Update on project Marseille, E31 850i (Patreon)

Guess who came back from the dead -- she's alive again, boys!

Man, what a struggle though. I repaired stripped spark plug threads with the head in situ, I'll talk about this more in the video, but used axle grease on the tap which minimizes the amount of shavings that land in the engine, which is inevitable with this method.
After enlarging the threads, used timesert (a sleeve with threads) that goes onto the spark plug and was able to torque all 3 plugs to 30 Nm. Now when I remove plugs, timesert stays in the head and you replace spark plugs as you normally would. This is a permanent repair for that.
I gambled with this method as aluminium shavings are soft and the risk of them doing any damage is low, in theory they melt upon start up and go out through the exhaust valve. Plus M70 can take a beating!

Happy to report that after everything that this turd has been through, it survived! Running okayish, got it up to temp and stays in the middle, doesn't overheat. Then I pulled the plugs out and performed a compression test. Remarkably got between 180-200 PSI across all 12 cylinders so it's very healthy. Used endoscope and cylinder walls are perfect, no scoring. Bit of carbon on pistons but normal given the age and kilometres. 

In not so good news, the timing chain noise is present. You can actually hear it in the video, that humming/scratching noise, that would be it. I had the same on project Bilbao (green E31) and was resolved by replacing the timing chain tensioner, but here when I let off the throttle and it's coming back to idle, there's also rattle and loud mechanical noise. It's not happy! Tomorrow going to put engine flush, then drop the oil pan and see what lurks inside. 

Out of all E31s that I revived, this was the most difficult one and all becuase of improper starting procedure after 10 years of sitting and stripping the spark plug threads which I still cannot comprehend.
Anyway, I gave it my best and it's running again with healthy compression which is a huge achievement given where we started. Every muscle hurts from leaning over that engine bay, but tomorrow back at it again!

Not sure yet when the video will drop, probably next week but lets see. Thank you for being here and for your kind support!