Jeff,
What you did is just masking the real
issue.
The real issue is that the bottom rear
quadrant of cylinder fins on cylinder #2 is not getting air.
And they CAN NOT get air without the more
difficult baffling adjustment that you avoided. It is a knuckle buster.
What you have done is to cool off #2 by
about 10 degrees.
If you do this correctly, it will drop #2
by about 25 to 35 degrees and it will become one of the cooler cylinders on the
engine.
Number 2 can, will, and does go “out
of round” a bit because the lower set of cooling fins on the back side
get almost no air flow from the normal baffling installation. What you did
does not address the “block” in the air flow that affects that
issue.
Regards, George
From: Lancair Mailing
List [mailto:lml@lancaironline.net] On Behalf
Of Jeffrey Liegner, MD
Sent: Monday, June 11, 2007 1:54
AM
To: lml@lancaironline.net
Subject: [LML] TSIO550E: Oil
Cooler Door Scoop to Help Cyl 2 Cooling (LIVP)
I was recently given guidance to lower Cyl 2 temps to make the CHT
grouping tighter and improve overall power options, particularly in
climb. The suggestion and demonstrated method was to cut a hole in the
front wall of the oil cooler airbox to encourage air to get around the aft side
of Cyl 2, and add a box to the opening (extending into the airbox in front of
the oil cooler) so the ram air for the cylinder does not mix with the air
heading through the oil cooler. With the engine installed, this is a
tough modification in a narrowed space, and my fingers/knuckles would take a
beating if I tried this without removing the oil cooler en bloc from the back side of the engine.
Instead, I tried something different and created an alumimum bilayered
flap/scoop coming off the oil cooler door, anchored via the same three oil
cooler door hinge screws, to catch incoming air and divert more to the Cyl 2
aft side.
I should have taken a picture before I zipped up the
cowl...sorry. If there's an interest, I'll send it as an addendum.
The pre-installation temps were (level cruise):
Cyl 2 394 364
Cyl 2 running hottest, a problem with full power climbs.
After installation of oil cooler door scoop (level cruise):
Cyl 1 339 334
346
Cyl 2 352
346 356
Cyl 3 330
328 340
Cyl 4 328
323 340
Cyl 5 330
330 337
Cyl 6 309
307 318
No change in oil temps observed. Power settings were not matched
pre- and post-.
I do not have climb out data yet, when the power settigns and temps are
much higher and the airspeed is lower.
Looks like CHT#2 is a bit cooler with this simple mod. Nicely,
the more the oil door is open, the more the hinged aluminum piece takes a
diverting bite of incoming rushing air.
I share this for those who might be
curious. Not very sophisticated, but my knuckles are not
complaining.