I only have about 15 hours behind our IO-520

80Deg ROP - 2300RPM, 22" MP = 13.5 GPH

Running the IO 520 engines LOP in cruise is fine and should be considered. As Squash says, it can make a serious difference in operating costs.

My comment regarding feeding these engines lots of fuel was directed at takeoff and climb, but particularly takeoff. Fuel is a major cooling method at takeoff. Some mechanics set fuel flows up a little on the low side. I like hem setup a little on the high side.

When the IO 550 engines first came out, people were setting fuel flows to Continentals recommendations.....and they were too low. We jacked up the fuel flows (based on a TCM tech rep's recommendation) and solved the issues with that engine.

MTV

mtv wrote:Running the IO 520 engines LOP in cruise is fine and should be considered. As Squash says, it can make a serious difference in operating costs.

My comment regarding feeding these engines lots of fuel was directed at takeoff and climb, but particularly takeoff. Fuel is a major cooling method at takeoff. Some mechanics set fuel flows up a little on the low side. I like hem setup a little on the high side.

When the IO 550 engines first came out, people were setting fuel flows to Continentals recommendations.....and they were too low. We jacked up the fuel flows (based on a TCM tech rep's recommendation) and solved the issues with that engine.

MTV

I believe the key to running LOP is having GAMI injectors installed.

Tim

Thank you very much for the clarification and additional input MTV. I had my 470 tuned the same way as far as fuel flow goes.

Yeah, the key is a low Fuel flow spread between your richest and leanest cylinders which one might get without Gamis. But if you don't have a spread less than 0.5 gph, then Gamis (essentially getting injectors that will tweak your fuel flow and thus when the cylinders peak) are the tools to achieve the desired spread. And if needed, they sure pay for themselves very quickly.

behindpropellers wrote:

mtv wrote:Running the IO 520 engines LOP in cruise is fine and should be considered. As Squash says, it can make a serious difference in operating costs.

My comment regarding feeding these engines lots of fuel was directed at takeoff and climb, but particularly takeoff. Fuel is a major cooling method at takeoff. Some mechanics set fuel flows up a little on the low side. I like hem setup a little on the high side.

When the IO 550 engines first came out, people were setting fuel flows to Continentals recommendations.....and they were too low. We jacked up the fuel flows (based on a TCM tech rep's recommendation) and solved the issues with that engine.

MTV

I believe the key to running LOP is having GAMI injectors installed.

Tim

GAMI injectors are so commonly used now, and the requirement for them in running LOP that I didn't even bother mentioning them. Then again, all new Continental fuel injected engines come out with injectors that are virtually identical to GAMIs.

In any case, when running LOP, running tuned injectors and a full engine analyzer is pretty much accepted practice these days.

MTV

I watched the first video linked above. Good stuff and good to hear it from someone from Continental.

My C206 with IO520 didn't have GAMI injectors. I was never comfortable with LOP operations so always ran it 50 rich of peak using the first cylinder to peak. I had three engines in that AC and for all of them, the faster they turned the smoother they were. I found best and smoothest economy cruise for that engine was to operate the RPM at the top of the green, pull manifold pressure to near the bottom of the green (it's been a few years, I think the MP was at 17) then lean to 50 rich of peak. Average fuel burn was 11.5 gph.

I flew two engines past TBO, one of them went to 2100 hours, never had any top end work done.

As far as the cylinder swap game on big continentals I would say a lot of that comes from the guy sitting in the seat and using the knobs and levers in front of him.

+++
Since you don't know how it was flown, I would consider an engine with that many hours about $1000 more than run-out

Those two webinars are 3 hours long and painful to get through. The entire thing could (and should) be edited down to no more than 15 minutes worth of useful information. The first one in particular. DRY!

handsrdirty wrote:

As far as the cylinder swap game on big continentals I would say a lot of that comes from the guy sitting in the seat and using the knobs and levers in front of him.

+++
Since you don't know how it was flown, I would consider an engine with that many hours about $1000 more than run-out

Hopefully some of that will be revealed when I go see it. It's got an engine analyzer on it and I'll take my box to dump the data so we can look at its history.