DIY: Vanos timing question

[nextelbuddy]

I'm at the end of my Vanos refresh.

I've been watching the videos in the Vanos thread here on the forums
I've also been following along the beisan procedures for everything.

The one part that I'm stumped on is after I have installed my hubs and attached my intake an exhaust splines onto the Vanos unit and pushed the Vanos pistons all the way in

I attached the Vanos unit to the intake and exhaust hubs according to the beisan procedure tightening the bolt in the proper sequence

Before all of this, I made sure my timing bridge was installed correctly and my timing pin dropped in smoothly on the intake and exhaust camshafts while the crankshaft was a TDC

at this point after i finish tightening the bottom hub bolts and rotating the crank back to TDC 360 degrees and the cylinder 1 lobes are pointed at each other.

All the videos I watch just show and say :

Put the timing bridge on and check that alignment pin drops in smoothly and your timing is good at this point.

In beisan procedure they say:

Take 24mm wrench and rotate camshaft counterclockwise to retard cams fully (with a Foot note that says cams should already be retarded) why do they say this?

Are they suggested that the only reason to move the cam is that it shouldn't move?

In my case it does move like literally the amount of a spec of dust and it's just enough to make my alignment pin not drop in smoothly anymore and I have to force it in. If I breath on the 24mm wrench to move it back the minute amount then the pin drops in a smoothly.



All the videos I watch no one moves the cam with the wrench to retard anything. Every one just tightens the bolts, rotates the crank 180 degree, tightened rest of the bolts and rotates another 180 and check timing with bridge and alignment pins and it's good to go for them.


So main question is basically, are we to equate that the camshafts fully retarded == alignment pin and timing bridge drop in smoothly?

In my case if I fully retard my cams, my alignment pin does not drop in smoothly with the bridge.

[Slideways]

This is possibly caused by a small amount of slack in the system, maybe in the chain or the gears. As long as the cams are timed and the VANOS splined gears and hubs have their full adjustment range (hubs rotated fully clockwise), the ECU won't care if there is a hair more adjustment in the system.

The reason Beisan might say that is if cams move slightly within the VANOS adjustment range while rotating the engine to tighten the hub bolts.

[sapote]

I'm at the end of my Vanos refresh.

In beisan procedure they say:

Take 24mm wrench and rotate camshaft counterclockwise to retard cams fully (with a Foot note that says cams should already be retarded) why do they say this?

It should not say this at this step.

Before all of this, I made sure my timing bridge was installed correctly and my timing pin dropped in smoothly on the intake and exhaust camshafts while the crankshaft was a TDC

at this point after i finish tightening the bottom hub bolts and rotating the crank back to TDC 360 degrees and the cylinder 1 lobes are pointed at each other.

I think you meant rotating the crank 2x360 deg or nx360 where n is any even number. Just one turn 360 won't work.

[nextelbuddy]

It should not say this at this step.


I think you meant rotating the crank 2x360 deg or nx360 where n is any even number. Just one turn 360 won't work.

Yes correct two times not one. My apologies. I know if you rotate just once then you are 180 out and that's just to tighten the bottom bolts that you couldn't read earlier.

I think I've tried taking everything apart and resetting the hub bolts and the Vanos unit and resetting the timing probably 6 or 7 times at this point and I can never get to a point that makes me happy
Whenever I start over I reset the crank at TDC and make sure my cams are at TDC with the lobes on cylinder One pointed towards each other. I use my timing bridge and make sure that the sides are flat and the pins can go in very smooth one at a time and there is no gap on the bridge rising up on the cylinder head

I removed the pins, Remove the bridge, reattach the splines to the Vanos unit and push the plungers back in all the way until they bottom out and then I start reattaching the splines and the Vanos unit according to the beisan procedure. I follow the correct sequence for tightening the hub bolts just the four in and outer bolts and then backing out one quarter of a turn. Then I tighten up the Vanos unit to the cylinder head and I watch everything. Nothing moves. At that point, when I've tightened everything up before I rotate to get the bottom bolts tightened on the hub. I checked my timing just to check it and it's good. Everything is smooth then I go ahead and rotate one time to get to the bottom bolts. Then I rotate one more time to get back to top dead center on everything and I check my timing and the exhaust is always off. I have to wiggle the wrench to get it to fall back into place. Usually I have to advance it just slightly like a hair.

Every single video I watch. I don't know if it's people that are cutting the video to make it look like there's is just perfect every single time but that's what they do. They rotate tighten their bolts, rotate again, check their alignment pins and they just drop in no wiggling of the wrench.

I'm using a genuine BMW bridge and the updated pin with the chamferred end and it is not bent because when everything is in time I can spin the pin 360° in any direction and it's smooth rotation while it's aligned in the cam and the sides of the bridge do not rise up and down. I have another pin that is bent that I got from a friend and you can definitely tell that it's bent because it gets tight when you rotate it and it causes one of the sides of the bridge to lift up so I don't use that pin.

Very frustrating.

[nextelbuddy]

It should not say this at this step.


I think you meant rotating the crank 2x360 deg or nx360 where n is any even number. Just one turn 360 won't work.

