Newbie in need of a bit of help. Recently did a an engine rebuild on a 2007 R56. At first startup, after building fuel pressure it started and ran smooth. I promptly shut it off because I was still bleeding air out of the coolant system. I was thrilled at the time.

Now it is running very rough and misfiring on all cylinders. I checked for a possible vacuum leak and didn't find any. After all the usual checks I popped the valve cover back off and found that when the crank is locked 90 degrees before TDC on 1, the exhaust cam is lined up properly but the intake cam is off. The intake cam is the VANOS sprocket cam and as I understand it, it should be at zero advance when the motor is off and there isn't any oil pressure, right?
See attached picture of how far it is off.
When I reassembled the timing chain and tensioners I used the cam and crank locking and dummy tensioner kit and I used new bolts and torqued them to factory spec + the required angle past the initial torque spec. (Intake cam 15ft/lbs + additional 180 degrees, exhaust cam 15 ft/lbs + 90, crank 36.8 ft/lbs + 180). I turned the engine over by hand several times to make sure it stayed in time.

Has this happened to anyone after a timing chain kit replacement?


Full back story for those who may need additional information of how I got this far:
The car is a friends and she left it with me because it quit running. After a bit of diagnostic work I discovered there was very little compression and then found the cams out of position when I took the valve cover off.
Hoping for the best I removed what was left of the old tensioner guides including fragments in the oil pan and oil pickup screen. I then replaced the timing set with one of the newer revised kits from ECS Tuning (thanks guys).
After replacing that I fired it up and it ran now but sounded like a diesel. I checked compression again and it was all over the place. At that point I was pretty sure the valves were bent. Took the head off and yes it looked like the exhaust valves hit pistons. Great...
At that point I could have just replaced the valves and rebuilt the head but I figured in this far, why not just rebuild everything with new bearings and rings. So I did. I got all the parts necessary to do it from ECS Tuning (again thanks guys. Your website is great).
Motor out so full tear down and build, new clutch, etc.
Put the motor back in and put everything together. First startup was smooth. Second and from then on running rough.
Found intake cam out of position. Thinking that is the cause now. Luckily I do have more new cam bolts to attempt to reposition the intake cam and try again but I am hesitant because I don't understand why it moved in the first place. Do I need a new VANOS sprocket, solenoid valve, or is it okay for it to be slightly off? I doubt it's okay to be that far off at rest.

Sorry for the long post. This site has been helpful during the rebuild process. Happy to be here.

 

Slight update. I decided to try to manually rotate the intake cam back with a wrench. It moved and as I moved it I could hear and feel oil being squeezed out of the VANOS sprocket area. Is that normal? Is this sprocket bad in some way?

Maybe that is normal and I have another issue like a valve cover leak? I have a pending p1497 code indicating that I do have a vacuum leak but also couldn't this just be a cam stuck out of timing?

 

As far as the P code goes, P1497 0x2B64 Downstream Throttle Air Leak. I have seen more than a few people report this code with timing issues, but since you just did yours it may not be the case. Thread HERE. Definitely could be related to the valve cover if you cannot find any vacuum leaks. Check out post #20 and #23 HERE.

 

timing I definitely off, maybe you installed the top guide (T guide) last?
or if you didn't crank to build up engine oil pressure before start and the timing got skipped?
Either way, whatever caused it doesn't matter, get new gear bolts, retime the engine and try again, badly timed engines can cause all sorts of problems and weird codes,... good luck!

 

Chain tensioner tool should be used in a very specific sequence of bolt tightening, all described in the Bentley manual. Basically, all sprockets should be loose (acceptable exception is the crank sprocket), cam and crank locks in place, then tensioner tool installed. After adjusting tension, tighten sprockets and re-assemble. It's a little more complex than this, but essential to be done correctly. I've read that some repair manuals don't even mention the chain tensioner. Improper use causes lots of grief!

 

Thanks for the replies. I think there is more to this. As I mentioned in the second post I was able to manually rotate the intake cam back to zero position and oil came out of the VANOS sprocket which tells me it is not working correctly. I could be wrong about that but it seems like it should return back on its own.

The sprockets are on tight, all of them. I followed the Bentley book and actually this is not the first time I have done this. So with the cam back in position it is definitely timed correctly but the VANOS sprocket was stuck in an advanced position. So that will probably have to be replaced too??? Joy.



Anyway I actually put the valve cover back on and started it back up after having moved the cam back and it still is running rough. I am back to suspecting a bigger vacuum leak.... possibly the valve cover.

 

Did you find the solution? Looks like we have the same issue as I was able to rotate the intake cam also and see oil coming out of the vanos.

 

fjohn624 I had the same issue as you - cam could moved back counterclockwise and oil would come out around cap / vanos area. After swapping a lot of parts ( I have a second Mini with same engine ) the issue was resolved by replacing vanos unit.
So if your cam is able to move then the vanos unit is bad.