Continental IO-550 G Overhaul

[Pieter]

Hello ,

My Ovation 2 has 2.300 hours since new. it is in for an annual and compression is down on two cylinders!

Do the overhaul now and my plane will be down for most of the summer or re-do the two cylinders and [plan an overhaul somewhere mid-winter?

I do have a Harzell 3 blade Top prop and is it possible to do the 310 Hp upgrade at the same time with the overhaul?

[Openwheeler3]

Pieter, I'm by no means an expert but there is a lot of experience on this board. Welcome! I suggest you search all of the threads about overhaul and some others may respond to this post as well.  Bottom line is just because you have a couple of bad cylinders doesn't mean you need to overhaul the entire engine. 

[carusoam]

Are the cylinders 2300 hrs since new?

Depending on how the cylinders have been run,  some get swapped out earlier than others.  Run gently LOP while maintaining CHTs, cylinders last a long time.  Running 50° ROP at high power settings cylinders don't make it to TBO...

An important thing to consider, prior to OH of a Continental engine...

The Compression reading method can be misleading.  It takes a lot of effort to get the compressions actually read.

Also, the compression numbers that are considered normal are much lower than the equivalent Lycoming numbers.

Since you are at 2300hrs, how is the oil usage?

When taking photos of the interior of the cylinders how do the 'bad' two compare to the others?  People take cylinder photos now using a camera sent down the spark plug hole.

 

When you decide to go OH, consider the factory reman route.  I got the 310hp (n) update in place of the (g).  Delivery took two weeks compared to the two months that the TopProp took.  STCs & tach adjustment for 2500 vs 2700rpm redline.  I added some other steps to include mount inspection and cowl work and paint.

It is a few days of work spread out over a month to get it all done.

Last question...  Is this your first set of cylinders?  Or has there been an OH of the cylinders along the way?

somebody has recently posted a photo of an IO550 cylinder head with an exhaust valve that had stopped rotating...  

 

These are PP ideas.  I am not a mechanic.

Best regards,

-a-

[M20F]

I would retest the compression on the cylinders and if truly bad replace.  I would examine internals with a borescope while the cylinders were removed and if the cam/crank looked good I would keep flying it.  I don't know about Continentals but for a Lycoming the cylinders need to be worked as part of an overhaul.  

I did all the work of an overhaul on mine but put on a 4hr old cylinder and thus my engine is repair/return.  If your intent is resale in the near future that could impact selling price, but there is no practical difference in reality. 

[Guest]

10 hours ago, Pieter said:

Hello ,

My Ovation 2 has 2.300 hours since new. it is in for an annual and compression is down on two cylinders!

Do the overhaul now and my plane will be down for most of the summer or re-do the two cylinders and [plan an overhaul somewhere mid-winter?

I do have a Harzell 3 blade Top prop and is it possible to do the 310 Hp upgrade at the same time with the overhaul?

Verify that your shop is testing per SB03-3.

http://www.continentalmotors.aero/xpublications/xservice bulletins/pdfs/sb03-3/

Clarence

[Pieter]

12 hours ago, carusoam said:

Are the cylinders 2300 hrs since new?

Depending on how the cylinders have been run,  some get swapped out earlier than others.  Run gently LOP while maintaining CHTs, cylinders last a long time.  Running 50° ROP at high power settings cylinders don't make it to TBO...

An important thing to consider, prior to OH of a Continental engine...

The Compression reading method can be misleading.  It takes a lot of effort to get the compressions actually read.

Also, the compression numbers that are considered normal are much lower than the equivalent Lycoming numbers.

Since you are at 2300hrs, how is the oil usage?

When taking photos of the interior of the cylinders how do the 'bad' two compare to the others?  People take cylinder photos now using a camera sent down the spark plug hole.

 

When you decide to go OH, consider the factory reman route.  I got the 310hp (n) update in place of the (g).  Delivery took two weeks compared to the two months that the TopProp took.  STCs & tach adjustment for 2500 vs 2700rpm redline.  I added some other steps to include mount inspection and cowl work and paint.

It is a few days of work spread out over a month to get it all done.

Last question...  Is this your first set of cylinders?  Or has there been an OH of the cylinders along the way?

somebody has recently posted a photo of an IO550 cylinder head with an exhaust valve that had stopped rotating...  

