S54 Vanos Info Thread

[Mspir3d]

I did the timing, rotated the engine and the cams line up perfect when the crank is between the 1 and O. I can move the crank back a tiny bit without moving the cams and it all lines up. Is this close enough or should I do it again?

picture is without moving the crank back to line up.

[marksae]

The instructions seem to say that you replace either the oil disc or the exhaust hub depending on if the tabs on the stock hub are cracked. Is there any harm or benefit in replacing both items? Does replacing both make the vanos bulletproof or would I just be waisting money?

I replaced both for peace of mind. There's no harm in replacing both. If your original oil pump disc has a bunch of chatter marks on there, that would likely mean the exhaust hub tabs have taken a lot of abuse and should be replaced. My oil pump disc was clean, so I probably didn't need to replace my hub. But my car has 168k on it, so I figure I should just replace it while everything was apart.

[YoungDinosaur]

The instructions seem to say that you replace either the oil disc or the exhaust hub depending on if the tabs on the stock hub are cracked. Is there any harm or benefit in replacing both items? Does replacing both make the vanos bulletproof or would I just be waisting money?

[marksae]

I have a question regarding the rocking the cams back and forth with the crank locked at TDC. I am able to rock the intake cam back and forth and see the vanos piston move in and out of the vanos housing. When I try rocking the exhaust cam back and forth, it just moves within the slack of the timing chain. No matter how hard I try rocking it back and forth, the vanos piston does not move. Is this something I should be concerned about? I did change the exhaust hub to the Beisan systems unit, and I didn't lube the splines.

[SWRT_M3]

Interesting I thought Liam “Stickied” this thread when we rebuilt it after the M3 Forum went down. What a PITA that was, it took me days to gather all this info.

Moderators can we possibly get this placed under the “S54 Dyno Database” thread? Thanks…

You can find it under the DIYs section. DIYs > Engine > S54 Vanos info

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/2747-diys

[WOLFN8TR]

Interesting I thought Liam “Stickied” this thread when we rebuilt it after the M3 Forum went down. What a PITA that was, it took me days to gather all this info.

Moderators can we possibly get this placed under the “S54 Dyno Database” thread? Thanks…

[cakM3]

This is a very informative thread . . . I don't know why this is not a sticky so others who come to this forum can have easy access to this information... Why make things more difficult for people new to the M3 to look for info when you can have a sticky?

[sapote]

What exactly is the reason to switch to the S62 diaphragm springs? I'm not finding a lot of definitive info other than: "people do it" something something "rattle". Is there evidence that swapping to these springs is actually beneficial?

Because someone sells them. I think the stock spring plate is just fine.

[Pklauser]

What exactly is the reason to switch to the S62 diaphragm springs? I'm not finding a lot of definitive info other than: "people do it" something something "rattle". Is there evidence that swapping to these springs is actually beneficial?

[sapote]

I’m with you but surely setting to full retard after rotation shouldnt change the results at all. Right?

Then there is the infamous chain slop issue..

During bolting down the vanos module with the hubs already pretensioned, the only way the hubs could be pushed (by the vanos module) and rotated CCW (a few degrees) is that the vanos pistons are bottomed in the module (with the solenoid plate removed). Therefore the cams should be at their most retarded position already, and rocking them won't help but might cause error (turn the crank).

There should be no chain slack in this case, as slowly rotating the crank CW (to TDC) should take out all chain slack.

[sapote]

After rotating the engine the procedure calls for rocking the cams back and forth to ensure they are back at full retard before checking timing. If the cams were at full retard when timing was set rocking the cams should simply reset them back to the original state they were in when the engine was timed.

Are you claiming that after rotating the engine by hand adjusting the cams back to full retard is not necessary?

* After setting the timing (torqued down the vanos module and all of the hubs bolts), one needs to rotate the crank 2, 4, 6 even numbers of turns and set crank at TDC, then just check if the cam holes fit to the bridge pin or how little it is off. One should not rock, turn, or touch the cams.

Rocking the cams is to turn them for the purpose of setting the cams at TDC (by fitting the bridge pin to the cam hole). That's it, one should never need to touch the cam again.

[Cubieman]

I’m with you but surely setting to full retard after rotation shouldnt change the results at all. Right?

Then there is the infamous chain slop issue.

If I am being candid I think people chase perfection here when as long as you’re within a couple degrees its not going to affect performance as dual VANOS can easily correct it. The check engine light doesnt even come on unless the mechanical timing is like 10 degrees off. That being said it is definitely something you need to do the best you can to get right.

It shouldn't change the results however I wrenched hard on the EX cam one time in any effort to fully retard following Beisan instructions and it did turn the crank ever so slightly CCW skewing the initial set timing.
The crank lock pin was more or less dead center but after wrenching on the EX cam hard it turned the crank CCW enough to were the lock pin was now touching the left side of the "locking hole" as opposed to dead center were it was.

I personally would leave the cams alone, after turning the crank a number of times they can't be anything but fully retarded, but I may be incorrect.
Maybe if the plugs are left in cylinder compression could "kick back" the crank CCW a bit as its turned by hand, then throw in the chain slack you might have a scenario were making sure the cams are fully retarded could be worthwhile.

[eacmen]

This part does confuse me as when timing the engine and turning it over by hand the cams should already be fully retarded and there should be no need to retard them.
It's only when the engine is run and the DME sets the EX cam slightly advanced one would need to retard the cams *I would think*.

This step must be to 100% ensure they are retarded before checking timing, the issue is if you wrench on the cam too hard CCW in an effort to retard it you may also move the crank CCW and if there is slight movement in the cam lock pin/hole you may end up slightly off.

I’m with you but surely setting to full retard after rotation shouldnt change the results at all. Right?

Then there is the infamous chain slop issue.

If I am being candid I think people chase perfection here when as long as you’re within a couple degrees its not going to affect performance as dual VANOS can easily correct it. The check engine light doesnt even come on unless the mechanical timing is like 10 degrees off. That being said it is definitely something you need to do the best you can to get right.

[Cubieman]

Are you claiming that after rotating the engine by hand adjusting the cams back to full retard is not necessary?

This part does confuse me as when timing the engine and turning it over by hand the cams should already be fully retarded and there should be no need to retard them.
It's only when the engine is run and the DME sets the EX cam slightly advanced one would need to retard the cams *I would think*.

This step must be to 100% ensure they are retarded before checking timing, the issue is if you wrench on the cam too hard CCW in an effort to retard it you may also move the crank CCW and if there is slight movement in the cam lock pin/hole you may end up slightly off.

[eacmen]

When checking the cams timing with the bridge tool, either the pin fits the cams holes or not. Why the need to rock the cams at this step (it sounds more like to set the cams timing and not to check their timing)?

After rotating the engine the procedure calls for rocking the cams back and forth to ensure they are back at full retard before checking timing. If the cams were at full retard when timing was set rocking the cams should simply reset them back to the original state they were in when the engine was timed.

Are you claiming that after rotating the engine by hand adjusting the cams back to full retard is not necessary?