S54 Vanos Help

[Savageblunder]

The whole point about setting the vanos timing is to have the following 5 requirements:
- crank and cams at TDC compression
- vanos pistons at max retarded position
- cam holes lined up with bridge pin
-splined shafts pushing hubs with certain amount of force to eliminate plays between them. This only can happen when splines are pushing the pre-tensioned hubs.
- chain has no slack on the pulling side (opposite of the tensioned side)

If the hubs are not pre-tensioned, there is no guarantee that the pistons are at their most retarded positions, and so the timing is not precise.

Yes, even when timing is not set precise, engine can run fine if the error is within the acceptable value, but why not do it as spec.

That’s why it made sense for me to install vanos with piston caps off, so I can 100% see & measure where they are in the bore. Doing it that way you can also manipulate when / if they go back in their bore by loosening / tightening the 6 hub bolts as the vanos gets slowly bolted towards the head. Anyway, worked perfect for me & car runs great.

[sapote]

I’m missing how pre tightening the hub eliminates backlash that wouldn’t eventually be eliminated in the final tightening of 6 bolts in each hub?

The whole point about setting the vanos timing is to have the following 5 requirements:
- crank and cams at TDC compression
- vanos pistons at max retarded position
- cam holes lined up with bridge pin
-splined shafts pushing hubs with certain amount of force to eliminate plays between them. This only can happen when splines are pushing the pre-tensioned hubs.
- chain has no slack on the pulling side (opposite of the tensioned side)

If the hubs are not pre-tensioned, there is no guarantee that the pistons are at their most retarded positions, and so the timing is not precise.

Yes, even when timing is not set precise, engine can run fine if the error is within the acceptable value, but why not do it as spec.

[Savageblunder]

1. I see. These cup springs are not for creating any kind of friction that the vanos needs, but they are for eliminating the axial plays between the hub and the cam to avoid oscillation during vanos closed-loop servo control. Unfortunately the springs also create the friction which is a negative side effect.
2. When bolting down the vanos or the piston caps to press the spline shafts into the hubs to turn them CCW to set the timing, without pre-tension the hub using 2 opposite bolts then there is backlash in the hub/spline shaft and resulted the timing is not precise as it should. Seeing the pin in the bridge and cam, and piston touching the cap are not enough if there is plays between the spline shaft and the hub at max retard position. If you don't have the hub pre-tension, then no guarantee that zero backlash in the hub/spline.
3. Sweet spot is useless and a waste of time as it doesn't gain anything.

I’m missing how pre tightening the hub eliminates backlash that wouldn’t eventually be eliminated in the final tightening of 6 bolts in each hub? It seems BMW has revised the service procedure on this Vanos procedure multiple times I think there are an endless amount of ways to do it & the car drive fine.

I feel like the serviceability of the system is awful. Other manufactures you line X up with Y & your good.

[sapote]

1. I meant the cup washer system behind each hub

2. The idea of video was to share the way I found to do it specifically on e85 Z4 M without the 2 above BMW specialty tools & be 100% sure the pistons are bottomed out where they should be, since you can’t put vanos/splined shafts in together on that car. I did it with 1 or 2 of the bolts completely tight on the hubs, which held the splined shafts in place & in turn the pushed the pistons back till they were past where the caps stopped them.
But honestly I realized in the process it doesn’t matter how you do it, as long as the bridge goes through the cams / the crank is at TDC & the vanos pistons are completely bottomed out. Thats all that matters for timing to be correct.
3. You could argue if a “sweet spot” matters or not, but to me it seemed every few teeth was a sweet spot.

1. I see. These cup springs are not for creating any kind of friction that the vanos needs, but they are for eliminating the axial plays between the hub and the cam to avoid oscillation during vanos closed-loop servo control. Unfortunately the springs also create the friction which is a negative side effect.
2. When bolting down the vanos or the piston caps to press the spline shafts into the hubs to turn them CCW to set the timing, without pre-tension the hub using 2 opposite bolts then there is backlash in the hub/spline shaft and resulted the timing is not precise as it should. Seeing the pin in the bridge and cam, and piston touching the cap are not enough if there is plays between the spline shaft and the hub at max retard position. If you don't have the hub pre-tension, then no guarantee that zero backlash in the hub/spline.
3. Sweet spot is useless and a waste of time as it doesn't gain anything.

[Savageblunder]

So you prefer not to pre-tension the hub 2 bolts? Why do you think BMW requires their worker to do this and wasting expensive labor on the production floor?

In your video at 12:59, you're talking about the important of torquing the hub bolts to spec because there is the "friction clutch" somewhere between the hub and the cam. I don't know there is a friction clutch in there for what purpose.

I meant the cup washer system behind each hub that require a certain amount of resistance to be overcome for the vanos to move the hubs CW / CCW & splined shafts in & out once the 6 x 10mm bolts are tightened on each hub. I apologize for being vague.




The idea of video was to share the way I found to do it specifically on e85 Z4 M without the 2 above BMW specialty tools & be 100% sure the pistons are bottomed out where they should be, since you can’t put vanos/splined shafts in together on that car. I did it with 1 or 2 of the bolts completely tight on the hubs, which held the splined shafts in place & in turn the pushed the pistons back till they were past where the caps stopped them.