So I think I might have found the culprit of why my alignment pins weren't lining up after a couple rotations

I noticed that when I would rotate the crank so that I could put the alignment pin in to be a TDC a lot of times. I miss the mark because I'm holding the crank alignment pin ready to push it in place as I rotate the crank and that doesn't always work and when I miss it I will rotate the crankshaft counterclockwise to get the mark back. I only rotated it counterclockwise because in the beisan procedure? He states quite a few times. It's okay to rotate the crank counterclockwise.

It's during those times when I rotate counterclockwise. I am at TC crankwise but there's now slop in the chain and the alignment pins don't line up anymore. So I actually have to rotate clockwise properly several more times and then make sure that I actually hit the mark on the crank the first time with the crankshaft pin and if I do that then the alignment pins on the camshafts do line up

[heinzboehmer]

So I think I might have found the culprit of why my alignment pins weren't lining up after a couple rotations

I noticed that when I would rotate the crank so that I could put the alignment pin in to be a TDC a lot of times. I miss the mark because I'm holding the crank alignment pin ready to push it in place as I rotate the crank and that doesn't always work and when I miss it I will rotate the crankshaft counterclockwise to get the mark back. I only rotated it counterclockwise because in the beisan procedure? He states quite a few times. It's okay to rotate the crank counterclockwise.

It's during those times when I rotate counterclockwise. I am at TC crankwise but there's now slop in the chain and the alignment pins don't line up anymore. So I actually have to rotate clockwise properly several more times and then make sure that I actually hit the mark on the crank the first time with the crankshaft pin and if I do that then the alignment pins on the camshafts do line up

I've noticed the same thing when timing my engine. Have never had trouble with stuff lining up doing it this way.

[eacmen]

Slop in the chain will cause some variance. But not worth the effort to replace the chain unless the engine is out of the car.

You need to set timing with both cams fully retarded. This is why beisan and TIS tells
you to put a wrench on the cam and rotate to the exhaust side when checking time.

When checking timing after locking down hub bolts you rotate the crank several times, this puts tension on the chain and can cause some drift in relative crank/cam position.

When putting the wrench on exhaust cam to check timing after rotating crank I don’t put too much force on the wrench. I look at the chain and will rock the wrench back and forth and as long as I can get the pin in the hole without the chain actually moving I consider that “in time”.

Remember the ECU only throws a code if timing is off by more than 5 deg. Since VANOS can easily fix timing errors within that range.


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[sapote]

“I only rotated it counterclockwise because in the beisan procedure?”
Don’t rotate CCW to set the crank TDC; it caused chain slack which caused bad timing.

[sapote]

“Then I rotate one more time to get back to top dead center on everything and I check my timing and the exhaust is always off. “
Off which way — retarded or advanced — and how much is the bridge off the head?

[nextelbuddy]

“Then I rotate one more time to get back to top dead center on everything and I check my timing and the exhaust is always off. “
Off which way — retarded or advanced — and how much is the bridge off the head?

Here's a video made last night showing my steps

https://www.youtube.com/watch?v=M2umLie6a1M

[George Hill]

“I only rotated it counterclockwise because in the beisan procedure?”
Don’t rotate CCW to set the crank TDC; it caused chain slack which caused bad timing.

Agreed, you can NOT go past TDC and rotate it a couple degrees backwards and be correct. IF you need to rotate backwards you need to go at least 45* backwards and then you crank it forwards and pin the crank.

[sapote]

Here's a video made last night showing my steps

https://www.youtube.com/watch?v=M2umLie6a1M

A few thing in the Beisan instruction that I don't like:
1) torque the hub bolts to 11 ft-lbs by feel? I also don't like to turn the crank after timing with only 3 tighten hub bolts. Instead, after snug up the top 3 bolts on each hub, remove the vanos module and the pistons LH threaded shafts off the splined shafts, then torque all hub bolts using a normal torque wrench.
2. Installing the vanos with the 2 splined shafts attached is more difficult; instead I install the splined shafts to the hubs first, pretention the hub bolts, then install the vanos to the head and connect the LH threaded shafts.
3. After the hub bolt torqued down to spec and rotate the crank an even number of turns to TDC, no reason to use a 24mm wrench try to turn the cam CCW (front vu) before checking the cam timing.

[heinzboehmer]

I also don't like to turn the crank after timing with only 3 tighten hub bolts. Instead, after snug up the top 3 bolts on each hub, remove the vanos module and the pistons LH threaded shafts off the splined shafts, then torque all hub bolts using a normal torque wrench.

I saw you mention this once and have done it this way since. Like it a lot more than guessing at torques or tightening the bolts on only one side of the hub and then rotating the engine.

[Slideways]

For the timing chain replacement, does anyone know how Mr. VANOS is replacing it without removing the front timing cover? My guess is by temporarily removing one of the links, but how would anyone feel comfortable doing that on a brand new chain?

[eacmen]

For the timing chain replacement, does anyone know how Mr. VANOS is replacing it without removing the front timing cover? My guess is by temporarily removing one of the links, but how would anyone feel comfortable doing that on a brand new chain?

he is purposely secretive about it. removing a link is the only way. With the proper tooling it is quite safe. But finding the right tooling for that chain may be difficult.


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