-------------- Original message from Mark Steitle <msteitle@gmail.com>: --------------

Bill,

 

I'm not sure what's changed, but my oil temps are up from what I reported earlier.  I routinely see 220-225 on climbout, then they settle down to 200 in cruise.  Maybe I'm producing more hp now, or maybe the earlier temperature report was not in mid-summer, or possibly my system is not cooling as well as it did earlier.  I'm just glad that I installed TES o-rings throughout. 

My cowl flap initially had an aluminum lip, that protruded into the airstream about 1".  This was a quick and dirty test to see the result.  I couldn't open or close it, it was open all the time.  I have since replaced the 1" lip with a servo-controlled door so I can open/close as desired.  When closed it is the same as a stock cowl.  This is very helpful in cooler climates, not so much during triple-digit Texas summer months.

 

I also added an "airfoil shaped" piece on the firewall directly above the cowl flap opening.  This was done in the hope of helping coax the heated air out of the cowl.  But I didn't detect any great improvement in cooling.  Oh, well.  Next thing I plan on adding is small air dams on each end of the flap door.  The idea here is to promote more efficient airflow out of the cowl flap.  I've heard that these make a big difference.  We'll see.  

 

If you are considering installing a cowl flap, you may want to consider locating it on the side, or possibly install one on each side, back near the firewall.  This would allow you to make the opening larger, and this location may be in a lower pressure area than the bottom, especially during climbout.  Just a thought.

 

Cooling is still marginal in the Texas heat, and it will be worse with the new P-port 20B engine.  So, I may be forced to make some major changes to get the more powerful engine to cool, or else be forced to throttle back during climbout.  I've been considering relocating the radiator from under the engine to the cool side of the engine (fore/aft).  This would allow me to use a slightly larger radiator.  It would clean up the plumbing and significantly shorten the cooling lines too.   

No, I haven't experienced SAG.  But then I'm running Renesis type irridium spark plugs.  I'm at 143 hours now.  Personally, I won't use anything else. 

 

Mark