Another timing issue thread (S54)

[AZ-LSB-M3]

So I’ve been tackling timing issues all week with my S54 after doing vanos preventative maintenance but now when it comes to bolting everything up, I can’t seem to get the timing just right. I have watched dozens of videos and read various threads about the process as well as looked at the beisan’s and ECSTuning’s guide but nothing seems to be working. The timing throughout the whole process mating the vanos with the engine is correct. Then when I go to rotate the engine to tighten up all the bolts and go back to TDC, the timing on the exhaust cam is always off.

Here are a couple of videos I’ve been following to try and get the timing correct:

https://youtu.be/_nMUCe7TD2o?si=swWH71BYjdKQeqxR

https://youtu.be/DxUwd4aTWzw?si=T4WlG4iE0-AzwHTn

https://youtu.be/kbX1vfki75g?si=qcB6qB2jErwMPScO

Even though my exhaust hub wasn’t snapped I still replaced it with beisan’s exhaust hub as well as used their oil pump disk. I also replaced the diaphragm spring set with the S62 pair just in case any of that info matters.

I also found the “sweet tooth” on both splines which you can see marked in the video below.

Here’s a short 6 minute video of the entire process I go thru every time that just doesn’t seem to work. If you skip to around the 4:00 minute mark you can see the issue I’m having. Does anyone see what I’m doing wrong during this process? Is that amount of lift on the cam timing tool ok? Or should I try and loosen all the exhaust hub bolts again and adjust the cam once more? I appreciate any info!

https://youtu.be/YJpF3tLr6CI?si=kOQYSpWyNGzjvyAl

[sapote]

Here’s a short 6 minute video of the entire process I go thru every time that just doesn’t seem to work. If you skip to around the 4:00 minute mark you can see the issue I’m having. Does anyone see what I’m doing wrong during this process? Is that amount of lift on the cam timing tool ok? Or should I try and loosen all the exhaust hub bolts again and adjust the cam once more?

So the EX cam is set too retarded (the bridge leg on the intake side lifted). What caused the issue?

1. was the chain tight on the pulling side (opposite side of the tensioner), and between the two sprockets? A little slack on the chain can cause cam timing retarded. When turning the crank to TDC, never ever turn it CCW to adjust the position.
2. You didn't know or verify that the EX piston was at its max forward before tighten up the 2 bolts pulling the vanos to the head. If the pistons were not at their max forward then while tightening the vanos to the head, the pistons could move instead of the pretensioned hubs move, leading to retarded timing.

To ensure that the pistons are at max forward, remove the caps, push pistons protrude out about 5mm, then bolt down the caps to set the pistons at max forward.

As about setting the 5mm gap between vanos and head, I would set this gap 10mm to give you more chances of pushing the pistons to their max forward during tightening up the vanos to the head.

[BL92]

Follow TIS, under the section setting the timing, do you have ISTA? i can post it for you?

you are skipping the pretension stage on the hubs before fitting the vanos, that is why you are having trouble, pretension after, pulls the vanos pistons forward

Follow Sapote, He is spot on and got mine perfect = Read this entire thread from start to finish

[sapote]

OP, after the splined shaft was inserted into the hub, how did you know if the piston was still bottomed on the front cap? So before tightening the vanos to the head, the pistons must be checked to ensure they are bottomed on the caps; if not bottomed then this can cause retarded timing.

[AZ-LSB-M3]

Hey Sapote, previously I attached the spline shafts to the vanos directly before bolting up to the head and going thru the procedure of pre-tensioning and timing.

Today, I tried the method you mentioned in the other thread where instead of attaching the splines to the vanos, I inserted them into the hubs directly about 5mm or so in, then pre-tensioned and then bolted the vanos up and slowly torqued the two hex bolts until the vanos bolts to the head. This method seems to work a bit better since the timing tool seems to be going in a bit better than before but I’m still getting a bit of lift on the intake side.

I measured the lift using the OEM bmw feeler gauges and the .45mm guage goes underneath but just barely so I think it’s still acceptable. I rotated the engine a few times to confirm and its the same timing every time.

What’s interesting is I think chain slack is my issue. When I had the vanos off and the hubs loosened, I felt slightly less tension on the chain. Once I bolted the vanos up, performed your recommended timing procedure, and rotated the engine a few times, the chain was much tighter.

When I set crank position hook to between the 1 and 0 (just barely after the 1), the timing tool goes in perfectly with no issue.

Can I remove the vanos caps to check if the pistons are all the way back?

[sapote]

1. Today, I tried the method you mentioned in the other thread where instead of attaching the splines to the vanos, I inserted them into the hubs directly about 5mm or so in, then pre-tensioned and then bolted the vanos up and slowly torqued the two hex bolts until the vanos bolts to the head. This method seems to work a bit better since the timing tool seems to be going in a bit better than before but I’m still getting a bit of lift on the intake side.


2. What’s interesting is I think chain slack is my issue. When I had the vanos off and the hubs loosened, I felt slightly less tension on the chain. Once I bolted the vanos up, performed your recommended timing procedure, and rotated the engine a few times, the chain was much tighter.

