Hours on your Continental 310 hp 550 Cylinders

[Little Dipper]

I am wondering how many hours you all are getting on your cylinders on your 310 hp IO'550s?   I only got 650 hours on the cylinders on this motor that I purchased brand new.   They are now being replaced due to low compression.     I did much better on my first 280 hp engine as I got 2295 hours out of it with only one top overhaul.    My John Deer lawn mower engine is lasting longer than this and each of these cylinders are almost expensive as a case of eggs.    I'm curious to learn the longevity others have had with the same engine.    

 

[jetdriven]

what is "low compression"?   I would start there.

[irishpilot]

For a continental, it's gotta be real low before I'd pull jugs.

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[A64Pilot]

650 is low, but not uncommon for one that’s run hard.

Average I believe isn’t much if any above 1,000

People that really baby one can get TBO, maybe

But most didn’t buy the fire breathing monster to treat it like a pony

[StevenL757]

1 hour ago, Little Dipper said:

I am wondering how many hours you all are getting on your cylinders on your 310 hp IO'550s?   I only got 650 hours on the cylinders on this motor that I purchased brand new.   They are now being replaced due to low compression.     I did much better on my first 280 hp engine as I got 2295 hours out of it with only one top overhaul.    My John Deer lawn mower engine is lasting longer than this and each of these cylinders are almost expensive as a case of eggs.    I'm curious to learn the longevity others have had with the same engine.    

First engine on my first Ovation was an IO550G6B with 643 hours when I bought it.  I added about 700 more hours when I started having issues.  As the core was over 17 years old at that point, I decided to buy the 310HP STC and get a factory reman IO550N8B (2700rpm and 310HP out of the box).  Ran that engine LOP, 2550RPM and put around 1250 hours on it before selling the airplane.  My compressions on the second engine were never below 70.  I understand the new owner immediately started running the engine ROP, and within his first 100 hours, started having issues with cylinders.  Still haven’t understood whether ROP ops would’ve contributed to the issues, but I can’t help wondering.

Just finished installing a factory-new IO550N on my present Ovation but it’s not running yet, as we’re still working through cockpit and avionics upgrades, replacing some interior components, and making other improvements.

[irishpilot]

I have the 550N in my Lancair. It's a great engine.

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[Guest]

Continental cylinders as a general rule don’t last as long as Lycoming cylinders.  I’ve taken several pickup truck loads to the scrap, err junk dealer over the years.  They should get Lycoming to give them lessons in building reliable cylinders.

[Fly Boomer]

1 minute ago, M20Doc said:

Continental cylinders as a general rule don’t last as long as Lycoming cylinders.  I’ve taken several pickup truck loads to the scrap, err junk dealer over the years.  They should get Lycoming to give them lessons in building reliable cylinders.

Mike Busch has proven that Continental cylinders can go the distance, but they wont take as much abuse as Lycoming.

[Guest]

21 minutes ago, Fly Boomer said:

Mike Busch has proven that Continental cylinders can go the distance, but they wont take as much abuse as Lycoming.

Obviously my experience differs from his.  I’ve pulled more Continental cylinders with cracked heads than I can count. I’ve seen many just start burning oil out of the blue when the rings coke up and seize in the piston, and this is across many airframe types and owner operators.  Never see this in 520 series engines.

In my experience any that make TBO are miracles.

[Fly Boomer]

1 minute ago, M20Doc said:

Never see this in 520 series engines.

Maybe that accounts for Mike's success -- his 310 runs TSIO-520s.

[Guest]

1 minute ago, Fly Boomer said:

Maybe that accounts for Mike's success -- his 310 runs TSIO-520s.

Ask him about 550’s

[Fly Boomer]

Just now, M20Doc said:

Ask him about 550’s

You have alluded to your opinion on the 550s in other posts.  Do you think the 550s have been run hotter than the 520s you have seen?  I'm assuming that most of the 550s you see are Cirrus?

[Guest]

1 minute ago, Fly Boomer said:

You have alluded to your opinion on the 550s in other posts.  Do you think the 550s have been run hotter than the 520s you have seen?  I'm assuming that most of the 550s you see are Cirrus?

A Continental tech rep I spoke with the other day regarding sticking rings suggested that they are being run too cold.  I’m not sure who the high priest of cold/cooler CHTs is?

[Fly Boomer]

1 minute ago, M20Doc said:

A Continental tech rep I spoke with the other day regarding sticking rings suggested that they are being run too cold.  I’m not sure who the high priest of cold/cooler CHTs is?

That is a new one.  I have heard of Lycs with sticking valves because they were not run hot enough.  I am surprised there is so much difference between the 520 and 550.

