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jonnyboy

Long Ez TBO Hour Requirements

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I'm looking for a little help on a few questions about Long Ez engine hours. I'm looking into the purchase of my first plane and have found a few planes with several different engines hours.What is the TBO for an Lycoming 0-235-L. One plane that I have interest in has 2000 hours on the engine and had a top overhaul 500 hours ago. Millenium high compression cylinders were installed during this overhaul. The engine has compression ratings in the mid to high 70's with no corrosion or wear. I'm look for advice on what to expect in the engine for useful life and when a major overhaul may need to be performed.

 

Thanks!

 

Jon

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My C-152 has the Lycoming 0-235-L2C and it is now at a little over 2500 hours. The comps are all in the upper 70's and it uses about a quart of oil every 40 hours. The L2C's have been known to be very durable engines and have been known to go WAY past the 2400 hour TBO. I fly alot which is good for the engine. I change the oil every 40 hours and I got a differential compression tester to monitor the comps. I also have the oil analyzed at oil changes to let me know whats going on inside the motor.

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Could it be that the engine had a complete overhaul when the new cylinders were installed? That would be the normal thing, I think. The crank and cam could have been ground undersized and new bearing installed, new oil pump gears installed, etc. That sort of thing essentially brings it back to zero time but it ain't cheap.

 

If so, you could now consider it a 500 hour engine (good). If new cylinders were installed without reconditioning the bottom end, that wouldn't make much sense to me.


-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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The owner says that he did a top overhaul replacing the cylinders with Millenium high compression cylinders (SL10302-A20P) making the engine an O-235-J. From a little digging around on the internet it actually looks like this would have reduced the TBO from 2400 to 2000. Does this seem correct? I know this is another beginner questions but how does the TBO work? Can you continue flying the engine past TBO if it is good condition? Do you need a mechanic to review the engine on a hour mark or just annually if you are over TBO?

 

Just trying to decided if the Long Ez is priced correctly and what the engine might be like for the next 200 -400 hours. I would be very grateful it anyone would like to take a look at the ad and give me their thoughts.

 

Thanks!

 

Jon

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Pretty simply put, if the engine has been modified, or even simply de-certified, the TBO requirement no longer exists. The Repairman or the A&P that conducts the Condition Inspection can determine that it is perfectly acceptable to continue flying well past TBO if he or she so chooses. So, as far as regulations are concerned, there is no requirement to adhere to TBO.

 

Now, that said, the manufacturer (Lycoming) sets a TBO for a reason, and we have to assume that reason is other than making money on re-mans. So, at 2000 hours they expect that enough wear has taken place to require an overhaul. In your case, if you're purchasing this aircraft, you should consider how many hours you will be able to fly before you need to overhaul the engine. If the engine currently has 2000 SMOH, it is, by Lycoming standards, run-out. You should consider the cost of a rebuild and figure that into the purchase price.


Kevin R. Walsh & Michael Antares

Cozy Mk-IV #413

N753CZ

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Pretty simply put, if the engine has been modified, or even simply de-certified, the TBO requirement no longer exists....

Everything Kevin said about what Lycoming intended is true, but modified or not (there's no such thing as "de-certified"), there is no requirement to do anything to an engine that is not used for commercial purposes just because it reached some arbitrary hour limit.

 

In other words, unless the airplane is being rented (or something equivalent commercially), you can run it as long as you want, no matter what the TBO is - the TBO in that case is merely advisory. Many people run their engines well past TBO.

 

I would be very grateful it anyone would like to take a look at the ad and give me their thoughts.

What ad?

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Lycomings generally get overhauled because of something in the top end--valve wear, excessive oil consumption (rings), stuff like that. Since you've got a low-time top end, you might expect the engine to go for a while yet. Personally, if the airplane has been flown regularly and had regular oil changes, I would price it like a 1000 hour engine and hope to get another 1000 hours out of it (10-20 years of flying). That would be 3000 hours on the crank and cam. I presume they inspected the cam lobes when they replaced the cylinders. It would have been easy to do.

 

Lycoming has an AD to check for internal crankshaft sludge and pitting.

http://www.lycoming.textron.com/support/publications/service-bulletins/pdfs/SB530B.pdf

You'd want to make sure that was done. A reconditioned replacement crank is $3500-4000.


-Kent
Cozy IV N13AM-750 hrs, Long-EZ-85 hrs and sold

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