Hey guys! I’ve been having a question lately, but no one seems to have a clear answer.

I have a JPI EDM-700 installed on my Cessna 205
With a Continental IO-550

The thing is, that it shows the head temperatures digitally, but it doesn’t have a Green or Red arc.

On climbs temperatures would normally go above 415°F on Cylinders 1,3 and 6

And during cruise flight around 350°-380°

How Hot is TOO HOT?

The original Cessna manual says never go above 450°F
But some pilots and the Continental Website recommend always below 380°F

It seems almost impossible to stay below 400°F even with 50% power


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Do you have the little shark fin vents on the lower cowling? If not I would highly recommend them. They make a big difference for cooling.
I really don't like to run over 400 for any extended periods of time.

A1Skinner wrote:Do you have the little shark fin vents on the lower cowling? If not I would highly recommend them. They make a big difference for cooling.
I really don't like to run over 400 for any extended periods of time.

Yes I do, but no matter what I do, even with the aux fuel pump on, its hard to run them below 400 specially #6 and #3


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Very interesting. #6 is usually hard to get warm as it's getting the most of the airflow. Sounds like you may need to do a little baffle adjusting or repair.

I prefer to keep my CHTs below 380. 415 is definitely too hot. Start with checking the baffles but if they look good I would definitely get the cowl louvers. I would also make sure you are showing 29-30 gph FF in the climb on that IO550. Do you live in a warm climate ? I usually use a cruise climb between 120-130 mph on my O520 above 1000 feet AGL. I can see 380+ temps in the summer with steep climbs.



Josh

Dog is my Copilot wrote:I prefer to keep my CHTs below 380. 415 is definitely too hot. Start with checking the baffles but if they look good I would definitely get the cowl louvers. I would also make sure you are showing 29-30 gph FF in the climb on that IO550. Do you live in a warm climate ? I usually use a cruise climb between 120-130 mph on my O520 above 1000 feet AGL. I can see 380+ temps in the summer with steep climbs.



Josh

You are getting 29-30gph with how much Manifold Pressure and how many RPM’s?


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My 520 see 23-24 which is a little bit low. I have had issues with it and therefore it creates some heat during the climb. Ideally I should see 25-26. The IO550s should see at least 28 gph and preferably 30 during climb out. This could be the reason you're see reasonable temps in cruise but high temps in the climb. I also see you live in Cancun. Knowing that alone would make me obtain the cowl louvers. I live in Oregon where it is mostly cool. I might see similar CHTs in climbs if I lived in a hot tropical climate.



Josh

First thing I would do is get someone who actually knows how to set up fuel flows on this engines to set up your fuel flows RIGHT.

These engines need to flow a LOT of fuel. Go to recommended flows, then about 20% higher.

If you have a standard Cessna “fuel flow” gauge (it’s actually a pressure gauge), at takeoff power, that needle should be waaaay over into the other side of that instrument…..way over the max reading.

If it’s not, you’re not giving that engine enough fuel. Flows need to be higher than Continental calls for.

The fact that temps are normal in cruise but hot in climb says to me your WOT fuel flows are low.

Maybe.

MTV

I also agree, that’s too warm. I also agree with check your fuel flow. I have a io550 in my 182 and it used to get hot on climb out when for was set at about 25pgh. After a few adjustments it’s now at about 30.5gph at max power at about 700ft elevation. Can easily keep temps below 390 on climb out, even when hot. I usually shoot for 380. I couldn’t achieve this without upping the fuel flow. It can always be leaned when too much. I usually cruise at 60-65% 350 degrees and yields about 15gph. I have 3 small lovers on each side in my cowling. I agree that you might also need some baffling tweaking

[mention]mtv [/mention] [mention]BlindPilot [/mention] You guys are right, I believe that’s exactly whats going on
I did an experiment last week on the ground
With the throttle fully open (full power) I was only getting about 28 gph

I believe I should be getting more fuel flow.

Also, were does the mechanic adjust the mixture like you are saying? Is it complicated?


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I still think you have a baffle issue. If you can't keep it below 400* at 50% power then something other then fuel flow is going on.

A1Skinner wrote:I still think you have a baffle issue. If you can't keep it below 400* at 50% power then something other then fuel flow is going on.

The weird thing is, they replaced all the baffles already, they are new and supposedly “well installed”

What else could it be?


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Adjusting the fuel pump to get more flow is super easy… takes a long Allen wrench through the bracket of the alternator at rear of the engine to reach the fuel pump. At least that’s where mine is on a io550d. If I had to guess, about a 1/2 turn to the right will probably be a good starting point.

pabloecanales wrote:

A1Skinner wrote:I still think you have a baffle issue. If you can't keep it below 400* at 50% power then something other then fuel flow is going on.

