Cylinder No. 2 is hard up against the entry air box for the oil cooler.  The
air can not flow from top fins to bottom fins in this position.  The sheet
metal at the front of the air box blocks air from passing around the
cylinder from top to bottom on the back side of the cylinder.  On other
cylinders, the flow can go over to the adjacent cylinder, and then back
again.  It is a known problem.  The solution is either to cut a window in the front of the oil cooler inlet
box to air flow to the bottom of the no. 2 cylinder cooling fins
(problematical with the oil door opening and closing) or to cut the window
and put in a fibreglass blister in the front wall of the box to allow air to
bypass the portion of the cylinder where the fin depth goes to zero. I have attached a photo of my oil cooler inlet air box with the blister
installed.   To get oriented, note oil cooler door at top. Fred Moreno

-----Original Message-----
From: Jim Cameron [mailto:toucan@Satx.rr.com] Sent: Monday, 6 April 2009 7:41 PM
To: lml@lancaironline.net
Subject: Hot #2 on IO-550-N

    Friend of mine is scratching his head over his #2 cylinder on an IO-550-N.  Runs about 40 degrees hotter than the rest, although all his EGT's are nearly the same.  He spoke to a retired Continental engineer, who told him that a lot of the IO-550's had that problem.  My friend has checked all the obvious, baffling leaks, shrouds fitting properly, etc.  He tried putting the oil cooler door on and closing it part way, thinking maybe that would push more air over the cylinder.  No dice.  The problem seems to be not enough air flowing down between #2 and #4 -- that's the exhaust side of #2.
    Has anyone else run into this?  Any ideas how to push more air through there?

Jim Cameron
Legacy N132X