KR>Re: Airventure "KR Building and Flying" forum date and time at Oshkosh
Bummer that you are doing that on Monday. I have a work meeting that day. My vacation starts Tuesday and I am looking forward to going to Oshkosh as soon as I can after that. I am very tired of the last year and a half. And I am looking very forward to getting back into aviation. So if there is a meet up planned at Oshkosh for the KR guys, let me know. Ray_pilot New Orleans 504-616-9098 On Fri, Jun 18, 2021 at 6:11 PM Mark Langford wrote: > We've received a date for the "KR Building and Flying" forum date and > time at Oshkosh, Monday, July 26 at 11:30 AM - 12:45 PM. I'm not sure > what the topics will be yet, but am open to suggestions. After the > forum, we'll adjourn to the flightline where we'll park our KRs, which > will be out front of Homebuilders Headquarters. We hope to see y'all > there. > > I was worried that I might miss OSH as the exhaust system on the KR2 > disintegrated and I was facing building another one from scratch. But > thanks to Marc Baca and Doug Pearce, I now have a serviceable > replacement, probably built from the same fixture. Mike Sylvester flew > up today and assisted with the installation, which was a two man job due > to the extra width of my VW engine. Thanks Mike! > > While the exhaust was off I did a valve job, replacing exhaust guides, > recutting the valve seats, and replacing the exhaust valves, as well as > the pistons and cylinders (just for good measure). I had 250 hours on > the Revmaster heads since they were installed, and they were leaking > pretty badly between the valves and seats, perhaps due to lead deposits. > It still ran great, but 116 psi compression numbers (down from 158 > previously) had me concerned, even before the exhaust system failed. I > plan to run Decalin in the fuel to reduce the lead deposits (Aircraft > Spruce sells it). We'll see how that goes. Still, 250 hours is a > record between valve jobs for me, so I'm already impressed with the > Revmaster heads. > -- > Mark Langford > m...@n56ml.com > http://www.n56ml.com > Huntsville, AL > > -Please see LIST RULES and KRnet info at http://www.krnet.org/info.html > -Change list delivery options at > https://list.krnet.org/list/krnet.list.krnet.org/ Affinity List Info Board > -Search recent KRnet Archives at > https://list.krnet.org/empathy/list/krnet.list.krnet.org/ > -Search <https://list.krnet.org/empathy/list/krnet.list.krnet.org/-Search> > John Bouyea's decades of archive at > https://www.mail-archive.com/krnet@list.krnet.org/ > -Please see LIST RULES and KRnet info at http://www.krnet.org/info.html -Change list delivery options at https://list.krnet.org/list/krnet.list.krnet.org/ Affinity List Info Board -Search recent KRnet Archives at https://list.krnet.org/empathy/list/krnet.list.krnet.org/ -Search John Bouyea's decades of archive at https://www.mail-archive.com/krnet@list.krnet.org/
KR>Re: Airventure "KR Building and Flying" forum date and time at Oshkosh
John Bouyea wrote: > How much did you space your cylinders out from the case to increase overall > exhaust flange widths? > On your efforts to rework the heads, was there any measurable slop in the > guides? Which brand of valves do you use? Do you use a differential pressure > tester as well or just the compression gauge? P&L's too? My 2180cc VW engine is over a half inch wider because I have .258" spacers under each cylinder. Why? Because the crank is designed for Chevy rods, which are a bit longer (5.7" rather than the stock VW ~5.4" rod center-to-center length), so the pistons protrude from the cylinders if you don't have spacers. What made me stupid enough to buy that crankshaft? It's all Marty Roberts had when I called him at GPASCdesperate for a Force One prepared crank so I could make it to OSH in 2017. I don't know why he had one, but my guess is he was either desperate or inattentive when he bought it. They are definitely not worth the hassle. The problem is that it's not trivial to stretch an exhaust system a half inch to install it on the heads, and even then, the pipes are always under that stress (although it's probably relieved a bit after repeated thermal cycling). But before I even noticed the exhaust was cracked and leaking badly, I checked the compression (hot after a flight) and it was down from something like 158 psi on all four to a range of 116-118 psi.consistent, at least! Still ran great, just worrisome compression numbers. Leakdown test showed a lot more disparity (I suspect the adapter sealed better) showing between 40/80 and 60/80! The leaks were from both intake and exhaust valvesLOTs of leaking! I was debating whether or not I wanted to fly the thing to OSH that way. I KNEW it wouldn't be smart, because if the exhaust valves aren't sealing well against the seat, they aren't dissipating all their heat to the head, and they are getting hot, and getting weak, and then you suck a valve head. Then I found the split collector, broken exhaust pipe, and metal erosion, which gave me a definitive answerfix it right now! So I pulled the exhaust and started looking for a replacement, and ordered new Mahle forged pistons and cylinders.while I'm going to so much trouble, might as well eliminate any concerns with those also. After a few dead-stick landings, this is how you think. Then I pulled the heads and ordered some Total Seal second rings and a set of exhaust valves from Revmaster. Make that TWO sets of exhaust valvesa spare set for next time. Since these heads have required almost NO valve adjustment when checked every 25 hours, I'm super impressed with the design and metallurgy of the Revmaster heads, so I'm not changing to somebody else's valves! Then after ordering the pistons and cylinders, I found a brand new set exactly like them sitting in the hangarfrom the same place (Moore's Performance Parts), so now I'm already