Thread: IMS center bolt
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Old 01-09-2021, 07:11 AM   #37
Homeoboxter
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Quote:
Originally Posted by paulofto View Post
I wonder about this as well. Does the hollow shaft fill with pressurized oil? If so you now have quite a mass of liquid rotating at relatively high rpm resulting in inertia and perhaps imbalance when the rpm’s decrease and increase. If it doesn’t fill but only partially then you have a liquid being sloshed around that has its own issues like cavitation. I just don’t think the shaft was designed to be an oil journal.
Generally thinking, it`s indeed not a very good idea to fill the IMS with about a quart of oil. But actually this happens every time soon after you turn off the engine if the seals are not perfect any more, or you have an open bearing, because the entire shaft is submerged in engine oil. As for the imbalance: this may have some significance at idle, when the IMS speed is around 4-500 rpm, but once you hit the accelerator pedal the liquid mass is quickly going to move to the periphery and will be perfectly balanced, and will be pressurized. The pressure will even force most of the oil mass out, through the bearing. Think about it as a centrifuge
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