X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from zproxy.gmail.com ([64.233.162.201] verified) by logan.com (CommuniGate Pro SMTP 5.0c4) with ESMTP id 761303 for flyrotary@lancaironline.net; Tue, 11 Oct 2005 03:47:04 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.233.162.201; envelope-from=wdleonard@gmail.com Received: by zproxy.gmail.com with SMTP id p8so801638nzb for ; Tue, 11 Oct 2005 00:46:19 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:references; b=qivnj9CqD/oVUWs93mqzX3cv0ASIsOqYVCmZQqKPpp3nZ5T2twOVSrSNEy08Zx70phdqMmdyvxrpOQjfVZEKWL9gtKtLT5QZlJTFLLrP0UM+SLsOhQJZ8Pq4v9KbZSx81tkKm3FAYSur6Jp2jjB4TKy2q5T4uu+XXbL+WsyVUj4= Received: by 10.37.12.17 with SMTP id p17mr2826543nzi; Tue, 11 Oct 2005 00:46:18 -0700 (PDT) Received: by 10.36.222.6 with HTTP; Tue, 11 Oct 2005 00:46:18 -0700 (PDT) Message-ID: <1c23473f0510110046x25321e2dycc194c3637903eec@mail.gmail.com> Date: Tue, 11 Oct 2005 00:46:18 -0700 From: David Leonard To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Carbon Build up. In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_10435_26338939.1129016778760" References: ------=_Part_10435_26338939.1129016778760 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On 10/10/05, Tracy Crook wrote: > > Hi Dave, > There are too many factors here to draw any firm conclusions. Possible > reasons for the broken side seal are detonation, flawed seal or installat= ion > damage. Being sintered iron and only .7 mm thick, they are fairly delicat= e. > Were they fitted properly when installed? New side seals are slightly too > long as furnished and must be individually fitted to the groove by carefu= lly > grinding to length. > Words of wisdom as always Tracy. The side seals were re-used, out of a "30k" mile engine from Japan.... I re-built the engine myself, repalcing only the rubber components and apex seals. I did not keep track of which side seal came from which slot so maybe some were too tight after swithing to a new slot. BTW, what apex seals were you using? These are usually the first thing t= o > go with detonation. RA seals will frequently not break leading many racer= s > to conclude that they did not have detonation. The failure mode of our se= als > in detonation is heat damage which eventually causes them to sag into the > groove and have low compression when hot. Better than a fractured seal th= at > typically takes out a rotor and rotor housing. > I was using the stock 3-piece seals and they were all unharmed (renound at as the weakest seals made by Mazda?). But that was a nice plug for your ape= x seals :-) I must admit that I am using your seals for my rebuild. Have you considered making special side seals that wont break? :-) Lots of carbon? You call that lots of carbon? (I've seen lots of carbon > and that isn't it : ) > As I received the used rotors from Mazdatrix I realized that you are righ again. My used rotors had much less buildup than the ones I just spent all night cleaning. But the really important thing about carbon is the nature of the carbon > buildup. If it is the "fluffy" type that is easily scrapped off it is not > really a problem. > I seem to be getting a fair amount of both. Typical 4 stroke oil leaves an almost varnish like carbon deposit that is > very difficult to remove and causes seals to stick in the groove. This is > the really significant difference between 2 & 4 stroke oil. Also remember > that 99+ percent of what is being burned in the combustion chamber is > gasoline. It leaves carbon deposits especially if the mixture is too rich= . > Tracy > > ----- Original Message ----- > *From:* David Leonard > *To:* Rotary motors in aircraft > *Sent:* Monday, October 10, 2005 1:47 AM > *Subject:* [FlyRotary] Carbon Build up. > > The first picture is the front rotor with the stuck and broken side seal > with a piece missing. Wouldn't fit in the last message. > So the big question now is why. Note the picture of the rotor face. Ther= e > is LOTS of carbon build-up. So much for 2-stroke oil burning very cleanly= . I > am mixing less than 1:100 (about 5 oz per 6 gal gas can). I have thought = of > the following possible causes: > 1 My oil may be running a little cool. It maxes out at 160 and is usuall= y > closer to 140-150. This could keep the rotors too cool and prevent burnin= g > of the oil. Add in the modification to the oil bypass and this may be it, > but it seems unlikely to me. > 2 Running rich. Because it is so hard to get the engine tuned, I am > probably running very rich (the only way to keep it running), especially = at > low RPM. > Some of both? Poor quality 2-stroke? I have noticed that the 2-stroke oi= l > does accumulate in the crank case. That of course indicates that it does = not > all burn, and what doe burns does not necessarily burn cleanly. Maybe usi= ng > crank-case oil would burn less, and there would be less needed and less > residue. > Anyone else seen this? Any ideas? > > -- > Dave Leonard > Turbo Rotary RV-6 N4VY > http://members.aol.com/_ht_a/rotaryroster/index.html > http://members.aol.com/_ht_a/vp4skydoc/index.html > > > > > -- > Dave Leonard > Turbo Rotary RV-6 N4VY > http://members.aol.com/_ht_a/rotaryroster/index.html > http://membersaol.com/_ht_a/vp4skydoc/index.html-- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ > > -- Dave Leonard Turbo Rotary RV-6 N4VY http://members.aol.com/_ht_a/rotaryroster/index.html http://members.aol.com/_ht_a/vp4skydoc/index.html ------=_Part_10435_26338939.1129016778760 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline

