Field overhaul vs. Corona Aircraft Engines

[par]

As my C approaches TBO,I have the option of a field OH that will save me a substantial amount of money (>5k) when compared to using Corona Aircraft engines out in CA. This is considering the worst case scenario of needing a new crankshaft and camshaft. 

So, my first questions is, does anyone have a PIREP on the shop in question? I did a search on here but did not come up with anything positive or negative about Corona A/C. Second question, how much value will I potentially lose for doing a field OH vs shipping it off to a shop? No matter which way I go, I'm going to go with factory cylinders and will be doing all accessories and fuel system as well. If I go the field OH route, I can get the prop OH'ed as well. Please share your thoughts on this delima.

[Andy95W]

Unless we're talking about a factory new, 0 time engine, it has always been my experience that after 100-200 hours, name brand shop overhauls don't really affect value or buyer perceptions.  I'd much rather see the prop overhauled.

[M20F]

If I knew or spoke to the AI who did the field overhaul and it had 100-200hrs on it than I probably would prefer that to a shop.  I field overhauled mine because I wanted to be involved in the process and knew the person doing it. 

[slowflyin]

Here is a Don Maxwell opinion.

http://www.donmaxwell.com/publications/MAPA_TEXT/Field Overhaul/Having Your Engine Overhauled In The Field.htm

[Jim Peace]

The engine in my 64c was done by Corona about 750 hours ago by the prior owner of my plane.  So far so good with great oil reports.  Using aeroshell 15w50.  The cylinders were replaced about 300 hours after overhaul by Corona due to an AD.  Not due to anything Corona did......

I have been to their shop several times just to say hello while at the airport for other reasons.  The people there seem nice and I would not hesitate to use them.....

 

 

[stevesm20b]

I had Corona hone and re ring cylinders for me. They do good work and their prices are reasonable.

[PTK]

What's the difference beteeen OEM vs. PMA besides cost?

Are there any parts that only should be OEM?

My experience is limited to my engine. It's a factory reman by Lycoming and therefore genuine OEM.

It has been great to me. Everything about it is perfect. Never a hickup. Not one. Most importantly, when I fire her up for a flight I trust it. Should and would I feel the same with field oh utilizing PMA parts? I don't know.

[NotarPilot]

I don't have any personal experience with them but their rates seems reasonable. I do notice a good number of planes advertised for sale stating their engines were overhauled by Corona Aircraft Engines which leads me to believe they must have a fairly decent reputation if they have that much business. When the day comes for me to overhaul my engine I will likely go with Corona.

[par]

11 hours ago, Jim Peace said:

The engine in my 64c was done by Corona about 750 hours ago by the prior owner of my plane.  So far so good with great oil reports.  Using aeroshell 15w50.  The cylinders were replaced about 300 hours after overhaul by Corona due to an AD.  Not due to anything Corona did......

I have been to their shop several times just to say hello while at the airport for other reasons.  The people there seem nice and I would not hesitate to use them.....

 

 

My initial impression of their operation was very good, even though it was just over the phone. They provided me with all the info I wanted and did not seem annoyed or in a hurry to get off the phone. Hearing good things about them from you all certainly gives me confidence in their ability to do the job well. Even though they are completely across the country from me, I will most likely take my mooney there as well, if I decide to go the shop route.

 

[NotarPilot]

Without knowing anything about your engine I have to wonder why you're planning an overhaul. Are you planning based on it approaching 2,000 hours or are there other factors involved? If your engine is still showing signs of good health you might want to listen to a webinar by Mike Busch called "TBO and Beyond" and read some of his articles about engine TBO. You may find you don't need one yet and every hour flown past TBO are like free hours.

EAA Webinar TBO and Beyond

How risky is going past TBO

Debunking TBO

[MHemperly]

A guy I know at my home field is currently having a bad experience with corona engines. 6 months ago dropped it off along with 10k cash to start and as of last week the engine had only been taken apart. Not sure if this is the way they do business but it's good to know ahead of time. 

Mike

[Jim Peace]

On July 25, 2016 at 4:40 AM, MHemperly said:

A guy I know at my home field is currently having a bad experience with corona engines. 6 months ago dropped it off along with 10k cash to start and as of last week the engine had only been taken apart. Not sure if this is the way they do business but it's good to know ahead of time. 

Mike

There has got to be more to this story.  Did you find out more?

[N9201A]

Thanks for posting DMax article. Extremely informative.

[MHemperly]

4 hours ago, Jim Peace said:

There has got to be more to this story.  Did you find out more?

He did get his engine back and they did a great job. I didn't poke anymore on what the hold up was. But their work is great and he is happy. 

[tony]

The OEM is the only company that can zero time your engine.  Everything else is a field overhaul. So if you have the knowledge, time, and experience of doing it yourself, then I would go with that.  That way you, as the pilot who's butt is going to be sitting in the plane, working with your A&P gets to decide what part you want replaced and what part you can live with if its within tolerance. 

Edited September 12, 2016 by tony

[glafaille]

Do you keep accurate records of REAL flight time or are you going by the tach?  No need to overhaul just because your tach says so.  Tachs lie, 2000 hours on the meter does not always mean you have 2000 hours on your engine.  Maybe you do and maybe you don't.  

I've been flying for years and just learned that a tach hourmeter is accurate ONLY at a specific RPM.  Any RPM lower or higher will cause the meter to run fast or slow.

Why not find a more reliable way to determine the condition of your engine as others have mentioned.  Oil samples, boroscope, operating performance etc.

[cliffy]

It really comes down to how well the overhaul is done and documented. It's not difficult but paying attention to each and every detail in the overhaul manual is vital to a good outcome.

