Let’s talk about a serious procedure. Calling big bore Turbo engine operators !

[goodyFAB]

Good evening everyone ! 
 

I am hoping to hear from fellow Mooney operator / owners. specifically, operators of  big bore continentals. tsio520’s- or similar.  I’m looking for real life feedback from other operators that can share their experiences with cylinder life and top overhauls. 
 

How long do you expect to get out of a set of cylinders ? Time in service ?

How long have you gotten before needing cylinders ? What symptoms made you remove cylinders ?

Is it common to do a top overhaul on such engines ?

As an owner/operator how do mitigate the risk associated with choosing the right shop to perform a top overhaul? 

My inquiry would only apply to map turbo systems, which produce the same boost at sea level or at the service ceiling. Not turbo normalized engines which have a much easier life. 

finally, can you share your experience with top overhauls ? 

Thank you -
 

 

 

[slowflyin]

16 hours ago, goodyFAB said:

Good evening everyone ! 
 

I am hopping to hear from fellow Mooney operator / owners. specifically, operators of  big bore continentals. tsio520’s- or similar.  I’m looking for real life feedback from other operators that can share their experiences with cylinder life and top overhauls. 
 

How long do you expect to get out of a set of cylinders ? Time in service ?

How long have you gotten before needing cylinders ? What symptoms made you remove cylinders ?

Is it common to do a top overhaul on such engines ?

As an owner/operator how do mitigate the risk associated with choosing the right shop to perform a top overhaul? 

My inquiry would only apply to map turbo systems, which produce the same boost at sea level or at the service ceiling. Not turbo normalized engines which have a much easier life. 

finally, can you share your experience with top overhauls ? 

Thank you -
 

 

 

Good afternoon,

I may not be the best to answer as I don't fly a Continental.  My Bravo has a Lycoming TIO-540 and my Skylane has a Lycoming IO-540 with Cessnas bolt on Turbo.  Since no one else has responded here ya go:

How long do you expect to get out of a set of cylinders ? Time in service ?

Bravo ran to TBO.  About 2100 hours.  Skylane 1400 hours (previous owner)

How long have you gotten before needing cylinders ? What symptoms made you remove cylinders ?

Above

Is it common to do a top overhaul on such engines ?

Not unheard of on the Lycoming's but I wouldn't call it routine.    Others can comment on the Continentals.  

My inquiry would only apply to map turbo systems, which produce the same boost at sea level or at the service ceiling. Not turbo normalized engines which have a much easier life. 

finally, can you share your experience with top overhauls ? 

What would you like to know?

 

 

 

[goodyFAB]

1 hour ago, slowflyin said:

Good afternoon,

I may not be the best to answer as I don't fly a Continental.  My Bravo has a Lycoming TIO-540 and my Skylane has a Lycoming IO-540 with Cessnas bolt on Turbo.  Since no one else has responded here ya go:

How long do you expect to get out of a set of cylinders ? Time in service ?

Bravo ran to TBO.  About 2100 hours.  Skylane 1400 hours (previous owner)

How long have you gotten before needing cylinders ? What symptoms made you remove cylinders ?

Above

Is it common to do a top overhaul on such engines ?

Not unheard of on the Lycoming's but I wouldn't call it routine.    Others can comment on the Continentals.  

My inquiry would only apply to map turbo systems, which produce the same boost at sea level or at the service ceiling. Not turbo normalized engines which have a much easier life. 

finally, can you share your experience with top overhauls ? 

What would you like to know?

 

 

 

Thanks ! 
Seems like the more I look into it, the tsio520 uses cylinders. 
the lycomings seem to go much further on cylinders than the bb continentals. 
 

curious about other owners- 

then again, not many moneys use the turbo continental. 
 

 

 

[mcarterak]

2 hours ago, goodyFAB said:

Thanks ! 
Seems like the more I look into it, the tsio520 uses cylinders. 
the lycomings seem to go much further on cylinders than the bb continentals. 
 

curious about other owners- 

then again, not many moneys use the turbo continental. 

No Mooneys had TSIO-520. That's like a Turbo 210 engine. Bravos have the Lycoming TIO-540, and the Acclaim has the Continental TSIO-550.

[goodyFAB]

The rocket conversion does , quite a few rocket guys on MS.
The 550 in the acclaim is very similar.


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[exM20K]

14 minutes ago, goodyFAB said:

The rocket conversion does , quite a few rocket guys on MS.
The 550 in the acclaim is very similar.


