splines.

BM wrote:

... As far as I know, it was a Mercedes. ...

In Germany already, but not worldwide... in Germany, this manufacturer was number 2.

@Bertil and everyone, GolfoSaurus:

I just hope no one from VW is reading this...

I'm quite certain that there are people from VW reading, and even writing, here; but I'm not allowed to, and don't want to, provide any more information about that .

Nebelwerfer_TDI wrote:

... I'm quite sure that there are people from VW reading this. ...

I am personally familiar with such things .

"Unfortunately, quality is often neglected these days. These engines are also not very easy to maintain, and there are various design flaws in these high-tech engines (e.g., the water pump driven by a timing belt, different screw types everywhere, many parts can only be removed with special tools, and underdimensioned materials). You can see this in many VW workshops, where the technicians sometimes have less knowledge than the customer. This is certainly the case with many other car manufacturers as well, but up to the Golf 4, these were still cars where you didn't encounter these problems to such an extent." The current price levels are even more depressing.

But let's get back to the topic:
I've examined everything very carefully again, and I can't find any foreign object. Either it somehow got in there on its own, or the engine already had this damage when I received it.
It would be interesting to know what these engines have to endure on test benches or in test vehicles; mine had approximately 17,000 test kilometers under its belt.
After inspection (in addition to the discovered damage), it still looks very good, with virtually no visible wear marks in the cylinder, and no other damage to the pistons/rings/connecting rods.
The camshaft shows very few signs of wear, and neither do the rocker arms.
However, there are also some things that have already lost their appeal.
Twin-turbocharger, turbocharger (VTG turbine blades and pressure sensor), pistons, 4 valves, head gasket (minor oil leak), mass airflow sensor, 3 coolant hoses (the person who invented the design with the brackets and mounting tabs should be stoned... ).
Quite sad and doesn't speak well of the quality!!!

Well, for us, these are specialized tools for the screws... and one of the main reasons for this is to make them easier to handle for the machines/robots that are used to fasten them.

Yes, the quality. However, there is significant variation, which decreases with increasing age. My electric scooter has not had any defects yet, or any potential defects have been quickly resolved.
The tandem pump seems to have had real problems in the early production years and is also prone to making noise. With the newer model years, things seem to be running more smoothly (although I'm also noticing a lack of high-mileage examples among my acquaintances).

But then you'll soon have everything refurbished, and if it was sold to you in that condition, then the search is over.

Hi,

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It would be interesting to know what these engines have to go through on the test bench or in test vehicles; mine had approximately 17,000 test kilometers behind it.

How did you acquire the engine? Isn't it possible that the damage (whatever part caused it) has already been repaired? The notches in the cylinder head and piston aren't pretty, but they're not terrible either. If the connecting rods, bearings, etc. have been replaced, that is okay (even for a test engine ).
Why can't anything be seen on the valves? Especially around the edges of the valves, something should be visible if the same valves were installed now as they were at the time of the damage. It's also possible that I can't see that in your picture --> please check it "live."

Why would you want to machine the head if it's already within the tolerance?

Regards,
Sure, here is the translation of the text from German to English:

"Micha"

There's nothing visible on the valve itself, and there's nothing noticeable at the "grinding point" either. However, the valve is leaking, but there are no apparent defects.
I was planning to remove the head to address some indentations on the 3-cylinder engine. It might not be necessary, but I wanted to prevent any cracks from forming in those indentations, which can sometimes occur between the valves (although, according to...). (Repair manual, even though the use of a cracked part is permitted under certain circumstances), and most of the time, these cracks don't stay small; they tend to get bigger...
Furthermore, after assembly, there is an increase in pressure within the system, which subjects the head to higher loads again.
I doubt I'll let him design it; otherwise, holes might form in the piston because the fuel jet could be hitting the bottom of the piston. This could happen because the nozzle is closer to the piston after the facing operation, unless I use the 3-hole ZK gasket instead of the 2-hole one.

Yes, the engine is almost completely overhauled now, so hopefully there's not much left to do (which is what I'm really hoping for...).

I (as I mentioned yesterday) also sought a second opinion regarding the damage. In the process, we also noticed that the valves were completely intact. Therefore, I now have the following hypothesis:
- There was a foreign object (possibly the dowel pin used to secure the head gasket/cylinder head) inside the engine, and it entered the cylinder directly during assembly.
- The engine was making noises and was disassembled.
- The valves were replaced because the seats were damaged.
- The "marks" on the cylinder head and piston were considered acceptable for the test engine, and the reconditioned cylinder head and block were reassembled.
- Possibly, the valve seat was re-ground beforehand because it was also affected. If not, that would also explain the leak today.

The marks on the cylinder bore were either overlooked or deemed acceptable for testing purposes.

If the car has 17,000 km on the odometer and the engine (presumably) was still running on a dynamometer beforehand, you can add some extra mileage to its supposed total mileage.

Since no foreign objects were found, I think this whole discussion is pointless.

If the engine hadn't been leaking oil, it might have continued running for a long time longer without the damage being noticed.

VW probably saw it the same way and therefore reinstalled it .

- There was a foreign object (possibly the dowel pin used to secure the head gasket/cylinder head) inside the engine, and it entered the cylinder directly during reassembly.
Pass case? Are these only available from PDs? Okay, I haven't replaced a timing chain on a TDI engine yet, only water pumps, and I'm not familiar with any kind of spacer sleeve being used.
Based on the notches, one can roughly infer what it was. The long and narrow notches are particularly interesting or suspicious. Possibly, multiple people were involved in this, or they were working separately on different aspects of the problem related to the piston.

@Zak1976:
I would suggest removing the valves and carefully inspecting the valve seats. If the damage occurred before the issue with the LL hose, you should have noticed it in the idle speed control system if a valve was leaking. Do you perhaps have any old logs from the idle speed control system?

Also, here's the translation:

'The notches on the sides of the ventiltaschen (ventilation pockets) / vent depressions are also interesting.' Do the valves have so much clearance from the pistons that you can't actually see anything touching the valves?
The large, rectangular scars suggest that something hard or large was present, and the motor was running against it for an extended period. I also can't imagine something that big disappearing into the exhaust without leaving a mark on the valve seat. If there are signs in the valve pockets (and flanks), then there *must* be signs on the valves as well. Valves can't be that hard that you wouldn't see even the smallest scratch. My guess is that you bought the engine in this condition. But that's just a guess. The truth is probably only known by the engine itself .

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Passport holder? Are they only available at PD's

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According to the "parts uncle," this is also the case with the VP. A colleague of mine also told me that these valve seals sometimes ended up inside the cylinder on older 5-cylinder TDI engines.
If it's crushed by the piston, corresponding fragments with imprints could result.

A colleague of mine told me that these casings sometimes ended up in the cylinder of the older 5-cylinder TDI engines.
'Where exactly are these housings installed? Are they only needed for the ZK assembly?' I'm a bit lost right now .

The (sleeve) is located at the top, between cylinder 1 and 2, on the rear side (towards the injection molding wall) of the cylinder head. 1.6L engines do not have them. However, 1.9L engines do. It's actually designed to help position the ZKD and ZK more accurately during assembly, so that nothing shifts out of place.