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backwoodsboy

School me on EA81 DUAL-CARB engines

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School me on the DUAL CARB EA81.

 

 

Ive done some searching, and have been gleaning bits and pieces here and there... but I havent found a definite source of information.

 

This has gone from a passing curiosity for me to a reality. I scored a set of dual-carb heads with matching cam and rockers/pushrods.

 

 

I have a solid lifter EA81 shortblock that Id like to slap the heads on once I change out to the dual carb cam.

 

 

It all looks very do-able, and I would ASSUME all the clearances/torque specs etc are the same.

 

Id rather save myself any unpleasant suprises though.

 

Anybody done one of these before?

Anybody have a book?

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never a deul carb but just built a strong ea 81 for a hovercraft. we reground the cam used the bigger heads from a 87 chaser on the 81 solid lifter engine and put on a carb and intake from a 86 ea82 simplfyed down thiss engine worked realy good and i think the ea82 carb whould out pull the deul carb setup. we were shooting for 120 hp and i think we are realy close to that. was the snapyest ea81 iv'e seen even better than my TBI ea81.

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Thanks for the reply.

 

Im no stranger to EA81 performance builds. This will be no exception.

 

Ive done 2 of em in the last 4 years with reground cams, port/polish jobs, upgraded carbs with bigger jets, and taller pistons. They can make really decent power if you want to spend the money and time.

 

I actually have no intentions of using the dual-carb manifold believe it or not.

 

The EA81 dual-carb engines make better power because the cylinder heads have a reverse valve setup than the standard EA81. They flow better = more power.

Edited by backwoodsboy

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Do you have the intake? I have one that I will sell if I can't fit it on my car, I think it will not fit with the power steering pump. I will know soonish, drop me a line if interested.

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Im just outside of Oneonta (near Cooperstown/Natl baseball hall of fame)

 

Im thinking Ill do a ported/polished out EA82 carby manifold

 

neato. my sister went to school for a year in Oneonta

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The biggest difference with the Dual carby heads is the reversal of the inlet and outlet valves (on the true Dual carb heads) do yours have 2 inch or bigger exhaust ports? and a visible separator on the inlet port making 2 D's

 

as for available information all I can give is that I owned one of these motors for a few years. sadly I sold the car as I moved country (wish I never had now) And when I came back to Australia the car had vanished along with the motor :(

 

Inlet and outlet clearances are the same, not sure if you will need solid or hydraulic lifters, mine had solid.

 

Mine was mated to a 3.9 ratio straight cut 4 speed dual range box (came with the motor) and I was able to tune it to get between 95-100 km/h out of second gear.

 

Timing was set at 8 degrees any less and the motor ran like a chaff cutter, any more and it pinged its little head off.

 

they are a fantastic motor and will rev way higher than the normal EA81.

 

you will be amazed :)

 

TOONGA

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I JUST caught this thread. Figures im out of the subaru world not even a year and you find what i was looking for all along for the coupe :banghead:. At any rate if you are to build it, you wouldn't be realizing its full potential with just the single weber on a ea82 intake. When i was looking and planning i decided that i would either make or have someone make me a custom intake that would mount dual carbs directly over the heads like some of the old VW crowd does. They would most likely be single barrel Webers of a bigger size than the secondary of the 32/36. That was what i figured would be the most fun with that car.

 

Oh another note give me a ring sometime. I havent heard from you or jess in ages. :)

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I JUST caught this thread. Figures im out of the subaru world not even a year and you find what i was looking for all along for the coupe :banghead:. At any rate if you are to build it, you wouldn't be realizing its full potential with just the single weber on a ea82 intake. When i was looking and planning i decided that i would either make or have someone make me a custom intake that would mount dual carbs directly over the heads like some of the old VW crowd does. They would most likely be single barrel Webers of a bigger size than the secondary of the 32/36. That was what i figured would be the most fun with that car.

 

Oh another note give me a ring sometime. I havent heard from you or jess in ages. :)

 

The carbs came on the heads of the EA81 RX overseas. Seen an old brochure picture and in it they show a couple different shots of the engine.

 

 

Mmmmmmm....:popcorn:

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The carbs came on the heads of the EA81 RX overseas. Seen an old brochure picture and in it they show a couple different shots of the engine.

 

 

Mmmmmmm....:popcorn:

 

Im pretty sure those were just the rally versions that got that setup.

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Im pretty sure those were just the rally versions that got that setup.

 

I think thats the case. My RX has twin carbs on the manifold then it goes straight to the heads.

Not Carb staight to the heads.

My RX is nz new but has Japanese writing all over it.

Edited by kiwi subbie

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The biggest difference with the Dual carby heads is the reversal of the inlet and outlet valves (on the true Dual carb heads) ...

 

Factory Twin Carb Subaru EA Engines were available since the EA62 (1300) engine which came on the Subaru FF-1 "Star" or "G" versions, that engine came with dual carburetors as a factory option for the Sport Package, but the valves and everything else came equal to the Standard version engine.

 

But both the EA71 (1600) and the EA81 (1800) engines that came optionally with Twin Carburators from Factory, and those were defined by a following "S" at the end on their engine codes. This was Subaru's way of calling it the Sports model. 

 

The engines were completely differently designed to the standard models. The "S" models had Dual Ports and Opposite Valve configuration, which means different cams and rocker gear.

 

They were available in Japan in the Subaru Leone GSR and in the later first gen Leone RX Models. These engines has Higher Compression Ratio and had ~10% more power output. They were used heavily in the late 70's and early 80's Rally cars.

 

 

 

... When i was looking and planning i decided that i would either make or have someone make me a custom intake that would mount dual carbs directly over the heads like some of the old VW crowd does. ...

 

Do you Mean like This?