set for the next rebuild. Then I ordered everything required to build a new exhaust system out of 304 stainless steel. The hardest thing to find was the VW exhaust flanges (to the head) in 304 stainless, but finally found them at AeroConversions (Sonex), ready to ship. Right after all of that was ordered, I heard from Doug that he had an exhaust system for me, so welding up the stainless system will be done when I have more spare time...and preferably during the winter when flying days are more sparse. It takes a looog time to weld up an exhaust system, so it can wait. Inspection of the valve guides found the clearance still quite tight, with no wear apparent, but three were slightly cracked on the combustion chamber side, so out they came.I put in new guides, and then reamed them out a bit to spec minimum. Intakes were fine...no discernible wear at all, so I left them alone. I recut the seats with a three angle valve job to the proper contact surface width, and had the intake valves resurfaced at the local speed shop. He did it while I looked over his shoulder, and said it was free but I gave him $10 for his time. These were the same intake valves that came with the Revmaster heads. I reassembled the heads with the same low pressure springs and keepers and they are now installed on the engine, along with the exhaust system. One thing about the engine being a half inch widerthe pushrod tubes need to get longer! The local dealer was fresh out, so I had to reuse the old ones. This means stretching the bellowed ends of the eight tubes out quite a bit to get a good seal, which was one of the biggest pains of the whole affair! Now it's just baffling, intake pipes, primer lines, etc which isn't exactly trivial on this plane. I really need to tidy up the baffling, but it may have to wait a while. I've got a lot going on and would rather just get it back in the air for now. For more on what's involved in rebuilding a 2180cc
KR>Re: Airventure "KR Building and Flying" forum date and time at Oshkosh
Mark, Great report, thank you. How much did you space your cylinders out from the case to increase overall exhaust flange widths? On your efforts to rework the heads, was there any measurable slop in the guides? Which brand of valves do you use? Do you use a differential pressure tester as well or just the compression gauge? P&L's too? Wow, a complete Top Overhaul... Thanks. John Bouyea N133RM KR-2S - imported, fixed & flying www.bouyea.net/cur_proj/N133RM OR81/ Hillsboro, OR ...Mike Sylvester flew up today and assisted with the installation, which was a two man job due to the extra width of my VW engine. Thanks Mike! ...While the exhaust was off I did a valve job, replacing exhaust guides, recutting the valve seats, and replacing the exhaust valves, as well as the pistons and cylinders (just for good measure). Mark Langford -Please see LIST RULES and KRnet info at http://www.krnet.org/info.html -Change list delivery options at https://list.krnet.org/list/krnet.list.krnet.org/ Affinity List Info Board -Search recent KRnet Archives at https://list.krnet.org/empathy/list/krnet.list.krnet.org/ -Search John Bouyea's decades of archive at https://www.mail-archive.com/krnet@list.krnet.org/
KR>Airventure "KR Building and Flying" forum date and time at Oshkosh
We've received a date for the "KR Building and Flying" forum date and time at Oshkosh, Monday, July 26 at 11:30 AM - 12:45 PM. I'm not sure what the topics will be yet, but am open to suggestions. After the forum, we'll adjourn to the flightline where we'll park our KRs, which will be out front of Homebuilders Headquarters. We hope to see y'all there. I was worried that I might miss OSH as the exhaust system on the KR2 disintegrated and I was facing building another one from scratch. But thanks to Marc Baca and Doug Pearce, I now have a serviceable replacement, probably built from the same fixture. Mike Sylvester flew up today and assisted with the installation, which was a two man job due to the extra width of my VW engine. Thanks Mike! While the exhaust was off I did a valve job, replacing exhaust guides, recutting the valve seats, and replacing the exhaust valves, as well as the pistons and cylinders (just for good measure). I had 250 hours on the Revmaster heads since they were installed, and they were leaking pretty badly between the valves and seats, perhaps due to lead deposits. It still ran great, but 116 psi compression numbers (down from 158 previously) had me concerned, even before the exhaust system failed. I plan to run Decalin in the fuel to reduce the lead deposits (Aircraft Spruce sells it). We'll see how that goes. Still, 250 hours is a record between valve jobs for me, so I'm already impressed with the Revmaster heads. -- Mark Langford m...@n56ml.com http://www.n56ml.com Huntsville, AL -Please see LIST RULES and KRnet info at http://www.krnet.org/info.html -Change list delivery options at https://list.krnet.org/list/krnet.list.krnet.org/ Affinity List Info Board -Search recent KRnet Archives at https://list.krnet.org/empathy/list/krnet.list.krnet.org/ -Search John Bouyea's decades of archive at https://www.mail-archive.com/krnet@list.krnet.org/
KR> building and flying
I have finally found a way to afford to build and keep flying at the same time. I joined the local glider club. $30 a month, about $12 for a tow depending on height, and $6, yes six, dollar rental for the glider. They have five gliders, never have enough people waiting to need them all in the air at one time, and I will be able to get checked out in the tow plane soon. Flying the tow plane is FREE flight time and does not require a commercial rating. Also met another member with an L-39 that will give me jet time for fuel cost only, about $250 an hour. If anyone wants to find a local glider club go to www.ssa.org. Brian Kraut Engineering Alternatives, Inc. www.engalt.com
