Intermediate shaft question

[White, Walter]

I am interested in knowing how much engine oil is in the IM shaft when the motor is off.
If I park my car with the nose lower than the tail, will all the oil drain out of my IMS?

[tonythetarga]

I take it you mean IMS bearing? The bearing is supposed to be sealed and contains grease. Oil eventually gets in and washes out the oil . If you are leaking it is probably the rear main seal.

[Cajundaddy]

Originally Posted by White, Walter

I am interested in knowing how much engine oil is in the IM shaft when the motor is off.
If I park my car with the nose lower than the tail, will all the oil drain out of my IMS?

If oil is in there it's not moving based on your parking angle. If you are leaking oil, find the cause and fix it soon. A Boxster should not leak oil like a 911SC.

[feelyx]

Think of a 2 stroke motor and how the crank bearings get oil. Even with the seals on, the "wobble" will break the edge of the rubber seal of the bearing and let oil in and out of the bearing, and eventually fills up the shaft behind the bearing itself.
This is why the seals will look good on most bearings, not melted from heat.
Parking will have no effect.

Get back to cookin' Walt

[Bristol]

I think it just depends on how bad the bearing seals are to let oil in. It seems to vary from car to car when they remove the bearing and find oil in the shaft. In my C4S that I just did last weekend the seals on the bearing looked fine, but when I removed it I found that the shaft had a significant amount of oil in it, a lot more than what I've seen in other posts.

Kirk

[White, Walter]

Originally Posted by Bristol

I think it just depends on how bad the bearing seals are to let oil in. It seems to vary from car to car when they remove the bearing and find oil in the shaft. In my C4S that I just did last weekend the seals on the bearing looked fine, but when I removed it I found that the shaft had a significant amount of oil in it, a lot more than what I've seen in other posts.

Kirk

Kirk,
I noticed in your most excellent Tune RS DOF install thread that the seals on your old bearing looked good, but that there was no grease and only a bit of oil in the bearing. It seems to me that this is a typical situation. Most bearings appear to loose their grease and take in oil even when seals appear intact.
My point to this thread is that if the IM shaft has oil in it, then the bearing will be bathed in oil when the car is parked nose-up (Boxster). If the car is parked nose-down, the oil will drain to the other end of the shaft leaving the bearing high and dry, especially if the car is parked for long periods of time. I am not completely sold on the high versus low RPM theory. There may be something there but I don't think it has to do with loading of the bearing. Probably higher RPMs throws more oil on the bearing

[ppbon]

Originally Posted by White, Walter

I am interested in knowing how much engine oil is in the IM shaft when the motor is off.
If I park my car with the nose lower than the tail, will all the oil drain out of my IMS?

... How much oil is in the IMS?
It depends on the bearing itself and how well (or not-so-well) it sealed.
The average we generally see is 4-8 oz of oil inside the IMS.

If you park your car with the nose lower than the tail (for a Boxster) the oil in the IMS will all go towards the sealed end and will not drain. If you park the nose higher than the tail the oil inside the IMS will drain back to the bearing but the oil in the pan will submerge most, if not all of the bearing so the oil in the IMSD won't drain completely. --- The contrary is true for the Carrera which has the engine backwards.

Happy Porscheing,
Pedro

[White, Walter]

Thank you Pedro, that is good to know.
Would you by any chance know how many degrees angle the Boxster would require for a sump filled to the maximum level to submerge the lower portion of the bearing seal in oil?

[ppbon]

Originally Posted by White, Walter

Thank you Pedro, that is good to know.
Would you by any chance know how many degrees angle the Boxster would require for a sump filled to the maximum level to submerge the lower portion of the bearing seal in oil?

When the car is parked on level ground with the correct amount of oil in the engine about 25% of the bearing is immersed in oil.
But, once the engine starts running all of the oil is shed from the bearing due to centrifugal force.
Happy Porscheing,
PEdro

[White, Walter]

Thanks again for that information. I am wondering how many of the IMSB premature failures come from cars that are usually parked at an angle for long periods of time that keep the bearing above all oil levels (oil sump and oil in the IMS).

[White, Walter]

Is there any place to easily collect drain-off or return oil from the Boxster engine that is higher than the top of the IMS bearing?

[White, Walter]

I did a little experiment with a ball bearing. I purchased a sealed ball bearing similar to size of an IMS bearing and removed one seal and washed the grease out with WD40. Then I placed the bearing in a jar, remaining seal down, and filled the jar with 5-30 motor oil to the top of the bearing outer race. 12 hours later the oil covered 50% of the balls. 18 hours later the oil level was the same on the inside and outside of the bearing.
I know this isn't a scientific experiment, it is not the exact bearing used for the IMS, not the same conditions as inside the motor. But it does make me think that the grease in these bearings might be gone within hours of operation.

[thom4782]

If the bearing's seals are intact, there is no place for the grease to go and the IMSB is adequately lubricated. If the outer seal is removed, any grease present would wash out quickly and sump oil would adequately lubricate the bearing thereafter.

The lubrication problem only exists if the seals leak such that oil slowly penetrates the bearing, mixes with grease and the mixture stays there for a long time. Then lubrication is compromised and friction destroys the bearing.

BTW: if all oil was shed due to centripetal force when the engine is running, IMSBs would fail quickly. Real world data shows unsealed IMSBs don't fail.

[White, Walter]

On further examination of the bearing seal, I noticed that the seal has a tight seal to the outer race (almost bonded), and the inner race rotates inside the seal inner edge. On the IM shaft, the outer race and seal rotate around the inner race. So with heat making the rubber seal softer, and the rotation speed of the seal, it is easy to see how centrifugal force could easily pull the seal inner edge away from the inner race.

[White, Walter]

Has it ever been proposed that the failures of the single row bearing start with the ball cage coming apart?