Aircraft Engine Overhaul – The Getting Started Guide

By: Alan Depauw, Founder of

May 3rd 2015

I always like to compare aircraft engine overhaul to buying a new car. You spend about the same amount of money but compared to the nearly perfect data on buying cars, engine overhaul is a stab in the dark. Sure, you have the engine shop to educate you but can you trust the salesman with your best interests? This is what made me a little queasy when I was looking for an engine overhaul. I tried to educate myself via the internet and found plenty of specific content focused on one aspect or another but nothing oriented as an broad overview. So here’s the first of its kind – a Getting Started Guide to Aircraft Engine Overhaul.

When is Aircraft Engine Overhaul Required? What is my TBO?

All aircraft engines have a recommended TBO or Time Before Overhaul. Most piston engines recommend engine overhaul at 12 years or 1,200-2,500 hrs of tach time. You can look up your TBO by clicking here and browsing by popular aircraft.

If you’ve hit TBO, do you have to get your aircraft engine overhauled? The surprising answer is ‘no’ if you’re a part 91 operator (not for hire). If you’re a for hire operation like flight school, airline, charter, ect., you can’t fly 1 hour past TBO.

Most of you reading this are probably part 91 operators and wondering at this point why you should spend tens of thousands of dollars getting an engine overhaul if it’s not even required. It’s a legitimate question and I’ll be honest with you – a lot of people fly past TBO until something goes wrong with their engine. Before you make up your mind on this, you have to answer 3 questions on

  • 1.Liability
  • 2.Insurance
  • 3.Annual inspections

Click here and scroll down to ‘Alternatives to Overhaul and Factory Engines’ to read about those three questions.

Types of Aircraft Engine Overhaul

There are 3 types of engine overhaul.

1. Service Limit Overhaul – A service limit overhaul means that parts will be put back into your engine that are within ‘serviceable limits’. Basically, this means that if a part is allowed to measure + – .010” it can be put back if it is .009”. The big question here is how long does it take to wear an extra .001”? Don’t you want enough time to wear your parts out until the next TBO? If so, Service limit overhaul is out of the question. Shops only recommend these for lower-time prop strikes and other midlife crisis situations.

2. New Limit Overhaul – The engine and its parts must meet criteria for a new engine. For all practical purposes, your engine will be restored to ‘new’ limits. It will have margin for its parts to hopefully wear and stay within ‘service limits’ through its TBO (time before overhaul) life. As a personal note – when I called every shop in the country for an engine overhaul in 2014 every single shop quoted a ‘new limit overhaul’. But after the engine is in the shop’s hands, how do you know they are actually putting ‘new limit’ parts in, and not ‘service limit’ parts? There’s certainly financial incentive to do the latter so read Rip-off Alert in my learning center.

3. Factory Rebuild – Only the factory, or reseller thereof can give you a ‘factory rebuild’. Basically, this engine is made to new limits but is given a zero time logbook since all of its parts don’t have the same age. You may have crank that is 500 hours and a cam that is 200 hours. Both parts must meet ‘new limit’ standards but would be impractical to assign an age in the logbook. When I spoke with Continental, they offered 2 options – 1. An engine that was 80% new parts and 2. A 100% new part engine. Note: Some factory engines have longer TBO’s. A Cont. IO 550-C has a 1,900 TBO from the factory and 1,700 elsewhere (on older serials). But you’re talking 30-50% more in price. About 20% of pilots go this route.

Finding an Aircraft Engine Overhaul Shop

The best way to find an engine overhaul shop for Lycoming and Continental is by using our find shop tool. There, you can even map all the shops and see which ones are close to you.

But having a shop nearby is not as big of an advantage as you might think. I’d rather spend a few hundred bucks to ship my engine to a high quality shop than fly in to a mediocre shop. But how can you tell great shops from the mediocre ones? Good question.

Remember me saying that I spoke with every Lycoming and Continental engine overhaul shop in the country? Well, I wasn’t just getting quotes. I was interviewing them from the customer perspective to see which I would do business with as a consumer first. Then I would review the shops of interest to verify their reputation. Through this process I was able to play ‘fantasy baseball’ with engine shops and came up with a network of the best in the country.

You can connect with these a-list shops by posting a project and start with quotes. Then move the conversation offline with a phone call or a visit. Oh, and after you post a project I’ll send you a list of interview questions to talk about with shops to help you narrow down your list.