On 10/10/05, Tracy Crook <lors01@msn.com&g= t; wrote:
Hi Dave,
There are too many factors here to draw any firm conclusions.  Po= ssible reasons for the broken side seal are detonation, flawed seal or= installation damage.  Being sintered iron and only .7 mm thick, they = are fairly delicate.  Were they fitted properly when installed? &= nbsp;New side seals are slightly too long as furnished and must be individu= ally fitted to the groove by carefully grinding to length.
 
Words of wisdom as always Tracy.  The side seals were re-used, ou= t of a "30k" mile engine from Japan....  I re-built the engi= ne myself, repalcing only the rubber components and apex seals.  I did= not keep track of which side seal came from which slot so maybe some were = too tight after swithing to a new slot.

 
 BTW, what apex seals were you using?  These are usually the= first thing to go with detonation.  RA seals will frequently not brea= k leading many racers to conclude that they did not have detonation.  = The failure mode of our seals in detonation is heat damage which eventually= causes them to sag into the groove and have low compression when hot. = ; Better than a fractured seal that typically takes out a rotor and rotor h= ousing.
 
I was using the stock 3-piece seals and they were all unharmed&nb= sp;(renound at as the weakest seals made by Mazda?).  But that was a n= ice plug for your apex seals  :-)    I must admit that = I am using your seals for my rebuild.  Have you considered making spec= ial side seals that wont break?  :-)

 
Lots of carbon?  You call that lots of carbon?   (I've = seen lots of carbon and that isn't it : ) 
 
As I received the used rotors from Mazdatrix I realized that you are r= igh again.  My used rotors had much less buildup than the ones I just = spent all night cleaning.

But the really important thing about carbon is the nature of the carb= on buildup.  If it is the "fluffy" type that is easily = scrapped off it is not really a problem.
 
I seem to be getting a fair amount of both.

  Typical 4 stroke oil leaves an almost varnish like carbon depos= it that is very difficult to remove and causes seals to stick in the groove= .  This is the really significant difference between 2 & 4 stroke = oil.  Also remember that 99+ percent of what is being burned in the co= mbustion chamber is gasoline.  It leaves carbon deposits especially if= the mixture is too rich.
 
Tracy
----- Original Message -----
Sent: Monday, October 10, 2005 1:47 = AM
Subject: [FlyRotary] Carbon Build up= .

 
The first picture is the front rotor with the stuck and broken side se= al with a piece missing. Wouldn't fit in the last message.
 
So the big question now is why.  Note the picture of the rotor fa= ce.  There is LOTS of carbon build-up.  So much for 2-stroke oil = burning very cleanly.  I am mixing less than 1:100 (about 5 oz per 6 g= al gas can).  I have thought of the following possible causes:=20
 
1 My oil may be running a little cool.  It maxes out at 160 and i= s usually closer to 140-150.  This could keep the rotors too cool and = prevent burning of the oil.  Add in the modification to the oil bypass= and this may be it, but it seems unlikely to me.=20
 
2 Running rich.  Because it is so hard to get the engine tuned, I= am probably running very rich (the only way to keep it running), especiall= y at low RPM.
 
Some of both?  Poor quality 2-stroke?  I have noticed that t= he 2-stroke oil does accumulate in the crank case.  That of course ind= icates that it does not all burn, and what doe burns does not necessar= ily burn cleanly.  Maybe using crank-case oil would burn less, and the= re would be less needed and less residue. =20
 
Anyone else seen this?  Any ideas?

--
Da= ve Leonard
Turbo Rotary RV-6 N4VY
http://members.aol.com/_ht_a/rotaryroster/index.html
http://members.aol.com/_ht_a/vp4skydoc/index.html




--
Dave Leonard
Turbo Rot= ary RV-6 N4VY
http://members.aol.com/_ht_a/rotaryroster/index.html
http://membersaol.com/_ht_a/vp4skydoc/index.html --Homepage:  http://www.flyrotar= y.com/
Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/



--
Dave Leonard
T= urbo Rotary RV-6 N4VY
http://members.aol.com/_ht_a/rotaryroster/index.html
http://member= s.aol.com/_ht_a/vp4skydoc/index.html=20 ------=_Part_10435_26338939.1129016778760--