Mailing List flyrotary@lancaironline.net Message #41816
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Re: Disaster Averted
Date: Thu, 6 Mar 2008 20:31:00 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Errr.... Yes, if it is coming out the spark plug holes then as you know the housing is fair thee well flooded with coolant.  So that would lead me to suspect one of these causes (in order of likelihood):

1.  Most likely bad coolant O ring - I presume you are using the Teflon Encapsulated Silicone "O" rings?   Generally only two things make them leak, damage during installation (i.e. perhaps pinched) or over heating (and it takes a whole lot of that - I turned an area of the side housings blue with heat before that O ring failed).  If stock coolant "O" rings were used then they are more easily damaged by over heat and prone to leaking.

2.  Damaged groove in the iron side housing in which the "O" ring fits which then provides a leak path - Hope its not this one as that means a new side housing.  This  is sometime caused by shifts in the casting core when the molten iron is poured in or can be caused by corrosion as these walls are fairly thin.

3.  Intake porting too extreme - leaving too thin a wall of metal between port and coolant galleys. Also requires another sidehousing

4.  Foreign object damage to inside of housing.(punching through into the coolant system - not likely)

I hope its the coolant "O" ring.

Good luck, Dave

Ed

----- Original Message ----- From: "David Staten" <Dastaten@earthlink.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Thursday, March 06, 2008 7:58 PM
Subject: [FlyRotary] Re: Disaster Averted


Coolant was observed coming out the lower plug holes when he removed the spark plugs on the front rotor. I was overly brief. Its an internal leak for sure.

Chris is there now, just texted me regarding that finding.

Dave

Ed Anderson wrote:
Dave,

Before you tear into it, I have on two occasions had green fluid dripping from a tail pipe with the same Oh S--- !!  reaction.  However, they happened after pretty cold temps and after firing the engine up expecting to see the coolant pressurized by combustion gases, the leak went away. I don't know but, I suspected that the cold temps caused something to shrink just enough for a bit of coolant to leak through.

Before tearing it down, I would remove the exhaust and shine a light (borescope would be idea) and do a visual inspection inside the rotor housing looking for signs of a leak.  It might help to use a compressor to pressurize the coolant system to 15-20 psi.  It you have a coolant O ring leak, the pressure will either seal it OR you will likely see the coolant leaking into the housing.    Check around the bottom of the engine where the PSUR attaches if it is caused by a loose tension bolt you will likely see signs of green coolant there.  Most of the time if its a bolt it leaks on the outside so you shouldn't see in it the exhaust - but, it might run along the bottom of the pipe giving the impression its coming out the exhaust.

Good Luck


Ed

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