X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao105.cox.net ([68.230.241.41] verified) by logan.com (CommuniGate Pro SMTP 5.2.3) with ESMTP id 2978141 for flyrotary@lancaironline.net; Sat, 21 Jun 2008 10:59:17 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.41; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo02.cox.net ([70.169.32.72]) by fed1rmmtao105.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20080621145827.SMHS4466.fed1rmmtao105.cox.net@fed1rmimpo02.cox.net> for ; Sat, 21 Jun 2008 10:58:27 -0400 Received: from wills ([68.105.85.56]) by fed1rmimpo02.cox.net with bizsmtp id geyb1Z0051CvZmk04eychz; Sat, 21 Jun 2008 10:58:36 -0400 Message-ID: <005801c8d3af$47ed4a10$38556944@wills> From: "Mike Wills" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: The SAGA continues; More checking basics and development progress Date: Sat, 21 Jun 2008 07:58:35 -0700 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 Bob, Early on in my tuning trials Tracy suggested this. I'm using a more or less stock lower 6 port manifold and using a couple of vacuum ports on that in the primary runners. I tried tapping in all the way out in the DC near the throttle body at Tracy's suggestion and it made absolutely no difference. But that was back when I had gross errors in the MCT. Now that my tuning is a lot closer it may be worth another look. Mike Wills RV-4 N144MW ----- Original Message ----- From: "Bob White" To: "Rotary motors in aircraft" Sent: Friday, June 20, 2008 9:36 PM Subject: [FlyRotary] Re: The SAGA continues; More checking basics and development progress > It could be the manifold vacuum signal. My engine was always a little > unstable below 2000 rpm but I didn't have the vacuum tap in a very good > location. I'm not sure why it would be worse some of the time unless > you're getting some sort of resonance under just the right conditions. > > Bob W. (Just a WAG) > > On Fri, 20 Jun 2008 21:21:00 -0700 > "Mike Wills" wrote: > >> Well, I'm pretty sure it's not a burnt valve. :-) >> >> In the early tuning stages I was all over the engine with starting fluid, >> soapy water, you name it, looking for vacuum leaks. Never found a thing. >> Timing is set per Tracy's manual. >> >> Odd thing is the lack of consistency. Most of the time it runs great. I >> think if there was a vacuum leak it would be more consistent. >> >> Acts to me like there is something just a little off in the tuning. Get >> everything in just the right (wrong) condition and it sets up a >> resonance. Most of the time this doesnt happen. Changing mixture kills >> the resonance and its fine after that. >> >> Mike Wills >> RV-4 N144MW >> ----- Original Message ----- >> From: Greg Ward >> To: Rotary motors in aircraft >> Sent: Friday, June 20, 2008 8:56 PM >> Subject: [FlyRotary] Re: The SAGA continues; More checking basics and >> development progress >> >> >> I hate to say it Mike, but in a recip, that's a sure sign of a burnt >> valve or a major vacuum leak. Maybe in this case, there's a leak in your >> intake? A bad gasket or loose bolt could do it. Timing is a possibility >> for sure. >> Greg Ward >> Lancair 20B N178RG in Progress >> ----- Original Message ----- >> From: Mike Wills >> To: Rotary motors in aircraft >> Sent: Friday, June 20, 2008 8:33 PM >> Subject: [FlyRotary] Re: The SAGA continues; More checking basics and >> development progress >> >> >> I too still have intermittent surging issues that havent been fully >> conquered. Doesnt happen all the time. Always in the 2000 - 3000 RPM >> range. Usually happens when I'm taxiing and back off the throttle. In my >> case the A/F reading is useless. The engine surges rhythmically at about >> a 1Hz rate with RPMs varying several hundred, MAP varying from high to >> low (hard to pin down exact numbers - its moving around too much), and >> the A/F bouncing back and forth from the rich stop to the lean stop. >> Fiddling with mixture always stops it, but its a little disconcerting >> (and embarassing) when it happens (usually as I'm taxiing away from the >> crowd at the local EAA chapter while everyone is watching). For a while I >> thought adding some capacity to the MAP sensing line (Dave Leonard's >> suggestion) had cured it, but not entirely. I'll need to get this figured >> out before it flies. Could be a real problem if it happens on short >> final. >> >> I occasionally have a pretty good backfire at the secondary staging >> point. The operational solution seems to be to not linger in the area - >> just advance the throttle or retard it right on through and it seems to >> be OK. Advancing the throttle too slowly almost guarantees a big pop! I'm >> told it's particularly impressive after dark! >> >> I havent worked on the tuning in months while I've been tweaking >> other little issues in prep for my DAR inspection. Just about ready to >> get back to it. I'm sure i'll get it more or less figured out eventually. >> >> Mike Wills >> RV-4 N144MW >> ----- Original Message ----- >> From: Mark Steitle >> To: Rotary motors in aircraft >> Sent: Friday, June 20, 2008 7:06 PM >> Subject: [FlyRotary] Re: The SAGA continues; More checking basics >> and development progress >> >> >> Chris, >> >> As you've probably read from the archives surging is usually caused >> by an overly lean air-fuel ratio. What is your A/F reading during the >> surging? >> >> Mark S. >> >> >> On Fri, Jun 20, 2008 at 8:41 PM, Christopher Barber >> wrote: >> >> Well, to continue the saga, I have not run the new 13b much since >> I got it running a few weeks ago due to the EM2 not showing oil pressure >> as it should. It was giving me erratic readings like -1, -3 etc. I hand >> propped the engine before I ran it and oil pumped through the system >> fine....much onto the hangar floor...alas, the sacrifices for certainty >> ;-). Also, during my short runs everything heated up in the oil system >> evenly and the oil temp stayed pretty much in line with coolant temp. >> BUT, since I was not sure if this was a gage/sender issue or an actual >> oil system problem I was very cautious about my few short engine runs. >> >> Well, today while dreading the idea of dropping my pan, I >> happened across an extra oil pressure sender (still in the package) I >> happened to have. I had seen it laying around for a while, but didn't >> give it much thought until I was thinking about dropping the pan. Low and >> behold, The problem was the sender. I am getting good pressure reading >> now, along with coolant and oil temp. Yeah. I am surprised at the temps >> as they seem to be staying in check considering the 95 + degree Houston >> weather. >> >> I am able to start the engine, shut it down and restart it >> (something I was not able to do with the old engine). It is somewhat >> difficult, but seems to be getting easier as I continue to tweak things >> (ie timing). I am trying to do the various tuning via Tracy's manual. >> To be honest a lot of the information in the manual is seemingly >> abstract until I actually get to the step and/or problem. So, tonight, I >> got it to run, and it seems to run better, but...... >> >> I am having a surging problem. It seems intermittent, but it >> just may be I have not been setting the throttle quite the same way as I >> get use to it all. Also, I have had the coil C/B pop on me several times >> now....it seems as if this is when the engine is near or at idle. I have >> not had a chance to look into this as of yet. Also, I have gotten a >> number of horrendously loud/powerful backfires. Not sure what changes as >> the engine may have run fine. It backfires when attempting to start. I >> wait a few minutes and it may then start. Gee, isn't inconsistent crap >> fun >> >> I just did a search of the archives on the surging issue, but >> have just started reading the 105 post on the topic. Seems our own Mr. >> Slade had the same problem back in the day . >> >> Well, it is the middle of my work week and I gotta turn in soon, >> but I wanted to share that it seems as if actual progress is being made >> (hmmmm, wonder what will screw this positive statement up) as the Saga >> continues. >> >> All the best, >> >> Chris >> >> > > > -- > N93BD - Rotary Powered BD-4 - http://www.bob-white.com > 3.8 Hours Total Time and holding > Cables for your rotary installation - http://roblinstores.com/cables/ > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html >