I've had cylinder work done by Corona and have had no problems. I did my own overhaul (O-360) 800 hrs ago and haven't had a bit of problems.

I sent the case to Divco for cert. Used new Lyc cylinders, new cam and lifters. All parts magnafluxed/replaced per Lyc overhaul requirements and each and every part was documented by part# and/or s/n.

How many engines has your field guy done?

Here's a question to ask him-

Is your torque wrench in calibration date? Prove it, show me the calibration sticker.

If it hasn't been calibrated then maybe he's not the one to do the overhaul.

Look at the shop area where he will do the work. Is neat and clean? Or, is it a trash pit?

Talk to a few who have had their engines done by whom ever. You might learn a lot.

One thing to remember, if you break it in on the airplane and you don't have your engine instruments calibrated beforehand it can't be signed off as an overhaul, only a repair, as the overhaul instructions specifically require run in with calibrated instruments.(let the arrows fly!)

I strongly also recommend that you follow Lycs break in program to the letter. The Feds have hammered some shops/A&Ps for using something other than the manufacture's break in procedures. Make sure the break in program is logged in the engine log book. The more documentation the better the resale will go if you need to sell.

[N201MKTurbo]

10 minutes ago, glafaille said:

Do you keep accurate records of REAL flight time or are you going by the tach?  No need to overhaul just because your tach says so.  Tachs lie, 2000 hours on the meter does not always mean you have 2000 hours on your engine.  Maybe you do and maybe you don't.  

I've been flying for years and just learned that a tach hourmeter is accurate ONLY at a specific RPM.  Any RPM lower or higher will cause the meter to run fast or slow.

Why not find a more reliable way to determine the condition of your engine as others have mentioned.  Oil samples, boroscope, operating performance etc.

Yes, but the tach is counting revolutions of the engine. I think that might be the most reliable measure.

[Guest]

41 minutes ago, tony said:

The OEM is the only company that can zero time your engine.  Everything else is a field overhaul. So if you have the knowledge, time, and experience of doing it yourself, then I would go with that.  That way you, as the pilot who's butt is going to be sitting in the plane, working with your A&P gets to decide what part you want replaced and what part you can live with if its within tolerance. 

The only real "zero" time engine is a new one.  The factory zeros the log book on "reman" engines because they are a hodge lodge of parts assembled from disassemble engines.  The log book represents the data plate which is riveted to the oil sump, they do not provide documentation telling you if the parts are new or used or how many hours each component has.

At least with a field overhaul you will know details of the parts and who did what to them.

Clarence

[gsxrpilot]

1 hour ago, N201MKTurbo said:

Yes, but the tach is counting revolutions of the engine. I think that might be the most reliable measure.

The point is that TBO is based on hours, not revolutions of the engine. And further, the tach time is a calculation of time based on a specific RPM, and not a count of revolutions. But then of course, TBO is just a wild guess made by the manufacturer. So any number you use, is probably as good as any other number.

[N201MKTurbo]

15 minutes ago, gsxrpilot said:

The point is that TBO is based on hours, not revolutions of the engine. And further, the tach time is a calculation of time based on a specific RPM, and not a count of revolutions. But then of course, TBO is just a wild guess made by the manufacturer. So any number you use, is probably as good as any other number.

The tach odometer absolutely counts revolutions of the engine. There is a gear train that goes from the cam shaft through the tach cable to the tach odometer. There is nothing calculated about it. the calculation is from revolutions to time. If you know the gear ratio of the tach, which you can look up. you can tell with absolute precision how many times the engine has gone around sense the tach was installed.

[glafaille]

The point is that the manufacturer recommends maintenance at specific hourly intervals, the tach does not record flight hours except at a specific RPM.  Therefore the hours displayed on the tach do not precisely represent the hours on the engine.  

The tach shows an approximation of  engine hours.  It would be prudent to more closely monitor the condition of the engine when the tach suggests the overhaul is approaching.

Alternatively, one could record the flight time of every flight, and then calculate actual hours on the engine. 

The tach hours could be off by several hundred hours by the time an overhaul interval is reached.  Other indications could be used to confirm the necessity of an overhaul.

[MB65E]

Get a quote from Pacific Continental at Whitman. John Jackson has been building engines his entire life.

I'd also give Lycon a call. Both great shops. 

Between the three shops, you'd be well ahead of yourself. 

When your engine goes thru 5 nose seals, or the plunger for the fuel pump didn't fit because Divco added too much metal, or the case cracks because it wasn't torqued properly, or he didn't know about xyz SB and you now need to split the case....is your field overhaul guy going to back you up? 

There is not much margin with shops these days. How they make their money is they do things right because they have done thousands of engines before yours. I'd pick the shop that you think would be around at your next overhaul not this coming OH! Trust me, you IA doesn't want to field overhaul your engine. Have you asked him? I'm sure he said he could, and he thinks he can save you money, but does he really want to?

-Matt

p.s I field overhauled mine myself. With the guidance of Pacific Continental.  150hrs, runs great, learned a lot, probably do it again with what I know now. However. It took me about 7 months, I didn't know about all of the SB's PCE told me about, and yes, I did go thru 5 nose seals.

 

[Guest]

How many engines really make it to the recommended TBO anyway?  Most privately run engines have some sort of failure longer before TBO, so the number is meaningless.

Clarence

[cliffy]

Most engines don't make TBO for reasons other than who did the overhaul.

Most of the time it is because the engine sat around and rusted for 20 years trying to get TBO hours.

There's a reason why Lyc will go for 2200 hrs for TBO, IF YOU USE IT UP IN A HURRY, but only 2000 if you take your time.