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subaru ea 81

Discussion in 'Engines and Props' started by mr badger, Dec 2, 2007.

  1. mr badger

    mr badger Member

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    hi
    just want a few views on subaru ea 81 o
    engines , how good , tuff, reliable are they? diffrent people tell me "aircraft engines for aircraft, car engines for cars" also the ea81 has only one set of spark plugs is that a problem? do you need 2 sets??? or would duel ignition compensate for this.

    cheer s to all
  2. bushcaddy105

    bushcaddy105 Member

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    Gooday Mr Badger

    Go to the post titled "Subaru Engine" on page 3 of the engine section of these forums and read through. I have now done 195 hours on my EA81 with 1 electronic ignition system and 1 platinum spark plug per cylinder, and intend to do many hundreds more. Why would you need to add the complication of 2 systems when the simplicity of one minimises the number of components which could cause trouble? I also am a strong believer in regular inspections and preventive maintenance as the key to reliability.
  3. Yenn

    Yenn Well-Known Member

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    One reason for going to 2 systems is that usually with ignition the breakdown of one of a pair of systems doesn't stop the engine, but the breakdown of the only system will stop it. One place where complexity is not all bad.
  4. mr badger

    mr badger Member

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    that was my thoughts on duel ignition better two "JUST IN CASE" but still want to know about reliability tuffness etc

    cheeers all
  5. allowera

    allowera Member

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    After reading "Subaru Engines" I feel the need to defend the EA81.
    Firstly; I am sure that whilst he was employed at the dealership, micgrace would certainly have performed the mandatory 1500Km Cylinder Head re-tension, just as he would have adjusted valve clearances every 25000Km and changed coolant every 2 years. However, sometimes it didn't happen.....
    Secondly; after the advent of Unleaded Fuel, it was almost impossible to convince Brumby owners to use Premium or Octane boosters. This resulted in Subaru supplying heavier Distributor Advance springs, cooler heat range Spark Plugs and cooler Thermostats. Even then some owners were able to enduce detonation.
    Finally; overheating an all alloy Boxer Engine is avoidable and can be terminal. Crankcase distortion and Main Bearing Tunnel ovality must be considered before any Cylinder Head work is carried out. Dual Spark Plug Heads were being manufactured in New Zealand; knowing true Engine history is vital before fitment.
    In my experience over an extended period in automotive applications, if it is maintained correctly and used wisely, the EA81 gives years/decades of reliable service and will often outlast it's EA82 successor.
    Safe flying, Paul.
  6. mr badger

    mr badger Member

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    is it true

    can anyone tell me if subaru engines have anymore problems than rotex engines , most people i talk to rubish subaru engines in aircraft and tell me that they are the one that cause the most engine failers in aircraft is this true is there any evidence to suport this i think jabaru engines seem to be the worst offender for problems always seeing them in reports with problems or is this just because there are so many of them now .
    any thoughts on this anyone .
    cheers mr badger (gary)
  7. mr badger

    mr badger Member

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    can anyone tell me if subaru engines have anymore problems than rotex engines , most people i talk to rubish subaru engines in aircraft and tell me that they are the one that cause the most engine failers in aircraft is this true is there any evidence to suport this i think jabaru engines seem to be the worst offender for problems always seeing them in reports with problems or is this just because there are so many of them now .
    any thoughts on this anyone .
    cheers mr badger (gary
  8. facthunter

    facthunter Well-Known Member

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    Engine comparo.

    Comparing engines is difficult, Gary. What sort of an aeroplane do you want to put it in?. Do you want a direct drive, ( Continental, Lycoming, UL, Corvair, lower-power VW ,Jabiru etc.) If you have in mind a draggy, slower type, then you need a larger prop,for thrust at lower speed & not able to turn at very high revs, because of tip speed limitations.
    Then you need a high displacement, low revving engine, or you use a reduction gear/belt. This has its own problems. Most EA 81s use a toothed belt, as far as I know. An american reduction gear box (of extremely complex design) has taken years to develop and comes as a package with a version of the later OHC motors. (I don't think you buy this to save money).
    The Foxcon uses the EA81 and it is reputed to be very quiet.
    What allowera says is right on. Some of these engines have had a bad history, (overheating & detonation, distortion misalignment, corrosion and incorrect tensioning being some of the problems) and in things mechanical, nothing is perfect. Starting with quite old components for an aircraft powerplant does seem to be doing it the hard way. You also have a liquid cooled engine, which is an advantage in some ways, but it is heavier and is more to go wrong. eg. A small leak at the head face,(or porosity) will put you out of the sky with a liquid cooled engine, but you will get home with a Jab. You can get all the parts for a type 4 VW brand new as a contrast and there are a lot of options there. I'm not making your decision for you (as you may have noticed) I'm not trying to "bag" the Subaru either, as long as you start with a good one. Regards Nev..
  9. mr badger

    mr badger Member

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    thanx guys for the feed back will think on all this !
  10. Knighty

    Knighty Member

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    One thing that hasnt been mentioned about redrives available for the EA81 and bolt straight on without any mods is the Autolight unit made in NZ (Sub4 uses this drive). This unit cost me $3500 about 3 years ago and comes with an inspected/tested second hand starter to keep costs down to a min. It is supplied as far as I know with 2 ratios roughly 1.8:1 & 2.21:1, this unit is fairly heavy in comparison to toothed belts BUT can handle 160hp for 2000 hours before TBO. I had to choose this geared PSRU over a toothed belt as my engine developes too many hp's as the belt PSRU manufacturers suggest no more than 120hp max and many props on the market have the 120hp max as well. Just do your homework and ask a lot of questions and you should come out on top!

    Knighty

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