Porsche intermediate shaft bearing repair and upgrade
Porsche engines (M96 engine designation) used in Boxsters and 911s have a weak link in the bearing that’s used to support the intermediate shaft. The intermediate shaft runs through the engine underneath the crankshaft. It’s the pivot point for the timing chains.
The bearing fails due to lack of oil flow — there’s no pressurized oil to the bearing and the oil seeps through the seals of the bearing slowly. Failure of this bearing usually starts with a screeching and grinding sound that’s soon followed by catastrophic engine failure. The shaft contacts other rotating engine components and can easily cause most of the major engine components (block or case, crankshaft, connecting rods etc..) to be damaged beyond repair.
We repair and upgrade this bearing
At Autobahn Performance Inc. we’re familiar with the procedure to replace this bearing (hopefully before it fails). A great company, LN Engineering, has developed an upgraded bearing and cover assembly.
Porsche Boxster at Autobahn Performance Inc for intermediate shaft bearing upgrade kit
This shows the bearing cover removed. The cover has the pilot thet centers the bearing. The housing in the block is a larger diameter than the bearing. The bearing centers on the intermediate shaft and the center pilot of the cover and then is affixed to the block by the cover bolts only. The seal on this cover is the newer / updated type (red seal strip on the cover)
www.lnengineering.com intermediate shaft update kit. Billet steel cover
Using the proper KUKO puller to remove the old bearing. Some are locked in with a spriolock retaining ring on the outside of the bearing. The retaining ring must be removed prior to pulling on the bearing. If there is no external ring visible, there is an internal snap ring that will pop free with the puller.
One of the reasons the bearings fail is from lack of flow of clean oil. The oil trapped in the center of the intermediate shaft is old and dirty. The engine oil on this car when drained was fairly clean; it did not look anything like the oil you can see here draining out of the intermediate shaft cavity.
The Kuko puller and specially designed shell spacer allows the bearing to be pulled without the legs of the puller pressing on the engine block. The bearing is inside the spacer in this photo. The spacer distributed even pressure to the engine block to prevent damage.
Here you can see the inferior factory bearing. Note the snap ring (internal non-accessible type).
Note the difference in the size of the center stud. It’s also much better quality steel. The center stud also now has a cutout groove for an o-ring seal. What you cannot see is the much higher quality ceramic bearings inside that can take more abuse without failing. There are no seals on the bearings to allow the best possible oil flow.
The back side of the bearing locates into the intermediate shaft. This is what keeps the shaft centered and transfers the load to the block through the billet replacement cover.
This is the purpose-designed installation driver. We use a rubber / plastic dead blow hammer to seat the new bearing in place.
New bearing installed
Notice the bearing is not retained / centered by the bore in the block, with the timing chain tensioners