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Hangar Flying / Not so hot anymore
« on: May 02, 2006, 05:21:02 PM »
Hello again everyone, I am Mark Schwendeman owner of O-235 L2C powered Long Ez 83DF.  As some of you will recall I had a problem with #4 cylinder running way hot at about 435 F.  I’m happy to announce the problem is now cured.   It was not an air leak in the intake system as many of you suggested, I took the entire intake system apart and had no change in temps when it was carefully reassembled, however I do appreciate all the letters, suggestions, and clarifications from those who responded to my e-mail inquires.  I finally cut a 2 inch by 3 inch hole in the front of the top cowling and built some ducting from this hole to #4.  This worked; I got the temps down to about 390 F and flew to Memphis for help from the gurus, Robert and Valerie Harris.  Robert plugged both my intake hole and the ramp exit on the top cowl.  He built new baffles on the bottom side of  #2 and #4, and built new baffles on the front side of #4.  Essentially #4 cylinder is now enclosed in baffling except for a couple inch intake area on the bottom side of the cylinder and a couple inch exhaust area on the top side of the cylinder.  Here are the before and after temps:

8500 ft, OAT 50 F, 2800 RPM, 146 KIAS, oil 181 F / 69 PSI, throttle cracked to slight RPM loss.

  ......... Before.......................           After
#4  435 F / 1400 F.....                         376 F / 1400 F
#3  365 F / 1300 F.....                         365 F / 1320 F
#2  370 F / 1360 F.....                         336 F / 1343 F
#1  373 F / 1300 F.....                         362 F / 1250 F

Some of you may notice the head temp on #2 is also down as it is benefiting from the new underside baffle between #2 and #4.  The #4 temp goes up to about 400 F when leaned out at 12,500, but that’s way down from 460 F.  Those of you wondering about my experience with the “Vortex Valve” intake mod, it is now removed but I will be sending it back to get a shorter one built.  I hope this will get the 20 RPM static thrust loss back and better mixture distribution.  I’ll let everyone know how it works when I get it installed.  For those who don’t remember my first posting it’s back on 3  Jan 06 entitled “One Hot Cylinder”.  Thanks everyone,

Mark Schwendeman :D

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Hangar Flying / One hot cylinder
« on: January 02, 2006, 08:06:27 PM »
Hello everyone, I’m Mark Schwendeman and I have owned Long Ez 83DF since 1994.  It is still O-235 L2C powered but in 1999 I had it top overhauled (TT 1293 since FN) and put in the 9.7/1 pistons.  At this time I also installed EGT and CHT probes on #4 cylinder (previously only #3 had probes on it).  The EGT unit and probes are Electronics International the actual unit is an EAC-1.  At this time I learned I had a problem with #4 CHT.  Several things intervened including the aircraft spending 3 years at the EZ hanger getting tornado damage repaired (no Robert and Valerie aren’t that slow I took the repair it between jobs option to lower the cost).  Anyway she’s back flying now and I need help, #4 CHT is about 70 degrees F above everyone else.  I have checked for induction leaks and can’t find any.  I put in a ramp air outlet above #4—cost me 4 knots and only helped by 10 F.  I have swapped the probes with #2—no change.  I have even gone so far as to swap #1 and #4 cylinders because I was sure it was the cylinder—no change.  Fuel provided by an MA3 carb. Here’s the #’s:

At 8500 ft.  AOT 50 F  2790 RPM  22 inches manifold  146KIAS oil 181 F 64 psi and throttle cracked back to just at RPM drop (it helps enrich #4 and leans #1)
                                                                     :evil:
#4 430 F 1350 F   #4 435 F 1400 F   #4 448 F 1500 F (peak)
#3 360 F 1250 F   #3 365 F 1300 F    #3 389 F 1406 F
#2 370 F 1320 F   #2 370 F 1360 F   #2 385 F 1460 F
#1 370 F 1280 F   #1 373 F 1300 F   #1 387 F 1360 F

This problem gets worse as altitude increases, the temps climb on all cylinders by about 15 degrees at 12,500.  Climb temp on #4 runs about 440 F.
 
For my latest attempt I called Air Synergy Labs (www.Betterperformance.com) and had them build me an induction “Vortex Valve”.  These are very nice people, I sent them an intake gasket and they built me a test unit with mounting flange for FREE.  Results with this are mixed, I loose about 30 RPM static so there is some power loss, but the mixture distribution is better and temps are down to about 425 on #4 in the climb.  In addition I can now run WOT at altitude without #4 temp getting quite so high, although pulling the throttle back to just at RPM loss still enriches #4 and leans #1.  However, it won’t run smooth LOP which is what I was hoping for.  Here’s the #’s with the vortex valve:

At 8600 ft. AOT 53 F   2820 RPM  22inches manifold, 147 KIAS, oil 181 F 64 psi  WOT

#4 431 F 1350 F      #4 439 F 1400 F
#3 345 F 1204 F      #3 360 F 1252 F
#2 360 F 1292 F      #2 377 F 1367 F
#1 371 F 1248 F      #1 373 F 1305 F

Here’s how it looks with the vortex valve and throttle pulled back to RPM loss:

#4 431 F 1350 F      #4 440 F 1400 F
#3 349 F 1230 F      #3 362 F 1273 F
#2 370 F 1340 F      #2 379 F 1397 F
#1 379 F 1380 F      #1 375 F 1418 F
Lastly, here’s the #’s at 12,500 ft. WOT, 137 KIAS 2760 RPM OAT 40 F:

#4 456 F 1340
#3 369 F 1189
#2 386 F 1309
#1 381 F 1241

I forgot to mention I have a mag and a Jeff Rose electronic ignition (also a fine piece of equipment).  Anybody got any ideas?

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