Kurbelwellenrad 1Z nach einem Monat wieder ausgeschlagen | Posts 48+

There's something true about that

I meant by "original condition" also the screw. So, should I use Loctite or not? I have no experience with it. What would be the disadvantages? The advantages are clear!

Best regards,
Tobi

Hi,
I've taken a look at the breakaway torques from Loctite (data sheets on the Loctite website):
- Loctite 243 (medium strength) 26 Nm for M10 thread;
- Loctite 278 (high-strength) 42 Nm for M10 threads;
Using a M14 thread, I'm adding approximately 40%, while Loctite 278 provides around 57 Nm. These are still values that are far below the specified torque. I think that thread locking agents don't really provide any benefit.
Regarding Loctite 121078 (for bonding): please consider the following point for discussion:
According to the datasheet, Loctite 121078 has a shear strength of 20 N/mm2. Assuming a 30 mm diameter for the KW stub and a usable shaft length of 20 mm, the surface area of the connection is approximately 1900 mm2. The shear strength would therefore be around 38 kN. Converted with a 15mm radius of the KW, this corresponds to a torque of 565 Nm.
Maybe someone else should check it out for verification.
The values for the KW Stump are estimated, so please measure again and correct for the chamfering.
hg
Herbert

Hi,

Even if it doesn't necessarily relate to the topic; I'm just not understanding one thing.


Yielding moment without preload, ISO 10964:
compensation, black steel screws and
–nut M10 (without pre-tension) Nm 42
(lb.in.) (372)

A M10 has a height of approximately 8mm - would that mean that the breaking torque wouldn't add up with a continuous thread (crankshaft)?

Greetings

One should get to the point.

What's missing is the shape. It needs to be recreated. The KW suspension should also fit snugly on the axle, so that it cannot "work" or move excessively.
Without this form, the materials will rub against each other again, resulting in the corresponding outcome (see title description). The same principle also applies to the screw head, and once a certain point is reached, the screw will come loose.

Honestly, I wouldn't know how to recreate this condition to some extent using workshop tools without using Loctite. It seems that using only `for` loops might not be sustainable in the long run.

Welding can only be done in isolated areas, and the slot or flattening cannot be precisely reworked (in terms of the surface) once it is in place.

Therefore, I would additionally glue the KW wheel radially (not on the face), and use Loctite to minimally secure the screw. It doesn't hurt anything.

If a Klimafreilauf (also known as a "KW Rad") has not yet been installed, it should be considered to retrofit it to relieve the pressure on the refrigerant.

Hello everyone!

So, ich habe jetzt ein neues Kurbelwellenrad montiert. Zuerst wurde es plan geschliffen. Hier muss ich euch zustimmen, beim Planen konnte man deutlich erkennen, wie uneben die Fläche war. I have re-established the connection as follows:

Initially, I cut small pieces from a measuring tool so that they had the same surface area as half the diameter of the crankshaft. Then, I tried different thicknesses (i.e., sheet metal densities). Of course, some were still too loose, and some I couldn't even fit the crankshaft onto. But one piece fit perfectly. This way, I created a precise fit that could still be assembled by hand. Then everything is assembled, and the screw is left untreated, and this time it is tightened with the correct torque and angle (90 Nm and 90°).

Here are the observations I made:

Now the car starts perfectly again.

Before the splash loop, I observed strong vibrations in the belt drives. This was particularly noticeable in the deflection of the tension roller (amplitude 10°) for the V-ribbed belt. I always thought this was normal, or at least I didn't know the reason. Therefore, the crankshaft surface was probably not perfectly flat for a very long time. Now the tension roll almost doesn't move at all (Amplitude 1°).

In retrospect, I can derive two indicators for a dislodged crankshaft or a no longer planar crankshaft end face.

1) Naturally, poor starting with white smoke. I reacted to this symptom much too late.

2) Vibrations of the belt drives or the tensioning pulley.

Unfortunately, these symptoms appear relatively late, but they definitely protect against the connection being completely severed.

Now, of course, I'm interested in your opinion regarding my repair method, especially concerning the method of restoring the form. Do you see any problems? I find that, unlike welding and stiffening, the method offers several advantages. The form is restored relatively evenly, and the crankshaft material is initially unchanged. There is no effect on the grain or no crack formation. Material Shift.

So, I'm looking forward to hearing your opinions. The topic seems to be of great interest to many of us.

Best regards

Tobi

Hi,

pretty, but superfluous.
The taper does not transmit any force; if it does, the screw will come loose and the taper will quickly fail.

The power is transmitted through the tire pressure, therefore it is important that the tire and the wheel are verschandeln and free of dirt.

And therefore, any method that reduces the area is counterproductive.

