Something I hoped to never see....
 

Balance shafts - some of mine! Had to replace o-ring seals at the rear of the housings. This is a lot of work for what could have been a relatively easy repair with a different design. All for the joy of replacing the o-ring that surrounds the aluminum disc pictured.

Wow! Is that the bottom of the engine as seen from a lift?

Hey Paul - the top pic on the right is the from under the car - and yes, on a lift. Pic is passenger side of the engine with the balance shaft housing removed. That housing is the one pictured in the upper left pic.

The pic on the lower left is the drivers side of the engine with the intake and balance housing removed. The lower right pic is the balance shaft housing reinstalled showing the rear aluminum disc that is sealed by the o-ring.

I had oil seepage but mostly the symptom was this "puttering" sound as the aluminum discs would vibrate in and out (at idle) from the variation in crankcase pressure as each combustion cycle occurred. This movement occurs when the o-ring shrinks and can no longer hold the disc firmly.

Porsche uses a 3 bolt housing with an o-ring seal for the front of these housings. I see no reason that the same design would not have worked on the rear. It would have greatly reduced the repair time here and I suspect all of our cars are destined to have this failure as they age. This car only has 78,000, but the o-ring was 22 years old.

I also took this opportunity to replace engine support mounts, every front engine oil seal, thermostat, etc. I attempted to install the redesigned pivot for the T belt tensioner lever but couldn't get it (with its o-rings - something the original does not have) to fit into the tensioner bushing. I've got to get with my P buddies and do some research on that.....

Cliff

And while we're on the subject...
 

Here is the comparison - original T belt tensioner lever pivot (upper) and new style. The new one uses o-rings to seal the bushing, but pushing the tensioner lever onto it damaged the o-rings. Yes, I had it properly lubricated....