Van's Air Force
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advice needed on buying an 8 with a Subaru engine
- Thread starter mking275
- Start date
Sam Buchanan
been here awhile
If you have extensive mechanical background, are a real gearhead, preferably have owned and maintained several aircraft, know a ton about the pros and cons of Subie conversions, enjoy searching for insurance policies, enjoy being a permanent test pilot, or can buy it for a price that makes it practical to install a Lycoming, then you might consider this RV-8. Otherwise, keep looking.
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We'd have to know more about the conversion. Specific engine and gearbox especially.
Walt
Well Known Member
+1, pretty much nailed it.
Mike S
Senior Curmudgeon
Welcome to VAF
Matt, welcome aboard the good ship VAF
You asked for advice-----well, here it is. Listen to Ross, he actually flies a Sube powered plane, and he has one of the higher time Sube powered RV out there. He is very knowledgeable in the field.
Sam brings up good points, but as far as I know he does not fly a Sube.
If you are not into tinkering with mechanical stuff you might be better off with a Lycoming or a clone.
Matt, welcome aboard the good ship VAF
You asked for advice-----well, here it is. Listen to Ross, he actually flies a Sube powered plane, and he has one of the higher time Sube powered RV out there. He is very knowledgeable in the field.
Sam brings up good points, but as far as I know he does not fly a Sube.
If you are not into tinkering with mechanical stuff you might be better off with a Lycoming or a clone.
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Sam nailed it. I have personal experience trying to put a Subaru on an RV-8, and it did not go well.
I was much smarter than every one of the dozens of people who told me that I was making a huge mistake trying to put a different engine on my RV-8. People invested a lot of time explaining in great detail the things that Sam wrote - but I was too smart to listen to them.
In the end, I wasted a lot of time and money, but I did learn a lot. I now have a Lycoming IO-360 - and I'm delighted with it.
And to all of you that tried educate me, thank you, and I have (finally) learned something. If 1000s of people are running in one direction, you should have a good reason to run in the other, and know what you are doing.
I was much smarter than every one of the dozens of people who told me that I was making a huge mistake trying to put a different engine on my RV-8. People invested a lot of time explaining in great detail the things that Sam wrote - but I was too smart to listen to them.
In the end, I wasted a lot of time and money, but I did learn a lot. I now have a Lycoming IO-360 - and I'm delighted with it.
And to all of you that tried educate me, thank you, and I have (finally) learned something. If 1000s of people are running in one direction, you should have a good reason to run in the other, and know what you are doing.
Lufthans
Well Known Member
I'm flying a Subaru on my Jodel, have done several more conversions and I am doing one on my RV3 now. They CAN work well. I’ve got over 600 hours on my Jodel, the Robin is close to that one too. Operation is a non-issue. It just works. Always. Maintenance is a breeze. Temperatures are rock solid to within 2F, summer and winter. And it does so without a huge drag penalty. It runs on anything that remotely smells like gasoline without any vapour lock issues.
HOWEVER
It took a LOT of effort to get to this point, including some things that most builders shy away from, like not placing radiators up front in the nose, and a complete redesign of the electrical and fuel system.
Your biggest concern will be to figure out where on this development curve this particular aircraft is. How well does it cool? What is its cruise speed and at what power setting / fuel burn (so in other words: how draggy is it at this cooling?), do you have to worry about vapour lock? How well does the gearbox hold up? Any torsional vibration issues that aren’t dealt with? And most of all - how would you determine all of the above, other than having blind faith in what the current owner tells you?
If you’d send a lot of info and photos, I am sure Ross and I (and several others who’ve gone down this path) could point out any potential nono-s, however even the absence of these would still leave you vulnerable for a lot of headaches.
Tread with caution…..
HOWEVER
It took a LOT of effort to get to this point, including some things that most builders shy away from, like not placing radiators up front in the nose, and a complete redesign of the electrical and fuel system.
Your biggest concern will be to figure out where on this development curve this particular aircraft is. How well does it cool? What is its cruise speed and at what power setting / fuel burn (so in other words: how draggy is it at this cooling?), do you have to worry about vapour lock? How well does the gearbox hold up? Any torsional vibration issues that aren’t dealt with? And most of all - how would you determine all of the above, other than having blind faith in what the current owner tells you?
If you’d send a lot of info and photos, I am sure Ross and I (and several others who’ve gone down this path) could point out any potential nono-s, however even the absence of these would still leave you vulnerable for a lot of headaches.
Tread with caution…..
Ed_Wischmeyer
Well Known Member
Saying that it is a "Subaru" engine is an incomplete statement. Get the history of the engine and conversion. Years ago, I talked to one purveyor of Subie engine conversions, and he said, "I have two competitors. I respect one."
If you want to fly, get a Lycoming. If you have the skills and desire to tinker with the engine, and have considered all the risks, go ahead with the Subaru.
And do your homework as to which conversion this plane has. As somebody else pointed out, one particular conversion is to be avoided at all costs.
If you want to fly, get a Lycoming. If you have the skills and desire to tinker with the engine, and have considered all the risks, go ahead with the Subaru.
And do your homework as to which conversion this plane has. As somebody else pointed out, one particular conversion is to be avoided at all costs.
I see this is an Eggenfellner EZ30 setup with 960 hours on it. The fact that the engine has that many hours means that part is basically sound and we usually expect that to be so if the EFI part is properly tuned and cooling is good.
The main worries are in the gearbox area. If this has the Gen 3 gearbox, there have been several concerns and problem areas here-
Spline wear- has to be inspected and lubed frequently
Weld failures- had some welded parts on the gear sets, some are sound, some crack
Bearing failures- some last fine, others don't
There are a few other things to watch out for depending on the vintage of the engine kit with regards to flywheels and EFI systems.
If you're not up to the inspection and maintenance on the gearbox, it would be best to move on to a different airplane or consider installing a Lycoming in this one since the price is pretty attractive.
The main worries are in the gearbox area. If this has the Gen 3 gearbox, there have been several concerns and problem areas here-
Spline wear- has to be inspected and lubed frequently
Weld failures- had some welded parts on the gear sets, some are sound, some crack
Bearing failures- some last fine, others don't
There are a few other things to watch out for depending on the vintage of the engine kit with regards to flywheels and EFI systems.
If you're not up to the inspection and maintenance on the gearbox, it would be best to move on to a different airplane or consider installing a Lycoming in this one since the price is pretty attractive.
