Anyone had experience with this?
Pilot flying our IVP (TSIO550E3B
with 4 blade MT) and reports:
"Had backfires(?) couple of nights back. Was
running lean of peak with
temps 1590 at FL150, around -15C, light
rain, 29Hg 2500rpm .
Happened twice so went rich of peak for remainder
of flight with no
problems. Any reason come to mind?"
Be grateful
for any thoughts
Phil Sexton
Melbourne
Phil;
I have had one backfire
(afterfire) that got my attention while going LOP. I have a 4P with TISO
550E. I had about 30 hrs on a new overhaul and was just going to test it LOP.
Previously, I had 300 hrs on the 4P with about 50 of those hours LOP. So when I
tried it, just like in the past, it gave one big pop. I didn't try that again.
But while looking for why I had a strange vibration in this new engine I found
that one injector had a piece of dirt in it and it caused the EGT for that
cylinder to run slightly higher than the others while ROP. After cleaning the
injectors the vibration was gone and the LOP works correctly again. Without
GAMI's, which I should have anyway. The engine will pop if too lean,
and in this case one cylinder got too lean. I wouldn't just accept that this
would not do any harm. I have heard of very bad things happening if it blows off
a hose from the Turbo. Like loss of pressurization, engine stopping and won't
start at that high altitude, etc.
As a side bar, I don't run LOP
anymore unless I need to stretch the range. This after replacing all 6 cylinders
at 215 hrs from new and then the second set after only 82 hrs. Both times the
exhaust valve stems and guides were out of serviceable tolerance. This could be
a very long thread but will have to wait.
Also, I lost one Mag, from water
in the cap from pressurization moisture, just like Carl Cadwell said. But mine
didn't show up in the air, it just wouldn't work on the next flight Mag, check.
I have since Inspected the Mag. every 100 hrs. There is a very small weeping
drain hole in the high voltage cavity that can and did get plugged.
For what it's worth,
Jim Hergert
L4P, N6XE
(An Sexy)
408
hrs.