Why use a method that you can't torque the VANOS hub bolts to spec?

[sapote]

If the final timing check is not 100% as you expect, say after tuning the crank 2 or 4 turns and locked it at TDC and check the cams with bridge and pin, and the pin only get in the cam hole with the bridge lifted up off the head on the intake side by 1mm or so. (This has nothing to do with having old chain that stretched a little longer. This can be corrected by compensation:

At the beginning of the whole procedure, instead of blocking the crank at TDC, we set it at about 2mm BEFORE TDC turning CW. Perform the rest of the step the same as in the instruction.

For those that worry about engine damaged if the timing check result is not perfect as expect, here is the important points to avoid pistons hitting the valves when doing the final timing check with bridge/pin:

* No intake advanced (bridge should not lifted up on EX side). Advanced IN could lead to hitting valves at high RPM at end of exhausting stroke.
* No exhaust retarded (bridge should not lifted up on IN side). Retarded EX could lead to hitting valves at high RPM at end of exhausting stroke.
Valves are far away from pistons during compression stroke.

From this, I think money shift damages mostly are exhaust valves bent.

[BubbaTree]

Here's a gadget that I've used on VANOS and other tight spots where fasteners need to be torqued. I bought it at a local motorcycle shop, and it's pretty flexible, in that you can use it with basically any size spanner.

[Arith2]

That tool is used on Porsches as well. Do not use a crows foot. It's a special tool that is like $600. You just have to calibrate the 'ole internal torque guage when using a box wrench. The issue was probably not torque related anyways.

[sapote]

1.
I did this by feel, they were not torqued.


2.
I did not note the gap between the vanos and head before moving on to tightening/loosening 1/4th the left/right hub bolts. I pushed the vanos onto the head and hand tightened the top vanos mounting bolts. This may have been the issue, or part of it.

Bingo! These are the root causes.

1) You could have tighten them too tight leading to cams being turned instead of hubs rotate against sprockets.
2) You didn't know the gap between vanos and head before pretensioning the hub bolts. Assuming the vanos was touching the head before you pretension the 2 hub bolts, this would lead to couple errors: the pistons were not moved to their most forward positions; the spline shafts were not pushed to rotate the hubs to their precise timing location relative to the sprockets. This caused cams to have retard timing.

Now one can see that the method I suggested leaves no room for errors because the hubs are pretensioned with the vanos off the head, and the same as Tis. I really don't understand why Beisan wanted to deviate from Tis method.

[sapote]

It is practically the same thing as a crowfoot.

A crowfoot is a short open wrench with a square hole at one end for any standard 3/8 drive. The 117200 tool is not a crowfoot, but a special insert to use with a calibrated torque wrench. I agree that one can use any crowfoot for this task if doing the math to compensate for the offset, but why need to add more maths and complexity to the task which is prone for error? Why not deviate the Tis slightly so we can use a standard torque wrench with 10mm socket? I also prefer a socket over an open wrench when torquing anything.

My method is only different from Tis that I remove the vanos off so we can use a 10mm socket and torque wrench to torque the bolts to spec, then install the vanos back. What's a big deal of deviating from BMW for a better experience? Beisan is much more deviated from Tis. No?

[Cubieman]

Maybe this is the reason why your timing failed:
1) did you torque the left/right bolts to spec then back out 1/4 turns, or just tightened by feel?


2) after the top 2 vanos bolts are hand tight, was there more than 5mm gap between vanos and head? If not enough gap then the result timing could fail.

1.
I did this by feel, they were not torqued.


2.
I did not note the gap between the vanos and head before moving on to tightening/loosening 1/4th the left/right hub bolts. I pushed the vanos onto the head and hand tightened the top vanos mounting bolts. This may have been the issue, or part of it.

[Slideways]

This pic show the open wrench is not a normal crowfoot but a torque wrench by itself.

https://www.newtis.info/tisv2/obj/EqQdvfT

Sure, but a crowsfoot used at a 90 angle from the wrench results in the same torque (or you can do the calculation like heinz describes above, if you use the crowsfoot wrench inline with the torque wrench). Crowsfoot wrenches are cheap and get the job done while having the VANOS and hub splines mounted (no guesswork needed for the spline depth).

[sapote]

Certainly looks like a crowsfoot attachment. newTIS.info

This pic shows the open wrench is not a normal crowfoot but a torque wrench by itself.

[sapote]

After this the remaining hubs bolts are tightened by hand to 10.5ft lb.

Per your procedure the splined shafts are only installed 1/4 to 1/3 of the way into the hubs and the left/right hub bolts are tightened/backed out 1/4 turn. Isn't that different from Beisan in that when tightening the left/right hub bolts (per Beisan) the vanos/head top mounting bolts are threaded in hand tight thus I would *think* the splined shafts would be further than 1/4th to 1/3rd of the way into the hubs.

I guess I am just pointing out that your procedure MAY have the splined shafts sticking out of the hubs further vs. Beisan.

I may be wrong here and am not saying anything is wrong with your procedure at all(yours is closer to TIS than Beisan) but I just wanted to ask about that.

