M30 cam timing all f-ed up? How best to fix...

[paanta]

I've been missing a bit of top end power and dealing with a 1222/Lambda control value. Car kinda fizzles at ~5000 rpm. Idles fine and has good mid-range, though.

I thought it might be ignition related, especially since there was oil in the dizzy from a leaking cam seal. So I went to fix the leak...

Pulled the upper timing chain cover and please tell me I'm wrong about this next part:

O|T mark is lined up with the line on the engine. Sighting along the cam sprocket bolts, they don't appear to be either straight up and down, or in line with the TDC mark. A line through the left and right bolts wouldn't be parallel to a line between the timing chain cover bolt holes. A line through the top and bottom cam sprocket bolts doesn't point quite towards the TDC mark. I assume that's wrong. It'd need to turn at least one or two chain links to be in line with that horizontal or vertical line.

The bentley doesn't really have a procedure for setting the cam timing all by itself. What's the best way to do it?

Do I loosen the chain tensioner (the weird cylinder that juts out of the engine towards the passenger side), pull the chain off, rotate the cam+sprocket a notch, and re-tighten the tensioner?
Or do I undo the sprocket bolts and turn the cam independent of the chain itself? It's not real clear from looking at things whether the sprocket, gear and cam can be moved relative to eachother?

Is it possible for the sprocket itself to be mounted on the cam wrong? It doesn't look like it, but I've never had one of these cylinder heads apart.

Also the bentley says the sprocket bolts should be straight up and down. I assume that means straight up and down relative to the angle of the engine, not straight up and down towards the sky and ground.

[Martin in Bellevue]

I'd start by finding out where the cam is timed. Rotate the crank a couple times, by turning it away from the tensioner side, the way the crank spins when running. Turn it to where the lower timing mark lines up with the notch on the lower cover. If the cam is correctly (relatively closely) timed, the cam indicator will be perpendicular to the surface of the head & block. This is with the tension installed.
If the cam is out of time with stock gears, it is at least 10 degrees off. Check this a couple times before yanking the upper gear, please.

[paanta]

Rotating the engine clockwise, lining up the TDC mark on the vibration damper with the lower timing cover, the sprocket bolts are not perpendicular or parallel with the head. They're off by quite a bit...10 degrees is probably about right.

The previous owner had the head off the car ~4K miles before I bought it. I've spent months trying to diagnose a really weak top end...gone over literally everything that didn't involve pulling the timing cover off.

Compared to the other 535i in the family (with 40K more miles on it) mine is probably down about 20% on power up there. It's pretty reluctant to pull up to redline. Also, I've heard that having the timing off can cause a very smooth idle, which is a "problem" I've noticed.

Personally, I'd be pretty shocked if the timing were off, but those sprocket bolts are not parallel to anything on the head when the crank is at TDC. *shrug*

What's the right way to go about fixing this?

[Martin in Bellevue]

Rotating the engine clockwise, lining up the TDC mark on the vibration damper with the lower timing cover, the sprocket bolts are not perpendicular or parallel with the head. They're off by quite a bit...10 degrees is probably about right.

What's the right way to go about fixing this?

Pull the tensioner & unbolt the upper timing gear to realign the cam. Don't move the crank, and only move the cam as much as you need to to get the upper timing gear back on with the notch lined up once the tensioner is installed.

[paanta]

Is there an indicator of the cam's timing other than the bolts that hold the sprocket on?

Someone else said the sprocket bolts should be lined up vertically/horizontally relative to the ground, not the engine. From what you're saying and from what I'd assume, that's wrong. Right?

[Martin in Bellevue]

Is there an indicator of the cam's timing other than the bolts that hold the sprocket on?

Yeah, there's a hole in the end of the cam. It should be nearest the block profile at #1 top dead center.