Cam sprocket 1Z has failed again after one month.

Hello everyone!

Vor ca. einem Monat hatte ich die bekannten Probleme mit dem Kurbelwellenrad. Erkennungsmerkmal war bei mir vor allem schlechtes Anspringen und weißer Rauch. Das Thema ist ja hier auch ausführlich diskutiert. Hab nach ausführlichen Recherchen hier im Forum dann Zahnriemen und Kurbelwellenrad ausgebaut. Nach dem Lösen der Kurbelwellenschraube konnte ich beim Drehen am Kurbelwellenrad schon großes Spiel feststellen. Ich habe ein neues Kurbelwellenrad im Laden meines Vertrauens gekauft (Marke: FEBI Bilstein), eingebaut, und die neue Schraube nach Anleitung wieder eingebaut. Allerdings ohne Loctite oder so! Die Sicht- und Spielprüfung des Sitzes haben meiner Meinung nach ergeben, dass nur der Sitz des Kurbelwellenrades ausgeschlagen war. Nicht das Gegenstück der Kurbelwelle. Also nach Aufsetzen des neuen Rades null Spiel!!! Nach dem Tausch sprang der Motor wieder an wie neu!

I regularly drive long distances (500 km at a time) in my Golf III. While I don't always drive at full throttle, I do drive at a brisk pace, but in a way that is gentle on the engine. In addition, the engine has been modified with a chip. So, also doch höhere Momente am Kurbelwellenrad?

I have now observed that the starting behavior becomes worse again after each longer drive, or that the white smoke increases. Yesterday, it was so bad that it wouldn't start at all. My suspicion was, of course, the crankshaft. My theory is that it has become significantly deformed again on each longer drive. This morning, I examined it and it was indeed like that. The new crank sprocket is actually more deformed after one month than the old one was between 1995 and 2011!!!

However, the crank shaft's mounting is not damaged. However, the crankshaft screw was surprisingly easy to loosen.

Now, my actual questions:

Why is the new crankshaft sprocket wearing out so quickly?

What can I do about it? Are there specific, heavier crank arm wheels?

How can I install the screw so that it doesn't come loose again?

I've had my Golf for a very long time now (350,000 km) and I'd like to keep driving it for a while. It's in really good condition. The horror stories I've read here about broken crankshafts and the subsequent engine failure are of course worrying. Maybe someone has some specific tips for me. "While I have read a lot, I generally don't have enough specific knowledge about my particular problem with the 1Z."

So, I would really appreciate some tips.

Best regards

Tobi

There is a tool that allows you to plan the crank shaft surface. Then you can also immediately see if it is really level.

The answer: Certainly, the KW was not planned

Check this /viewtopic.php?t=25707

So habe ich es gelöst, but I still lack the experience to know how long it will last.

If the front surface is no longer flat, the clamping force is likely to engage faster, or how can I think about it?

No, it only detaches when the KW strut deforms due to the load.

The tool is from Sauer, and there is another manufacturer that I don't have in my system.
Some engine repair technicians, as well as well-equipped independent workshops and VW workshops, have the KW-Planfräser. Unfortunately, it's quite expensive, around 300 eggs...
The power transmission occurs via compressive force on the plane surface.

Hi,
Wie hast du genau das Stirnrad montiert?

Quote:

Ich habe ein neues Kurbelwellenrad im Laden meines Vertrauens gekauft (Marke: FEBI Bilstein), eingebaut, und die neue Schraube gemäß Anleitung wieder eingebaut. However, without Loctite or anything like that!

I have been using the KW central screw in my 1Z for 12 years now, with approximately 240,000 km on it, since replacing the KW seal ring. Installation and torque were performed according to RLF. No problems.
hg
Herbert

Hi!

So, I've installed the new bevel gear and tightened the screw lightly with 300 Nm, as stated online and in the instructions! Is this okay?

If your screw has lasted this long, it would be great if you could tell me how you mounted it. Did you plan the crankpin surface beforehand?