But honestly I realized in the process it doesn’t matter how you do it, as long as the bridge goes through the cams / the crank is at TDC & the vanos pistons are completely bottomed out. Thats all that matters for timing to be correct. You could argue if a “sweet spot” matters or not, but to me it seemed every few teeth was a sweet spot.

[sapote]

This method does not require luck, gueswork, “pre-tensioning” of hub bolts

So you prefer not to pre-tension the hub 2 bolts? Why do you think BMW requires their worker to do this and wasting expensive labor on the production floor?

In your video at 12:59, you're talking about the important of torquing the hub bolts to spec because there is the "friction clutch" somewhere between the hub and the cam. I don't know there is a friction clutch in there for what purpose.

[oceansize]

Maybe next I’ll do rod bearings - but I’m starting to think with that just because a little copper is showing - it really doesn’t mean much. If you Google which metal is softer lead vs copper - it’s lead. Yes I understand if lead is worn away at one point - that means there is more critical.

But as we say in medicine - “is it clinically significant”? What is the thickness of that lead layer on a bearing? If just about every single person who has replaced rod bearings in their S54 has copper showing & l’m going to say < 1% of S54s throw a rod / rod knock - is that the root cause? BMW literally built ~ 100,000 of these S54 engines. Literally every person who changes their bearings & posts pics, almost regardless of mileage, has copper showing. And out of those “car forum people” that do get a rod knock - how many were tracked / abused cars? But yeah, I get it, better safe than sorry.

Rod bearings on an S54 are wear items and, as doctors are want to do, your moving outside your realm of experience and straight into anecdotal evidence land with a solid case of Dunning Krueger. Listen, there are guys who work on S54 engines by the hundreds (thousands?) on this forum. Rod bearings bother them enough that they will tell to change your rod bearings somewhere between 80 and 120k. I'm going with their outlook and these are solid forum citizens who don't need to drum up business by spreading fud.

[Savageblunder]

Savageblunder I'm glad that your method worked, but someone who has not done this work before could get confused by the tightening the hub bolts and removing the caps to check the piston depth. Also, the caps can only be torqued when the VANOS unit is off the car. For this reason, anyone performing this on a Z4M should put the splined shafts in the hubs first (as you did) with access to the threaded portion, put the VANOS unit on with the long bolts letting it dangle against the crossmember, attached the splined shafts to the VANOS pistons (making sure the pistons are out far enough to get to the hex portion), and use the 7mm wrench to grab on to the flat spot of the splined shafts and pry them towards the VANOS unit. Once the splined shafts (attached to the pistons) are out of the hubs, you can use your hands to press the splined shafts into the VANOS unit and fully bottom out the pistons. Then you can continue with the Beisan procedure exactly as it is for the E46 M3 and feed the VANOS unit with splined shafts into the hubs.

***For the Z4M, the Oil Regulating Valve has to be placed in the cylinder head first before mounting the VANOS unit. Beisan has you place this valve in the VANOS unit before mounting it to the cylinder head because there is much more space on the E46 M3. Getting it out on the Z4M during disassembly is also annoying as you have to use needle nose pliers or locking vice grips to grab the valve so it does not fall into the engine. After you figure out the method for doing this job on a Z4M, it becomes less annoying lol.

I tried it that way & was paranoid & took the caps off & it was close - but pistons were not all the way back. I know it because I put the caps on while the vanos was on the bench with the pistons hanging out, then removed the caps, & then measured piston depth from the end of the bore with a feeler gauge. I would’ve swore they were already back - but they were ~ 2.5mm from the end & they are all the way back @ 1.2mm & 0.6mm from end of the bore (exhaust / intake)- (at least on my car anyway).

Yes, this way you can’t torque the caps, but to me that’s much less critical that the vanos hubs. Caps never leak unless something is damaged or o-ring is missing. I had no problem with oil regulator / feed tube - I could take it out with the vanos - which means I could put it in with it. I slapped it in there when I was test fitting it & it fit on my car no prob. I can’t find a Besian procedure spec for Z4 M, although I’ve seen it referred to. Maybe it’s gone?

All in all, I’m beginning to think this really doesn’t matter. I’m just 1 guy w/1 car. I’d like to know from someone whose fixed botched vanos jobs or has done many of these is they have ever ran into an issue that was directly pin pointed to pistons not being bottomed out. I’m also fairly sure the “sweet tooth” is mostly nonsense as well. It seems to me like every 2 or 3 teeth there was a “sweet tooth”.

Maybe next I’ll do rod bearings - but I’m starting to think with that just because a little copper is showing - it really doesn’t mean much. If you Google which metal is softer lead vs copper - it’s lead. Yes I understand if lead is worn away at one point - that means there is more critical.