Sent from my iPad using Tapatalk

Dunno if I’d call them similar: TSIO520 is bottom induction and single (?) turbo.  TSIO550 dimensionally a stroked TSIO520 but with top induction and 2 turbos and intercoolers vs 1 (?).  The top induction seems to make the 550 more easily capable of LOP OPS.  TBO is also higher for the 550 for those that care about such things as TBO.

Which leads to your questions….. it is the received wisdom of enlightened piston aviators that LOP is kinder to the top end than ROP. If there is a higher percentage TSIO 550 hours done LOP vs the TSIO520, then “our” liturgy favors 550 cylinder life.

Here in the real world, disuse probably kills more engines or top ends than how you operate it. My one datapoint is the disuse-induced corrosion on my cylinders when I bought the plane.  When oil consumption fell below 4hrs per quart, I had all six cylinders overhauled.

CMI has had issues with improperly ground valve seats in the past.  This is probably the same for both the 520 and 550 and has lead to many a cylinder coming off for leakage past the exhaust valve and burned valves. I dunno if their fancy new machine tools have corrected this deficiency. 
 

I did and would again overhaul one or more jugs on condition. They will tell you when they are done and usually without catastrophic failure.  Burnt exhaust valves and low compression, corrosion and high oil consumption, cylinder/ring wear with high oil consumption, a pressurized crankcase blowing oil out of the breathers. These are all good reasons to fix one or more jugs. A borescope and careful attention to changes in oil consumption are your ally here.

How to make sure the shop does it right and doesn’t kill you with a spun bearing after leaving a through bolt finger tight? Good question.  Showing up a few times in the morning with a box of donuts or a pizza lunch can’t hurt. After my top, I found a dead EGT probe, a wrench sitting on top of one of the intercooler, and chased a MAP lapse issue that was finally diagnosed as as a cut in the MAP line going to the G1000 sender.  It was cut when the tech snipped a zip tied bundle of wires sitting on top of it.

oh, and I hit a bird in the pattern on the first test flight. Obviously that wasn’t the shop’s fault, and we’re still friends.  Me and the shop, not me and the bird.
 

bake a mid time top into your cake economically, and maybe you’ll be pleasantly surprised.  The cost and downtime aren’t nothing, but neither are they life-changing.

-dan

[goodyFAB]

2 minutes ago, exM20K said:

Dunno if I’d call them similar: TSIO520 is bottom induction and single (?) turbo.  TSIO550 dimensionally a stroked TSIO520 but with top induction and 2 turbos and intercoolers vs 1 (?).  The top induction seems to make the 550 more easily capable of LOP OPS.  TBO is also higher for the 550 for those that care about such things as TBO.

Which leads to your questions….. it is the received wisdom of enlightened piston aviators that LOP is kinder to the top end than ROP. If there is a higher percentage TSIO 550 hours done LOP vs the TSIO520, then “our” liturgy favors 550 cylinder life.

Here in the real world, disuse probably kills more engines or top ends than how you operate it. My one datapoint is the disuse-induced corrosion on my cylinders when I bought the plane.  When oil consumption fell below 4hrs per quart, I had all six cylinders overhauled.

CMI has had issues with improperly ground valve seats in the past.  This is probably the same for both the 520 and 550 and has lead to many a cylinder coming off for leakage past the exhaust valve and burned valves. I dunno if their fancy new machine tools have corrected this deficiency. 
 

I did and would again overhaul one or more jugs on condition. They will tell you when they are done and usually without catastrophic failure.  Burnt exhaust valves and low compression, corrosion and high oil consumption, cylinder/ring wear with high oil consumption, a pressurized crankcase blowing oil out of the breathers. These are all good reasons to fix one or more jugs. A borescope and careful attention to changes in oil consumption are your ally here.

How to make sure the shop does it right and doesn’t kill you with a spun bearing after leaving a through bolt finger tight? Good question.  Showing up a few times in the morning with a box of donuts or a pizza lunch can’t hurt. After my top, I found a dead EGT probe, a wrench sitting on top of one of the intercooler, and chased a MAP lapse issue that was finally diagnosed as as a cut in the MAP line going to the G1000 sender.  It was cut when the tech snipped a zip tied bundle of wires sitting on top of it.

oh, and I hit a bird in the pattern on the first test flight. Obviously that wasn’t the shop’s fault, and we’re still friends.  Me and the shop, not me and the bird.
 

bake a mid time top into your cake economically, and maybe you’ll be pleasantly surprised.  The cost and downtime aren’t nothing, but neither are they life-changing.

