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Posted

I know that virtually all GB engines in K models have been converted to LBs, but apparently not all. Does anyone know what is involved in the conversion.

Also, what kind of a hit is the owner of a 231 with a GB going to take at the time of sale, vs one which has been converted.

Posted

Higher serial numbered 231's can be converted to the MB (that's the 262 conversion), I don't know about the SB , but I am not aware of anyone having an STC to convert to an SB.  Probably you could do it if you have a few hundred thousand in spare change for the approval process, but then why wouldn't you just buy an Encore?  I am not sure that the holder of the STC for the 262 conversion still does it, either.  You can't just drop a different engine in without an STC or 337, and I doubt that a FSDO would do it on a 337.  

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Posted (edited)

For Don, There was a recent thread on this very topic but of course not titled as such, but I think the OP was asking about engine replacement. He provided a couple quotes from engine rebuilder(s) that didn't seem to be significantly higher than if he was already rebuilding a LB versus a GB. In fact, I got the impression he didn't realize the GB's were dead. I was impressed by that because some significant things changed like the entire induction system which I thought would appreciably raise the rebuild cost. But I think the best answer to your question is to make quick call to a large engine rebuilder like Western Skyways to get a quick quote and verify for yourself. They've done this a lot

As to what kind of a hit you would take on resale, I think that would entirely depend on 2 things, how many residual engine hours you would have at sale time and how savvy the new buyer is if its not a run out or near run-out engine. 

As for Kevin's -  LB to the SB? No, that is not possible; never was. John is right on about it being no longer possible to even go to the -MB because that was only authorized by couple different STC's neither of which is available any longer.

But going from a -MB to -SB is easily doable since no STC is required; (as long as the airframe was originally a 252 -MB, converted 262 are not eligible). Nor does it take a new -SB engine. The -MB engine is easily converted to the -SB engine configuration.  But you can't just convert the engine either, you have to upgrade the airframe as well.

Edited by kortopates
Posted
6 hours ago, kortopates said:

For Don, There was a recent thread on this very topic but of course not titled as such, but I think the OP was asking about engine replacement. He provided a couple quotes from engine rebuilder(s) that didn't seem to be significantly higher than if he was already rebuilding a LB versus a GB. In fact, I got the impression he didn't realize the GB's were dead. I was impressed by that because some significant things changed like the entire induction system which I thought would appreciably raise the rebuild cost. But I think the best answer to your question is to make quick call to a large engine rebuilder like Western Skyways to get a quick quote and verify for yourself. They've done this a lot

As to what kind of a hit you would take on resale, I think that would entirely depend on 2 things, how many residual engine hours you would have at sale time and how savvy the new buyer is if its not a run out or near run-out engine. 

As for Kevin's -  LB to the SB? No, that is not possible; never was. John is right on about it being no longer possible to even go to the -MB because that was only authorized by couple different STC's neither of which is available any longer.

But going from a -MB to -SB is easily doable since no STC is required; (as long as the airframe was originally a 252 -MB, converted 262 are not eligible). Nor does it take a new -SB engine. The -MB engine is easily converted to the -SB engine configuration.  But you can't just convert the engine either, you have to upgrade the airframe as well.

I am the OP of the thread...I absolutely realize the GB is a rare bird and I am one of the few still flying behind one. I also realize the GB to LB upgrade includes new throttle body, better induction and a couple of other things...that said, I provided quotes which would automatically upgrade a GB to an LB...My GB is a "hot runner" but running it LOP keeps the CHT's below 380 degrees....

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Posted
7 minutes ago, 231LV said:

I am the OP of the thread...I absolutely realize the GB is a rare bird and I am one of the few still flying behind one. I also realize the GB to LB upgrade includes new throttle body, better induction and a couple of other things...that said, I provided quotes which would automatically upgrade a GB to an LB...My GB is a "hot runner" but running it LOP keeps the CHT's below 380 degrees....

