Timing s54 after vanos rebuild installation

[eacmen]

30 seconds cranking is a long time. Where do you connect this switch to? I rather buy a dinner.

Yeah not recommending anyone buy it but the op asked.

I believe you connect it directly to the VANOS connector and supply it 12v from a battery source.

[sapote]

https://www.fcpeuro.com/products/bmw-tester-83300493429

30 seconds cranking is a long time. Where do you connect this switch to? I rather buy a dinner.

[eacmen]

Very interesting. I wonder if they still sell that device. I ended up loosening the unit a little bit to slip the new gasket on and the timing still appeared to be okay. Will be doing a valve adjustment today before putting the rest back together.

https://www.fcpeuro.com/products/bmw-tester-83300493429

[JokerElite]

Very interesting. I wonder if they still sell that device. I ended up loosening the unit a little bit to slip the new gasket on and the timing still appeared to be okay. Will be doing a valve adjustment today before putting the rest back together.

[heinzboehmer]

I looked into the "checking timing" thing out of curiosity and TIS does have a section on doing that. It says to loosen the hub bolts and rotate the cams into their correct positions.

However, it also says to first connect a special tool onto the VANOS unit to actuate the pistons. This fully retards the cams (by moving the VANOS pistons all the way towards the front of the engine), which is essentially the same thing you are doing when you bolt the VANOS down onto the engine. The cams are not fully retarded when the engine is shut off, as the DME moves them into the optimal position for the next engine start.
Without ensuring that the pistons are at the limit of their travel (cams fully retarded), checking timing doesn't really make sense. So unless you have a way to ensure this, it's best to take the VANOS unit off and put it back on.

[heinzboehmer]

+1 to what Mau said

Also, as long as you don't loosen the hub bolts now, the timing will not change. If you want, you can take the VANOS fully off by unthreading the splined shafts from the pistons and the timing will remain the same.

[maupineda]

Yes, is fine. We all want smooth as butter after spinning the engine a few rotations but the reality is that there is some slack on the chain, yet you could wiggle the cams with the 24mm spanner and the pin will go back in smoothly but rotate again and you will find the same condition again. Remember, the cams can even be out by a couple of degrees and the VANOS still be fully operational. Dont loose sleep on it.

[JokerElite]

Reporting back, I eventually reinstalled the VANOS unit and tightened the top 4 intake and exhaust hub bolts. I checked the timing right after and the dowel inserted into each camshaft smoothly. Then I rotated the crank once to TDC (to access remaining bolts) and performed a timing test. I noticed the dowel required slight pressure to fit into the exhaust camshaft hole and would line up with the intake camshaft hole but would not go in. After tightening the remaining bolts, I rotated the crank once more to TDC (cams back at ~45°) and performed another test and the dowel goes into both holes with slight pressure.

Is this fine?

If so, can I back out the VANOS unit a little to slip in the new gasket or would this ruin timing?

[JokerElite]

I’ll be going with the method that requires removal of the VANOS unit as it seems to leave less opportunity for error.

Going to take advantage of the warmer weather and will tackle this in the evening. Appreciate all the tips and will certainly report back.

[sapote]

The thing is that due to the helical cut splines, vanos piston moves linear to rotate the cam, and when we turn the cam then it could also move the vanos piston linearly. So even with the hub bolts loosen, turning the cam CW could pull the vanos piston.

Another point is that, what if the cam timing is off (i.e the bridge off the head by 2mm on the exhaust side) was due to the vanos piston was not its most retarded position (off from the cap end travel)? And so in this case, loosening the hub and turn the cam to the correct timing still ended up wrong because vanos is not its most retarded position.

So how does the OP know if the vanos pistons are at their most forward position when he just loosen the hub and correct the cam timing? Obviously he could do a trial-error of loosen the hub and correct the cam, then do a final turning the crank 2 turns then check the cam bridge at TDC, and repeat until the timing is correct.

[Cubieman]

Please show me the documentation that confirms your assertion that what I stated could lead to piston to valve contact.

I believe he meant piston in reference to the vanos piston not being all the way foward and at end of travel in the "cap". Sorry if that didn't make sense as thats likely not proper terminology.

[George Hill]

For example, checking with bridge pin on EX cam, and the bridge is 2mm above the intake side of the head (cam is too retarded), then I loosen the hub bolts and turn the EX cam CW to get the bridge flat on the head, then torque the hub bolts. But what if the vanos piston was pulled rearward (away form its most forward position) instead of the hub rotated when I tried to rotate the cam CW, then the timing is unchanged and still wrong. No?

The reason is that there are 2 things can move to get the EX cam advance and rotate the bridge CW 2mm: either the hub rotates couple degreed CW with vanos piston unmoved, or vanos piston moves rearward a little with hub unmoved, or both parts move some. There is no guarantee that the hub will rotate CW with the piston locked in place at its most retarded position. If the piston moved from its most forward position, then game is over.

I misunderstood what you said. I will pull the BMW repair instructions and OP can make a decision on what is best for their situation.

[sapote]

Incorrect, as long as the splines shafts were installed correctly you can adjust the timing without pulling the Vanos, this is a BMW approved method. I.E. when checking, the bridges is 2mm above the valve cover surface, loosen the hub bolts rotate the cam and tighten back up then spin the engine and recheck.

For example, checking with bridge pin on EX cam, and the bridge is 2mm above the intake side of the head (cam is too retarded), then I loosen the hub bolts and turn the EX cam CW to get the bridge flat on the head, then torque the hub bolts. But what if the vanos piston was pulled rearward (away form its most forward position) instead of the hub rotated when I tried to rotate the cam CW, then the timing is unchanged and still wrong. No?

The reason is that there are 2 things can move to get the EX cam advance and rotate the bridge CW 2mm: either the hub rotates couple degrees CW with vanos piston unmoved, or vanos piston moves rearward a little with hub unmoved, or both parts move some. There is no guarantee that the hub will rotate CW with the piston locked in place at its most retarded position. If the piston moved from its most forward position, then game is over.

[George Hill]

Beisan method kind of let's you "cheat" if final timing doesn't end up correct. But as others have said you really do need to pull vanos on each timing attempt.

Incorrect, as long as the splines shafts were installed correctly you can adjust the timing without pulling the Vanos, this is a BMW approved method. I.E. when checking, the bridges is 2mm above the valve cover surface, loosen the hub bolts rotate the cam and tighten back up then spin the engine and recheck.

[sapote]

From my understanding every two rotations to TDC gets the front cams at ~45°. Is that how the cams should be before following this procedure?

Not just randomly every 2-turn of the crank (if it was at TDC exhaust stroke then every 2 turns of crank is still wrong in exhaust stroke). Set crank to TDC compression stroke.