Dr Side VANOS Failed:P0021

It is unclear what step you are trying to avoid or parts you do not want to remove. So here are two thoughts:

1) To properly time the engine you need to start with Bank 2, and then do Bank 1. So working on only Bank 2 only is not an approach I would take. The slack is taken up from Bank 2, when Bank 1 is adjusted, plus the timing chain tensioner. I messed up on one run, doing Bank 1 first and ended up having to go back in. In addition, I have read people speculating that doing Bank 1 first and having the slight slack can lead to the vanos bolt loosening. (I had this happen also, but I did Bank 2 first).

2) Be cautious rebuilding your Vanos again, the plastic innards may be past their serviceable life.

You can pull both valve covers and the oil feed tubes, pin the engine and put on the block and then check through the upper timing cover timing hole. What you are seeing now may just be the valves fighting and causing the trigger wheel not to line up. I think the best way to check it is to put the timing blocks on. Either way, with the valve covers off, at least on Bank 2, you should see if you have a vanos issue.

So I worked on it late last night and this is what I did in the following sequence:

1) Removed both Valve covers.
2) Rotated Engine to TDC on Compression Stroke.
3) Pinned the Crank.
4) Installed locks on Bank1 (Exhaust and Intake Cams)
5) Installed locks on Bank2 (Exhaust and Intake Cams)
6) Removed Bank 2 Upper Timing Cover.
7) Noticed that the Timing wheel for Bank2 is off several mm, again, I think this is due to play in the VANOS.

I am not going to try and rebuild the VANOS again, already ordered one from Dr Vanos.

Now, What I want to do is to replace the Bank2 VANOS, if possible, Without removing the Upper Cam cover and VANOS on Bank1. I am thinking I can remove the Main Chain Tensioner on PASS side, and that should give me enough slack so that I can replace the VANOS on Bank2. If not, I guess I'll have to remove the Upper timing cover on Bank1, and Loosen VANOS CAM bolt so the gear with rotate to allow chain slack, I was just trying to avoid this.

Thoughts?

Yeah I installed the cam locks in opposite sequence. Did not think it mattered, as they all went on very easy, just had to rotate Intake Cam on Bank 1 a bit and lock slid right on, which I believe is normal on that cam due to lobe tension on lifters. Also, on GAS site, you can just use one pair of locks and do one side at a time as well:

https://www.germanautosolutions.com...m62_m62tu_cam_tools/m62_pro_cam_tools_diy.php



I thought that if I removed the tensioner then I could lift the chain over the sprocket on Bank1 to give me enough clearance on Bank2 to remove the VANOS, but then I figured I would risk not being able to get the chain back on Bank1 with sufficient tension to keep the engine in time when I installed the tensioner and removed the cam locks. I think, much safer as you say, to loosen VANOS on Bank1 to allow freewheel when I retention the chain.

I don't see the risk with Bank2 bolt coming loose, as regardless, I have removed Bank2 Cam cover to allow for Bolt and VANOS removal.

The order of cam lock installation is not really important. What is important is the tightening of the vanos bolts - here you want to do Bank 2 first, to take up any slack. Then Bank 1 - the timing chain tensioner adjusts for this slack. As the Bank 1 vanos still freewheels one can achieve optimal chain tightness. This will account for any chain stretch and vanos play due to wear and tear.

You can do what you describe, but what I just explained above, will not happen. I have changed the cam chain tensior on Bank 2 without disturbing Bank 1. As I knew the slack was already taken up correctly, 3k miles or so before, I was not worried. But in your case, from the start you have questioned the amount of play in your bank 2 vanos, which you do not want. The chain when new is a fixed length, after loads of miles it stretches.

Best do it by the book, and not have to go back in b/c of cam timing codes.