Timing s54 after vanos rebuild installation

[avusblue]

So I finished rebuilding my vanos and I followed the beisan instructions, I'm down to the last part where we are supposed to fully retard the cams and check timing with the OEM alignment bridge tool. I just couldn't get the alignment tool lined up after I fully retard the cams. I have tried adjusting the cams by loosening the hubs (after both cams fully retard), and was able to get the bridge to align perfect with crank at tdc, but after I tightened everything and spin the crank a few pass, fully retard the cams and the alignment bridge not lining up again, although I can get it to line up if I advance the cams a bit, so technically not fully retard or not to the adjustment end per Beisan instructions.

I have watched other tutorials on youtube, also read dr Vanos tutorial, none of them retard the cams first to check the timing. Most would just spin the crank a few times and check timing with alignment bridge without retarding the cams first

I asked Beisan and they stress it is important to retard the cams before checking the timing with the alignment tool.

am I missing something? lol
thanks

[eacmen]

When I check the cams after rotating the engine I put the wrench on it to fully retard the cams but I found that if I applied too much force on the exhaust cam then it would never line up. Ill lightly retard the cam after engine rotation but not "hamfist" it.

Most have blamed slop in the chain for this variance.

Not sure if this helps or not.


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[JamesSJ1]

eacman is right in regards to slop. Depending on the work you've done and where the chain is aligned, you may have virtually no slop, or enough to introduce a couple degrees of error. I've seen both on my car over the years.

Assuming your timing is close (you can put the bridge in place with a pin in the timing, but one side of the bridge has to be raise several mm to do it), then you can move on to the timing adjustments (next steps on Beisan directions). Essentially, put the pin fully into the timing bridge, then find the angle to put the bridge+pin down into the cam until one side is flat on the engine. The side that is raised should be less than about 6-7mm, and may be raised like that even if you followed the procedures perfectly. Now you just move on to the adjustment, and within probably two passes of adjustments (adjust, lock a few bolts, spin engine a few times, check) you'll have it perfect. Remember to do both intake and exhaust.

[avusblue]

I appreciate all the replies, I was thinking the same thing, my car has 160k so I wonder if there's a chain slop, also maybe the oil in the hydraulic chain tensioner drained out, it's been sitting for at least almost 2 months now lol.

The car was running perfect before I take it apart, no vanos noise or chain rattles, I was doing it as preventative maintenance.

I was going to pull the whole vanos off again, start over but I don't know if that'll help getting the timing right.

The way Beisan check for timing it actually tells you to rock the cams cw and ccw to ensure getting the maximum adjustment on retarding the cams. After I do that, the cam alignment tools never aligned perfectly ugh.

[yhp2009]

For what its worth the ecu that controls the vanos should easily adjust to cover the small variance in the cam timing as long as its just a few degrees

[JamesSJ1]

I appreciate all the replies, I was thinking the same thing, my car has 160k so I wonder if there's a chain slop, also maybe the oil in the hydraulic chain tensioner drained out, it's been sitting for at least almost 2 months now lol.

The car was running perfect before I take it apart, no vanos noise or chain rattles, I was doing it as preventative maintenance.

I was going to pull the whole vanos off again, start over but I don't know if that'll help getting the timing right.

The way Beisan check for timing it actually tells you to rock the cams cw and ccw to ensure getting the maximum adjustment on retarding the cams. After I do that, the cam alignment tools never aligned perfectly ugh.

Set the timing, spin the engine a couple full revolutions, and then keep rotating to TDC (line up arrow to the line). Don't mess with retarding, just drop the timing tool on there and check. Does the pin drop/push in? Bridge flat on both sides? You're good. Adaptations will take care of the rest, as you're probably already no more than +/- 1 degree at that point and any better is unlikely to gain an iota of power anywhere in the range. FWIW, adaptations won't fail until you're outside of +/- 6 degrees, though at that point you probably are losing some optimal timing adjustment by the VANOS somewhere in the powerband.

[yhp2009]

Set the timing, spin the engine a couple full revolutions, and then keep rotating to TDC (line up arrow to the line). Don't mess with retarding, just drop the timing tool on there and check. Does the pin drop/push in? Bridge flat on both sides? You're good. Adaptations will take care of the rest, as you're probably already no more than +/- 1 degree at that point and any better is unlikely to gain an iota of power anywhere in the range. FWIW, adaptations won't fail until you're outside of +/- 6 degrees, though at that point you probably are losing some optimal timing adjustment by the VANOS somewhere in the powerband.

^^^That is exactly how i did mine over a year ago and 5k miles later no issues since. And passes the vanos test

[avusblue]

I asked Beisan about this, and they wrote:

"A valid check is with the camshafts fully retarded. Otherwise you’re not checking anything.
A lift of ~1mm is acceptable.
There is an adjustment section at the end of the procedure.

The bridge should only be used with one pin at a time."

I saw a few videos tutorial on youtube, none of them retard the cams at the end of the installation, all they do spin the crank a couple of passes and check the timing. Also I read Dr Vanos procedure, it does not mention to retard the cams as well.