If not already present, you should install a centrifugal clutch on the Lima. This will greatly calm down the belt drive and thus extend the lifespan of the entire system.

Greetings,
Dieter

Quote:

pretty, but unnecessary. The taper does not transmit any force; if it does, the screw will come loose and the taper will quickly fail.

Then explain to us why the flattening is even present.

BM wrote:

Then explain to us why the flattening is even present.

Am I somehow obligated?

I suspect that the flattening, just like in older engines, serves as a mounting aid so that the ZR wheel and KW do not rotate relative to each other during assembly.

Greetings,
Dieter

Quote:

Am I somehow obligated? I suspect that the flattening, just like in older engines, serves as a mounting aid so that the ZR wheel and KW do not rotate relative to each other during assembly.

No.

The magic word is torsional vibration.

Here in the PDF file, you can find more information:
/viewtopic.php?p=189150#189150

For assembly, the KW can optionally be additionally secured via the flywheel.

I can't tell that the flattening is used for transmitting the driving force.

Maybe you could explain it to me.

Greetings,
Dieter

Quote:

After extensive detailed work, a slight adjustment of the crankshaft spline (Figure 16) finally provided the solution, which eliminated the previously critical keying stresses and also allowed the surface pressure to be reduced to acceptable values.

This is the key point. By reducing the surface pressure, it consequently (assuming otherwise identical materials) results in lower forces (without slip, i.e. (Friction) can be transferred.
Due to the snug fit (KW steering knuckle sits absolutely firmly, without play and is rotationally fixed on the KW), which ensures dimensional accuracy, the necessary forces can then be transmitted in relation to the pressure on the surface.

Without a complete adherence to the rules, the matter will eventually "fall apart".
(Similar to the piston head cylinder head flex, where everyone assumes it's a rigid connection -- but it's not).

The whole thing essentially works in a self-contained manner.

While using a form closure is also possible, it's only done to a fraction, so that the connection essentially holds, provided that all parameters (auxiliary drives) are within the acceptable range.

Now, for example, if the Limafreilauf system is completely sealed, then all the theoretical calculations are essentially valid for the A...h. ...and another imbalance in the damper occurs, leading to overstress and the connection only holding randomly.

I hope that I was able to contribute to a better understanding.

Hello everyone,

I completely agree with BM. We had actually already decided further up that the connection is a form closure. Nevertheless, I would be interested in hearing your opinions again on my method of re-establishing this form closure. So, those who also believe that the fit is the most important factor in the connection.

Best regards

Tobi

Hi!

So hab ich das damals repariert:







































































































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So far, it seems to be holding, I need to check the exact value, but it's estimated to be around 30 mm.

In the salad oil forum, almost all the connections that have been "stiffened" are still holding, so it can't be as bad as "correctly mounted according to regulations." It is estimated that it is approximately better than "correctly mounted according to regulations."
At least, the professional (?) repair carried out by the VW dealer in Ampfing 2.5 years ago did not last...

Hi, Jockel

Hi!

I've already read the report about my repair a while ago. Cool, also auch das selbstgebaute Fräswerkzeug!!!

And if it holds, that's great. My method was definitely faster, and I needed less tools (leaf spring method and a pair of scissors). Whether it ultimately holds as well, I don't know! What do you mean? (Description above)!!!

Best regards,
Tobi

BM wrote:

What's missing is the shape. It needs to be recreated. The KW suspension should also fit snugly on the axle, so that it cannot "work" or move excessively. Without this form, the materials will rub against each other again, resulting in the corresponding outcome (see title description). The same principle also applies to the screw head, and once a certain point is reached, the screw will come loose.

I think so too. On my Sharan AFN, the spare wheel from the previous owner was replaced while on vacation in Croatia.
New bike, new screw, new axle seal. But not pre-cut!
As a result, it took me almost 2 hours to get it back into shape, such was the undulating terrain.
By the way, I used the tool from eBay.
It gives a high-quality impression and is carefully thought out down to the smallest detail.
Definitely a worthwhile investment for the price.
I also used cutting oil for this, and then thoroughly cleaned it afterwards.
I was pulling with 100 instead of 90 nm plus 90 degrees, and the last few degrees were really very difficult, even with a very long extension.
I really hope that this thing never turns on by itself

One more question about adjusting the timing belt.
The gear on OT is misaligned by 1/2 tooth relative to the locked ESP.
How do you set it up?
Or does the engine control unit (ECU) reset it again?

Thank you in advance

KW determine using the swing arm marking on OT. Then, determine the NW (Neutral Point) on OT (Operating Table), then adjust the NW (Neutral Point) indicator, then remove the locking mechanisms from the NW and the pump, and finally, set up the pump's FB (Feedback) using long holes via VCDS or a measuring device.