Incorporating a used engine

Hi, All; I understand the ramifications of what I'm about to ask, but was looking mainly for actual experiences from other builders.

Has anyone ever placed a used certificated engine as-is on their project, without rebuilding it? (well, removing the data plate to de-certify it...) As an example, I've been able to find mid-time engines salvaged from hail-damaged planes. No prop strike, etc. Aside from changing the oil/filter, checking the plugs, etc., and assuming good compression, why not just slap it on your airframe and go with it?

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Originally Posted by CarlOrton

Hi, All; I understand the ramifications of what I'm about to ask, but was looking mainly for actual experiences from other builders.

Has anyone ever placed a used certificated engine as-is on their project, without rebuilding it? (well, removing the data plate to de-certify it...) As an example, I've been able to find mid-time engines salvaged from hail-damaged planes. No prop strike, etc. Aside from changing the oil/filter, checking the plugs, etc., and assuming good compression, why not just slap it on your airframe and go with it?

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I've done it twice, an O-320 (Cessna 172) on the RV-6 in 1998 and more recently an O-200 (Cessna 150) on the Fokker replica. I left the data plate on both engines. Just keep in mind it is a bit of a roll of the dice because you don't have first-hand knowledge of the internal condition of the engine. If the engine has been inactive or infrequently flown in recent years there may be issues with corrosion. But if you purchase the engine at a good price where you can afford overhaul if necessary down the road, it can be a reasonable option.

Why would you remove the data plate?

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Originally Posted by DaleB

Why would you remove the data plate?

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OK; was just going by memory here, and that sometimes fails.... I was under the impression that even if installed in an E/AB aircraft, the engine still had it's certification, and would therefore have to have only "approved" parts otherwise it could be deemed unairworthy. Personally, I don't care if the plate's on it or not, as long as I can add any ol' nut or bolt I want from the aviation department of Lowes (and I would never do that; except to perhaps attach a ground cable, and even then I'd think about it...)

My opinion is that I would rather use a tired old but still running OK engine on a first flight than a freshly overhauled one. The well used engine won't surprise you with infant mortality failures, and can better survive poor baffling & other cooling problems. Corrosion problems in the cylinders (assuming a reasonable inspection) won't cause a catastrophic failure - just high oil consumption. Once you got the other test flight wrinkles straightened out, go ahead and overhaul it. But expect the engine to run hotter until it is broken in. Just make sure the outside is reasonably clean so it can cool, and so you can spot oil leaks.

I view that as a valid aspect that I know about, but hadn't considered in this context. Thanks for the reminder!

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Originally Posted by nrpetersen

My opinion is that I would rather use a tired old but still running OK engine on a first flight than a freshly overhauled one. The well used engine won't surprise you with infant mortality failures, and can better survive poor baffling & other cooling problems. Corrosion problems in the cylinders (assuming a reasonable inspection) won't cause a catastrophic failure - just high oil consumption. Once you got the other test flight wrinkles straightened out, go ahead and overhaul it. But expect the engine to run hotter until it is broken in. Just make sure the outside is reasonably clean so it can cool, and so you can spot oil leaks.

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This can bite one in the rear end, though.

One of my EAA brothers bought what was billed as a "moderately high but sound" engine and had to perform a landing under stress on flight number three. Subsequent tear down showed it was in much worse shape than advertised; while the compression was good, the main bearings looked like termites had their way with them.

I'd say a tear down inspection before first flight is probably prudent if the engine isn't a completely known quantity.

I could tell several horror stories about "used" engines that looked great in the logs but were junk inside, but to answer the question; Absolutely not. Did that once 30 years ago. Nearly cost me my life when that "low time" engine packed it in at night in the mountains some 79 hours later. That "low time" engine was full of obsolete and superseded unairworthy parts, one of which failed. I made myself a promise then that I would never again have an engine on my plane that I didn't tear down and inspect first. If you want to fly behind an unknown pile of junk, have at it.

I am familiar with Frank's friend and his engine as well. That story was typical of the "good used engines" that look great in the logs being bought and bolted on to Homebuilts. Rarely does it work out good. A few I know have done OK with a used engine, but most have ended up with a pile of junk parts and an overhaul in the first 150 hours or less. Just bite the bullet and do the overhaul up front so you know exactly what you have on the front of your plane. Breaking in an engine just isn't that difficult, even on a new plane. Or if you buy a manufactured engine, the hard part of the break-in has already been done in a test cell under controlled conditions.

