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Old 02-13-2018, 07:13 PM
rkiefer2 rkiefer2 is offline
Join Date: May 2015
Location: Waukesha, WI
Posts: 103
Default Rebuilding your own engine...Bad Idea?

Hello Everyone,

Im starting an RV8 quick build and perhaps getting a little ahead of myself, but wanted to get some input on the engine.

I did some research on rebuilding an engine. Looks like their fairly simple and with little experienced guidance its doable to buy a run out one, mag flux parts that are getting reused, and buy replacement parts.

This feasible? Cost beneficial? Assuming I have the correct person looking over my shoulder any increased risk?

Let me know if your thoughts of if you have some examples.


Roger Kiefer II
RV-12 SLSA - Flying/Instructing
Rv-8 Building
EAA Chapter 18 Member
Waukesha, WI (KUES)
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Old 02-13-2018, 07:25 PM
gasman gasman is offline
Join Date: Mar 2007
Location: Sonoma County
Posts: 4,385

You might find something under 3ooo hours if so, with good records, I would change rod bearings and install a new top end. This would be a motor with no leaks and the 3000 hours used up in less than 5 years.
VAF #897 Warren Moretti
2021 =VAF= Dues PAID
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Old 02-13-2018, 07:31 PM
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9GT 9GT is offline
Join Date: Jan 2010
Location: Southern Michigan
Posts: 2,243

I bought a late model IO-540 for my RV-10 that had a mild prop strike. I found that the inspection/rebuilding process to be very rewarding in satisfaction of doing it myself, and it did save me quite a bit of money. That said,,,, you could really take a bath if you get a bad core engine that requires a lot of parts replaced. The crankshaft alone on my IO-540 would have been in the $13K range if I had to replace it. The disassembly/reassembly process is fairly straight forward following the Lycoming overhaul manual.
David C.
Howell, MI
RV-10: #41686 Under Construction/Sold 2021
RV-9A: #90949 Under Construction
RV-10: #40637 Completed/Sold 2016
Cozy MKIV:#656 Completed/Sold 2007
"Donor Exempt" but donated through Dec. 2021
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Old 02-13-2018, 08:05 PM
Kyle Boatright Kyle Boatright is offline
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 4,885

I bought a core engine and rebuilt it back in the day for my RV-6. The reality is that I saved a few dollars, but not many. The professional shops get better pricing on machine work and parts than I do, and probably get better deals on cores too. They offset their savings (and then some) with labor charges, but they also generally test run the engine and provide a warranty.

The one thing I will say is that these engines are very simple and I learned a lot by rebuilding mine.

This time around (RV-10, no longer an indestructible bachelor, and have a wife and kid), I had a quality shop build the engine for me.
Kyle Boatright
Marietta, GA
2001 RV-6 N46KB
2019(?) RV-10
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Old 02-13-2018, 08:39 PM
tim2542 tim2542 is offline
Join Date: Aug 2009
Location: Redding,Ca
Posts: 633

I think it depends a lot on your previous experience or lack of, and access to experienced help and importantly current service docs. These engines are pretty simple but there are places to get into trouble, and Lycoming doesn?t go out of their way to make current SB?s and SI?s accessible to us do it yourself folks. As already mentioned, any core you get can easily bite you on the but if the case, crank or rod cores red tag.
Another thing to don?t want to make your first flight of a new airframe with an engine with no time on it if you can avoid it. The engine rebuilder will run it for a couple hours before they ship. On a new airframe that?s something to consider.

Tim Andres
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Old 02-14-2018, 07:45 AM
Electrogunner Electrogunner is offline
Join Date: Aug 2016
Location: Quarryville ,pa
Posts: 624
Default Rebuild

