Subaru EA81 Conversion

[Chris Willars]

I know this has been looked at before but is there any new info about converting the EA81. Bushcaddy posted some useful info a couple of years ago but I wonder if he has an update on the flying of his EA81 with redrive.

 

Any advice on what needs doing to convert the engine? I'm pretty practical but am looking for a cost effective power plant with about 100-120HP.

 

All advice welcome:help:

 

Happy flying everyone

 

Chris

 

 

[Knighty]

100 - 120hp

 

Hi

 

The standard EA81 are around the 80 hp mark at full throttle so to get 100 - 120 out of the block is not going to be as cheap as you like to think. Major head modifications is the main thing to look at as the engine has some breathing difficulties stock standard. One of the Gyro fellas I knocked around with years ago imported a rally engine which had twin carbs and head modifications, I was told it produced around the even 100 at full throttle and it sat comfortably on 5400rpm all bloody day without concern.

 

Go and google you heart out as I did and its amazing the amount of information out there and engine mods for the suby to convert it to aviation. I have a Ram EA81 in my Aeropup which the outlay cost blew right out of budget so a lesson was learnt there I can tell you! Wont do that one again in a hurry.

 

PM me if you want and I may be able to recover some of the info from my files in regards to the EA81 etc.

 

Cheers

 

Knighty

 

 

[bushcaddy105]

Here's the requested update, Chris

 

BushCaddy 4564 has (as of this afternoon's flight) 335 hours of EA81 power. It has been as far as Bundaberg via Innamincka, been to 2 Avalons, 2 Narromines, 1 Edinburgh Air Show,1 Camel cup at Marree, several trips to Mildura and many shorter sorties inbetween. It has been flown by many other pilots, all happy!

 

So you can assume that I am quite happy with the conversion, and trust it implicitly. Only yesterday it had its first hiccup - an occasional miss on one cylinder. A lead fouled plug was the cause, not surprising as the same set of platinum plugs has done all those hours, with cleaning each 50 hr service, and a 99% of the time Avgas diet. I lashed out and fitted 4 new plugs - problem solved.

 

My installation is simple, as close to how the engine runs in a car as possible, and I estimate that with my mods it makes about 95 HP flat chat. I cruise at 75% power for 14 litres/hour. I personally take the claims of more than 100 HP from an EA81 with a grain of salt.

 

I trust that this gives you the info needed

 

 

[Chris Willars]

Hey John,

 

thanks for that, seems to fit my bill too. Just need to get hold of a suitable motor!!!:thumb_up:

 

 

[Guest Maj Millard]

Did see one that put out 100 hp. It had a Nissan

 

Starrion turbo on it, and 4 thou had been taken off the tops of the pistons. He was only running 2-3 pounds boost, on the turbo. It was on a really big gyro and had to be putting out 100 hp to fly it.

 

 

[Chris Willars]

Didn't see that one Maj, sounds a bit complicated for my taste, I like to keep it simple. I would love to have some more details of your conversion though John, if it's not too much trouble.

 

 

[bushcaddy105]

No trouble, Chris

 

The EA81 is basically standard with the following exceptions:-

 

Most important change is the camshaft - mine is a Wade 240

 

Heads are stock EA81, with 1.00 mm milled off the face, the inlet valve seat inserts have the ridge above the seat removed to match the port diameter. Valves are standard.

 

I run an EA82 inlet manifold with an adaptor to take a single 1.75 inch SU carbie.

 

An EA71 crank pulley slows down the water pump & drives an alternator off a Daihatsu Charade. An Alfa Romeo 33 radiator is mounted in the bottom of the pressurised cowl. A normal 13 psi radiator cap and overflow bottle take care of coolant. No oil cooler is needed or fitted - air flow over the standard sump is sufficient. The muffler is homemade - it simply combines both cylinder banks into a single central outlet. The distributor is a modified Nippon Denso electronic unit. This all drives a Foxcon redrive turning a 72 inch X 60 pitch Bolly 3-blade prop.

 

There you have it! All I can say is that it continues to work well

 

 

[Chris Willars]

Thanks John, Copied, saved, filed in triplicate for reference. Woo hoo, engine here we come

 

Chris:clap:

 

 

[loneflyer]

Ea-81 hp

 

I had a relatively stock EA81 in my CH701 and flew it from the Atherton Tablelands in FNQ to SE QLD.

 

Went like a dream till one of the conrods busted.

 

Now I have some specially made Billet Conrods (the standard ones have straight edges???)and had to modify the case so they would go round. The crank is balanced and I had a special CAM made to optimise performance for 4800RPM. The heads have been done up very nicely and I run 2 x SU carbs.

 

I have a "DUC" Windspoon prop and hope to get a consistent 100HP. It should be off the ground in a week or two.

 

Woohoo! Will let you know how it goes

 

Loneflyer

 

 

[Guest Maj Millard]

The secret to getting the EA-81 working good in aircraft is in the modified cam.

 

 

[Methusala]

EA 81 conversion for sale

 

G'day Forumers, I have an EA 81 equipped with a C-type gearbox advertised in the Rec Flying classifieds. It has the Wade 240 cam and is factory fuel injected with a Haltech ECU. Otherwise it is stock. It was installed on our A-Type Karatoo but was too much weight for the relatively light frame tubes. Done 20 hrs. Just puttin' it out there for anyone interested. Don