Aircraft Engine Overhaul Cost

Ok, brace yourself for sticker shock and click ‘Approximate Pricing’ on our homepage. After you get your nerves back in order, checkout my section on Price and Value in the learning center for expanded content. But if you just want the basics read below.

When I was looking for engine overhaul, the huge differences in price drove me mad! It actually prompted me to call every Lycoming and Continental overhaul shop in the country and talk about quotes. For a Continental IO-550-C the prices ranged from $23k to 60k and everyone offered the same end result – a new limit engine overhaul!

So how do you make sense of all this? Why such a range?

So here’s quick version of the major factors that influence price:

1. Cylinders – Overhauling cylinders is usually the cheapest option. But 70% buy new because it’s not that much more. Deciding which cylinder to put on is tough. This 2008 survey, sadly is the best thing I have to help you. Shop opinions vary on the matter.

2. Contingencies – Look carefully at the quotes. Usually you’ll see something like “Price is contingent on crank and case being [serviceable/repairable]. The quote what says “Repairable” is worth about $1,000 more than one which says “Serviceable”. The explanation would violate my ‘short and to the point’ email rule so see ‘Price Contingencies’ here.

3. Components – Are components like Camshaft, Fuel System, Magnetos, ect. being overhauled or replaced with new ones? Are they PMA or OEM?

4. Warranty – About 30% of aircraft engine overhauls have a warranty claim of some kind. There’s a lot more to them that what appears on the surface. I have a whole section devoted to this in the learning center.

5. Shop – The end result is a ‘new limit overhaul’ but the processes involved to get there, and how much is outsourced, may vary among shops. The overhead involved will vary and so may the quality. To get a feel for shop differences, print and ask the attached questions.

You may want to check out What’s Typically Included in Quotes for additional reading.

Aircraft Engine Overhaul Hidden Costs

There are 5 major expenses that may not be included in an engine overhaul quote. These costs range widely, but I’ll do my best to ballpark them so you have some idea. I meant the word ‘ballpark’ in that last sentence so don’t tell your shop “Well the website said it would cost X!” (insert serious face).

1. Dismounting and Mounting the Engine – You need to find someone who can remove your engine and install the new one. Typically, this is someone who is local like an FBO, or your favorite mechanic or shop. This process takes a significant amount of time and can cost between $2-5k per engine. Your engine overhaul shop will probably give you the best price so they can have control of this process (they have an interest to know it’s done right).

2. Shipping – The cost to ship an engine in the US is usually less than $1,000 round trip! This is paid outside of the Overhaul Bids website – often to the shop. Most shops don’t mark-up shipping and a few will include it in the quote. In 2014 I got a quote to ship a 500lb 6-cylinder engine from FL to CA for $350 one way.

3. Replacement Parts – This is a big question mark on an overhaul. When most shops quote, they anticipate replacing all required components and overhauling the rest. Occasionally a shop will find unrepairable damage on components and have to replace them. The upshot is, you’ll be glad they found this damage so you’re not flying around with parts getting ready to fail. Here’s a few examples of components that our shops see from time to time:

a. Crank case – An overhauled replacement for a Bonanza will be about $4,500. Your cost will depend on the exact model and the parts market. Around 20% have to be replaced.

b. Crank shaft – An overhauled replacement for a Bonanza will be about $4,500. Your cost will depend on the exact model and the parts market. Around 20% have to be replaced.

c. Cylinders – Talk to your shop about cylinders because there’s two ways to look at cylinders. About 70% of owners prefer to get all new cylinders instead of overhauling their existing ones. New cylinders can cost $2-7k for a full set. If the plan is just to overhaul existing, sometimes a shop will find a cracked cylinder and need to replace just one. Again, talk to the shop here to work out the best plan of action for your situation.

d. Camshaft – An overhauled Replacement will be around $650. This part has to be replaced around 65% of the time.

4. Component Repair – This may or may not impact your engine overhaul cost. Some shops include major component repair, some don’t. See “Price contingencies” above so you know how to tell if a shop will charge extra for this. It’s important because there’s about a 70% chance your case or crank will have to be sent out in order to be restored to ‘new limits’. If you do get charged for Case or Crank repair, you’re looking at around $1,500.

