Rick asked;

 

Jim,

I’ve seen many pictures of your plane – beautiful.

Thank you for the compliment.

Any data on the (nominal) LOP CHT’s associated with the cylinders that failed?

On the first set of cylinders I had to run LOP because my CHT's would go over 400F very easily. So climbing to FL250 I had to use HI Boost on the fuel pump to keep the hottest CHT below 420F, when level I would get the CHT's down to 390+- and could pull 32.5 mp at 2500 rpm. I was getting bragging rights airspeeds and using 18 gph. But that did the cylinders in at 215 hrs.

How many degrees LOP?  My understanding is that more lean is generally better (i.e. cooler) – at least on the margin (i.e. you’re best to be either rich enough or lean enough.  Peak is square is the red box)

I found that when going LOP I used 1640F TIT as my setting guide after testing for peak TIT which was 1690F on #2 turbo. The #1 turbo was less. This was about 50F LOP on EGT's also. I will say that I didn't have GAMI injectors but my fuel flow spread was very close and it ran perfect even if I leaned to 1620F. All Temps were just as GAMI advertised which is why I would add the last 1 in. of mp after everything was settled down in cruise. What I didn't pay much attention to was EGT while LOP which was TOO HIGH at 1550F, in my humble opinion. If anyone wants my opinion it is that the exhaust valves on the TSIO-550E can not cool themselves enough while LOP even when power is back to 28/2400 because it is still at 1550F EGT and that makes the exhaust valve so hot that the valve seat has to be wide and perfect to take all the heat ouf of the valve head, or the heat goes up the stem and burns the oil off the stem therefore wearing the stem and guide very fast. My second set of cylinders had stem and guides wore beyond limits at 82 hrs and I hadn't gone LOP for the first 40 hrs and then maybe half the time for the next 42 hrs. This is the mechanical fuse, so to speak, of the Continental engine, the exhaust valves. Now I run ROP and let the fuel save my exhaust valves and save money. I use about 4 or 5 gal. more on a 540 nm flight and go faster and quicker.

What engine monitor do you use?

Chelton Flight System. They used to have Peaks showing on all cylinders which showed degrees down from peak. Current software changed that to Peaks form 0 which is bad and I hope they change it back to the old system. What gives?

Rick

ES: TSIO-550 building

 

Jim Hergert
L4P, N6XE
(An Sexy)
409 hrs.