-dan

yes sir , single turbo on the tsio520. the log manifold on the tsio520 is not the best @ LOP operations. I am aware of the 550's differences, i meant similar in the sense of the cylinders are essentially manufactured the same, similar overhaul times, and therefore maybe similar enough to compare to ? maybe not- they are twin turbo and the tsio550 tuned manifold does an amazing job allowing LOP operations, i believe your correct that LOP operations may be kinder since the 550's seem to "go further".

after asking around with some well respected engine shops more than a couple times now ive been told the TSIO520 is the kind of powerplant that requires a top or so to get to TBO. i was just curious how other operators handle top overhauls since the internet is full of "failure after top overhauls", and mike busch has published content basically saying you should never do a top overhaul. 

i am thinking CMI has fixed their cylinder issues and a balanced pack from the factory would be the preferred cylinders. 

thanks! 

[Lois]

I am in the process of doing a top end on my rocket. They went 100 hours past TBO.  The failure that precipitated the rebuild was a cracked exhaust port on #3. It warped the exhaust flange. Parts and timelines for repair have been brutal. Rocket rebuilt the exhaust. Main Turbo overhauled the turbo. Overhauled nickel cylinders from Sal in Prosper. Controller was overhauled and all the required consumable parts/gaskets from RAM in Waco. Turbo was impossible to get rebuilt for about 4 months and it took an additional 3 for the cylinders. Exhaust valves were hard to come by and intake valves were impossible. I hope the supply chain has eased up for you. We found the cracked cylinder as part of an avionics upgrade so Garmin supply chain issues have further delayed progress. It’s in its third set of servos and has not flown yet. My plane is at a non Mooney repair facility so that also delays things a bit.  Their parts guy did not have a good parts supplier so I did the research for him. It saved me thousands in parts by me doing it. If you are in the planning phase I recommend getting ALL the parts ahead of time and schedule with your preferred MSC otherwise otherwise I recommend an investment in aspirin, Miller Lite, and TUMs.  Good luck. 

[A64Pilot]

No Mooney experience but in my limited experience with Turbo Continentals is the cylinder’s life span if flown frequently is directly related to how hard and Hot they are run. If MP and RPM are the same LOP is lower power and that means cooler and that I believe significantly increases life.

I think it’s pretty simple, significantly increase power and you run hotter and harder and those decrease life. TANSTAAFL 

It’s the price of going fast, want longer life? Slow down and run LOP. That’s true for NA engines too.

Biggest reason car engines last so long is they are operated at such a low power almost all of their life, it’s not that they are superior to aircraft engines. Run a Sportfisherman at high power and they don’t last long either.

Oh and it’s my opinion that if you take brand new cylinders to a GOOD cylinder guy and get them to replace and HONE valve guides and do a good 5 angle valve job that it’s not uncommon for them to go to TBO, but if you take them out of the box and install them it’s very likely they won’t.

I think a good overhaul to the above procedures will last longer than new as well.

Edited August 3, 2023 by A64Pilot

[M20F]

My experience is a TSIO-370 in a 320.  In 25yrs of flying it we never had issues getting 1500-2000 out of the cylinders and one of the engines was about 3000 total time.  It flew 75-100hrs a year.  
 
Boost is what eats cylinders up more than anything in my experience (especially true with no intercooler where you are pumping extremely hot air into the cylinders).  4hrs running 32” is a lot harder on things then running at 26” using the turbo more as a normalizer to restore power versus adding it.  

A friend just picked up a Seneca and he never uses full boost on take off as example unless it is hot and heavy.  For just him can easily and safely get off with 30-32”.  Then he just uses it as a normalizer in climb/altitude.

Run it with a lot of boost for a lot of hours you are going to replace cylinders.  Just a question of which is more important dollars or 10kts. 
 
In my F there is no possibility of LOP at altitude the CDT is just too hot.  Lots of richness and never had an issue with it or cylinders.  I am on about 800hrs on my current set. 

You see the same thing in cars.  Run 10+lbs a lot you are going to be redoing things more often than you would like.  
 

[goodyFAB]

1 hour ago, A64Pilot said:

No Mooney experience but in my limited experience with Turbo Continentals is the cylinder’s life span if flown frequently is directly related to how hard and Hot they are run. If MP and RPM are the same LOP is lower power and that means cooler and that I believe significantly increases life.

