Hello fellow M156 owners and fans. Note: posting this here as it seems there's more M156 users here than in the W212 forum. Anyways, I've been spending months and $$$$$ chasing down a specific issue with odd camshaft position angles correlated to misfires and engine lurching and think I may have narrowed down my problem to be misaligned or broken phaser wheel seal rings. These parts for reference (but OEM) https://www.63motorsports.com/afterm...156pulseorings

I've been digging for resources on how to best replace these and haven't found really any resources on how to best do this as it's own job. I've already done all the other common top-end work on this engine: camshaft adjuster rebuild with 63 motorsports kit, revised head bolts, SLS tappets, CPS replaced due to oil seepage into harness, intake manifold and throttle bodies cleaned.

Is it possible to access these by just removing the front timing cover or do I also need to remove the valve cover and camshaft adjusters themselves? Any videos or online guides would be extremely helpful! I'm just wanting to minimize my teardown considering I've already had all the other 'common' "while you're in there" work done.

The more I think about it, I'm thinking I may have to remove the valve cover just so I can properly do the cam timing.

Also does anyone know of any concrete tests or methods to confirm these are the culprit? I have a loooong troubleshooting history with this car https://mbworld.org/forums/w212-amg/...-m156-e63.html but TLDR, the latest evidence pointing me to this is a test drive I did with the bank 2 exhaust CPS disconnected. The car drove smoother than it ever has with no notable misfires and none of the previous issue behaviors. I then performed a manual camshaft actuation test and got really odd readings of the angle spiking way out of spec (with the CPS reconnected). Video: https://imgur.com/nVaRJL0

What prompting me to start digging deeper into VVT components was a recent code for "The position of the exhaust camshaft (cylinder bank 2) is implausible relative to the position of the crankshaft".

I plan to do this same manual camshaft actuation on known good bank 1 just to compare the readings to confirm the same out-of-spec angle spike doesn't happen there. Would going for a drive with the bank 2 exhaust camshaft solenoid disconnected give me any additional data to go off of? Any signs I could look for if I scoped through the CPS port?