I have a 07 MCS and it had 2 burnt exhaust valve with only 98K miles (still a little bitter about this). I when I rebuilt the head, replaced injectors, plugs, exhaust valves and guides, and replaced timing chain guides. At the time I didn't replace the timing chain because it measured within spec. But after the rebuild there was a rattle/noise from the valve cover and it runs a little rough at idle.

Replaced the chain tensioner....noise is still there and still running a little rough at idle.

Just got done replacing the timing chain....noise is still there and still running rough.

I'm running out of ideas on what the problem could be. My latest thoughts might be possibly something wrong with VANOS (although from OBD2 the timing advance seems to be changing with RPM) or possible valve sticking.

Any suggestions would be helpful

 

Lifter/bucket issue?

 

any misfires? might be valves not completely seating or the lash is off

 

No misfires...it runs fine for a few seconds, then pulls down for a brief moment, then recovers. At this point no errors (only ran for a few minutes at a time). Turning over with starter with the spark plugs out - no strange noises, when I turn it over by hand, I hear a slight tick every 180 degrees but I'm thinking that could possibly be injectors???

 

injectors don't do anything when you turn the crank by hand.

 

Here are a few pics of the burnt valves

 

Yikes!

 

Link to a video of the noise:

https://www.youtube.com/watch?v=YYVX...ature=youtu.be

I took it to the engine shop who rebuilt the head for me...he thinks it is lifter issues. Lifters were fine before the rebuild.

I also get P0108 and P0012 Errors. I'm thinking it is some issue with the VANOS. Does anyone know what the typical advance should be for a stock engine at certain RPMs? I'm seeing swings from -4 deg to 30 deg via OBD2 info.

Also stock turbo pressures?

I'll see if I can grab some screenshots during operation

 

I still get the P0012 Error - "A" camshaft position over-retarded.

Here are a few screenshots, the timing is changing up to 35 deg...this seems abit excessive but I'm not sure what the typical range is. especially under minimal load.

any thoughts?

 

Could very well be the VANOS solenoid. I'm not a mechanic, but 35 degrees does seem excessive. As I recall, an 07 only has one, on the intake side? Your mini is going on 7 yrs, why not just replace it? I think they are only $100 or so..