What is the proper procedure for re-timing S52 using the vanos air tool?

[hli]

I replaced my vanos seals a while back using the Beisan instructions. I'm wondering if my cam timing may be slightly off as it seems to properly time these engines you need to actuate the vanos back and forth with the 4 exhaust cam bolts loose, then lock it down wherever the vanos ends up after. It also seems the hydraulic chain tensioner doesn't keep enough pressure on the chain to take up all the slack.

From what I have gathered, I just need to lock the cams, loosen the exhaust cam bolts, insert the timing chain tensioner tool, and after actuating the vanos a few times, lock down the exhaust cam bolts. Is this correct? Thanks.

[ScotcH]

I've never used the air adaptor for timing, and I've done MANY engines. It's good for testing your max advance, but not used for timing. Your vanos might installed improperly (ie, not in the fully retracted position) so you might need to pull that off as well. Otherwise:

[Braymond141]

I've never used the air adaptor for timing, and I've done MANY engines. It's good for testing your max advance, but not used for timing. Your vanos might installed improperly (ie, not in the fully retracted position) so you might need to pull that off as well. Otherwise:

It actually does help you set the correct timing. Apply 12v to the solenoid with air pressure, remove 12v power with air pressure still applied... THEN lock down the exhaust sprocket.

Using the air tool method guarantees you are setting the position correctly. Doing it with the lollipop tool by hand is hit or miss if your cam timing is correct leading to VANOS jam codes.

[Hova]

The idea of setting the timing with the air tool is simple. If at 60psi air pressure the cam won't move, then under 60psi of oil pressure it won't move either.

I've timed lots of these motors, and I find the best way to do it is using the tool to get it initially within the zone, then test with the air tool, measure VANOS engagement, retest once assembled.

[hli]

I'm not getting any codes and the car runs fine, but I'm planning on tuning the car soon and wanted to ensure I had the cam timing set correctly and in a repeatable fashion, and not +/- .5 degrees off or something.

I figured using the air tool would ensure that the vanos actuator was in the fully retracted position before locking down the exhaust side with the chain properly tensioned. When I had followed the Beisan instructions, I was unsure if I had turned the exhaust side sprocket too much towards the counterclockwise direction and was also relying only on the hydraulic tensioner to pick up the slack in the main chain. I did have one more question; which direction should I be turning the crank to lock the cams at TDC? I imagine I would want the slack in the main chain on the tensioner side, which would mean I turn the crank bolt clockwise to TDC when locking the cams, correct?

I also wanted to verify that the steps I had listed were correct:
1. Lock cams at TDC
2. Loosen exhaust cam bolts
3. Undo lower hydraulic chain tensioner and insert chain tensioning tool
4. Actuate vanos using ~60PSI a few times leaving air connected in non-actuated state
5. Tighten down exhaust cam bolts

Thanks for the help!

[ScotcH]

You always want to turn the engine clockwise, never back it up.

Also, if you lock the cams, you won't be able to actuate the Vanos. you mean lock the crank?

[Braymond141]

Also, if you lock the cams, you won't be able to actuate the Vanos. you mean lock the crank?

That is incorrect. With the cam locks in place and the exhaust sprocket loose, you can advance and retard the VANOS no problem. This is why using air to cycle and then lock down the timing is beneficial. Provided you are seeing the correct range of travel, ending with air supply on and power removed from the solenoid, everything is in the exact position it needs to be locked down in.

https://www.youtube.com/watch?v=0GUHUkiDe9Q

[ScotcH]

That is incorrect. With the cam locks in place and the exhaust sprocket loose, you can advance and retard the VANOS no problem. This is why using air to cycle and then lock down the timing is beneficial. Provided you are seeing the correct range of travel, ending with air supply on and power removed from the solenoid, everything is in the exact position it needs to be locked down in.

https://www.youtube.com/watch?v=0GUHUkiDe9Q

Right, missed the exhaust bolts loose part ... carry on!

I've only used it to test the intake cam advance, with everything tightened to spec. Why would you not just do that instead of loosening the exhaust cam?

[JitteryJoe]

Here is another You tube video that does a pretty good job of showing the test procedure
https://www.youtube.com/watch?v=angrrw9TaRc

[hli]

Right, missed the exhaust bolts loose part ... carry on!

I've only used it to test the intake cam advance, with everything tightened to spec. Why would you not just do that instead of loosening the exhaust cam?

My understanding is that this is done so that it ensures the vanos actuator is fully retracted before locking the exhaust cam bolts. If you just use the exhaust cam sprocket wrench to draw the vanos in when installing it, you may inadvertently extend the vanos actuator slightly, causing your intake cam timing to be off relative to the exhaust sprocket where the main chain is attached.

[thisdavidg]

I also wanted to verify that the steps I had listed were correct:
1. Lock cams at TDC
2. Loosen exhaust cam bolts
3. Undo lower hydraulic chain tensioner and insert chain tensioning tool
4. Actuate vanos using ~60PSI a few times leaving air connected in non-actuated state
5. Tighten down exhaust cam bolts

Hi all, I'm in the process of reinstalling my vanos on my 96 328i after doing the beisan seal/rattle fix and was curious if the quoted method from hli was solid. Looks pretty good to me, but this is my first time messing with timing on the m52. Is the use of the chain tensioner tool needed even when the cams are locked down?

[Braymond141]

You do not need the chain tensioner tool.

[thisdavidg]

You do not need the chain tensioner tool.

Thanks for the reply!

I did just receive the tensioner tool in the mail yesterday...So I'm just wondering if using the tool would make the timing adjustment even slightly more accurate, or I should just not use it.

[Braymond141]

Thanks for the reply!

I did just receive the tensioner tool in the mail yesterday...So I'm just wondering if using the tool would make the timing adjustment even slightly more accurate, or I should just not use it.

Sorry, let me be more specific. You can proceed without it if you do not have it. You should use it if you do have it.

[thisdavidg]

Sorry, let me be more specific. You can proceed without it if you do not have it. You should use it if you do have it.

Thanks for the tip...I used the tool and feel pretty confident to put it all back together now!