Ovation with all new cylinders

[johnhoge]

Hi,

I'm looking at a nice Ovation but one thing that concerns me is that all 6 cylinders have been replaced between 900 and 1500 hours. I've seen the Mike Busch seminar warning about the perils of cylinder work and find it a bit troubling that all 6 jugs went bad.

Is this something that is common with the IO540? Is it a sign of careless engine operation? Would the prudent course of action be to put the old beast of it's misery and go straight to a full engine overhaul?

Thanks,

John

[kmyfm20s]

Most likely from just running high CHT's but could be a bad batch of cylinders or over an zealous mechanic. Doesn't mean anything is wrong with the bottom end. Bore scope and thorough compression check of existing cylinders should give you the current condition.

[flysamo]

don't know about the 540 but the io550 seems common item around a 1000 hrs many have been replace including ours, install a complete set of cylinders, balanced with pistons complete from continental 

[buddy]

If you have a M20R you have an IO 550 Continental. When I bought mine it was just topped at around 1450 TT and that seems to be the average. I now have 2140 TT and it’s still running strong but I’m in the process of replacing it with a factory overhaul....just because.

[johnhoge]

Sorry for the typo. I meant IIO550.  @buddy, what led you to do the top overhaul? Was it something that showed up in a boroscope? 

Edited November 25, 2020 by johnhoge

[V1VRV2]

Flying in fire breathing dragon mode will contribute to it. Everything full forward. 10/10. Pulling the power back only in the flare. The engine sitting for a long period of time without use will do it as well. There’s a sweet spot somewhere in the middle.

[Cruiser]

No one seems to know for sure. There are multiple reasons for cylinder replacement on these engines. I have three (3) original ones now at 2000 hours. The other three were replaced for three separate reasons. #5 cylinder was replace because of high temp due to the alternator cooling issue (stuck rings). #2 was replaced for a crack between the fuel injector and the top spark plug hole and #4 was replace initially for burned valve but the inspection found an internal crack in the exhaust port. 

[philiplane]

It's a Continental thing. It is rare to have a Continental cylinder make 2000 hours in service. No matter how well you manage the engine, it is mostly luck if you get past 1200 hours on cylinders. 

[StevenL757]

18 minutes ago, philiplane said:

It's a Continental thing. It is rare to have a Continental cylinder make 2000 hours in service. No matter how well you manage the engine, it is mostly luck if you get past 1200 hours on cylinders. 

Agree largely with the 2000 hour and 1200 hour comments; however, honestly it does depend largely on how you fly the airplane, manage the engine, and maintain it.  “It’s a Continental thing” may have been true years ago, but they’ve changed their tune and have been producing better engines...specifically, the 550 series.  Maybe I’m lucky with my maintenance routine, manage the engine correctly, or both, because I’ve never had any issues arising from poor engine construction, management or maintenance.

4 hours ago, johnhoge said:

I'm looking at a nice Ovation but one thing that concerns me is that all 6 cylinders have been replaced between 900 and 1500 hours. I've seen the Mike Busch seminar warning about the perils of cylinder work and find it a bit troubling that all 6 jugs went bad.

Is this something that is common with the IO540? Is it a sign of careless engine operation? Would the prudent course of action be to put the old beast of it's misery and go straight to a full engine overhaul?

John, I would investigate the logs more closely on the Ovation you’re looking at.  There are many reasons why an owner would choose to top an engine...not all are suspect.  More background info would paint a better picture here and help answer your questions.

Steve

Edited November 25, 2020 by StevenL757
Edits acknowledging Phil’s numbers after I read more carefully.

[carusoam]

Depending on how you like to fly your plane...

Mooney pilots have two choices for operation... both are acceptable.

1) Fly efficiently... save those cylinders...

• LOP
• At higher altitudes, WOT
• 65%bhp or less
• When climbing ROP, set the FF extra rich...

2) Fly quickly... exchange those cylinders

• ROP
• At lower altitudes
• > 65% bhp
• AKA Flaming Dragon Mode

An IO550 can get to TBO on one set of cylinders... but, it takes some dedication...

In raw numbers a set of cylinders is expensive....

In overall numbers... so is hangar fees...