[carusoam]

The good news…

1) Some people have reported… with careful use… the Continental cylinders can go the distance…

2) Other people have reported… with less than careful use… swapping them out somewhere near half TBO of the engine…

3) A few have reported… constant flight using the full Flaming Dragon Mode… nets an amazing short cylinder life of 1/3 TBO…

4) Everyone that has tried their first PPI on a plane with a Continental engine… gets surprising results… that make you think twice about the plane as you review the logs…

 

Chances are…

5) You don’t always fly in full flaming dragon mode… LOP has meaning to you…

6) You probably watch your CHTs on most flights using an engine monitor… 380°F has meaning to you…

7) The mechanic with this recommendation may not be familiar or equipped for measuring the cylinder compression for a Continental…

8) There is something wrong with the cylinders that they have such low compressions…  what is low compression for a Continental IO550 cylinder?

 

Usual next steps…

9) Fly the plane before taking the compressions…

10) Use the appropriate orifice for the Continental cylinders

 

The bad news…

11) You and your service have gone through all of the hoops and actually have bad compressions…

12) be on the look out for bad valves, and cylinder cracks…

 

Sooooo…

It is unlikely that you need to change the cylinders… so test properly again, with both eyes open…

Get an eye that can fit down inside the cylinder and be on the lookout for pizzas, and waffle patterns… or rust…

Post pics..

 

If the valves don’T show their pizzas… and the cylinder walls don’t have cross hatches…. You have probably found your cylinders have issues…

Compression tests are a simple test to use… to know if we need to look further… fortunately, today, we have methods of looking further….

PP thoughts only, not a mechanic…

Best regards,

-a-

[carusoam]

1 hour ago, M20Doc said:

A Continental tech rep I spoke with the other day regarding sticking rings suggested that they are being run too cold.  I’m not sure who the high priest of cold/cooler CHTs is?

With the O1, on winter days… flying LOP at altitude… it is possible to see CHTs lower than 300°F 

This is where we started the conversation of what temps does it take to convert the LL to its chemical by-products… (Shell reference)

And how tight is the choke of the cylinder as the CHTs drop below 300°F…

 

I don’t recall the answers… or I’d share them here… 

Best regards,

-a-

[ilovecornfields]

1 hour ago, M20Doc said:

A Continental tech rep I spoke with the other day regarding sticking rings suggested that they are being run too cold.  I’m not sure who the high priest of cold/cooler CHTs is?

I heard this from Top Gun as well - that people are running their CHTs too low. I thought lead deposits on the valves were the only issues but it can lead to stuck rings as well? How low is too low?

[GeeBee]

33 minutes ago, ilovecornfields said:

How low is too low?

Differing opinions. If you listen to Mooney, 250 degrees. If you read the Continental literature for the IO-550 they say 300 degrees. 

[Little Dipper]

4 hours ago, jetdriven said:

what is "low compression"?   I would start there.

-20 lbs on two cylinders...    I fly too much hard IFR to fart around with an engine that eats too much oil and has low compression and am not in for experimenting.     Not run like a rocket ship,  engine was never over heated, excellent mechanics,  oil changed every 25 hours, pre heated before starting cold, etc.    The top half of my first engine went much longer than this one.   I'm still wondering if this is normal for 310 hp 550 Continentals?  

   

[PT20J]

I don't think it's LOP vs ROP -- I suspect it's power. Run them hard and they don't last as long. Mike Busch runs pretty low power. I asked him once what power he ran and he said he had no idea but it was probably 60-65%. He just has a fuel flow that he likes to run at and watches the head temps and adjusts mixture accordingly. He summed it up with, "I'm a longevity guy, not a speed guy." The airlines used to run the big radials at around 55% rated power for economy and longevity. 

 

[Little Dipper]

12 hours ago, carusoam said:

With the O1, on winter days… flying LOP at altitude… it is possible to see CHTs lower than 300°F 

This is where we started the conversation of what temps does it take to convert the LL to its chemical by-products… (Shell reference)

And how tight is the choke of the cylinder as the CHTs drop below 300°F…

 

I don’t recall the answers… or I’d share them here… 

Best regards,

-a-

I have often flown with a few CHTs lower than 300F and never worried about it.  I wonder if there is something to your 3rd sentence?

 

[irishpilot]

how far on the lean side are y'all running to see less than 300 CHT?

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[Canadian Gal]

13 minutes ago, irishpilot said:

how far on the lean side are y'all running to see less than 300 CHT?

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Cold winter days are a big factor.

[Niko182]

9 hours ago, PT20J said:

I don't think it's LOP vs ROP -- I suspect it's power. Run them hard and they don't last as long. Mike Busch runs pretty low power. I asked him once what power he ran and he said he had no idea but it was probably 60-65%. He just has a fuel flow that he likes to run at and watches the head temps and adjusts mixture accordingly. He summed it up with, "I'm a longevity guy, not a speed guy." The airlines used to run the big radials at around 55% rated power for economy and longevity. 

 

TAT says to run their engines pretty hard in those terms. Climb at 100% and cruise at 85% and a lot of their engines make tbo. Those are with IO520 and 550B engines

[Niko182]

39 minutes ago, irishpilot said:

how far on the lean side are y'all running to see less than 300 CHT?

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Couple weeks ago at 16500 over the Colorado Rockies, I couldn’t get a CHT above 305 with the lowest being around 250. That was at 11 gph, so just barely LOP.