Piston at top dead center does not align with crankshaft stop (VAG)

Dear Diesel Gods,

I'm currently dealing with a topic where I have a lot of doubts about myself.

Problem:
After the motor mount screws were stripped, the timing belt was replaced. The NW (negative camshaft) and KW (crankshaft) timing marks were aligned. After the replacement, the engine would not start. DTC: Northwest sensor out of range.
Then I manually turned the key until the engine suddenly seized. So, the piston is hitting the valves.
ZK disassembled, no damage to pistons or valves.

Now the KW-stop has been reinstalled (marking OT between the 2nd and 3rd tooth), and it's visible on the piston that it's no longer at the top dead center (TDC) position, but is moving downwards again.

Normally, the piston protrudes 1.1mm above the top dead center (TDC) mark. When the knock sensor (KW-Stop) is installed, the piston is flush with the cylinder block, or even slightly below it (-0.x mm).

Is the kilowatt-hour meter stop installed in a way that the marking is between the 1st and 2nd position? When the "Zahn" mark is aligned, the piston is at absolute Top Dead Center (TDC).

Could it be that the connecting rod is twisted on the crankshaft? It shouldn't be, since there's a recess on the back, or shouldn't the piston be in absolute top dead center? I can't make sense of this anymore.

Ciao.
Oli.

Hello.

Okay, first of all, it would be helpful if you could tell us what we're talking about.
Vehicle, engine type, engine code, year of manufacture, etc. It refers to these details.
That makes it easier for me to assist you.

Okay, now let's talk about your KW-stop. The 1.4/1.9 TDI engines have a different one.
Stopper and another marking.

If it's a 1.4/1.9 TDI engine, then compared to the diagram in the manual, your timing belt is misaligned by one tooth.
Perhaps this could be a starting point for your problem.

Best regards,
The Mpire team.

Hello Mpire,

Thank you for your response and suggestions.

About the vehicle:
Polo 9N1 FUN, EZ 06/2004, engine code AXR, 74 kW.
Engine: 06/2007, Model: BLT, Power: 96 kW.

Just like the instructions said, and the piston is not at the top dead center (TDC). This was the reason why I double-checked the alignment position to ensure that the piston was at top dead center (TDC) when the shock absorber mount was in its original position.

"Essentially, it's important to determine whether the marking between the 2+3 pins of the crankshaft stop indicates a normal +x degrees or a general 0 degrees, while the NW (negative) stop is generally set to 0 degrees (valve 1)." Cylinders in intersection)

If NW-Stop means +x degrees and KW-Stop means +x degrees, then I can live with that.
I just wanted to save a little time during the assembly.

It's possible that it was intentionally designed for the KW to be ahead of schedule.

Ciao.
Oli.

The M8 threaded hole with the marking on it needs to be placed on the second one. Gap in the stopper.
- if it is the tool T10050.


She's beside you .

Regards, Mpire.

already clear

If the stop is engaged by 2-3 teeth, then the piston is not at Top Dead Center (TDC).

I took these two pictures to show when the piston is at Top Dead Center (TDC) but offset by one tooth to the left.

Please just check the OT marking on the flywheel. I'm not sure if the KW (keyword) placement at position 100 is 100% optimized.

However, it is also possible that if the valve and piston experience a close encounter, it can result in a compression.

matthiasTDI96 wrote:

... whether the KW alignment position is 100% OT. ...

No, she is not.
But even one tooth off to the side is not okay. It's roughly around 1 or 2 degrees before top dead center (BTDC), depending on the engine type.

Okay, since I'm an honest and helpful person who likes to share my knowledge, here's the solution.

If the crankshaft stopper is properly positioned and the mark on the crankshaft pulley is between the 2 and 3 o'clock positions, then everything is correct.

What happened with this engine? It wasn't like that before.

The car came to me with an error message indicating an implausible signal from the camshaft position sensor. So, I brought the camshaft to its top dead center (TDC) position, and the two locating pins on the camshaft pulley were also aligned at the 4Z mark.

Crankshaft properly aligned, and the camshaft sprocket positioned in the middle of the elongated holes.

Error message: implausible signal, still .

Then I noticed a strange ridge on the hole for the crankshaft stop, as if a pin had been torn out.
Unfortunately, I didn't pay attention to it, so I ended up going through the entire program. Look down, check if everything is okay, then look up again.

Timing set, and error message: "Implausible camshaft position signal..." F**k.

But then, the realization dawned. I removed the crankshaft pulley because I wanted to see if it might be misaligned on the crankshaft.
Lo and behold, as I held the wheel in my hand, it became clear why the valve timing was off.
The crankshaft pulley was seized, and the crankshaft had become embedded in the material. Therefore, the offset of one tooth was also explained by my picture from above.

New crankshaft pulley installed, timing belt reattached and adjusted. He started running immediately, and then I adjusted the settings by adding +3 degrees to improve his performance at higher speeds.

What happened?
Someone probably forgot to install the crankshaft stopper and attempted to start the engine. This ripped the crankshaft stopper out, and the crankshaft pulley rotated on the crankshaft. Just one tooth was enough to cause an error in the STG and prevent it from functioning.
That explains the frayed hole for the exhaust manifold stud.


BTW: The new transmissions no longer have a window to view the flywheel, so you can't read the top dead center (TDC) mark from there anymore.