FWIW and another data point
I did the buy a core and rebuild thing on my IO540 for the -10. I purchased a core from a salvage company with a warranty that the case and crank were serviceable. I disassembled myself and sent everthing out to aircraft specialties for check, overhaul and yellow tagged. The case went to chuck ney ( would not recommend, but that's another story). I purchased new superior cylinders, starter,BU alternator, prop gov, plugs,injectors, take off new servo, fuel pump injector lines mags, harnesses and distribution block from a guy going electronic FI and ignition on a new engine. I purchased all OH replacement items as well as all new hardware all the way through. I'm taking all of parts down to Watson Aero in GA for an assisted engine assembly and test/run-in in 2 weeks. All in I will be saving 15K on a new engine from vans. Good or bad opinions vary but that's what I did and have no regrets.
RV10 N821DB coming soon
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Old 02-14-2018, 08:09 AM
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Walt Walt is online now
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 6,669

If it matters to you, the aircraft value with a field overhauled engine vs a reputable shop or new engine is significant.
Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 2000+ hrs, New Titan IO-370, Bendix Mags, MTV-9 prop
Website:, Email:, Cell: 972-746-5154
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Old 02-14-2018, 08:10 AM
engineerorange engineerorange is offline
Join Date: Apr 2008
Location: Catawba, NC
Posts: 205
Default I did it

I bought a core and did the rebuild myself. Spent about the same as buying a mid-time engine, but got 4 new cylinders, a brand new Lycoming cam kit, all new bearings and everything else overhauled to new limits. I still have some leftover parts to sell and get a little money back. Anybody want an overhauled without yellow tags cam, lifters and hydraulic units?

The engine had about 20 minutes of run time at the time the tires left the asphalt for the first flight.

I would do it again. They say the first 25 hours on a new engine is the danger zone, so 2 hours on a test stand probably wouldn't really make that much real difference in the risk assessment anyway.
mangling aluminum since May 2009
RV7-A, flying
RV8 under construction
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Old 02-14-2018, 08:12 AM
krhea krhea is offline
Join Date: Nov 2011
Location: Peck, Kansas
Posts: 188
Default Rebuilding your own engine...Bad idea?

Here?s my experience: In 2013 bought a 1982 Mattituck 0-320 engine with 741 hours for 7500.00 including all accessories. I was assured that the followers weren?t spalled.

From 2014 initial flight until mid 2016 wasn?t happy with the amount of burned oil soot on the bottom of the polished RV7 so i got an inspection camera and looked at the cylinders, and didn?t like chrome look and striations in the walls. In 2016 the cylinders were replaced with ECI steel cylinders.
With the cylinders coming off you could easily see the lifters were spalling. All during the flying oil reports and cut filters reveled nothing worse happening. So I waited until Nov 2017 to do the overhaul. All parts taken to Aircraft Specialties and Crankcase Services for overhaul. I did the overhaul myself and all the research into SB,SI AD?s. The crankshaft passed but was $1170 to comply. The camshaft was red tagged so used a yellow tagged two piece cam.

To sum it up.

7500 engine price ( probably paid too much)
4000 Cylinders
5400 overhaul costs, includes consumables( does not include new lord mounts and new oil cooler)
1800 electronic ignition ( sold 32 year since overhaul bendix mags-price adjusted)
428 B&C 40 amp alternator special
660 Carb overhaul
50 custom pushrods

19000 and change for almost 0 time and i have a lot more confidence in the engine.
Off the top of my head i can think of about 15 or 16 engines i have had a hand in overhauling over the years, but only 1-lycoming, 1- Corvair flight engine, and 1-VW flight engine.

New engines 26000.

Was it worth it? i don?t know, but i know my engine right down to the last bolt, nut and washer.
Here?s a link to some photos:

364 hours in 3 years

Keith Rhea
2018 Donation
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Old 02-14-2018, 08:22 AM
pa38112 pa38112 is offline
Join Date: Mar 2008
Location: Clarksboro, NJ
Posts: 1,043

Very doable with the RIGHT assistance who has access to the correct tools/machining. Having said that, I always keep in the back of my mind what an A&P I know and trust once told me. He worked on engines all day long and when we discussed this he said: "I would never overhaul my own engine. It is better to just send it to the factory or one of three big shops".
There are little details that are not visible but make a big difference. The same could be said of building the rest of the airplane, but looking at all of the builders who are skilled and experienced. The majority choose to purchase their engine rebuild.
2004 RV6A Flying
2002 RV6A Flying
1978 PA38-112
2008 Wag-Aero Cub C-85
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