3. When I set crank position hook to between the 1 and 0 (just barely after the 1), the timing tool goes in perfectly with no issue.

4. Can I remove the vanos caps to check if the pistons are all the way back?

1. "but I’m still getting a bit of lift on the intake side."
Not so sure this is about the EX cam timing or the IN cam timing. I can't read your mind.
2. Felt slightly less tension because the sprockets carried no load at this step, as with the hub bolts loosen the sprockets are disconnected from cams.
3. I have no idea what this means; what is position hook, and what are 1 and 0?
4. The piston caps can be removed anytime and this doesn't change the timing. Keep in mind the inside of the cap is not a flat surface but it has a rise circle.

[BL92]

Make sure you chain tensioners are torqued down man

[sapote]

I’m sure the tensioner is torque down, but it has a weak spring load so doesn’t help much. TIS should specify to use a solid tensioner tool for this procedure as bmw instructions for non-M vanos timing. You just remove the spring and replace with a socket to convert to a solid tensioner, then hand tighten it to have a tight chain. DONT TORQUE AS THIS CAN BREAK THE GUIDE.

[Slideways]

You were good the first time you set the timing. Having done a VANOS removal and installation a few times now, I have never had the pins slide in perfectly after turning the engine. Just like you, they are perfect before rotating the engine but slightly off after. Also, the bridge was lifting a bit on the intake side for the exhaust/intake cam or both. TIS says that the checking bridge, which no one uses, can have no lift on the intake side. Technically, we are using the wrong tool to check cam timing. Almost everyone only buys the cam setting tool and not the checking tool.

To satisfy any OCD, a little nudge of the cam/s with the 24mm wrench will get the pin to slide in perfectly again. This is after rotating the engine back to TDC.

The VANOS will adapt if there is a slight error; typically it shows 1 or 2 degrees off. In other threads, a few people have posted their adaptation values. There were some where it has adapted 4 degrees or more. One person mentioned that their factory engine came like that.

Most recent result was -2.x on the intake side and 1.x on the exhaust side. The bridge was slightly lifted on the intake side for both intake and exhaust cam. It didn't need to be perfect and it was not going to be.

[bmwfnatic]

The setting bridge has the pins at an 88-89 degree angle, not a true 90. I think the purpose for this was to adjust for chain slack.

I recently obtained a bunch of special tools for the S54, S62, S65, S85 and more from a retired BMW engineer, and he told me in early S54 testing they were actually putting a valve shim under the bridge to play with chain slack and timing. I have a prototype S50/S54 timing tool of which the angle seems to be adjustable.

You are meant to set the timing with the tool you have, and after turning the engine over check the timing with special tool 83300493750 which is actually a true 90. In my personal experience if the pin didn’t go in on the setting tool, the checking tool would mostly send up sitting perfectly.

[sapote]

Due to the chain might be a little slack on the pulling side, you can cheat this to have better timing by not setting the crank at TDC but instead set it about 4 degrees BTDC at the beginning of the procedure.

[AZ-LSB-M3]

This is what I’m referring to when I say 1 and 0. The little hook at the end of the hold where you slide the TDC pin into. Here you can see it’s slightly passed the 1. It’s at this crank position where the timing pin slides into both cams with no issue. It’s barely passed the 1 like 0.5mm maybe, maybe even less but enough that the TDC pin doesn’t go in.

https://imgur.com/a/kn20ZN8

Slideways, that’s honestly quite a relief to hear as I’ve done this process well over 10 times trying to get the pins to slide in perfectly! When you say nudge the cams a little, do I do that with everything torqued down to final spec or do I have to loosen the bolts on the hubs again?

[Slideways]

After the bolts are tightened to spec and engine is rotated back to TDC. Basically, the wrench is being used to manually adjust the cams, similar to when Beisan states in the instructions to retard the exhaust cam during disassembly to push the VANOS exhaust piston out. To know which way to nudge the cams, the pin is installed into the bridge and the bridge with pin is inserted into the cam. The bridge is lifted on one side and the lifted side is the direction to nudge the cam to get the bridge to sit flat.

It really is not necessary because the cam setting pin won't line up perfectly again after rotating the engine another 720 degrees back to TDC.

[sapote]

This is what I’m referring to when I say 1 and 0. The little hook at the end of the hold where you slide the TDC pin into. Here you can see it’s slightly passed the 1. It’s at this crank position where the timing pin slides into both cams with no issue. It’s barely passed the 1 like 0.5mm maybe, maybe even less but enough that the TDC pin doesn’t go in.

I understand now
So the timing is just a tiny bit retarded which should cause no error. As I said, if you really want to have the bridge pin falls in after rotating the crank 2 turns after timing set, then just set the crank at 0.5mm BTDC then when checking at TDC the pin will fall in.

[AZ-LSB-M3]

Ok awesome thanks for all the help! I feel much more confident moving forward here. I’ll post an update once I finish if any issues arise on first start after re-assembly.