downdraft cooling for Long EZ

[n106nc]

After 20 years (or so)I thought N106NC was ready to fly,the engine was running well after several taxi tests,the brakes being the only squak to this point(saving my nickels for Extra heavy duty GROVE brake set)way under braked (in my opinion-and as PIC and owner) after many attempts to seat the brake pads in as per Cleveland's instructions ,still really wimpy.
Most taxi tests were conducted with the cowling off ,so one day (after another naked taxi test)it was time to taxi fully dressed(cowling installed)so after 20 minutes of installation-pushed her out(to the taxi way),and fired her up and the first thing I noticed was the Oil pressure had dropped from 65-70 psi at idle to 15-20 psi -90psi at 1800 to 30 psi at 1800 so I shut her down.The engine, a used, high time (1700 hrs smoh)0-320 E2A
never missed a beat, so at first I assumed insturmentation,the oil pressure gauge or wiring,or the sending unit must be faulty-WRONG!!
After consulting several A&P types I checked the oil pressure bypass valve and Lo and Behold-a large chunk of metal was lodged inbetween
the ball and seat- relativly easy to fix the effect but the cause was much costlier,lots of metal in the finger screen,oil sump and apparently throughout the entire engine. So,after carefull reading of the engine logs,the A&P who did the overhaul did as little as possibleand as cheaply as possible to bring this engineback to "Zero time".Buying used engines is always a gamble and this time I got bit!!
 So I having this engine remanufactured by Aerosport-brought up to 160 hp+ via high compression pistons-new Titan cylinders,porting and flow matching and a balance to within .2 grams,and dual p-mags.
 Getting to my original question does anybody out there use a down draft cooling setup(my plane has a Berkut updraft baffel setup,has a NACA belly scoop with a Hunt 4 pipe exhaust presently)? Is there any info available outlining the mods nessassaryavailable?Does anybody use a plenum setup?I know this opens a Pandora's box of conditions but most pilot owners of 0-320 Long EZ seem to have CHT and Oil temp issues right off the bat so I'd like any input available .
                                                                     Thanks,
                                                                                Mike B.-N106NC
P.S.     I'm based at the EAA hanger at CMA-Camarillo,CA-M.B.

[Drew]

Mike,
I came to look at your plane when I was also based out of Camarillo.  I was parked in the big hangar next to the Cafe.

After I trashed my first motor (0235), I installed an 0320 but went to downdraft cooling.  I did not bother to cut off the naca scoop since I was more interested in cooling than drag at the time.  I did, however, seal off the naca and ran hoses directly to it (ram air for carb, ram air for oil cooler, and 2 more ram airs for accessories.

The downdraft was for the cylinders.  The baffling was sooo much easier.  Temps were great----and of course I really knew what the temps were.  You can see some pix of the plane at the following site:
http://www.home.earthlink.net/~swensonaw/

I have sold that plane and now have a cozy with updraft cooling.  Since I don't have downdraft cooling on the Cozy, who really knows what my temperatures are since the charts are for downdraft at the bayonette fitting.  And yes, I have seen the info of one longez test in a climb and cruise with sparkplug thermocouples on all sparkplugs and also the bayonette fittings----but still don't trust it.

For the Cozy guys, what are your temps in cruise----and where do you have your thermocouples----and how are those temps working out for you.  I have read lots of info within the Cozy newsletters and on websites on CHTs---but they never say where they are measuring from.

[Charles Davis]

My brother, Mike, came up with what I think is a really neat downdraft cooling design.

He puts NACA inlets on the top of the strakes.  These feed into a kevlar plenum.  

The inlet is 10 sq in, and we're thinking about putting in a gate that can be controlled by the pilot to reduce the intake to about 8 sq in to keep the CHT's up on very cold days or high speed descents at low power.

I have some pics of the build so far, and can email them to anyone whose interested in a ZIP file if you send me an email.

[dave]

hi charles,
  whats your e-mail?

[Charles Davis]

charles@sandiegocadcam.com

I put the pics and our email correspondence in a .doc file.

A little rough, but enough pics and text for an experienced builder to replicate what we're doing.

We think it will work great.  It just makes a lot of sense.  But of course we've not flown yet, and you, as the builder, have to make all final decisions about your plane.