I'm just about finished with this engine rebuild and thought of all the most useful tools to include at delivery time would be the means to remove the flywheel. I followed Chris's lead with the EW designed extractor and first assumed the flywheels internal thread to be the same - NOT! Firstly, the flywheel internal threads were what looked like 20 TPI, so I turned one out at 1 7/16" - 20. Nope, too small. Turned another at 1 1/2" - 20 - too big! Thru careful measurements of the thread ID and adding thread depth I discovered it to be a 38 x 1.25mm, which is only .010" less than 1.5". This may fit the S6 family too.

[Attachments converted to linked images. 01Dec21 -Doug, Admin]