Quote:
Originally Posted by BYprodriver
I'm thinking the pressure relief holes in your IMS are functioning like carb jets made to atomize & aerate fluids.
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BYprodriver, here is the logic trail I followed along with "simpler is better" when I modified my engine by drilling carefully placed holes in my IMS shaft. "How much oil is in the IMS tube at startup? (maybe 8 Oz at startup) and how long will it be there? (maybe 10 seconds after startup due to the IMS spinning and casting the oil out the holes). Can more oil get into the IMS tube while it is spinning? (no, centrifugal force makes that impossible, the spinning shaft precludes that) where does the oil get slung for ~ten seconds? (onto the timing chains). How much effect does that have compared to the oil continuously spewing from the rod bearings as the crank rotates at thousands of RPMs slinging oil everywhere? (essentially nothing, not even in the noise) The real question here is whether oil can get past the IMS bearing seals to wash out the grease destroying the bearing
without the differential pressure that is relieved by the holes drilled venting the IMS shaft. The seals on the bearings I removed looked great, and still were grabbing the inner race as one might expect from good seals. Still there was no grease in that IMS bearing. I think the answer is that the seals do maintain their design integrity but have oil under pressure pumped through them which washes out the grease. To retain the grease as expected by Porsche engineers the differential pressure across the IMSB can be eliminated by venting the shaft.
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