Hi Mark, Live and learn I guess, I am amazed that no one picked this up, but your system really looks good. These baffles would cause a turbulence inside. We all have a tendency to make our inlets too large and this causes turbulence, it is better to have small inlets for a smooth cooling flow. Absolutely no obstructions from outside through the inlets to the cylinders. A hard lesson for sure but I hope this is a heads up for others that are at this point. Now for the Happy Flying when it gets together! Adrian
Mark Jones wrote: >A lot of you have e-mailed and asked what happened to my engine and why is >it torn down right now. Incorrect air inlet baffling on the front of the >cowl caused my two front cylinders to over heat. This in turn resulted in a >cracked piston and >a broken ring in the #5 cylinder. The resulting compression on this cylinder >was 14/80. The opposing #6 cylinder had problems also with a compression of >25/80. The rings and piston on #6 were not broken or cracked but the rings >were no longer sealed and the gaskets were leaking as were the gaskets on >#5. The front cylinders were blocked from any direct cooling air as you can >see in this link http://mywebpage.netscape.com/n886mj/baffles.html . Notice >how the air inlet baffles cover the entire front of the cylinders. A costly >design mistake on my part. The top half of the cylinders must be exposed to >the inlet air. The strange thing is that my FSDO inspector did not catch the >bad design nor did anyone else who looked over my plane. The photos on the >link above were posted long before I made the first flight and not a single >person on the net caught the design flaw either. That really surprised me >since everything posted on the net is picked over with a fine tooth comb. Oh >well, my loss, your gain since you learn from my mistake. I have a total of >about $250 in repair parts (one piston, one full set of 6 piston rings, >lifters, head gaskets, base gaskets, top engine gaskets, valve cover >gaskets, push rod tube o-rings, push rod guide o-rings, etc.) headed my way >and should be here by mid week. I have already surfaced my heads and cross >hatch honed the cylinders and cleaned up the five good pistons. The re-build >should be a piece of cake. If you guys remember, I had the EFS-2 crab which >was too small and replaced it with a EFS-3. After installing the bigger >crab, I did not get any performance increase and was doing everything >possible to figure out why. I finally purchased a differential compression >tester and that revealed the problem. Looking back over my flight records, I >see where my oil temps went from 190° to 220° back on 4-7-05. I also made a >notation that two days later, I had an oil temp spike of 260°. These >temperatures were discussed in depth with very knowledgeable Corvair guys >and I was assured by them that this was nothing to worry about. Of course I >worried anyway and made several changes to my oil cooling duct to improve >the temps. I honestly feel that the damage was done during the flight on >4-8-05 when the oil spiked to 260°. Since that day, I flew the engine for an >additional 23.8 hours. Cruise ranged from 135 to 145 mph and climb out on >take off was 1100fmp all the while basically flying on four cylinders. This >is a testament of just how strong the Corvair engine is. I am extremely >excited about getting back in the air with a healthy engine and seeing what >increase in performance I get. Another point is that I only had one cht >probe located at the GM stock location between #1 and #3 cylinders on the >head. I highly recommend getting six probes for mounting under the spark >plugs with a six way switch to monitor all six cylinders. > >Mark Jones (N886MJ) >Wales, WI USA >E-mail me at [email protected] >Visit my KR-2S CorvAIRCRAFT web site at >http://mywebpage.netscape.com/n886mj > > > > >_______________________________________ >Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp >to UNsubscribe from KRnet, send a message to [email protected] >please see other KRnet info at http://www.krnet.org/info.html > > > > > -- Adrian VE6AFY Mailto:[email protected] http://www.spots.ab.ca/~cartera
