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Date: Tue, 18 Nov 2008 07:43:24 -0700
From: Bob White <bob@bob-white.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: high EGT temps Rotor #1
Message-Id: <20081118074324.29da1ac2.bob@bob-white.com>
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Are you guys using EGT probes with grounded tips?  If not, is the red
wire grounded at the EC2 connector?  Just a WAG, and something else to
check.

Bob W.


On Tue, 18 Nov 2008 08:23:31 -0600
Dennis Haverlah <clouduster@austin.rr.com> wrote:

> Don:
> 
> I've had high and erratic EGT readings on my Renesis since I started 
> flying it early last year.  I've tried changing ground paths and 
> replaced one EGT wire with no change.  I get readings varying as much as 
> 75 deg. F. over 15 seconds with no change in engine operation.  My EGT 
> temps. go as high as 1800 deg F.!  If these were correct my muffler 
> would not have lasted.  I'm still trying to figure out what is causing 
> the unstable and high numbers.
> 
> Can you post some pictures of your installation?  I'm wanting to build a 
> new intake and your post shows a tuned 17.5 in intake.  That probably is 
> what I need also.  My intake is an RX-8, 4 port unit which I cut off 
> just below the first rotary valve.  It's runner length is closer to 10 
> inches.  I estimate I'm equivalent to a 175 to 180 hp lyc. in 
> performance with my current intake and exhaust.
> 
> Dennis Haverlah
> 
> Don Walker wrote:
> 
> > Rotorians,
> > Now that the airplane is painted, weighed, prop ballenced and etc.  
> > I'm into tuning and getting comfortable with the engine.  Yesterday I 
> > noticed that as I ran the engine up, #1 rotor EGT trailed #2 by 20 to 
> > 30 degrees and then at about 20 inches of manifold, #1 started 
> > climbing rapidly!   At max static throttle 5828 rpm (prop speed of 
> > 2045) or so,  #1 runs to 1640 degrees while #2 maxes at 1480 degrees.  
> > I played with the mixture etc.  No difference.  I have checked the 
> > plugs and swaped them.  No difference.  Stock RX-7 plugs.  Pulled one 
> > and then the other secondary inj. connector.  It starts and runs and 
> > then drops off as RPM gets high.  Same on both #1 and 2.  Swapped 
> > injectors.  No difference.  Tryed using Mode 4, both to increase 
> > mixture and then to decrease.  No difference.  Reset Mode 4 back to 
> > default.  Swapped EGT probes.  High temps showed up on #2 on EM-2.  
> > Swapped back.  Checked the archives.  Nothing.  The EGT probes are 
> > installed through holes in the exhaust 5 inches from the engine 
> > outlet.   So I am at a loss.  Any thoughts on what might be causing 
> > this?  Engine basically running smooth and strong.  Months ago, I 
> > remember getting 6150 RPM, but couldn't get it to run long enough to 
> > check out EGTs.  Cooling problems.  A couple of other things that may 
> > or may not have anything to do with this. Manifold display on EM-2 
> > sometimes jumps around some.  I have tried porting to the front of the 
> > intake and to the rear.  Now I have it teed to both.  Auto tune tries 
> > to work, but does not.  (O2 sensor installed at end of tangenial)  I 
> > ran it almost 2.5 hours total yesterday.  11.7 hours total. since last 
> > December.  Quietest airplane on the field.  Lots of attention from 
> > other pilots.
> >  
> > Don Walker
> > RV-8 N113BR
> > Renesis 4 port. RD-1c
> > EC-2 EM-2
> > Tuned 17.5 inch intake.
> > Tuned 24 inch exhaust into tangetial premuffler
> > catto 76/88.  Field elevation 5000 ft.  density 6200
> 
> 


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