Doing a timing chain replacement, but I just can't seem to remove the exhaust/intake cam bolts from the VVT sprockets. Is there a way to "unlock" them before removing the bolts? They are the torque to yield E14 bolts.

First time poster, huge thanks in advance!

 

Install the crank and cam locking tools BEFORE trying to loosen these bolts. THEN use at least a ½" drive socket wrench. Hope you're using the Bentley manual for guidance ---

 

I have the crank locking tool in place, but I cannot place the cam locking tools in place because the exhaust cam is over advanced. From what I’ve gathered, if the cam is not lining up with the locking tool, you’re to loosen the E14 bolt at the sprocket so you can turn the cam with a 27mm wrench until you can place the cam lock tools over both cams securely. Trouble is, I cannot get the cam bolt to loosen.

 

With the crank locked, all pistons are half way up / down the cylinder. It's safe to unlock the crank and rotate it 'til the cams can be locked --- AS LONG AS THE ROTATION IS CW AND NOT ENOUGH TO CAUSE PISTONS TO GET NEAR TDC. I'm told that Vanos units don't like CCW rotation. With cams locked, you should be able to loosen the bolt. Once both sprockets are loosened, they can be removed and the crank can safely be rotated either direction to return it to it's original locked position. Should be minimal rotation. Just remember to avoid being close to TDC on any cylinder while cams are in place and chain is loosened --- gotta avoid piston - valve contact, as this is an "interference" engine.

Remember to replace the two cam bolts with new ones during re-assembly.

 

Another option, just in case the last suggestion is out of your comfort zone, use an open-end wrench to hold the cam instead of the cam locking tool. There's room for both a wrench and the locking tool --- two sets of parallel surfaces right next to each other --- different sizes if I remember correctly. Still gotta observe the TDC warning if you unlock the crank, but either process should allow the bolt to be loosened. Just remember to lock everything down after the bolts are loose, and don't rotate the Vanos units CCW.

 

I’ve found the VVT unit has some play in it. I’ve usually needed to use the 27mm to rotate the cam slightly in order to make the jig fit.

The play also made timing a bit of a mystery. I installed the jig, torqued the cam bolts, removed the jig and rotated the engine a few times. Couldn’t reinstall the jig without rotating the intake cam a tad using the VVT “play”.

 

Thanks for the heads up on the ccw/cw rotation. Like I said earlier I have the crank lock tool in place, and my pistons are level in mid-cylinder. But here's my problem. The intake cam is in the correct position with the label facing up. My exhaust cam however is not. Its slightly off by about 10-15 degrees, preventing me from placing the cam lock jigs over the cams since both have to be level with the labels facing up. Now to my understanding, the only way to adjust the cam is by loosening the cam bolt (E14, Torque to yield)) at the VVT sprocket. My problem is that I cannot loosen this bolt at all. I've put an impact to it, used a wrench, muscled it and nada... Afraid to apply too much muscle to it in fear that ill break the bolt head off, damage the cam barrings/vanos, etc pick your nightmare.

 

if you were able to lock the intake cam, loosen that bolt enough for the sprocket to move. unlock the crankshaft, and rotate the engine until you can lock the ex camshaft. Lock it and then loosen the bolt. loosen it just enough for the sprocket to move and then lock the crankshaft again.

Hope this helps

 

I just recently installed a timing chain kit in my N18. Could very well be a stupid question but you are trying to install the locking tool before removing the tensioner, right?

 

Hey all,

Finally got the cam bolts loose. They were just in there way too tight. not sure if someone serviced it before and over-torque'd em or what. This is a great community, and I thank you all for your insight and responses!!