It must be a little bit of an adventure running that aircraft out of a home base like Sedona.  I bought my 231 (LB engine) in Scottsdale, and when we flew it home the mechanic that had just done the annual there had set the fuel flow up wrong.  We could only get 19+ GPH out of it at full power, full rich.  Had to make the climb due north.  The ground temp at PHX was above 100.  We could not climb faster than about 300 fpm without roasting the engine.  We saw some remarkable CHT's on that flight.  I have long since gotten the fuel flow sorted out and it is much better, but taking off from one of those northern AZ fields when the OAT is 100 and teens would still be interesting.  

Posted
It must be a little bit of an adventure running that aircraft out of a home base like Sedona.  I bought my 231 (LB engine) in Scottsdale, and when we flew it home the mechanic that had just done the annual there had set the fuel flow up wrong.  We could only get 19+ GPH out of it at full power, full rich.  Had to make the climb due north.  The ground temp at PHX was above 100.  We could not climb faster than about 300 fpm without roasting the engine.  We saw some remarkable CHT's on that flight.  I have long since gotten the fuel flow sorted out and it is much better, but taking off from one of those northern AZ fields when the OAT is 100 and teens would still be interesting.  

This is a good reminder to all 231/252 pilots out there to check your FF on every takeoff run. That is something that was engrained in my head from flying twin Cessna's. Glad it worked out for you.

I also have a GB in my 231, I even have one of those non-VAR cranks. Still running strong but it's going to be a pricey overhaul for someone. I think a crank is >$6k.



Sent from my XT1030 using Tapatalk

Posted

  I am also still behind the original GB(3) in my 231K.  Not a hot runner at all in my case though.  No aftermarket wastegate or intercooler.  Just under 1600 hours TTSN AF and eng.  Has had all new cylinders put on ~160 hours ago by PO.

 

24.5gph @36"-39" x 2700rpm on takeoff roll. Climb out at 33"-35" x 2600-2700 approx 110-120kias with TIT 1430-1440

 I run the engine somewhat conservatively in cruise as I'm not yet in a big hurry to get anywhere.  In the middle of instrument training right now so flying a bit slower gives me a little more room to be out in front of the airplane and adds more time to the lessons (which I need anyways).

 

Ron

 

 

  • 3 years later...
Posted
2 hours ago, Maden said:

Can a GB engine be converted to and LB in the field? If so what is required and what is the estimated cost of materials?

 

Read up on Mike Bush as he recommends against field overhauls as they seem to have more infant mortality failures than an overhaul shop does and who needs that headache later?

Posted
30 minutes ago, Will.iam said:

Read up on Mike Bush as he recommends against field overhauls as they seem to have more infant mortality failures than an overhaul shop does and who needs that headache later?

Actually any overhaul that is not done by the factory is a "Field Overhaul" I think you're suggesting an overhaul is best done by a specialty "engine shop" that specializes in engine overhauls - which is good advice.

The OP should call around to various engine shops since their ability to source the new required induction parts and others is going to weight heavily on the final cost. But others here have found shops that did it quite reasonably. A little googling of the topic will find many of these posts here in Mooneyspace - that include cost.

Posted
On 4/22/2017 at 7:01 AM, 231LV said:

I am one of the few still flying behind one.

I also fly a GB :-) 
It is possible to fly this version without any problems if you are careful enough to handle it.
The engine even reached more hours than the TBO specified. It has now been rebuilt, again in the original GB condition. 

 

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  • 2 weeks later...
Posted
On 3/7/2021 at 12:37 AM, HB-JAN said:

I also fly a GB :-) 
It is possible to fly this version without any problems if you are careful enough to handle it.
The engine even reached more hours than the TBO specified. It has now been rebuilt, again in the original GB condition. 

 

hmmm....not  really sure why it was rebuilt as the original GB...kind of like overhauling an Iphone 1 instead of buying the Iphone 10 but it may have been a monetary issue...in any event, the engine is no different than the LB...just runs hotter. You run it LOP to keep the CHT's down...avoid running it 50ROP at full power...at full power, run  it at full rich. TBO can be easily reached if heat is controlled...with new engine monitors, the rate of top overhauls should start dropping compared to running these engines with a single temp probe

Posted (edited)
3 hours ago, 231LV said:

hmmm....not  really sure why it was rebuilt as the original GB...kind of like overhauling an Iphone 1 instead of buying the Iphone 10 but it may have been a monetary issue...in any event, the engine is no different than the LB...just runs hotter. You run it LOP to keep the CHT's down...avoid running it 50ROP at full power...at full power, run  it at full rich. TBO can be easily reached if heat is controlled...with new engine monitors, the rate of top overhauls should start dropping compared to running these engines with a single temp probe

Only one that can change it from a GB to an LB is Continental.