The last used engine I bought (O-320) for my SuperCub project I found when I was asked to do a logbook review of the engine for someone that wanted it for their aircraft. Man, it looked great on paper at a very reasonable price and I recommended it as a good buy based on a logbook review that showed nothing irregular over the life of the engine. Life took another turn for him, and he couldn't use it. I asked if it would be OK with him if I bought it for my project and he agreed. First run engine a few hundred hours short of run out. Perfect engine to bolt on the plane after building, run a couple of hundred hours while I recover from the initial cost of building. I was really tempted, but decided to tear it down for inspection anyway. I found: cracked crankshaft, out of spec and cracked case, corroded cam followers and spauled cam, 4 cylinders that had been overheated so bad the cylinders were blue inside and all 4 heads cracked. I am so thankful that my customer didn't buy it on my recommendation. And I had nothing more than a pile of junk parts in need of a lot of new parts to build an engine.

While tempting, I'm thinking that if it weighs on my mind every time I'm flying, it's not worth it. Definitely worth a tear-down.

The thing is that a tear down is not a rebuild, unless necessary, and inexpensive. And with the right guidance isn't that difficult.

My initial thoughts on the logic that it's better to put an unknown on the aircraft in order to be sure it flies okay than spend the money and find the aircraft is a dog in flight was that it was kind of screwy were validated.

But hell, I strapped a VW engine on my plane so I never faced the financial challenges of a certified engine. I was poor mouthing the fact that I had to spend 200 bucks on a new crankshaft and another 200 on a new prop hub when I flipped my bird only to be politely told to hush up...and got a few prices for minor things on an O-200.

Some assumptions and blanket statements have been made in this thread that are unfortunate. One is that all used engines are unknown and a piece of junk. While there are certainly engines on the used market that should not be flown, the educated buyer can greatly reduce the odds of an unhappy experience. An engine with a well-documented history and recent time in the air should still be airworthy on a fresh airframe. After all, when we buy a used aircraft......we are getting a used engine and many used aircraft are happily flown by new owners.

But not all builders will want to go this route and that is ok.....builder's preference. In the first twenty years of the RV fleet very few new engines were installed in new builds. That has changed as the average cost of a new RV approaches six figures. Yes, there is some risk in installing a used engine, but it can be managed as can all the other risks associated with flying. Putting a 20 thousand dollar engine on a ten thousand dollar airframe is not going to be a viable option for all builders.

Frank, $200 will buy you a brand new gasket set for a Lycoming or Continental. ;)

The only blanket statement I made is that I wouldn't do it again. I've seen way too many "well documented engines" that looked great in the logs, but were a pile of junk inside. I think I also said that it does work out for some. IMHO, it's kind of like playing Russian Roulette and I'm not real big on gambling.

It's not about the value of the airframe. It's about the value of the person in the aircraft. Crashing a $5,000 airframe can be just as fatal as crashing a $200,000 airframe. Many times used engines work out just fine. Just understand that until you look, you don't really know what you have on the front of your plane. Personally, the 8 adrenalin filled minutes it took me to nurse my plane into an airport at night with a disintegrating engine was more than enough time for me to consider the value of the $$ I had saved by buying a used engine that looked great on paper. I came very close that night to leaving my young wife as a widow with two young boys to raise on her own. It changed my attitude towards the value of what is written in the logs vs the value of opening up the engine and inspecting the insides for myself.

The good news is that most aircraft engines are quite robust and usually fail gracefully in that if you listen to what the engine is telling you it will usually tell you it is in distress before it fails. In retrospect, had I been listening better, my failed engine had been telling me it was in trouble. I just hadn't learned the language yet and was missing the clues.

-Cub Builder
A&P
Former Tech Counselor
Former Flight Advisor

I don't fly at night anymore. Too many close calls, the risk isn't worth it.

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Originally Posted by Bill Berson

I don't fly at night anymore. Too many close calls, the risk isn't worth it.

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Me either. Only had one close call (that I know of...) but I don't have any flights that must be flown at night.

When you stop to think about it, everyone flys a used engine. it's simply matter of how much trust you have in it. How did your brand new engine gain your trust? by tearing it down or flying it?

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Originally Posted by Tom Downey

When you stop to think about it, everyone flys a used engine. it's simply matter of how much trust you have in it. How did your brand new engine gain your trust? by tearing it down or flying it?

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I don't think anyone is saying not to buy a used engine and use it; just that "buyer beware" is something to take very serious.

Loads of questions should be asked, and the fewer that can be answered, the more caution should be used.

For example, I know some folks that if I bought an engine from them and they said it was in good shape that would be good enough for me...I'd bolt it on and crank it. But from a stranger? Not so much.

Especially if I spent seven or ten years building the firewall back - I'd take a bit more and check the engine closely.