 

These are PP ideas.  I am not a mechanic.

Best regards,

-a-

Cylinders are 2300 hrs since new. Since I bought this Ovation (1300 hrs.) I ran it LOP!

Oil usage appr. 13 hrs/ quart.

Two years ago #2 cylinder is worked on (overhaul?)!

Thank you,

regards Pieter

[Jeff_S]

Pieter, you've gotten some good advice already. If you haven't before, you should look up articles from Mike Busch on "condition-based maintenance" to get his thoughts on if/when to overhaul. The short version: do the inspections as others have noted above, and let the results of these inspections guide your decision. Sounds like you've been a good operator of this engine to get it to 2300 hours including original cylinders, so it could be that all you need is some cylinder work and you're back in action.

[Yooper Rocketman]

14 hours ago, M20Doc said:

Verify that your shop is testing per SB03-3.

http://www.continentalmotors.aero/xpublications/xservice bulletins/pdfs/sb03-3/

Clarence

I was going to suggest the same thing.  I had a couple cylinders that wouldn't pass until I used the orifice tool several years ago.  Last year those cylinders were in the low 60's.  This year they were down in the low 50's and I was thinking it wasn't going to be long (well over TBO).  After my speed run to Florida, I decided to compression check again and both those lower cylinders went up 10 and 12 lbs respectively, with nothing lower than 64 lbs.  That just goes to show you the compression test is very subjective.  I believe the recent 12 hours of flight time in hot weather actually helped "seat the rings" a bit.  The leakage, in my case, was clearly not valves as they will not get better with more hours on them.

Tom

[Pieter]

19 hours ago, Yooper Rocketman said:

I was going to suggest the same thing.  I had a couple cylinders that wouldn't pass until I used the orifice tool several years ago.  Last year those cylinders were in the low 60's.  This year they were down in the low 50's and I was thinking it wasn't going to be long (well over TBO).  After my speed run to Florida, I decided to compression check again and both those lower cylinders went up 10 and 12 lbs respectively, with nothing lower than 64 lbs.  That just goes to show you the compression test is very subjective.  I believe the recent 12 hours of flight time in hot weather actually helped "seat the rings" a bit.  The leakage, in my case, was clearly not valves as they will not get better with more hours on them.

Tom

This morning I heard that one cylinder is back on an acceptabel compression level and the zero cylinder has a valve problem which will be repaired in the next couple of days.

Then I will be back in the air in approx two weeks!

Thank you guys for the reactions, It was great value for me!

Regards Pieter!

One question left, about upgrade 310 Hp.

Is there a change in the motor or only on the prop governor of the Top Prop (increase RPM 2500 to 2700)?  

[Jeff_S]

Pieter, there's no change to the engine. The prop governor is increased to 2700 RPM max, and depending on what equipment you've got installed you may need some placard changes and the like. You're a pre-G1000 plane so you shouldn't have to worry about adding a second tachometer. 

[gsengle]

And having the right prop... I think the acclaim type prop is an option now

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[Pieter]

Is it correct that my Harzell 3 blade top prop is the correct prop for the 310 Hp upgrade?

[carusoam]

The 310hp STC lists props by model number...

The TopProp for the O comes in at least three designs:

- thick blades

- thin blades  (acclaim prop?)

- composite blades

The fun part of paying for the STC was the ability to ask these questions.  Bob Minnis was the go to guy for a complete run down on the pluses and minuses of each choice.

personal choice of weight, ruggedness, or performance, of rotational momentum/flywheel effect....

Fun stuff...

Best regards,

-a-

[gsengle]

Is it correct that my Harzell 3 blade top prop is the correct prop for the 310 Hp upgrade?

Probably not unless you upgraded from original.

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[gsengle]

http://hartzellprop.com/hartzell-aluminum-composite-top-props-now-available-various-mooney-models/

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[Godfather]

You have the correct prop.  All you need is a different governor and to adjust the fuel flows.  A new tach is necessary if you are lacking a tso' jpi or ei guage.  The $5k stc paperwork is available from mooney.

I just had mine overhauled at 2500 hours...it was running like new.  However, it was a convenient time, I fly a lot of IFR, and I'm planning on another 15+ years of ownership.

[Guillaume]

Be sure that you don't want to put your aircraft under an EASA registration in the next few months as the 310hp STC is *not* EASA approved.