Quote:
Originally Posted by JFP in PA
Perhaps because the oil pump drives in these engine's are already notoriously weak before you grind a slot in them, punching a hole with a hammer in the pump end shaft seal may not be the best way to control oil flow, and running a flooded IMS shaft may not be the best approach to extending bearing life.
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I can agree with some of your point, but not entirely.
I have wondered if Porsche had originally sealed the end of the IMS as opposed to leaving it open might have made failing IMSBs a non-issue. But then that depends on what the majority mode of bearing failure is, rancid, acidic oil in the shaft eating at the bearing or simple failure due to stress.
But, the fact remains that the IM shaft does fill with oil on many/most cars and the oil has no means of escape, creating an oil flooded IMS. It seems to me that the EPS bearing being open allows the oil in the shaft to spin out past the bearing especially when subjected to centrifugal forces of a running engine, minimizing the amount of oil in the shaft while running. And new oil being metered through the pump shaft will provide continual lubrication for the bearing.
Regarding the oil drive shaft, I don't think it is a stock shaft with a groove cut in it. I looked, and they do not spell out how the shaft is manufactured. (which would be nice to see). But I am going to make the assumption that it has been engineered to account for the strength required in light of the groove. That is entirely an assumption. But then I have not read of any of these parts failing either.
I agree with you regarding the punch used to open a hole in the end of the IMS. It should be manufactured with a flange to prevent you from making the hole too big.
Now all of this is simply my understanding of the product and how it works. Many people here have vastly more knowledge than me regarding these engines.
But still, I pose the question: would their oil feed system and a standard un-sealed single row ball bearing be a viable option?