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Originally Posted by CarlOrton

(well, removing the data plate to de-certify it...)

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There's no need to remove the data plate from an engine when installing it in an experimental aircraft. The very fact that is operated under an experimental amateur-built airworthiness certificate means that the engine no longer meets its type certificate, so it's already "de-certified". Removing the data plate has no purpose.

I thought the whole remove the data plate thing was to denote it was on an experimental (and not subject to AD's) so that it couldn't be rotated back to a certified aircraft.

Any illumination on the matter would be appreciated. My want of trivia is never satisfied.

Does the engine and prop need the data plates to get the 25 hour test period instead of 40 hours for uncertified?

Does the prop/engine combination need to be certified? Or just any certified prop on any certified engine?

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Originally Posted by Frank Giger

I thought the whole remove the data plate thing was to denote it was on an experimental (and not subject to AD's) so that it couldn't be rotated back to a certified aircraft.

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That's the commonly-held belief, but it's not based on fact. The fact is, once the engine is mounted to and operated on an experimental amateur-built airframe, it automatically becomes an experimental engine. This is due to the fact that the maintenance regulations found on 14 CFR Part 43 do not apply to the experimental amateur-built aircraft. As such, there is no requirement that the person doing maintenance on the aircraft, engine, or any installed components, hold any sort of FAA certificate. In other words, ANYONE is allowed to perform maintenance, repair, or modification to that aircraft (including all installed equipment and components). And further, the maintenance recording requirements and return to service requirement found in Part 43 also do not apply, so there is no regulatory requirement for any maintenance to be recorded in aircraft records.

All this being the case, there is no way for the FAA to verify whether all maintenance has been performed by certificated individuals in accordance with appropriate regulations, as none of this is required. Thus, the engine cannot continue to meet its type certificate regardless of whether the data plate is installed or not. The very fact that non-certificated individuals "may" have performed maintenance on the engine is all it takes to make the engine "experimental".

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Originally Posted by Bill Berson

Does the engine and prop need the data plates to get the 25 hour test period instead of 40 hours for uncertified?

Does the prop/engine combination need to be certified? Or just any certified prop on any certified engine?

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Yes, the data plates for the engine and prop must be in place in order to get the 25 hour flight test period, AND the applicant must be able to show that the engine and prop have been certificated together on a standard category aircraft in order to get the 25 hour flight test. If the engine and prop have not been certificated TOGETHER on a standard category airplane, you'll get 40 hours even if both engine and prop are individually certificated.

Hope this helps!

In conjuction with Joe's excellent post, the question sometimes comes up "Can an engine that was on an experimental aircraft be put back in service on a certificated aircraft?".

The answer is "Yes" if compliance with FARs can be demonstrated. Some experimental aircraft owners have "kept their engine certificated" (their opinion, not the FAR's, see Joe's post) by having all work performed by an A&P and only PMA parts used in maintenance along with thorough documentation. This should theoretically allow the engine to be directly transferred to a certificated airframe.

However........an A&P must put his signature in the log book stating the engine meets all type certificate requirements and in the real world there may not be any A&Ps who would put their occupation on the line without a full disassembly of the engine to verify type compliance. This is a case where FARs run up against real-world prudence.

An experimental owner may wish to maintain their engine to FARs in order to maximize reliability, but attempting to maximize resale value by hoping to maintain the engine so it could be directly transferred to a certificated airframe is most likely not a possibility.

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Originally Posted by Bill Berson

I don't fly at night anymore. Too many close calls, the risk isn't worth it.

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You're in good company there, Mr Berson:


Genesis 1New Living Translation (NLT)

The Account of Creation

1 In the beginning God created the heavens and the earth. 2 The earth was formless and empty, and darkness covered the deep waters. And the Spirit of God was hovering over the surface of the waters. 3 Then God said, “Let there be light,” and there was light. 4 And God saw that the light was good.

Dark would be good if I had the ability to hover (like the "Spirit of God ", whatever that is)

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Originally Posted by Bill Berson

Dark would be good if I had the ability to hover (like the "Spirit of God ", whatever that is)

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No offense intended, but that sounds like a person who has never piloted a helicopter in a night doppler hover three hundred miles southwest of Iceland and 85 miles from the nearest ship in January with 500/2 under a solid overcast and rain.... :) ....be cautious what skills you wish for.

(not offended)
How would you know the ceiling and visibility at night?
I departed VFR from a remote Alaska airstrip at night with my brother once, and let him do the takeoff. At about 200 feet agl the landing light beam hit the low ceiling. I instantly took control and carefully leveled at 200 feet and returned for a landing. Lucky I knew the airfield.
That's why I don't fly at night. (dark night)