More VANOS info

[desbak]

I just did the VANOS job, and I wanted to share some car-specific info for follow Z4M owners that are also looking to do this. There's already lots of good DIYs out there withvarying methodologies, so I suggest reading those first (I used a mix of all of them based on my understanding).

I mainly followed SYT_Shadow's DIY on M3Forum:
http://www.m3forum.net/m3forum/showthread.php?t=411224

Along with the Beisan procedures: http://www.beisansystems.com/procedu..._procedure.htm
and http://www.beisansystems.com/procedu..._procedure.htm

And supplemented with information from Blind32's thread: http://www.zpost.com/forums/showthread.php?t=407826

Many thanks to all of the people above for making my life easier! Couldn't have done it without their info.

General info:
- My car is a 2006 Z4M Roadster with a 9/2006 production date. It had 41,750 miles (including ~300 track miles) on it when I did this job.
- The cam bolts were the old hex type and showed no signs of wear. The exhaust hub tabs were perfectly fine too.
- Services I decided to perform: upgrade cam bolts to the new hex version (12x 07129905536), update the diaphragm springs to the S65 version (2x 11367833218), update seals to the Beisan ones (BS021, BS024), upgrade the exhaust hub to Turbotoy's V3 hub, and clean VANOS solenoid valves.
- The only special tools I used was the flywheel lock (you need to cut it shorter to fit), and the timing bridge (along with extra lock pin). Part numbers 83300490861, 83300493749, 83300491086, respectively. I was able to do the job just fine without the special black box tool (save some money!).
- The entire process took me about 9 hours to do.
- I ASSUME NO RESPONSIBILITY FOR ANY POTENTIAL DAMAGE. FOLLOW THIS INFORMATION AT YOUR OWN RISK. I MAKE NO CLAIMS THAT EVERYTHING IS ACCURATE, THIS IS JUST BASED ON MY EXPERIENCE. I'm also writing this from memory, so this most likely won't be comprehensive.

First, remove the electric fan from the radiator, coils & spark plugs, valve cover, timing chain guide, etc. Pretty straightforward. Be anal about plugging up all the holes with rags or paper towels; you don't want anything falling in there.

On the Z4M, you will need to remove the plastic thing holding the hood release cable, as it will get in the way of VANOS removal. I just used some pliers and forcefully wiggled it out.



Unplug the solenoid pack (cut the zip tie), and unscrew the 5 bolts at the top of the VANOS to fully remove the solenoid. Cover belts underneath to protect from oil. Note: if you're doing the Beisan seals, loosen the oil pressure restrictor on the right side with a 22mm wrench or socket before unscrewing the 5 bolts.

Now, make sure your transmission's in neutral, and rotate the engine until the cyl#1 lobes are facing each other. Using your shortened flywheel lock, lock the bottom of the engine at OIT. The hole on the intake camshaft should be facing up such that you can slide the timing pin in through the bridge.



At this point, the hole in the exhaust camshaft is most likely not facing straight up and the timing pin won't go in. You'll need to be able to move the exhaust camshaft so that the exhaust spline shaft slides forward enough to access the tiny 7mm and 10mm shafts. To remove the pressure in the system, I just removed the VANOS caps instead of using the black box tool. Due to the clearance issues in the Z4M, you'll need a low profile 5mm allen wrench. The one from this set http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1 worked for me. The caps are also on there pretty tight, so tap it with a mallet until you can jam a small putty knife in there to pry the cap off (catch the oil with a towel).



You should now be able to move the exhaust camshaft with your 24mm wrench without too much resistance. Remove the 5 bolts (2x 10mm socket on top corners, 3x 5mm hex on bottom) to prepare for VANOS removal. Support the VANOS using the two long top bolts you removed earlier. Assuming nothing's still holding the VANOS body in, pull while tapping the VANOS with a mallet to free it. I had lots of trouble freeing the exhaust side - it just wouldn't budge. Just keep pulling at it until you can jam a pry tool (putty knife) in there. This simple part took me nearly entire hour.