So... Choose how you want to operate... And set your CHT goals... a good engine monitor is really helpful... knowing how to use it can take some learning...

The two operations are both clearly documented in the POH... so there isn’t any hocus pocus magic to figure out... wondering if all the LOP prosthelytizers are trying to get you to join their religion...

There can be one challenge when buying a used Mooney... how do you know it has been flown LOP, or in Flying Dragon Mode?

Buying a high end plane is full of challenges... this is just one of them...

Best regards,

-a-

 

Go O!

 

[MooneyMitch]

My former Ovation engine performed 2400 hours without any cylinder change.  At time of overhaul, compressions were in the mid 50’s range.  Oil consumption was approximately 15 hours per quart.

The previous owner flew that engine approximately 240 hours per year, lean of peak, full throttle in cruise, maximum 2500 RPM.

During my ownership, I continued the same operating parameters.

My opinion based on my experience....... fly your 550 often, LOP.

[philiplane]

Just to clarify, my observations are based on 25 years with Continental engines. primarily in fleet environments. Engine data indicates the engines are mostly LOP, except for full rich pattern work, and ROP climbs from sea level to 4000 feet or so. And in conjunction with two high volume engine shops that turn out 150-200 engines per year, plus thousands of cylinder repairs. The design of Continental cylinders predisposes them to premature wear. Because the pushrods are on the bottom, less oil gets to the valve springs and stems. This results in less exhaust valve guide cooling, and causes higher wear on the rotocoils that rotate the valves to equalize wear and keep the seats clean. This is why Continentals are more likely to have exhaust valve failure at mid-life. They also suffer from excessive blow by of the rings, mostly due to the plain steel bores. Microscopic rust occurs after every shut down. Lycoming nitrides their bores to prevent this.

If you have a Continental engine go 2000+ hours with no cylinder work, it's an outlier, and mostly due to luck of the draw. If you fly every week for several hours, you have much better odds than the typical 100 hour per year flier. That said, fleet airplanes operating 600+ hours annually rarely get more than 900-1000 hours from new cylinders. The new Continental nickel cylinders are better, but they are rare and haven't been out long enough to develop a real service history. I have one 2015 IO-550N engine with 1900 TT, and 800 hours on new nickel cylinders. They are still doing well, at the same hours the original cylinders were already junk.

Edited November 25, 2020 by philiplane

[StevenL757]

Appreciate the context and detailed info.

Any ideas on the OPs questions, or is more info needed?

[johnhoge]

How are the IO360s in the J models by comparison? 

[philiplane]

3 hours ago, johnhoge said:

How are the IO360s in the J models by comparison? 

The IO-360 in the J model is a Lycoming, and they have very few cylinder problems in comparison. 

[MooneyMitch]

13 hours ago, MooneyMitch said:

My former Ovation engine performed 2400 hours without any cylinder change.  At time of overhaul, compressions were in the mid 50’s range.  Oil consumption was approximately 15 hours per quart.

The previous owner flew that engine approximately 240 hours per year, lean of peak, full throttle in cruise, maximum 2500 RPM.

During my ownership, I continued the same operating parameters.

My opinion based on my experience....... fly your 550 often, LOP.

Out of fairness to this discussion, and to acknowledge @philiplane excellent information, and having his information jog my possibly age related memory laps, the 550 I inherited did indeed have some TLC just after its factory new beginnings. 

Now that I embarrassingly recall, my previous owner struck one prop tip during his initial days of owning the Ovation, with the less than 100 hours on that brand new factory powerplant.... yikes, darn it all is probably what he said.  

Anyway, off came the engine and up to Firewall Forward it went.  No internal damage was discovered, but FF did some TLC rework of things, including the 6 cylinders and associated stuff.

So, in truth, and I apologize for being accidentally misleading, the TCM factory new cylinders did not go the full 2400 hours as I previously stated.  They did however perform marvelously for 2300 after the FF massaging.

 I think that’s still quite a tribute to all......mechanical and operational techniques and lots of airplane flying time, and not sitting idle a lot.

Would the non-touched TCM factory cylinders have gone the distance?  I don’t know. 

[larryb]

One can always download the engine monitor data to see how the previous owner flew at least the most recent hours.