1) how do you tighten by hand anything to 10.5 ft lbs? Anyone can do this without torque wrench? This could be your root cause of bad timing.
2) The main difference is in Beisan method, it has the spline shafts threaded to the vanos pistons before mounting the vanos to the head. I think this is more awkward to do when inserting the 2 spline shafts simutaneously into the 2 hubs at the same time while the hub bolts are not pretensioned. This can cause mistakes and moving the hub more than 1 tooth trying to insert the spline shafts to the hubs. Do you have 4 hands to do this? Tis and my method have each spline shaft inserted to the hub just by one hand because it was not connected to the vanos and you only deal with one shaft at a time.

The goal is to have the shafts inserted about 3mm into the hubs with each hub turned CCW not more than 1 tooth during shaft insertion; 2 hub bolts pretensioned; Vanos connected to shafts and supported by top 2 bolts. You can use whatever means to get this goal. Once the vanos evenly bolted down to the head (I stress evenly to avoid cocking the vanos), hand tighten as many hub bolts as you can to avoid the hub from moving against the sprocket as this is the final timing position. Then remove the vanos and use torque wrench to torque all hub bolts to 14 Nm. The timing is done and to be verified with bridge pin.

[heinzboehmer]

1) Tool 117200 is not a crowfoot adapter. It's an accurate digital torque wrench. BMW would not recomment to torque anything this critical using a crowfoot adapter with torque wrench.

It is practically the same thing as a crowfoot.



It's meant to be used on one of those torque wrenches with interchangeable heads. Something like this:



Sure, the adapter and torque wrench are made so that the readings on the wrench will be the torque that is applied at the fastener. But once again, if you do the math (or use a trusted calculator) and set your torque wrench to a value that will yield the desired torque at the fastener, there is nothing wrong with using a crowfoot adapter.

[Icecream]

Certainly looks like a crowsfoot attachment. newTIS.info

I think he is just pointing out the two are calibrated for each other.

[Slideways]

1) Tool 117200 is not a crowfoot adapter. It's an accurate digital torque wrench. BMW would not recomment to torque anything this critical using a crowfoot adapter with torque wrench.
2) Beisan instruction says to torque these hub bolts to spec by feel, not using any torque wrench at all. Still think it is a precise method?
3) I just visited TIS site and here is the pic of the pretension torque spec on the bolts: 10 Nm and not 14 Nm then back out 1/4 turns. Where did you get your Tis instruction?

4) We don't have tool 117200 as Tis instruction called for, nor have other tools with compress air to move the pistons as instructed; therefore deviate from Tis instructions and develop a method for DIY is not a bad thing. Why Tis doesn't use a standard torque wrench with 10mm socket -- as in my method -- to torque the hub bolts? Because time is money and the factory didn't want to spend the times to remove the vanos off the head again to have room for using a standard torque wrench with 10mm socket on the hub bolts and swap out the used gasket. We have plenty of times for our cars.

Certainly looks like a crowsfoot attachment. newTIS.info

[sapote]

So per beisan the left/right hub bolts are tightened and backed off 1/4th turn while the top two vanos/head mounting bolts are only hand tight, then the vanos is pressed fully onto the head, bottom 3 vanos/head bolts are installed and torqued as well as the top 2 vanos/head bolts that were just previously hand tight are torqued.

Maybe this is the reason why your timing failed:
1) did you torque the left/right bolts to spec then back out 1/4 turns, or just tightened by feel?
2) after the top 2 vanos bolts are hand tight, was there more than 5mm gap between vanos and head? If not enough gap then the result timing could fail.

[sapote]

Using a crowsfoot wrench is what is recommended on the TIS and the torque before backing off a 1/4 turn is 14nm. The final torque is also 14nm.

I would not deviate from the Beisan or TIS instructions.

1) Tool 117200 is not a crowfoot adapter. It's an accurate digital torque wrench. BMW would not recomment to torque anything this critical using a crowfoot adapter with torque wrench.
2) Beisan instruction says to torque these hub bolts to spec by feel, not using any torque wrench at all. Still think it is a precise method?
3) I just visited TIS site and here is the pic of the pretension torque spec on the bolts: 10 Nm and not 14 Nm then back out 1/4 turns. Where did you get your Tis instruction?

4) We don't have tool 117200 as Tis instruction called for, nor have other tools with compress air to move the pistons as instructed; therefore deviate from Tis instructions and develop a method for DIY is not a bad thing. Why Tis doesn't use a standard torque wrench with 10mm socket -- as in my method -- to torque the hub bolts? Because time is money and the factory didn't want to spend the times to remove the vanos off the head again to have room for using a standard torque wrench with 10mm socket on the hub bolts and swap out the used gasket. We have plenty of times for our cars.

[sapote]

...I guess I am just pointing out that your procedure MAY have the splined shafts sticking out of the hubs further vs. Beisan.

More is better. Seriously it's not matter so much as long as the the spline shafts are not bottomed out on the hub when the vanos is not bottomed out on the head. Give them a gap of 3mm minimum should be enough.