V6 TDI: Engine won't start after camshaft replacement?

Hello everyone,

I am currently standing on the hose.

I'm currently in the process of replacing the camshafts on my AKN engine (with a timing belt).

Unfortunately, the engine cannot be turned over manually. It only rotates about half a 180 degrees at the crankshaft.


What did I do?

- The fixing screw was in place. I could feel the hole in the crankshaft.
- For all 4 camshafts, the plates can be inserted in this position.


Does anyone have any ideas?

Thank you very much.

Rainer.

It's me again.

I forgot to mention that the hydraulic lifters are also new. Could the problem be related to them?

The manual says to wait 30 minutes before starting until they 'settle.' What does 'settle' mean in this context? Can I test anything here?

Thank you very much.

Rainer.

Wenn Öl im Stößel ist, kann es sein, daß er 'zu lang' ist, dann wird das Ventil dauerhaft aufgedrückt und kann gegen den Kolben stoßen. Daher wait.

Best regards, Rainer.

datsun wrote:

The manual states to wait 30 minutes before starting until they are seated.

I'm imagining how a mechanic installs the camshafts and then, in less than 30 minutes, installs and adjusts both the main timing belt and the one for the ESP, and then has to wait until he's finally allowed to start the engine.
But the thing about the hydros sounds plausible to me.

Hopefully, the NWs (presumably referring to some component) aren't installed upside down. It shouldn't be possible because the slot for the locking mechanisms is offset. However, you can check near the filling spout, where there's an "OT" marking.

Thanks for your help.

This morning, when I started it, the engine was rotating exactly 350 degrees. Although I was sure it was more than 180 degrees yesterday (okay, that could be due to the throttle).

- The camshaft cannot be installed upside down because the teeth would then be facing the wrong direction.

- Currently, all the pistons are moving smoothly because they have likely never experienced any pressure buildup.


This morning, I:
- Everything has been disassembled, and the engine can be turned over.
- I installed the two main camshafts and the timing belt, and then I was able to turn the engine over.
- Then, I installed the three camshafts (skipping the first cylinder), and again, it only reached 350 degrees.
- Then remove that notch again. > Is the problem still the same?

Here's what it looks like when everything is set to 'OT' (see the pictures).


Could it be that one or more valves are misaligned and sometimes get stuck in the open position?

During the initial assembly, I strangely could only rotate it 10 degrees. After that, I reassembled everything. And then I encountered my current problem.

If you are absolutely certain that the timing is correct, then the only possibilities are that you either swapped the camshafts or didn't position the camshaft at Top Dead Center (TDC) during reassembly. This means that after removing the old camshaft, you installed the new one into the head and then tightened the bearing caps to guide the camshaft. If the lobe is misaligned at this point, you might be pushing the valve down at the exact moment when the piston is at TDC. You must pay attention to the alignment of the slot in the camshaft lobe with the alignment tool when installing it. Conclusion: the valve is bent. I rule out the possibility that you were trying to turn the engine over while the gear was engaged.

Do you notice any compression on the cylinders when you turn over the engine now?

Did you rotate the crankshaft slightly backward before installing the new camshafts? I don't want a valve to hit the piston at top dead center when you tighten everything.

Hello everyone,
Thank you very much for your ideas.

But you wouldn't think of something like that.

When installing the injector, the ring must have fallen down (and be held in place with grease).
'This valve was a bit difficult to install (cylinder 2), but the old one was also difficult to remove. During the installation, I damaged the ring. Unfortunately, the piece is now lodged in the combustion chamber.'

Die Blockade war genau beim Ot vom Zylinder 2. Everything makes sense.

On Friday, I have an appointment at the repair shop. Either they'll be able to figure out what's wrong using an endoscope, or it's going to cost a lot of money.


How do you beautifully say 'repaired'?

Rainer.

Wow... You're luckier than usual.
If you had started the engine, it probably would have cost somewhere between 3,000 and 4,000 euros.
What I don't understand is how the piece of material could have fallen onto the piston instead of into the piston groove.

That's true, it takes a creative idea to come up with that. I simply drop the new seals into the cylinder head. Then, you can use a long screwdriver and a flashlight to align them, and easily install the injector.

I can easily explain how the piece of debris fell onto the piston. It's a V-engine with a cylinder angle of, I believe, 90 degrees, which means it's still at a 45-degree angle relative to the vertical. This causes the debris to fall directly onto the side of the piston. And since the engine was at top dead center (TDC) for cylinder 1, cylinder 2 wasn't also at TDC, and therefore had more space for the debris to fall beside it.

Good luck with removing the fragment.
If you plan to keep driving the car for a long time and it already has around 200,000 km, I would recommend replacing the head gaskets. You've already done most of the work.
You basically just need to loosen the head screws now.

Well, it's definitely more than just the head bolts, especially because, for example, the bolts that connect the manifolds to the compensators are so "conveniently" accessible.