Thanks Steve
So to reduce the oil in the drive reducing pressure and possibly extra heat, required both enlarging the rear bottom drain and adding a breather to the top of the drive.

Steve Izett


> On 5 Mar 2021, at 3:19 am, Steven W. Boese SBoese@uwyo.edu <flyrotary@lancaironline.net> wrote:
>
> Both are possibilities.  See archive message 64583, Jan 13, 2019.
>
> Steve Boese
>
>> On Mar 4, 2021, at 12:51 AM, Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
>>
>> Whats the downside to the drive filling with oil?
>> Pressurising the beast and its seals?
>> Is there more frictional losses and heat?
>>
>> Steve Izett
>>
>>> On 4 Mar 2021, at 2:35 pm, Sboese sboese@uwyo.edu <flyrotary@lancaironline.net> wrote:
>>>
>>> Finn,
>>>
>>> When I installed a vent in the top of my RD-1C drive it acted as an additional drain.  The drive operated completely filled with oil until the size of the original rear drain was increased to an ID of ~5/8” (1/2” NPT pipe).
>>>
>>> Steve Boese
>
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