The weird thing is, they replaced all the baffles already, they are new and supposedly “well installed”

What else could it be?


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When you look into the front of the engine are the baffles pointed up against the top cowl? Or do they point down? A very common thing I see is when the cowl get put on they pull the baffle down and guys don't take the time to make sure they are up. The row along the back needs to pint forward not back. And any holes on the baffles must be fixed. It's amazing how a few holes add up.
Also, on #6, is there a plate coming up the front of the cylinder? If it's all new baffling then it may need to be shortened in front of #6.

BlindPilot wrote:Adjusting the fuel pump to get more flow is super easy… takes a long Allen wrench through the bracket of the alternator at rear of the engine to reach the fuel pump. At least that’s where mine is on a io550d

Great! So the adjustment is done directly on the fuel pump.
That sounds like a quick job for the mechanic.



Also, is it normal that my Electric Boost fuel pump delivers much more fuel flow than the mechanical one??

Or does that means that indeed the mechanical fuel pump is supplying low Gph?


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A1Skinner wrote:

pabloecanales wrote:

A1Skinner wrote:I still think you have a baffle issue. If you can't keep it below 400* at 50% power then something other then fuel flow is going on.

The weird thing is, they replaced all the baffles already, they are new and supposedly “well installed”

What else could it be?


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When you look into the front of the engine are the baffles pointed up against the top cowl? Or do they point down? A very common thing I see is when the cowl get put on they pull the baffle down and guys don't take the time to make sure they are up. The row along the back needs to pint forward not back. And any holes on the baffles must be fixed. It's amazing how a few holes add up.
Also, on #6, is there a plate coming up the front of the cylinder? If it's all new baffling then it may need to be shortened in front of #6.

Thats right, I figured the #6 cylinder front plate seemed a bit high, so we just cut it. And bent it a little towards the Cylinder.

Regarding the baffles, they changed the whole system but I still see temperatures above 415°F During climbs at 75% power


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pabloecanales wrote:

A1Skinner wrote:

pabloecanales wrote:

A1Skinner wrote:I still think you have a baffle issue. If you can't keep it below 400* at 50% power then something other then fuel flow is going on.

The weird thing is, they replaced all the baffles already, they are new and supposedly “well installed”

What else could it be?


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When you look into the front of the engine are the baffles pointed up against the top cowl? Or do they point down? A very common thing I see is when the cowl get put on they pull the baffle down and guys don't take the time to make sure they are up. The row along the back needs to pint forward not back. And any holes on the baffles must be fixed. It's amazing how a few holes add up.
Also, on #6, is there a plate coming up the front of the cylinder? If it's all new baffling then it may need to be shortened in front of #6.

Thats right, I figured the #6 cylinder front plate seemed a bit high, so we just cut it. And bent it a little towards the Cylinder.

Regarding the baffles, they changed the whole system but I still see temperatures above 415°F During climbs at 75% power


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During a climb 415 isn't terrible. Once you level out do they drop down to under 380?

A1Skinner wrote:

pabloecanales wrote:

A1Skinner wrote:

pabloecanales wrote:[quote="A1Skinner"]I still think you have a baffle issue. If you can't keep it below 400* at 50% power then something other then fuel flow is going on.

The weird thing is, they replaced all the baffles already, they are new and supposedly “well installed”

What else could it be?


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When you look into the front of the engine are the baffles pointed up against the top cowl? Or do they point down? A very common thing I see is when the cowl get put on they pull the baffle down and guys don't take the time to make sure they are up. The row along the back needs to pint forward not back. And any holes on the baffles must be fixed. It's amazing how a few holes add up.
Also, on #6, is there a plate coming up the front of the cylinder? If it's all new baffling then it may need to be shortened in front of #6.

Thats right, I figured the #6 cylinder front plate seemed a bit high, so we just cut it. And bent it a little towards the Cylinder.

Regarding the baffles, they changed the whole system but I still see temperatures above 415°F During climbs at 75% power


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During a climb 415 isn't terrible. Once you level out do they drop down to under 380?[/quote]Wow! What a relief! Haha

That’s right, during Climb half of the cylinders range between 400~415°F and the other half between 370~390°F

And during cruise they are all below 390°F


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Setting up fuel flows on a big Continental is not rocket science. BUT, I’ve seen several that were set up by mechanics who just followed the original Continental guidance. Those engines stepped cylinders, which turned them to junk.

Find a maintenance professional who knows how to set these engines up. Bring one from afar, if that’s what it takes……it only takes once to get them right.

Metered and unmetered flows are set…..it’s not just “turn a screw on a pump”.

On our 550s, at takeoff power, I’d see ~38 gph. It’s not just air that cools these engines.

MTV

Not disagreeing with you MTV, I was just sharing the info that fixed my heating issues on climb out, info directly from Airplains—-who originally did the conversion and set mine up