Timing chain slack

[Cubieman]

So after issues with timing my engine after my Vanos work I've come to the conclusion my problem is likely from the slack in the timing chain.

Here is a video of the slack, just for visual reference:

https://youtube.com/shorts/XacCjaD47Ig

To properly time the engine I must set the crank JUST before TDC, the crank locking pin is unable to be inserted.
If I set my cams up while the crank locking pin is installed the timing bridge does not sit flat, I've tired numerous times and I always end up with a small gap on intake side for both cams, the exhaust cam having the larger gap of about 1mm.

I have heard on the this forum that it might be OK to "cheat" the timing as I am doing, but after talking with a local BMW shop and the main dealer they didn't think that is the greatest idea.

The indie shop recommended replacing the tensioner as maybe the spring isn't 100%.

If I'm over-complicating things, sorry, but I just wanted to get a few more opinions as far "cheating" the timing goes.

[sapote]

So after issues with timing my engine after my Vanos work I've come to the conclusion my problem is likely from the slack in the timing chain.

Here is a video of the slack, just for visual reference:

https://youtube.com/shorts/XacCjaD47Ig

To properly time the engine I must set the crank JUST before TDC, the crank locking pin is unable to be inserted.
If I set my cams up while the crank locking pin is installed the timing bridge does not sit flat, I've tired numerous times and I always end up with a small gap on intake side for both cams, the exhaust cam having the larger gap of about 1mm.

I have heard on the this forum that it might be OK to "cheat" the timing as I am doing, but after talking with a local BMW shop and the main dealer they didn't think that is the greatest idea.

The indie shop recommended replacing the tensioner as maybe the spring isn't 100%.

If I'm over-complicating things, sorry, but I just wanted to get a few more opinions as far "cheating" the timing goes.

Is it bad to cheat? Sure it's bad to cheat in school examine or cheat your friends. But it's OK to cheat the VANOS to make it even more happier and better.

Look, at the end of the day, after verifying by turning the crank 2 or 4 turns and lock the crank at TDC and the cams are timed perfect with the bridge pin, if you don't tell everyone that you cheated, then who cares as long as it's perfectly timed? Why the BMW shop or the dealer need to know how one arrived at such a perfect timing?

I had looked at the video, and it's normal and not chain slack. You can't expect to have the chain stays as a solid piece of metal when pulled. The small error that you saw on the bridge is normal as everything has tolerance and not absolutely precise. Cheat by set the crank a little retard is to compensate for these accumulated tolerance to nullify it and this is perfectly fine. Don't listen to those shop or dealer as they just follow the book but don't care to know of how the whole system works.

[stash1]

Have you gotten so far as to see if the VANOS is adapting in the ECU?

[Icecream]

Thats about how mine looked. Its not going to be completely rigid. All the tensioners were in when you timed it right?
have you gone grey yet?

[Cubieman]

Have you gotten so far as to see if the VANOS is adapting in the ECU?

No, I still haven't set final timing and reassembled everything.

Before I removed the vanos the last adaptation numbers were -.60 exhaust and -4.5 inlet.

[Cubieman]

Thats about how mine looked. Its not going to be completely rigid. All the tensioners were in when you timed it right?

Yes.

[Cubieman]

have you gone grey yet?

Lol, this is what happens when OCD and not fully understanding what I am doing collides with things not going 100% according to plan.

[180SXTCY]

With the motor at TDC and the crank locking pin in, and the Vanos solenoid and valve pack removed, are you fully retarding the cams by rocking them back/forward, but in the end they need to be fully retarded ?

[Icecream]

Yes.

Then you have three options.
Get a new tensioner (probably wont change a thing)
Get a new chain (probably might have a little tiny bit less slack for a lot of work including removing the head)
Button it up and fire it up . if it is put back together correctly, it shouldnt damage anything and you can check the timing and go from there before spending a tin more on it.
maybe another forum member that is close can stop by.

[heinzboehmer]

Here is a video of the slack, just for visual reference:
https://youtube.com/shorts/XacCjaD47Ig

Mine is the same. As others have said, a chain is never going to be completely rigid.

[Cubieman]

With the motor at TDC and the crank locking pin in, and the Vanos solenoid and valve pack removed, are you fully retarding the cams by rocking them back/forward, but in the end they need to be fully retarded ?

I am retarding the cams before checking final timing, they up not being 100% retarded after rotating the crank. So my gap between timing bridge and head becomes a bit larger after retarding cams.

[sapote]

I am retarding the cams before checking final timing, they up not being 100% retarded after rotating the crank. So my gap between timing bridge and head becomes a bit larger after retarding cams.

You're confusing me here. You only should turn the crank CW and lock it at TDC compression cycle, then check the cams with the bridge; you should not touch the cams to retard them at this point, so what do you mean the gap become larger after retarding he cams?

[Cubieman]

You're confusing me here. You only should turn the crank CW and lock it at TDC compression cycle, then check the cams with the bridge; you should not touch the cams to retard them at this point, so what do you mean the gap become larger after retarding he cams?

After rotating crank to TDC for the final time to check timing I have a gap on intake side for both cams, at this point I can retard the cams just a LITTLE bit and its makes the gaps between bridge and head a bit larger.
Beisan instructions say to rotate crank to TDC and fully retard cams and then check timing.

[sapote]

After rotating crank to TDC for the final time to check timing I have a gap on intake side for both cams, at this point I can retard the cams just a LITTLE bit and its makes the gaps between bridge and head a bit larger.
Beisan instructions say to rotate crank to TDC and fully retard cams and then check timing.

TIS never says this. People should not touch the cams (retard them) during this final test step. The crank should turn the cam, not you or anyone.
What is the tolerance of the crank locking pin? When you tried to turn and retard the cams, this turned the crank CCW and enough to move it off TDC since there is clearance in the crank locking pin, and cause error in the test.

[Cubieman]

TIS never says this. People should not touch the cams (retard them) during this final test step. The crank should turn the cam, not you or anyone.
What is the tolerance of the crank locking pin? When you tried to turn and retard the cams, this turned the crank CCW and enough to move it off TDC since there is clearance in the crank locking pin, and cause error in the test.

That makes sense, my timing on exhaust side is still almost 1mm off before retarding cams.