TBO IS HERE

[Garrett Jacob]

The TBO is here for my grandparents Comanche 260 and i was wondering if you had any advice for me i could possibly give to them regarding weather or not Overhaul or Rebuild is the way to go!

[N3322G]

Garrett,

Lots of pros and cons to various approaches. Wrote an article about our experience and it is posted on this website at http://www.comancheflyer.com/NS/tech_ar ... erhaul.pdf

I would also suggest taking as much time selecting the shop that removes and installs the engine as you do the O/H shop if you go that way becasue they take on a lot of responsibility for the engine accessories such as vacuum pump, oil cooler, mags, hoses etc.

Most people overhaul.

Hope this helps.

[JIMICS2452]

Check out his webinar by Mike Busch titled "When to Overhaul". He has some interesting thought and good information on engine overhauls and TBO. He is a past FAA AMT of the Year and a long term mainteance advisor for the Cessna Pilots Association. This is on the EAA website.

http://www.eaavideo.org/video.aspx?v=1429764450001

Jim Hiatt

[David Pyle]

Garrett,

Are your grandparents members of ICS? Do you fly their Comanche 260? Who pays for the work? These are some of considerations that influence the advice you get and what they do. It often comes down to the engine cost, plus overall condition and the projected future of the airplane. Cost can vary from $20K for a creditable new limits field overhaul to $40K+ for a new engine. Location is a factor. I would seek the experience of owners with the late model 260's. There are also others whose opinions I trust...Pat Barry in the West and Charlie Melot in the East. I personally prefer a close facility where they can do the out/in and the overhaul. (Usually saves money.) Gives you the opportunity to make one source responsible for all the work. Like 'one stop shopping'...

[Kristin Winter]

When you say "rebuilt", do you mean factory rebuilt or do you mean overhaul to new limits which is the FAA definition of rebuilt?

The answer as to what to do with an engine at TBO depends greatly on how the plane is being used, projections of future use, risk tolerance, and financail condition. We are going to need some more input. Where is the aircraft based?

[David Pyle]

Kristin,

Great minds...etc.

Garrett is in Glendora CA. Don't know where the airplane is.

[Alan Cheak]

Garrett:

I too am fast approaching the magic 2000 hours of TBO. My plan is to run the engine a bit beyond TBO as the enginge is still running well and not making any metal. Last time I checked with Van Bortal (they are now a Lycoming dealer) the cost of a reman O-540 was around $33K. This of course has the new rollar tappet techonology, and is a wide deck engine. Adding the accessories plus overhauling the prop can easily add up. I also plan on sending my engine mount down to KOSOLA in Georgia. Average work can be around $2500. Then there is the cost of taking out the old engine and putting in thenew. All total I'm figuring around $40K for a new reman will all the bells and wistles. On the other hand if I go overhaul it would be less. If I go this route I'd be looking at ZEPHYER, no questions.

In the end I have to ask do I want to sink 40 grand plus in to a new engine that will definitely last the life of the airplane or maybe save a few bucks here and there but will still get the job done. In the end I figure general aviation has about 30-40 years left at best. Less if AVGAS keeps skyrocketing and the administration starts adding on fees every time you raise the gear handle. Makes me think one word, NORDHAVN. If you think aviation is expensive, try yachting. Will be watching this thread with interest as I'd like to hear others thoughts as they approach TBO.

Sincerely,

Alan

[Jerry Fitzgerald]

From the factory:

Lycoming Engines IO-540-D4A5

ENPL Number ORT6926

New

List Price: $82,946
Core Value: $17,600
Exchange List Price: $65,346
Discount Amount: $11,462

You Pay: $53,884
Payment: $653.48/Mo.
+ Add to Cart

Rebuilt

List Price: $62,262
Core Value: $17,600
Exchange List Price: $44,662
Discount Amount: $7,739

You Pay: $36,923
Payment: $447.78/Mo.
+ Add to Cart

Overhauled

List Price: $57,994
Core Value: $17,600
Exchange List Price: $40,394
Discount Amount: $6,971

You Pay: $33,423
Payment: $405.34/Mo.
+ Add to Cart

Engine Specifications
Aircraft application: PIPER PA-24-260
Alternator: ALX-8421-LS
Volts: 12
Horsepower: 260
Starter: ELECTRO, MZ-4222 (Starter Included on Factory New Engines Only)
Fuel Pump: LW-15473
Engine Mount Prep: DYNAFOCAL
Thermo Bypass Valve: 53E22144
Prop Governor DR Location: L FRONT


Flying my 260 to Tulsa today to have Chuck Ney install one of his rebuilts for $33K ($30K for engine, $3K installation).

