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Vanos timing for the pros?

3K views 5 replies 5 participants last post by  Motorsport39 
#1 ·
Hey guys, I'm having a terrible time with timing the cams at the moment. I'm becoming super frustrated, the cam timing mark is not lining up on the exhaust cam. No matter what I do it doesn't line up. I have tried retiming 3 times, then decided to take of the vanos and realigned the hubs another 3 times and still it will not line up.

What could be causing this?
I noticed that the exhaust hub, when aligning the splines, the hub needs to jiggle/move about 1/2 to 1 tooth to get to fit.

I attached the photo of the alignment. It is only the exhaust side thats no aligning. The intake is fine.
 

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#3 · (Edited)
Could be the short chains driving the exhaust cams are a bit slack when you lock down the bolts. What I did was:

Rotate crankshaft CW looking from front to take up chain slack. Lock at TDC with tool.

Loosen off 3 accessible sprocket bolts (I had new spring washers and they create so much friction, it's difficult to jiggle the VANOS piston to the "initial" position all the way forward where it hits the front cover. Loosening 3 bolts reduces the friction.)

Have solenoid board removed so trapped air doesn't stop piston going all the way forward.

Rotate cam in direction of rotation with 27 mm wrench past the timing mark.

Set 8 mm pin in hole.

Jiggle cam back to timing mark with wrench, making sure chains stay loaded, until pin drops into cam hole.

Tighten 3 loosened bolts.

Confirm timing.

Malcolm
 
#4 ·
motorsport i shot you a pm
 
#5 ·
Is this on bank 2?


Primarily I'd agree with Malcolm in that the slack in the chain is knocking you timing out when cranking with the direction of engine travel. Simply compensate for it slightly when tightening the 6 bolts up, so if you are too advanced when you check, set the timing slightly retarded and vice versa. After some small trial and error you should be inside the window.
 
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