OT Marking for AFN?

Hello.

Today, I wanted to check the valve timing (adjustment of the camshaft relative to the crankshaft).
Reason: The engine is running very roughly, but according to the VagCom diagnostic tool, the fuel injector is working correctly. Also, a new timing belt was recently installed by the previous owner.
"In addition, the machine suffers from vibrations, especially when idling with the air conditioning on (approximately 860 RPM). Is it possible to adjust the idle speed with the air conditioning on? Without the air conditioning, it runs at approximately 800 RPM, which is very good and without vibrations, although it feels a bit too high for my taste."

However, to answer my question, I couldn't see any timing mark on the crankshaft pulley. Is there a window near the vacuum pump, or is there another one? Perhaps it's obscured by the oil filter? In any case, I can't find a mark that I can use to adjust or check the camshaft timing.
Are there any other ways to do this, or should I just remove the first spark plug to check the position of the pistons?

The car is a Porsche 911 with a 4-speed automatic transmission.

Greetings to everyone.
Voss.

Hello voss,

To check the valve timing, you need to remove the rubber plug on the transmission (specifically, the clutch bell).
In the front of the opening, you'll see the starter ring gear. There's a (not very clearly visible) marking on it that needs to be aligned with the (suggested) protrusion of the opening. A small flashlight to illuminate the opening is very helpful here. You may also need to bend the cooling hose that runs nearby slightly to get a good view.
I also couldn't see any markings on my first attempt without using a flashlight!

Next, you need to remove the vacuum pump from the cylinder head (3 screws on the flange). To do this, it is usually necessary to disconnect at least the connectors for the coolant heater (3 glow plugs) to increase your working space.
With the vacuum pump disconnected, you can see the groove in the camshaft. To determine the angle, you actually need an alignment tool that is inserted into the groove. For this, it is necessary to remove the valve cover, as the tool must lie flat on the cylinder head.
Can the ruler be inserted when the first cylinder is at Top Dead Center (TDC)? If so, the valve timing is correct.

Regards,
Alex.

Hello.

Alex, thank you for the quick reply.

"On my vehicle, the vacuum pump is not mounted to the cylinder head, but to the engine block, and it's driven by an intermediate shaft. I couldn't find any markings on the opening where the nozzle would go."
Recognizable even with a flashlight.
Is that the opening, located pretty much from the top? Just a few centimeters to the right of the engine block?

And I already knew about using a ruler, and that's how I want to do it.
I'm going to check again today to see if I can find the marker. Maybe my new glasses will help.

Regards,
Voss.

Hello,

I once experienced something similar with an automatic transmission in a Passat.
At that time, I removed the first spark plug and...
The timing light is used to determine top dead center (TDC). After that, it required a lot of rubbing (long fingers).
and Q-tips!) to find the marking. It's really hard to see.
The marking is tiny!

Best regards,
Jürgen

PS: I did that back then because the car had poor acceleration, and...
There, the 'friendly' mechanics had done a shoddy job - the camshaft timing was incorrect.
corrected and pulled the cart!


My motto: Everything that one doesn't do themselves!

Hello Jürgen!

Now I'm curious. Can you tell me how far out of alignment the valve timing was (estimated angular deviation at the camshaft or crankshaft)?

I would also be interested in the specific symptoms of incorrect valve timing. Unfortunately, I haven't had the chance to make an alignment tool yet. My checks so far have only been based on visual observations. So, it's quite possible that I have a slight misalignment. I suspect this because the engine lacks the proper power in the lower RPM range, and it feels sluggish above 3000 RPM.
I was also able to confirm this through technical measurements (using VAG-COM), which showed a too-low mass airflow (MAF sensor value) and a too-slow build-up of boost pressure. I'm now interested to know if you experienced similar symptoms with your issue.

Regards,
Alex.

Hello.

Today, I searched again and found the marking for OT.
Looking at the motor from the front, near the crankshaft.
There's a line, and about 12 degrees further along, something that looks like a "0".
I assume that the "O" represents the OT brand?
But which brand marking on the clutch housing needs to align? I can see two possibilities.

http://people.freenet.de/rafaelma/OT_Marke.jpg
(A picture of the opening in the clutch housing, as I see it. And how do I display the image here?)
There's likely a difference of approximately 4-8 degrees between the two. In the instructions, there's a diagram showing that the "II" mark should align with the "O," but in my case, the "I" mark is aligned. However, the camshaft timing seems correct, and the dowel for the fuel injection pump also fits.

And that brings up the question: Is this okay as it is, or should I adjust it?

Who can check this for me?
Engine: AFN, Transmission: 4-speed automatic.
Sure, here's the translation:

"Thank you in advance."
Voss.

Hello Alex, hello Voss,

Alex - the car was sluggish and sounded rough - the camshaft was...
approximately 15 degrees. However, with that car, I had previously...
I've already done quite a bit because of this.
- LMM replaced - was right at the tolerance limit.
- Nozzles replaced.
- Pressure sensor on the charger replaced - membrane was soft.
All of these projects, individually, represented an improvement.
brought, and after the camshaft was properly adjusted.
He then ran like Lottchen!
The car now has 30,000 kilometers more on the odometer (155,000 km).
It's just great.
My conclusion:
Electronics are great, but first, the mechanics have to be right!

Voss - Unfortunately, I am unable to check the marking at the moment.
it looks like this, but my advice remains the same: remove the first glow plug.
out, and if you don't have a protractor with extensions and a holder.
'Did you build a small device for measuring OT?'
Now you can determine which marking is correct!

Regards,

Jürgen.

Hello Jürgen,

Quote:

Alex - the car was sluggish and noisy - the camshaft was faulty. It is adjusted by approximately 15°.

Wow, that's way off. Is it even theoretically possible to do that without messing with the valves?
Are you sure it was 15° at the NW (NW is marked on the OT)? That would mean a massive 30° KW difference at the crankshaft. If you oriented yourself based on the NW notch, you wouldn't have been able to see the OT marking, would you?
Do you have a set square, or how did you manage?

Oh, and my engine has also been running rough since the last timing belt replacement, with less power and higher fuel consumption.

Regards,
Alex.

Hello Alex,

The 15° angle on the KW (likely referring to a component or measurement) was roughly estimated - I don't remember the exact details.
but
It probably worked out okay without the 'valve salad' - but it was probably a close call.
Before that! The engine has since had a few thousand kilometers added to it and is running great!

Back then, I did it like this:

After I had determined the optimal torque (OT) mechanically using a torque wrench.
(In any case, this is the most accurate method) and after making the marking visible (using oil and cotton swabs), I adjusted the motor so that I could...
I used a ruler to mark the dimensions and a feeler gauge to center it.
loosened the screw on the camshaft sprocket, then loosened the sprocket.
Set the engine to TDC (Top Dead Center) and loosen the screw on the camshaft sprocket.
put it back on. Then, adjust the tensioner pulley for the timing belt.
eine dynamische Prüfung der ESP vorgenommen. And that's it.
Sure! But I'm being *very* careful when turning it.
KW took action to prevent the undesirable contact between the valves and the...
Avoid pistons.

Since the boys in the workshops are quite strict about the AW regulations,
to be tortured, and here also the understanding of the mechanical aspects.
Connections are missing. I can easily imagine that there is a...
A lot is going wrong!