Return-Path: Received: from out005.verizon.net ([206.46.170.143] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 572861 for flyrotary@lancaironline.net; Sun, 19 Dec 2004 01:00:36 -0500 Received-SPF: pass receiver=logan.com; client-ip=206.46.170.143; envelope-from=rotary.coot@verizon.net Received: from [67.225.117.20] ([67.227.200.155]) by out005.verizon.net (InterMail vM.5.01.06.06 201-253-122-130-106-20030910) with ESMTP id <20041219060000.LQKP28362.out005.verizon.net@[67.225.117.20]> for ; Sun, 19 Dec 2004 00:00:00 -0600 Mime-Version: 1.0 X-Sender: res0c5l1@incoming.verizon.net Message-Id: In-Reply-To: References: Date: Sat, 18 Dec 2004 22:05:12 -0800 To: "Rotary motors in aircraft" From: Ken Welter Subject: [FlyRotary] Re: Engine damage thoughts Content-Type: multipart/alternative; boundary="============_-1108686173==_ma============" X-Authentication-Info: Submitted using SMTP AUTH at out005.verizon.net from [67.227.200.155] at Sat, 18 Dec 2004 23:59:59 -0600 --============_-1108686173==_ma============ Content-Type: text/plain; charset="us-ascii" ; format="flowed" > Something I will ask is at what rpm and power setting did the >engine seize at?? > >The engine did NOT seize. As I stated before, it quit because I >tried to throttle up with the mixture set way lean. I have no >reason to believe the engine is damaged, aside from what feels like >a bit less compression than normal. > >As for the bearings, Bruce also said the bearings would be the first >to go, but I have to wonder now if that isn't a car vs airplane >experience. He sees car engines that have run for some time without >oil, but at very low power settings. In that case, the bearings may >be the first to go. In your case, you ran at high power, which >would probably generate enough heat to seize the engine, possibly >before the bearings got damaged. > >I still find it very hard to believe the engine ran without oil >pressure for more than about 30 seconds, and did so at very lean >mixture, and idle power. I can't see how this is any more damaging >than cranking the engine several times. Maybe I'll learn something >from the oil filter tomorrow. > >Cheers, > >Rusty The low compression is from the side seals being stuck from rotor damage but I bet its light and you can save the rotors by tapper cutting them, also you may have no side housing damage as I have toasted the rear rotor and saved the front rotor under high loads and in you case the damage may be light on the rear one to. Still the engine need to come apart as you risk doing more damage by running it. Also I will note that in a seizure the apex seals never get damaged, just the side seals so it could be a cheep rebuild, some side seals and gaskets may do it for parts and maybe tapper the rotors if it isn't done already. Ken --============_-1108686173==_ma============ Content-Type: text/html; charset="us-ascii" [FlyRotary] Re: Engine damage thoughts
   Something I will ask is at what rpm and power setting did the
engine seize at??
The engine did NOT seize.  As I stated before, it quit because I tried to throttle up with the mixture set way lean.  I have no reason to believe the engine is damaged, aside from what feels like a bit less compression than normal. 
As for the bearings, Bruce also said the bearings would be the first to go, but I have to wonder now if that isn't a car vs airplane experience.  He sees car engines that have run for some time without oil, but at very low power settings.  In that case, the bearings may be the first to go.  In your case, you ran at high power, which would probably generate enough heat to seize the engine, possibly before the bearings got damaged.  
I still find it very hard to believe the engine ran without oil pressure for more than about 30 seconds, and did so at very lean mixture, and idle power.  I can't see how this is any more damaging than cranking the engine several times.  Maybe I'll learn something from the oil filter tomorrow.
Cheers,
Rusty

   The low compression is from the side seals being stuck from rotor damage but I bet its light and you can save the rotors by tapper cutting them, also you may have no side housing damage as I have toasted the rear rotor and saved the front rotor under high loads and in you case the damage may be light on the rear one to.
 Still the engine need to come apart as you risk doing more damage by running it.
 Also I will note that in a seizure the apex seals never get damaged, just the side seals so it could be a cheep rebuild, some side seals and gaskets may do it for parts and maybe tapper the rotors if it isn't done already.
 Ken
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