I think it’s pretty simple, significantly increase power and you run hotter and harder and those decrease life. TANSTAAFL 

It’s the price of going fast, want longer life? Slow down and run LOP. That’s true for NA engines too.

Biggest reason car engines last so long is they are operated at such a low power almost all of their life, it’s not that they are superior to aircraft engines. Run a Sportfisherman at high power and they don’t last long either.

Oh and it’s my opinion that if you take brand new cylinders to a GOOD cylinder guy and get them to replace and HONE valve guides and do a good 5 angle valve job that it’s not uncommon for them to go to TBO, but if you take them out of the box and install them it’s very likely they won’t.

I think a good overhaul to the above procedures will last longer than new as well.

That’s interesting , 

what is wrong with the continental valve guides ?

good points made !

[A64Pilot]

25 minutes ago, goodyFAB said:

That’s interesting , 

what is wrong with the continental valve guides ?

good points made !

I don’t know for a fact, but a few that have visited the factory claim the guides are pressed into place and then drilled out and valves installed, they aren’t even reamed.

Reaming is a type of drill, it’s used when only a very small amount of metal is required to be removed but you want a smooth and accurate sized hole. Drill is a sledgehammer, reaming is better controlled, honing is the finest controlled. If you want serious accuracy and a fine controlled finish, but have to have a hole that’s very close to finished size, you hone. Honing is of course what’s done as a finish for the cylinders because boring just isn’t nearly good enough.

I have friends that ream every hole for rivets they are so anal for example, then deburr every hole. They even refrigerate the rivets so they fit tight, that’s something Consolidated did to PBY hulls back in the day to get a watertight hull. It’s all about if your willing to spend time on perfection, or does production rate rule.

Very good overhaulers like Carlos Gann hone the guides to size, this ensures a hole that’s concentric to the valve seats and size is tightly controlled, a tight fit prevents wobble of course, cools the valve more as more is in contact with the guide and the tight tolerance helps prevent coke build up in the valve guide that leads to sticking valves, but it’s time consuming and time is money.

Edited August 3, 2023 by A64Pilot

[WilliamR]

1 hour ago, goodyFAB said:

That’s interesting , 

what is wrong with the continental valve guides ?

good points made !

1. seats and guides are laser cut rather than honed
2. rotocoils break thus ending the valve rotation

 

[exM20K]

2 hours ago, A64Pilot said:

Oh and it’s my opinion that if you take brand new cylinders to a GOOD cylinder guy and get them to replace and HONE valve guides and do a good 5 angle valve job that it’s not uncommon for them to go to TBO, but if you take them out of the box and install them it’s very likely they won’t.

I agree 100%.  It’s sad that factory new parts need to get worked to last.

[geoffb]

What procedure are you referring to? 

If you're asking for what to expect, I think most Rocket (and 231 owners) would tell you to budget for a mid time set of cylinders and a turbo overhaul at 1,000 hours.  Maybe you get lucky on the cylinders, maybe you don't, but continental cylinders seem to be softer than Lycomings and the valve train is laughable.

[1980Mooney]

7 hours ago, Lois said:

 I recommend getting ALL the parts ahead of time and schedule with your preferred MSC otherwise otherwise I recommend an investment in aspirin, Miller Lite, and TUMs.  Good luck. 

I am curious why you recommend an MSC for engine work on a Rocket 305. Firewall forward, it had almost nothing in common with a factory Mooney. The turbocharged 305 hp Continental TSIO-520-NB and McCauley three-blade propeller combination had long been used as standard on the twin-engined Cessna 340 and 414. The engine mount is proprietary to Rocket Engineering and is much more complex and costly than the factory 550 mounts (and way more labor intensive to work on/remove/replace.)  Also the oil filled tubulars on the mount get progressively thinner with 3 thicknesses - the smallest amount of corrosion can render them non-airworthy.  As you said Rocket still repairs them - at considerable cost and time for shipping and refurb.  

@goodyFAB might be better served asking the Top O/H and cylinder questions on a Cessna Twin Owners site or talking to RAM who are specialists in these particular engines. 
 

[Lois]

Mooney shops (at least shops with a lot of Mooney experience) already have a level of knowledge dealing with the idiosyncrasies of the brand. Otherwise you’re paying for them to learn on the job. 