Undo the 7mm & 10mm bolts (reverse thread) to completely remove the VANOS. Here, I went ahead and put the second lock pin through the timing bridge so that both cams are locked in place for the remainder of the job.



Remove the bolts from the intake hub (once these are loosened, you are playing with timing, so make your markings and see how much the splined gears are sticking out beforehand). My bolts where the old hex kind that are prone to failure. Pic below with 3 new bolts already replaced (clean hole with MAF cleaner, add blue loctite to new bolts).



After changing out all the bolts, I elected to use the S65 diaphragm spring and pressure plate (cup side down in the hub) to get rid of more rattling. Put the hub back based on your markings; finger tighten two bolts, and rotate it all the way CW, insert the splined gear, and slowly rotate the hub CCW until the gear catches and slides in. Your markings should now line up. How far in/out the splined gear sits will determine your timing. Once it's set correctly, tighten all 6 bolts and torque them down. Repeat for the exhaust side.



If you use the TT hub like me, position the splined gear such that the face of the gear is flush with the ring of the exhaust hub. Perform the Beisan seals upgrades and solenoid cleaning at this time. Before putting the VANOS back on, I put the piston caps back on since the Z4M lacks clearance and I didn't want to deal with the low profile allen wrench. However, this made it a pain while mounting, especially in the exhaust side - every time I try to bolt the 7mm/10mm splines back together, the bolt would push the piston back in and I'd have to remove the VANOS unit and undo the piston cap to push the piston back out.

After failing 3 times and wasting another hour, I found the easiest way was to compromise: put the piston cap back on for the intake side, but leave it off for the exhaust side so that you can push it back out with your finger if it gets pushed in. This means you won't be able to use a torque wrench on the three cap bolts - just get it tight enough with your low profile allen wrench afterwards. The intake side is easier since you can almost always grab the piston back out with pliers due to the recess. If you choose to put the piston caps on before mounting, make sure the piston comes out enough that you can grab it with some pliers (but not too much or else you won't have enough room).



Also, put the control valve in the hole on the engine first, and not with the VANOS body - it makes install easier with what little room you have on the Z4M.

Screw the reverse-threaded 7mm/10mm shafts back together (hand tight is fine, they're reverse-threaded after all), and rejoice that the hardest parts are all behind you! Now you just need to remove all the rags and put everything back together. Make sure you remove ALL the rags from the hole of death! One of my rags got kinda deep in there (but still reachable with my fingers), and I couldn't see it without a flashlight. You don't want to leave anything in there that could mess with the timing chain. Remove the flywheel pin and rotate the engine a few times to make sure nothing binds.

I put everything back together, and the first few seconds of startup seemed a bit rough: it took 2x as long to crank, and engine had more vibrations in the cabin (I have Vibratechnics engine mounts). It went away after less than 30 sec, I assume it's due to the VANOS not having pressure & scavenging for oil. First impressions after half an hour of test drive: the engine feels much smoother! I found myself shifting 500 rpms later than usual since the 3.5k rattle was gone.

Feel free to correct me on any of this. Ideally at this point I'd get the BMW INPA software to check VANOS offsets or something, but I'm too cheap for that at the moment...

[StickMon]

Nice write-up!!

"At this point, the hole in the exhaust camshaft is most likely not facing straight up and the timing pin won't go in."
"I had lots of trouble freeing the exhaust side"

I gave up on trying to turn the exhaust camshaft, using the black box.
I unbolted the Vanos and then drove off the exhaust side off by turning the camshaft.

BTW, INPA with a cable is only 40 bucks, or so.
But based on how you put it back together, I'll bet it's spot-on.

Good call on replacing the exhaust hub. Mine broke at about 80k miles, and it's a lightly driven DD.
Mine's going back under the knife in 2-3 months to replace the timing chain guide and swap in a rebuilt Vanos.

[itdnwiwbp]

Thanks for this. If I ever get brave enough to tackle this project myself this will be invaluable.

[Blind32]

Sweet! Great work! Glad my guide helped!