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Rebuilding your own engine...Bad Idea?

rkiefer2

Well Known Member
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.


Thanks,


Roger
 
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.
 
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.
 
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.
 
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 consider....you 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
 
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.
 
If it matters to you, the aircraft value with a field overhauled engine vs a reputable shop or new engine is significant.
 
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.
 
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: https://www.dropbox.com/s/8aa2vrqumlxjpyu/o320 ohaul.pdf?dl=0

364 hours in 3 years

Keith Rhea
RV7
2018 Donation
 
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.
 
Another possible option.

I was going to assemble an O-360 myself that I bought as a box of yellow-tagged parts.

I had a finish question on the con rods and stopped by the local engine building shop to get an answer and found that the head of QC builds experimental engines on the side for a very, very reasonable amount of money.

He assembled it and I paid the shop to test run it. Saved lots and ended up with an assembler who had already built over 1000 Lycomings. :)

Ask around for help at your local engine shops.


PS My Lycoming con rods didn't look that nice on the sides, but they all look like that.
 
Intially, I thought I'd rebuild or IRAN the one I got off eBay. I got as far as taking a jug off at home to check out the camshaft, and as soon as I did, I got the strongest in-over-your-head feeling I've ever had.

Tim's Aircraft Engines did a superb job of doing a full IRAN (inspect and repair as necessary) and also installed my AFP FI kit. I may have missed out on the experience of rebuilding my engine, and it certainly cost more than if I'd done it myself, but the piece of mind that came with the paperwork from Tim's was totally worth it.

Also, it helps to have the right tools, know where to send stuff for testing and machining, and a mentor who can catch you before you do something dumb in real time. I had none of those, so I made a choice based on my comfort level.
 
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.


Thanks,


Roger

Rebuilding an engine may be advisable for someone familiar with the process but most of us are not.

A good aircraft mechanic spends a lot of time in a school or as hands on assistant as trainee in the field before he really knows enough to do it right.

It can be a useful learning experience, I suppose. You will flying behind it, do you need that point of failure in addition to flying an experimental airplane and its inherent risk?

I've thought a lot about it over the years and chose not to go that route 4 times. Its either been an engine rebuilt by an over haul shop or a new engine.
 
If it matters to you, the aircraft value with a field overhauled engine vs a reputable shop or new engine is significant.

I am planning a FACTORY new engine for the RV-8 build before reading the above. I made that decision because I believed the above before reading it.

BTW. Not only have I been an A&P for more than 20-years, I have also been to the the Lycoming Engine School. Yes I would not hesitate to build my own engine BUT to be honest, the FACTORY or shop built engine is worth more money and does not cost much more than doing it yourself IF you have the skills and use only NEW SPEC parts.
 
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