Need help diagnosing problem after vanos update

[sapote]

To recap, regardless of whether I put in my old vanos or old exhaust hub or new vanos and new exhaust hub I still get the same results. Every time I take it apart I get the timing perfect then rotate the crank several turns and recheck the timing. But then when I start it the exhaust cam is off significantly.s.

off significantly? Physically observed or testing data?

keep in mind that when engine turned off, the EX cam rested at max advanced as in the first 2 pics, so it’s normal that the pin cannot lineup to the cam hole.

[Rosie]

Do you have the shafts fitted to the correct cams?

[sapote]

I pulled the cap off

With the cap off, you cannot tell the piston is bottomed to the cap. Lineup to the end of the cylinder is not the same as bottoms on the cap.

[boadly]

This might be a dumb thing to ask but is it possible the intake and exhaust cams are swapped?


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No, I'm certain they are correct. You can see in the first photo in post 27. The intake has the thin line near the hole.

[eacmen]

This might be a dumb thing to ask but is it possible the intake and exhaust cams are swapped?


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[boadly]

Do this to confirm the EX cam timing: remove the piston cap, then turn the cam CCW until it passed the bridge pin position about 10 degrees, then install the cap and torque the bolts properly and this should push and turn the cam back to the bridge pin position. If yes then the timing has not changed since you last bolted everything together.

Not sure why this is necessary. As I've said I have correctly timed it multiple times, reinstalled the vanos correctly and then rechecked the timing after rotating the crank multiple times. It is always correctly timed when I bolt everything back up.

[boadly]

What voltage test? I didn't know that the cams were removed. Should let us know the whole thing at beginning so we have a full view of what had been done. Did you remove the cam sensing wheel?

You didn't answer about the piston bottomed on the cap -- how did you know?

The test I described in post 32. No, I didn't remove the cam sensing wheel.

[sapote]

Do this to confirm the EX cam timing: remove the piston cap, then turn the cam CCW until it passed the bridge pin position about 10 degrees, then install the cap and torque the bolts properly and this should push and turn the cam back to the bridge pin position. If yes then the timing has not changed since you last bolted everything together.

[sapote]

Wouldn't the voltage test I did be conclusive for the cam sensor? I did pull the cams so as to clean the rocker arm rods as I couldn't initially slide the rocker arms over to do my valve adjustment.

What voltage test? I didn't know that the cams were removed. Should let us know the whole thing at beginning so we have a full view of what had been done. Did you remove the cam sensing wheel?

You didn't answer about the piston bottomed on the cap -- how did you know?

[boadly]

I start to think you might have EX cam sensor reading issue even though it was timed correctly. But why as you only worked on the VANOS.

Wouldn't the voltage test I did be conclusive for the cam sensor? I did pull the cams so as to clean the rocker arm rods as I couldn't initially slide the rocker arms over to do my valve adjustment.

[sapote]

I start to think you might have EX cam sensor reading issue even though it was timed correctly. But why as you only worked on the VANOS.

[sapote]

If you cannot turn the cam CCW passed the bridge pin position, then mechanically nothing have changed since you bolted them up.

Yes, it's very hard to turn the cam with 24mm wrench, because the splines were made with shallow slope (angle) for easy to turn cams by pistons linear motion but not the other way around. It's normal.

[boadly]

How can you see the piston bottomed on the cap? Not a clear plastic cap.

I pulled the cap off

[sapote]

I'm guessing that it wouldn't go as I can see the piston is bottomed on the cap.

How can you see the piston bottomed on the cap? Not a clear plastic cap.

[boadly]

Did you work on the EX cam sensor/wire? I don't think you touch the cam sensing wheel at the rear end.

I checked the exhaust cam sensor by checking voltage as I turned the crank. It changed from 5 volts to 0 as the cam rotated so my understanding is it is working correctly. However, I tried checking the crankshaft sensor the same way and it never changed from 2.5 volts. Not sure if that is indicating a problem as the sensor is only a few months old and I put my old sensor back in which as far as I know was still good and it showed the same results.