But as we say in medicine - “is it clinically significant”? What is the thickness of that lead layer on a bearing? If just about every single person who has replaced rod bearings in their S54 has copper showing & l’m going to say < 1% of S54s throw a rod / rod knock - is that the root cause? BMW literally built ~ 100,000 of these S54 engines. Literally every person who changes their bearings & posts pics, almost regardless of mileage, has copper showing. And out of those “car forum people” that do get a rod knock - how many were tracked / abused cars? But yeah, I get it, better safe than sorry.

[Slideways]

Savageblunder I'm glad that your method worked, but someone who has not done this work before could get confused by the tightening the hub bolts and removing the caps to check the piston depth. Also, the caps can only be torqued when the VANOS unit is off the car. For this reason, anyone performing this on a Z4M should put the splined shafts in the hubs first (as you did) with access to the threaded portion, put the VANOS unit on with the long bolts letting it dangle against the crossmember, attached the splined shafts to the VANOS pistons (making sure the pistons are out far enough to get to the hex portion), and use the 7mm wrench to grab on to the flat spot of the splined shafts and pry them towards the VANOS unit. Once the splined shafts (attached to the pistons) are out of the hubs, you can use your hands to press the splined shafts into the VANOS unit and fully bottom out the pistons. Then you can continue with the Beisan procedure exactly as it is for the E46 M3 and feed the VANOS unit with splined shafts into the hubs.

***For the Z4M, the Oil Regulating Valve has to be placed in the cylinder head first before mounting the VANOS unit. Beisan has you place this valve in the VANOS unit before mounting it to the cylinder head because there is much more space on the E46 M3. Getting it out on the Z4M during disassembly is also annoying as you have to use needle nose pliers or locking vice grips to grab the valve so it does not fall into the engine. After you figure out the method for doing this job on a Z4M, it becomes less annoying lol.

[Savageblunder]

Took my time & went super slow. Careful not to drop a copper washer, pinch a wire, break a plastic connector, etc… Decided to skip the RTV anywhere on valve
cover gasket, as I’ve never had an issue with it leaking & Besian says it’s viton (OEM) & if it’s in good shape you can use it again. The old one has been on since I adjusted valves last; maybe 6 years ago & looked perfectly usable except for the little RTV I used last time.

I cleared Vanos adaptions car started right up, shaky idle for 10 seconds, & then it evened out super smooth. No CEL, no leaks, no problems. I ended up making a video where I explain what I think is the best way to do a vanos overhaul / set timing on a Z4 M e85 secondary
to the clearence issue & also quick walk around video just showing the car. This method does not require luck, gueswork, “pre-tensioning” of hub bolts, spacers, removing the vanos twice, or trying to guess when your at 14nm of torque for hub bolts when installing helical gears / splined shafts on car separately from vanos unit on Z4 M.

https://youtu.be/HR91NgnUhiY?si=iNTCYGz3x_yzuyMe

Thanks to everyone who helped.

[Slideways]

I’m getting ready to button everything up - I have it as below. Everything seems normal now & chain isn’t excessively tight when you push down on it. For whatever reason stuff other people struggle with o never do - but I always have difficulties with the oddest stuff. I hade no issues getting the timing to stick or dealing with that side oil return pipe on the valve cover with the 2 copper crush washers.

Replaced the plugs & have VC sitting on head w/ new grommets now. Getting ready to put the bolts on.

You shouldn't have to take it all apart. Take the valve cover off and look down their with a flash light to check the timing chain guide. Take a picture if you are not sure.

[Savageblunder]

Sounds like you probably have the Beisan upper guide sitting behind the lower guide, instead of in front in its designated slot, that would cause excessive chain tension, there should be plenty of slop without the tensioner installed to get the gears in without struggling.

I’m getting ready to button everything up - I have it as below. Everything seems normal now & chain isn’t excessively tight when you push down on it. For whatever reason stuff other people struggle with o never do - but I always have difficulties with the oddest stuff. I hade no issues getting the timing to stick or dealing with that side oil return pipe on the valve cover with the 2 copper crush washers.

Replaced the plugs & have VC sitting on head w/ new grommets now. Getting ready to put the bolts on.

[maupineda]

as above, your stack of guides may have been flipped. I never struggled putting the sprockets on on my Z.

[bmwfnatic]

Timed the engine w/ bridge. Spun it multiple times. No issues - pins go in bridge w/ crank pin in & engine spins normally. Seems like in videos the exhaust cam gear goes on no problem, but they are mostly using old chain guides or if new - a BMW one. I’m wondering if anyone out there has used the Besian one & experienced this?

Sounds like you probably have the Beisan upper guide sitting behind the lower guide, instead of in front in its designated slot, that would cause excessive chain tension, there should be plenty of slop without the tensioner installed to get the gears in without struggling.

[sapote]

Had an experience I can’t really explain… Finished rebuilding vanos(easy), removed exhaust cam gear took off chain tensioner & L upper timing chain guide. I replaced the worn (wasn’t broke) guide w/ Besian - which is beefier. Went to put it back together & had an awful time getting exhaust cam gear back on.

Cam sprocket is the standard name vs cam gear which is rarely used.

Do you have the new top guide's bottom end under the bottom guide? I didn't have any issues when installing the Beisan top guide.