Greetings

Tobi

Hi,
The part numbers for the KW central screw for your Golf and my Audi 80 with 1Z engine are identical: N 905 77 101. This is the newer screw with higher strength. It was installed around 1994 and can be identified by the short pin in the center of the screw head.
Therefore, the assembly should also be identical. Following Audi RLF:
- Always use a new screw.
- Screw and thread, unlubricated
- Suit with 90 Nm plus 90° further rotation (i.e., adjustment screw!).
To use a placeholder. Instead of the VW 3099 or 4015, I will attach a flat bar to the gear rim.

Your assembly with 300 Nm, oiled, is therefore useless. You can't even say whether the screw has already been over-tightened or not yet sufficiently tightened. I suspect the first one, since you oiled it.
I would immediately replace the screw with a new, original screw, as well as the spur gear.

It is important that the mounting surface on the KW gear is clean, and that the chamfer on the KW pin and the inside of the gear are verschandeln and not worn.
Planning the front surface of the KW (Kingpin) shaft with a milling cutter is purely cosmetic, as there must already be a gap between this surface and the wheel. Otherwise, there will be no tight fit between the spur gear and the KW (Kingpin) shaft due to the chamfer.
If there is rust or scale on the forehead, a brass brush and a fine file are sufficient.
If the KW shaft is deformed, it would have to be completely reworked on a precision machine, if possible.
hg
Herbert

Where do the torque values of 300 Nm originate from?
Exactly like Herbert Schreibt! 90 NM then 90 Crad.
A new spur gear is required, just as a new screw.
While there's mention of screws and oil, this is not recommended, as the oil can reach the flat surfaces due to the force of gravity. The rest of the thoughts, I leave to you.

Quote:

It is important that the mounting surface on the KW gear is clean, and that the chamfer on the KW pin and the inside of the gear are verschandeln and not worn. Planning the front surface of the KW (Kingpin) shaft with a milling cutter is purely cosmetic, as there must already be a gap between this surface and the wheel. Otherwise, there will be no tight fit between the bevel gear and the KW spindle due to the chamfer.

If that were the case, the KW (suspension) strut should be securely mounted on the KW (suspension) in a radial manner (as is usually the case), but it is not. The existing few millimeters are not sufficient on their own to provide adequate guidance.

Do you mean that the shape of the KW tappet serves "solely" as a guide, and the central screw presses the spur gear against the face of the KW?
hg
Herbert

Okay.

Hello everyone!

First of all, thank you for your answers! I have already ordered a new crankset with a new bolt. I will install it tomorrow with 90 Nm and 90° of unlubricated space. Before, I will thoroughly verschandeln it.

I can't really address the forehead issue right now. But since it's been like this with Herbert for so long, I'll try it this way first. If the whole thing eventually resolves itself, I'll notice it through the familiar symptoms.

What do you think?

Greetings

Tobi

Unfortunately, without planning, it won't last long, and the pulley will wobble.
If you're unlucky, the timing can be adjusted so drastically that the valves become damaged, and the Nut is already worn out.

Oh dear now you've made me feel guilty again.

But 300,- € is actually a lot of money for such a tool. I don't know anyone here who owns one of these tools either. I'll try it again at a workshop here in town later.

So, there seems to be no way? Can I sharpen the files or something? That would also be very unlikely, as it is difficult to achieve a flat surface with a file.

Hello,

tobi124 wrote:

I can't really plan the forehead area right now. But since it's been like this with Herbert for so long, I'll try it this way first. If the whole thing eventually resolves itself, I'll notice it through the familiar symptoms. What do you think?

Believe us, this won't hold. It's a shame about the work and possibly the engine. The friction between the parts must transmit all the forces, but it can only do so as long as there is sufficient initial tightening. If irregularities appear on the KW's crown face due to the material used, the wheel only sits on 2-3 raised areas, which are quickly leveled out during operation, causing the initial preload to be lost -> loose wheel after only a few 1000km.
Some workshops provide the planers. I use this method with a file, but I don't recommend trying this yourself. It's only for experienced metalworkers who have been properly trained in using files.

Best regards, Uli


Edit: Overlapped with Tobias' post...