If you guys think it's fine, then I won't retard the cams again after I'm done adjusting the time.

[sapote]

So I finished rebuilding my vanos and I followed the beisan instructions, I'm down to the last part where we are supposed to fully retard the cams and check timing with the OEM alignment bridge tool.

Define "fully retard the cam"? Do you mean try to turn them (turn only the EX cam since they are both linked together by chain) CCW with 24mm to take out any chain slack, but not enough to turn the crank?

The final check should be "turn the crank CW 4 turns and stop at TDC with both #1 cam lobes pointing at each other then the bridge pin should be aligned with the cams holes."

[avusblue]

Define "fully retard the cam"? Do you mean try to turn them (turn only the EX cam since they are both linked together by chain) CCW with 24mm to take out any chain slack, but not enough to turn the crank?

The final check should be "turn the crank CW 4 turns and stop at TDC with both #1 cam lobes pointing at each other then the bridge pin should be aligned with the cams holes."

I basically follow this beisan instruction:

(crank at tdc with cam lobes pointing at each other, crank locking pin also in place)
Fully retard intake and exhaust camshafts.
For each camshaft, place open wrench (24mm combo wrench) on camshaft hex between cylinders 1 & 2 and turn camshaft counter clockwise to adjustment end position.
Note: Camshaft rotation is most effective when standing at exhaust side of car.
Note: Rock camshaft back and forth to release bind and allow rotation.
Note: Camshafts should already be in fully retarded position.


then the instruction tells you to put the bridge and make sure it's aligned.

so you only need to turn the exhaust cam ccw? should I rock it cw and ccw to release any bind and get the maximum adjustment ?

link to beisan instruction:
http://www.beisansystems.com/procedu..._procedure.htm

[mrgizmo04]

Exhaust cam will only retard so much - until the spline moves out/forward (toward the front of the car) and spline front face hits the oil pump disc and/or the pistons in the vanos unit retract and bottom out against the end caps. It physically can not retard more as parts of the vanos unit start interfering (I am assuming timing is set correctly, yada yada).

To make the next engine restart easier, at engine shutdown, ecu advances exhaust side and retards intake side, this reduces pressure. That is why instructions tell you to only retard the exhaust cam.

Timing is checked when both cams are fully retarded, think of this position as "TDC" for vanos.

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[avusblue]

Here’s a pic where I’m at






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[sapote]

I just couldn't get the alignment tool lined up after I fully retard the cams. I have tried adjusting the cams by loosening the hubs (after both cams fully retard), and was able to get the bridge to align perfect with crank at tdc, but after I tightened everything and spin the crank a few pass, fully retard the cams and the alignment bridge not lining up again, although I can get it to line up if I advance the cams a bit,

I see your confusion here.

I don't see why you need to turn the cams CCW to fully retard them before checking with the bridge pin, since this could move the cam slightly and causing the pin tool not aligned with the cams holes.

I guess the reason Beisan wanted to turn the cams CCW (if everything was done correctly the cams should not move at all in the process) to ensure that the 2 VANOS pistons are at their max forward position and stopped by the caps. However, if one had followed the steps correctly with pretension the hubs, then the hubs rotational friction is high enough to force the pistons to max forward position already (instead of the hubs rotated CCW) during the VANOS bolting to the head.

Here what you should do in the final timing check after everything was bolted down to spec: just turn the crank 4 turns (or 10 turns if you're so anal) to ensure that the rotating hubs splines action had pushed both pistons to their most forward, then stop the crank at TDC (if overshot then turn crank CCW passed TDC about 45 degrees, then turn CW to land it on TDC. The bridge pin should be aligned to the cams holes, (or it is off just a fraction of a degree and we can discuss about this.)

[sapote]

I basically follow this beisan instruction:

(crank at tdc with cam lobes pointing at each other, crank locking pin also in place)
Fully retard intake and exhaust camshafts.
For each camshaft, place open wrench (24mm combo wrench) on camshaft hex between cylinders 1 & 2 and turn camshaft counter clockwise to adjustment end position.
Note: Camshaft rotation is most effective when standing at exhaust side of car.
Note: Rock camshaft back and forth to release bind and allow rotation.
Note: Camshafts should already be in fully retarded position.

This instruction probably had caused so many unnecessary tears. Think about this: even with a brand new M3 just rolled out off the factory, a guy like Mike Tyson would be able to turn the cams CCW just enough for the bridge pin to not aligned with the cams holes.

[mrgizmo04]

This instruction probably had caused so many unnecessary tears. Think about this: even with a brand new M3 just rolled out off the factory, a guy like Mike Tyson would be able to turn the cams CCW just enough for the bridge pin to not aligned with the cams holes.

That instruction is the final step after all 6 hub bolts are torqued so the cam should not turn independently. It should not cause tears. And as discussed at that point spline to front of vanos unit or piston end caps will limit how much the cam can be retarded.

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