5. Sales Tax – Most shops quote overhauls without tax initially. They do this to see if you meet sales tax exemptions before adding that in. When you get down the details with a shop, talk to them about sales tax and if there are any ways to avoid it. Some states charge sales tax on parts and labor, others just parts, and some don’t charge at all. The percentage can range from 6-10%, so the tax could easily exceed $1,000. Sometimes there’s creative ways to avoid it. For example, one shop was able to save his client sales tax by selling to a broker in a neighboring state, and then have that broker sell it to the client. Again, talk to your shop about legit loopholes.

Whoa! Am I scaring you? If this post has created more anxiety and questions, give me a call at (317) 550-0030. Or, we have an overhaul anxiety support group that meets Monday nights and you’re welcome to speak there.

Buy a Factory Rebuilt or New Engine

After the last scary section it’s appropriate to introduce the factory option which has less to worry about. Factory engines cost about $3-11k more than overhauled engines. You can get bids for BOTH overhauled and factory engines by posting a project.

Factories are more likely to not charge you for bad parts. But, they do have standards and requirements so be sure to cross the T’s and dot the I’s. I have heard nightmare stories. See If your Parts are Junk, are you Better Off with a Factory Engine? For more info

Aircraft Engine Overhaul Timeline

Engine overhaul takes about 3-6 weeks to complete depending on if your case or crankshaft has to get sent out. If downtime is a concern, contact me and I’ll find you a shop that can get an engine ready for you to swap out with yours on site. This is called an ‘overhauled exchange engine’. If you’re sentimental about your engine, an exchange might be heartbreaking for you because you’ll never see it or its parts again.

Options for Aircraft Engine Overhaul

While considering the overhaul, you should weigh your upgrade options. I like to think of options in two different categories – 1) Special processes and 2) STC’s or Supplemental Type Certificates.

Special Processes

There are four main special processes that I see some engine overhaul shops offering:

  • Dynamic Balancing – Balancing a rotating part like a crankshaft (different from ‘static balancing’). Click here for a video explaining this option at 5:35. It’s kind of like getting your tires balanced after they shake your car on the highway.
  • Nickel Plated Cylinders – It’s a corrosion/rust resistant treatment. Great for airplanes that sit for a month or more at times.
  • Porting – Click here for info on porting. Basically, it promises improved airflow in the intake and exhaust ports by removing some material and polishing the channels so you develop more power. Average gain is 2.5-4 horse power per cylinder. Shops that do this include Ly-con Rebuilding (CA), Johnson (CA), Victor (CA), Performance Aircraft Powerplants (AR), and a few others.
  • Cryogenic – Dunking your parts in liquid nitrogen may improve their reliability (yes I’m serious). Only two shops have this ability: Performance Aircraft Power Plants (AR), and Victor Aviation (CA). PAP was the first to use it and has reported improved reliability on cylinders, camshafts, and crank cases. You might think of it as a cheap insurance policy for your cylinders for about $120 each (depending on weight). Racing pilots swear by it.


STC’s are Supplemental Type Certificates. Basically, these are FAA approved modifications. Here’s just a few I’ve come across.

  • Rubber gasket – To seal the case halves on Lycoming cases – Ly-con Rebuilding in CA
  • Turbo Normalizing – Maintain sea-level power at altitude. Western Skyways in CO
  • Bigger engines – Put a 300hp engine in your Cessna 182 for example. Many shops have STC’s like this. RAM Aircraft has the largest selection in TX

Looking for something specific? Contact me and I’ll find it for you. There’s a mountain of STC’s out there.

Eventually, I plan on making a complete list of STC’s by Aircraft type and where to find them. Stay tuned.

Further Reading

This article is limited to just the basics. There are other topics that you may want to check out like

  • Warranties – 30% of engine overhauls have warranty claims so this is worth checking out. I take a crack at the local shop advantage fallacy.
  • Alternatives to Overhaul – Weigh your other options before you drop the bank account. Used engines, or what to consider when flying past TBO
  • Financing – Find out what qualifies you for financing and the companies who can offer it.
  • More Options – More about accessory overhaul and cylinders. Ways to spend even more money ☺
  • Much more…

All this can be found in our learning center.


Hopefully you have a better understanding of engine overhaul but I’m sure you have questions unique to your situation. I’m happy to help with any concerns or issues that you’re considering. Just contact me and I’ll help you out. My main goal for Overhaul Bids to help aircraft owners make confident well-informed decisions on engine overhaul.