Brodhead Pietenpol Association

Original Posted By: Waytogopiet(at)aol.com
Hi again Pietnics!What might be an expected, static RPM range for a zero-timed, healthy, stockFord engine/Zenith Carb with a Hegy 76x42 scimitar prop? Educated guessesor empirical knowledge anyone?Thanks,Larry Prangenx1929a________________________________________________________________________________

Original Posted By: Waytogopiet(at)aol.com
Subject: Re: Pietenpol-List: Ford/Piet Static RPMs?Larry, After much effort to get my 'A' adjusted, it now runs quite well. I have nothing against which to compare it but I recently ran it for a full fiveminutes at full throttle (static), then closed the throttle quickly, followed by a quick move back to full throttle. It had started on the first pull and ransmoothly in all modes and did not hesitate at all through the throttle changes. It registered just a bit over 1650 RPM at full throttle and idled at about500 RPM.It is stock throughout. Original head and manifold, Zenith model B carb and babbit bearings. Timing set at 27 degrees BTC Total time to date 22 hours (mostly fighting the original carburetor and timing problems). I won't be runningit again until I start taxi tests ( hopefully in the next couple of weeks) I'mcomfortable with flying it as it now sits. Hope this helps. Don Hicks ________________________________________________________________________________

Original Posted By: Ron Hargrove
Subject: Re: Pietenpol-List: Ford/Piet Static RPMs?Larry,Forgot to mention in my last post, one rather important item. My prop is also a 76x42 ( made by Chad Willie and is top quality work) Don________________________________________________________________________________Date: Mon, 24 May 2004 18:56:25 -0700 (PDT)

Original Posted By: Waytogopiet(at)aol.com
Don, Thanks for your comments! My A also gets 1650 RPM static, wide open. I wastrying to get a good baseline to work from before I make any changes fromstock. I would do it the correct way, in the air, but my Piet is notcovered yet. I have purchased a Weber progressive two barrel carb andmanifold kit from Snyder's Antique Auto Parts. I am interested inmonitoring the change. The only drag is that I will have to modify myfour-into-one exhaust system because of the new intake manifold's shape. InRon Kelly's dyno testing of the A engine, (http://users.aol.com/gmaclaren/dyno.html ) he finds that giving the A betterrespiration is the most effective and direct means to get a little more umphout of it. Also in Mr. Kelly's article, I found the results of spark plugtesting to be very surprising. "A plug is a plug is a plug. Right?" Not!Larry Prangenx1929a

Original Posted By: "DJ Vegh"
Subject: Re: Pietenpol-List: Ford/Piet Static RPMs?In a message dated 5/24/04 7:57:13 PM Central Daylight Time, Waytogopiet(at)aol.com writes:>Larry,Mine was very similar to Don's, except I had a bit more prop (74 X 48). My Tach reads a little low, so I think I was getting something just over 1700 rpmstatic. I changed the plugs several times (Champion W16Y set at .018" to .020" gap). I had a Wico mag in the beginning, then altered the bracket to accept a Slick mag. Ran fine on the ground, and holding the tail up in the air,but on short final if I pull power to idle, the engine would quit. That happened 3 times. Changing the mag did not help. I got to where I would leavein just a tiny bit of power to land, then pull power to idle just at the end of theflair. It never quit when I did that. I had that carb apart quite a few times, comparing jet size, adjust float setting, inspecting, and so fourth, butI never did get all those gremlins out of that Model B carb. I have the jet sizes stored on my computer, if anyone is interested. Chuck GantzerNX770CG________________________________________________________________________________

Original Posted By: Rcaprd(at)aol.com
Subject: Re: Pietenpol-List: Ford/Piet Static RPMs?In a message dated 5/25/2004 10:25:41 PM Central Standard Time, Rcaprd(at)aol.com writes:Ran fine on the ground, and holding the tail up in the air, but on short final if I pull power to idle, the engine would quit. That happened 3 times. Changing the mag did not help. I got to where I would leave in just a tiny bit of power to land, then pull power to idle just at the end of the flair. It never quit when I did that. I had that carb apart quite a few times, comparing jet size, adjust float setting, inspecting, and so fourth, but I never did get all those gremlins out of that Model B carb. I have the jet sizes stored on my computer, if anyone is interested. Chuck, Thanks for the 'heads up'. I have thought about carrying power through to the flair on the first flight..now I KNOW I will !!I also had my 'B' carb apart several times, finally built a test stand and re-sized those Chinese after-market jets that I had acquired in a re-build kitfrom Snyder's Antique Auto and that, along with another tweaking of the timinghelped it smooth out. I am using an Eisenmann mag and am pleased with it. The Model A carb book ( I forget the author's name) warns about problems with those jets. Don________________________________________________________________________________