Since attending the cooling show put on by George Braly in Ada , I have
implemented most of the changes suggested.  With the exception of the heat
shields for the turbo's and exhaust stacks, I have manufactured lower
cyclinder ducts for the front and rear cyclinders, opened a hole for the #5
cyclinder with a diverter and made a channel for the air to move around the
flat spot in the #2 cyclinder inside of the oil cooler box.  In addition, I
reset the fuel flow at take off power to 45.3 GPH.

Last week I made a trip from California to Wisconsin and back.  With a climb
at 140 Kts indicated, Gross weight, the VSI was showing 1200 to 1500 FPM all
the way to FL200.  The cyclinders never got over 375 degrees with a MP of
34" and 2600 RPM.  In the past the routine was 160 Kts indicated and 500 to
800 FPM with the temps going to 390 to 400. In cruise flight the temps were
just as good with maybe a little to large a hole in the #5 baffle.  All
temps in the 330 range or lower.  #5 was showing 296 at FL200 with an OS
temp of +10f.  I will close the opening for the #5 cyclinder about a third.
This is a great improvement and my thanks to the ADA group for their very
generous contribution.

Been watching the arguments about plenums with interest, but with these
modifications I can't see any need for going to those extremes.

An old issue is still plagueing me, when switching fuel tanks, ususally only
once a trip, the engine falters for 3-8 seconds, finally catches and it does
not occur again on subsequent tank changes in that flight.  Stop enroute,
full fuel and climb to altitude and it may or maynot occur.  I have moved
the fuel pump to the lowest location on the side panel, replaced the fuel
selector with an andair, inspected all lines for leaks and still I at a loss
to explain it.  The lines from the tank are 3/8" as opposed to the current
lines which are 1/2".  Would appreciate any thoughts the group has.

Pat Brunner
N98PB IVP  524Hours