Continental changes every GB they get into a LB. No one else can.

not a lot of difference between the 2 versions. MB on the other hand is a big difference.
 

or so I was told when I had my GB magically transformed into a TSIO520NB.

 

Edited by RJBrown
Posted
1 hour ago, RJBrown said:

Only one that can change it from a GB to an LB is Continental.

Continental changes every GB they get into a LB. No one else can.

not a lot of difference between the 2 versions. MB on the other hand is a big difference.
 

or so I was told when I had my GB magically transformed into a TSIO520NB.

 

LY-CON overhauled my TSIO-360-GB. They offered me the option of rebuilding it as the original GB  or the upgraded LB....I opted for the LB and got the logbook entry showing the engine as a TSIO-360-LB and the engine data plate was stamped to show it as an LB

Posted (edited)
14 hours ago, RJBrown said:

Only one that can change it from a GB to an LB is Continental.

Continental changes every GB they get into a LB. No one else can.

not a lot of difference between the 2 versions. MB on the other hand is a big difference.
 

or so I was told when I had my GB magically transformed into a TSIO520NB.

 

Actually any A&P can convert an a GB to LB, they just need access to the different LB parts to replace and make it a conforming LB - then stamp the data plate that it was converted from a GB to LB as mentioned above - the stamp shows its a conversion. Although not necessary, I also filed a 337 when I converted my MB to a SB. But my conversion required much less changes than a LB!

Edited by kortopates
Posted (edited)

When my GB had issues at 1200 hours in 1994 I was told that Continental automatically updated every GB to an LB when they did a “zero time” factory overhaul. I was told that field overhauls did not change the data plate. Only Continental could do that. Updated parts could be used but it was still a GB and still had the original time and serial number. I was unaware that anyone could modify a data plate beside the manufacturer. 
If the data plate can be changed who has the authority to modify a data plate. This changes my understanding of who can create and who can modify a data plate.
Is there someone here that can state with authority (an IA or AP) an answer to this question.

Thanks for any opportunity to learn.

Edited by RJBrown
Posted (edited)
9 hours ago, RJBrown said:

When my GB had issues at 1200 hours in 1994 I was told that Continental automatically updated every GB to an LB when they did a “zero time” factory overhaul. I was told that field overhauls did not change the data plate. Only Continental could do that. Updated parts could be used but it was still a GB and still had the original time and serial number. I was unaware that anyone could modify a data plate beside the manufacturer. 
If the data plate can be changed who has the authority to modify a data plate. This changes my understanding of who can create and who can modify a data plate.
Is there someone here that can state with authority (an IA or AP) an answer to this question.

Thanks for any opportunity to learn.

Sorry but lots of miss-information above, likely from marketing folks perhaps wanting to sell you a new engine. Conversion is commonly done, see: http://www.tcmlink.com/pdf2/M75-6R1.pdf   

The only thing the manufacturer can do that an A&P can't do is set the clock back to 0 since New with a "Rebuilt" engine - which is a factory overhaul to new limits. Any one else can also overhaul to new limits, but it won't reset the time since new to zero, only time since major overhaul.  But also, the factory isn't rebuilding your engine, their bulding up an engines mixed new and used parts of unknown time the concept of conversion doesn't even apply.  Where as a field overhaul is overhauling your engine. Lastly you don't have to overhaul an engine to convert it, only change out the parts that make it conform to the desired model. 

Edited by kortopates
Posted

Thank you Paul.

I don’t like to spread disinformation. When not sure I try to post my source. In this case a 25 year old memory of “what I was told”

The GB to LB conversion became unimportant to me as I had the plane converted to a Rocket instead of dealing with the GB.

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