Do you think that I could have an intake leak that is causing this fluctuation? This makes no sense to me.  How could it be fluctuating??

 

Bill B

 

 

I noticed that the manifold pressure was fluctuating between 26.7 and 27.1 during cruise today and I was getting some hiccups.

 

Did you block both ends of the filter or just one end?  I don’t think I have a drill bit smaller than 1/16.  What did you use to drill the holes?

 

Bill B

 

 

----- Original Message -----

From: Bill Bradburry

To: Rotary motors in aircraft

Sent: Tuesday, September 04, 2012 4:33 PM

Subject: [FlyRotary] Re: Intermittent hiccup

 

That is good data, Dennis.

 

I changed my plugs this afternoon (I had a set of RX-7 plugs so that is what I used) and will fly tomorrow.  I will check the stability of my manifold pressure then.  I installed a plastic fuel filter in the line a while back.  I have two manifold pressure lines from the intake manifold.  Each of them is “T”ed into the lawnmower fuel filter and then they separate at a “T” and go to the two inputs to the EC-2 controller.  If it is not stable, I will try your idea of a partial blockage of the filter inlet.

 

So with 95% the hiccup is not totally eliminated.  How often would you say you now get a hiccup?

 

Bill B

 

---

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Dennis Havarlah
Sent: Tuesday, September 04, 2012 11:00 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Intermittent hiccup

 

I've been using iridium plugs in my Renesis for 300 hrs.  I am using the iridium plugs that come from the factory.  When I changed them at 250 hrs I did not notice any change in performance!  I use regular car gas with ethanol and very seldom do I use 100 LL.

 

I had a hiccup every so often and could not eliminate it until I put damper chambers in my manifold lines.  I used the small plastic fuel filters for lawnmowers (Purolator F21124).  This eliminated at least 95 % of the hiccup and my manifold pressure is very steady.  With the dampers my manifold pressure varies about 0.1 in hg up or down in cruise.  Without the damper it would vary  as much as 0.3 to  0.4 in hg in cruise.  I plugged the inlet of the filter with JB and drilled a hole about 0.032 inch in diameter through the epoxy.  Check your manifold pressure and see if it is stable.

 

Dennis H.

----- Original Message -----

From: David Leonard

To: Rotary motors in aircraft

Sent: Tuesday, September 04, 2012 1:29 AM

Subject: [FlyRotary] Re: Intermittent hiccup

 

Yup, I suspect SAG.  I go through plugs very quickly..  like 25hrs.  No cleaning will help as the electrode is worn out.  You can milk them to 100 hrs but its not really worth it.  SAG gets really bad by 75 hrs.  The platinum onea last an extra hour or two.  Have not tried the iridium.  Always change plugs before a long trip.  Also, they come out much easier after only 25 or so hours.

--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net

On Mon, Sep 3, 2012 at 8:46 PM, Bill Bradburry <bbradburry@bellsouth.net> wrote:

Has anyone ever noticed a hiccup associated with sparkplug SAG?  I have a hiccup that is occurring at random intervals from seconds to several minutes.  Sometimes it is pretty mild and sometimes it shakes the plane!  I also seem to be down in power and I am beginning to suspect plug SAG.  I have 38 hours with the Iridium plugs plus a lot of time over the years of running the engine before flight.  I had a couple instances of flooding which required that I take the plugs out and sandblast them to get them to fire.  Just drying them out didn’t work.

 

Thoughts??

 

Bill B