Mailing List flyrotary@lancaironline.net Message #26729
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] pressure in the crank-case
Date: Sat, 24 Sep 2005 14:09:37 -0500
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
Hi Dave,
 
Sorry to hear of the odd problem. 
 
So I fix the oil filler stem but on a ground run there is now oil coming out of the turbo. 
 
When you say coming out of the turbo, where exactly is it coming out?  The exhaust?  The turbo housing?   
 
If I take the oil filler cap off, oil stops coming out of the turbo.  So something is pressurizing the crank-case.  Engine is running fine otherwise.  The crank case vent is not plugged (but is too small to let out large amounts of gas).  The oil does not appear to have water in it, so it seems to be either compression or exhaust gas that is getting in.
 
What causes that?  A blown side seal?   
 
That's all I can think of.  When you leave the oil cap off, and rev the engine, do you get a lot of oil fog out of the filler opening?  If so, I'd say the side seals, or corner seals are history. 
 
Have you been running the snot out of the engine recently? High RPM and boost?   Are you absolutely sure you haven't lost oil pressure, or severely overheated the oil recently? 
 
You really do seem to be finding the failure modes for everyone else.  Good luck.
 
Cheers,
Rusty (Slingshot likely to be HKS powered, shopping for new project for the single rotor)
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