[Michael Rath]

[BSAND47]

Garrett -

As you know, TBO is not mandatory. If the engine is running strong, cool, and dry, what's the
hurry to split the case?

My 1964 IO-720 has 1900 TTSN (TBO is 1800), and never been split. Earlier this year it developed a
compression problem in #1 cylinder. So, popped the cylinder, sent it to Zephyr (who did a great job
repairing it), re-installed it and engine running as good as ever. When it starts making metal or blows oil
or any other evidence that it's time, then a decision will be made to either overhaul it (most likely using
Zephyr) or, if it's a couple of years from now, just sell it and leave GA (another issue entirely but a
consideration nonetheless for us grandpa types with bum knees!).


Bill
PA-24-400

[Kristin Winter]

One small word of caution on waiting until the engine makes metal before overhauling. There are two possible outcomes to that which are not good. One is that you may turn the crankshaft into a mailbox post. I am guessing that IO-720 cranks are not cheap, and may not be readily available. Worse would be that the disintegrating bearing shifts and covers the oil passage on one of the journals and then the crank seizes when the unlubricated bearing and journal weld themselves together. Depending where the airplane is when that happens, things could get really regrettable in a hurry.

That is not to say you can't go past TBO, but I wouldn't wait for bearing metal in the suction screen to tell me when it is time to overhaul either.

[Michael Rath]

Statistics show that you have a better chance of turning that $$$$$ crankshaft into a mailbox post right after overhaul. Engines usually talk to you before things go terribly wrong. I would say that if you go over or even near TBO, oil analysis is manditory if you have not done so already. Most likely you will see signs of trouble before things go wrong.

My good friend on the field just spent close to 40k to have his AEIO-540 overhauled by a very reputable shop that we would all know the name of. It was running perfect before overhaul. From day one after the overhaul he had high oil temperatures. At ten hours they found a small amount of metal in the filter. They told him to fly it another 15 then check again. At 25 hours after major it was making even more metal. It is currently on a shipping truck headed back to the engine shop!

[Kristin Winter]

Do you know where I could view those statistics that you reference? I know that infant mortaility is an issue with engines, but haven't seen the statistics.

Thanks!

[Michael Rath]

Check out the link below: http://www.avweb.com/news/savvyaviator/ ... 241-1.html


If you scroll down to "SHOW ME THE DATA" you will see a study done by Dr. Nathan Ulrich Ph D. He is a mechanical engineer and also a Bonanza owner. The results are pretty surprising.

I am in no way saying an engine will run forever but in my opinion the 2000 TBO is meaningless. Why not overhaul once your engine reaches 12 years SMOH? That is also manufacture recommended as well.

If someone posted on this site and said that they had a great running O-540 but it is 13 years SMOH and they were sending it off for major we would all tell him or her that they were crazy to do so. However, if you presented the same situation but the engine had 1950 SMOH we would all be recommending overhaul shops. I just don't see a difference between the two situations. An overhaul should be based on condition not some arbitrary number.

[Kristin Winter]

I would offer qualified agreement with Busch's thesis. Running safely over TBO requires some reasonably sophisticated monitoring. Not all owners are really equipped to do that. I plan to push past TBO, but I watch my engines like a hawk. I am in the process of doing my second 400 hour valve inspection. A lot of Lycoming owners don't do that. I monitor oil pressure, have a graphic engine monitor, cut filters, check screens, do oil analysis, borescope the engines, and will pull a cylinder in a heartbeat if a valve is leaking and staking won't solve the problem.

I know operators that fly these engines way over TBO safely, but then usually the aircraft are flying every day. Most of us don't fly that much. For the average pilot with average equipment, and an average attention span, TBO is probably a valid time to think about overhauling the engine.

As for the statistics, I found them interesting, but not really enough data there to assess the validity. I do think that the first couple of hundred hours are somewhat more dangerous as human error on the part of the engine shop is a reality. But so too is swallowing a valve on Lycoming engines that are higher time. Those may, or may not show up in the statistics as a lot of those make it back to the airport. I once swallowed a valve on a Navajo on approach into MSP. I didn't know it until I touched down and the engine wouldn't idle. I was a little busy on the low mins ILS to be too cognescent of what the engines were doing.