[Lois]

The 3 Mooney shops I have worked with are all familiar with Rockets and Missles. . 

[Lois]

I would agree talking to RAM is worthwhile also. They are very helpful as well as knowledgeable. 

[1980Mooney]

1 hour ago, Lois said:

The 3 Mooney shops I have worked with are all familiar with Rockets and Missles. . 

My point was that I suspect that when contemplating an Overhaul or what will likely be a $20,000 +/- Top Overhaul, many would consider the big-bore Continental experience/reputation of the shop first and knowledge of Mooney idiosyncrasies second.
 

As @exM20K highlights above, how they reassemble the engine, retorque thru bolts etc is absolutely critical.  The best Continental engine shop in your region may or may not be an MSC. It’s just a consideration - one of many that an owner will grapple with. 

[goodyFAB]

 

3 hours ago, 1980Mooney said:

I am curious why you recommend an MSC for engine work on a Rocket 305. Firewall forward, it had almost nothing in common with a factory Mooney. The turbocharged 305 hp Continental TSIO-520-NB and McCauley three-blade propeller combination had long been used as standard on the twin-engined Cessna 340 and 414. The engine mount is proprietary to Rocket Engineering and is much more complex and costly than the factory 550 mounts (and way more labor intensive to work on/remove/replace.)  Also the oil filled tubulars on the mount get progressively thinner with 3 thicknesses - the smallest amount of corrosion can render them non-airworthy.  As you said Rocket still repairs them - at considerable cost and time for shipping and refurb.  

@goodyFAB might be better served asking the Top O/H and cylinder questions on a Cessna Twin Owners site or talking to RAM who are specialists in these particular engines. 
 

RAM has been a great wealth of information since this engine is literally plucked from a 340 and transplanted onto the m20k

ram also has some really good options for replacement. 

 

RAMs legendary engine is a long lead time ( over 6 months)  but their value time with nickel cylinders is attractive in price and lead time. still waiting to talk to their service department about topping said engine.

[goodyFAB]

4 hours ago, geoffb said:

What procedure are you referring to? 

If you're asking for what to expect, I think most Rocket (and 231 owners) would tell you to budget for a mid time set of cylinders and a turbo overhaul at 1,000 hours.  Maybe you get lucky on the cylinders, maybe you don't, but continental cylinders seem to be softer than Lycomings and the valve train is laughable.

The procedure would be to top overhaul… 

theres a lot of information out there that points to catastrophic failure after cylinder replacement. 

[goodyFAB]

10 hours ago, WilliamR said:

1. seats and guides are laser cut rather than honed
2. rotocoils break thus ending the valve rotation

 

Hmmm 

seems odd- 

laser cut guides with no team or hone? As a fabricator/machinist that seems insane. No ream? No sizing? Laser cut and go?

 

how does a good valve job eliminate roto-coils ? 
 

RAM uses either a nickel overhauled CMI CYLINDER . Or a superior millennium. 
mom not impressed with superior. I don’t know if cmi would be better. 

[goodyFAB]

10 hours ago, exM20K said:

I agree 100%.  It’s sad that factory new parts need to get worked to last.

 

13 hours ago, A64Pilot said:

No Mooney experience but in my limited experience with Turbo Continentals is the cylinder’s life span if flown frequently is directly related to how hard and Hot they are run. If MP and RPM are the same LOP is lower power and that means cooler and that I believe significantly increases life.

I think it’s pretty simple, significantly increase power and you run hotter and harder and those decrease life. TANSTAAFL 

It’s the price of going fast, want longer life? Slow down and run LOP. That’s true for NA engines too.

Biggest reason car engines last so long is they are operated at such a low power almost all of their life, it’s not that they are superior to aircraft engines. Run a Sportfisherman at high power and they don’t last long either.

Oh and it’s my opinion that if you take brand new cylinders to a GOOD cylinder guy and get them to replace and HONE valve guides and do a good 5 angle valve job that it’s not uncommon for them to go to TBO, but if you take them out of the box and install them it’s very likely they won’t.

I think a good overhaul to the above procedures will last longer than new as well.

Who does cylinder work like that? 
 

maybe drop shipping a set of cylinders makes sense !

[aviatoreb]

My rocket TSI520NB engine had about 1400 hrs on it when I was forced to remove 6 perfectly good ECI Titan cylinders due to an AD and put 6 new ones which I got from Victor because I had them do the multi-angle valve job described here.  Now I am at about 1950 hrs.