(this is an EA71):

 

WorthlessWithoutPics.gif

 

 

100_4119.jpg

 

 

100_4121.jpg

 

 

I've seen such conversions, even done to EJ engines...

 

2104061330094569859S425x425Q85.jpg

 

 

...Usually to be Mounted in VolksWagens...

 

IMG_0895-1.jpg

 

 

 

The carbs came on the heads of the EA81 RX overseas. ...

 

Yes!

 

 

...Seen an old brochure picture and in it they show a couple different shots of the engine. ...

 

Yes, it is this:

 

e.jpg

 

 

safari-1.jpg

 

 

safari-2.jpg

 

 

And this are Photos of the Car on the 1983 Safari Rally Race:

 

Safari1.jpg

 

 

safari-4.jpg

 

 

safari-3.jpg

 

 

safariengine.jpg

 

 

 

When Subaru Developed that Head-Mounted Twin downdraft Weber Carb EA81S engine with Reversed Valves, they already had the Turbo EFi Technology; so, very Few of those EA81S with Twin Webers were made, since Subaru started to sell the "Turbo Traction" Models in 1982 in Japan, and in 1983 worldwide...

 

subaru_1983_turbo_brat.jpg

 

 

TurboTraction.jpg

 

 

Very Few Twin Weber Carb Models were Available for Sale,

 

mainly in Japan and New Zealand,

 

like This one, which was for sale some months ago:

 

 

Portapapeles01-7.jpg

 

 

I'll Love to Own one of those Second Gen Leone RX with Twin Weber Carbs!

 

Kind Regards.

Edited by Loyale 2.7 Turbo
To center the images ;)
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Wow !!! I've been into Subarus for some time and have never seen anything like these's....WOW !! is right..Thank you for posting this stuff...Man they must have screamed !!!!! Well ,I have a duel carb set up on my 84 brat(the thrasher).Years back we were getting the import engines for like $400 bucks and I would go through the line of them with a breaker bar testing the compression by ear on the duel carb engines.They were the same price.I don't remember if I changed the engine out and kept the duel carb set up over the years? How can i tell if the engine is for duel carbs without taking off the intake ??I also remember talking to the guy that sold the import engines and he said the stock import carbs won't work over here(in the USA.I said that i have used the import carbs everytime and they worked fine.(For awhile we were swaping engines like starters..They came with everything carb,distributer ,everything, so all you had to do was drop it in , plug it in and it ran..)He just frowned and looked at his junk pile of import carbs that he had pulled and thrown on the junk pile....I have had the 2 carb set up for at least since 1997 and its still running.I did rebuild one carb 6 years ago..hey i know,I should have done both of them but...It worked and they still run so...??.Now lately i have thought of gettine 2 new hitotchi? carbs for it but I procrastinate. Mabey next summer...So , where is the engine vin # to see if I have a stock duel set up? C ya. OSF:banana:

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Wow !!! I've been into Subarus for some time and have never seen anything like these's....WOW !! is right..Thank you for posting this stuff...Man they must have screamed !!!!! ...

 

You're Welcome!

 

I always thought that the Boxer Rumble Sound coming thru a Single Weber Carb in the Middle, Compared with the Boxer Rumble Sound coming thru Twin Weber Carbs, one on each Head, shall Be like Comparing Mono sound to Stereo sound... isn't it?

 

EA81S = the StereoBoxer! :lol:

 

Kind Regards.

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Nope, EA81 on the block, "S" imprinted in white on the rocker covers.

 

I haven't noticed that on my RX. Will have to have a good look lol.

 

Did they do the same on the GSR with the S printed on the rocker cover?

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... Did they do the same on the GSR with the S printed on the rocker cover?

 

 

As far as I know, the "S" Version came in the Sporty Models, However, Subaru did made other Sporty versions in the Past; the First EA81 Dual Carbs, had twin Hitachis on a Single intake manyfold, but those engines already got the Reverse valves, etc...

 

So the Twin Weber Carbs setup was the Last "S" Sporty engine with twin Carburetors from Subaru, in 1983; the same Year they intruduced the Turbo EFi engines, so very Few Twin carb EA81 engines where made, even fewer with the Late twin Weber Setup.

 

 

But subaru did the Twin Carb (Hitachi) setup Before, in the EA63 and the EA71.

 

Here is a Picture of the Twin Carb EA71 on the Subaru Manatee:

 

 

Manatee2.jpg

 

 

Manatee5.jpg

 

 

More info on the Subaru Manatee, on this Thread: "Strange & Weird Subaru Stuff"

 

 

Some EA63 Sporty versions, came with Weber Carb and Weber intake manifold:

 

 

WeberintakewithCarb-EA63.jpg

 

 

webermanifold1.jpg

 

 

Kind Regards.

Edited by Loyale 2.7 Turbo
Misspelled Word

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First Subaru Twin carb engines were in the 1400 GSR coupe and GS Coupes from 1st December 1972 these were the EA63 type Engines in a more sporting Variant.

Weber Carbs were never fitted to any production Subaru but only available as a Sports option kit for Motorsport use and then only in very small numbers.

 

Australia was the first place outside of Japan where Subaru competed internationally in the Southern Cross Rallies in NSW,I should have some photos from back then I will scan and upload.

Here is also a Link to Subaru Philosophy,It can be not so intuative to navigate through to find information so I suggest searching via google or some other search engine for topics on the Subaru Philosophy site.

It is full of information not available in the past.

http://subaru-philosophy.com/post/27968951632/leone-debut

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... Australia was the first place outside of Japan where Subaru competed internationally in the Southern Cross Rallies in NSW, I should have some photos from back then I will scan and upload...

 

Great! ... icon14.gif ... I'll Love to see your Photos from that Races! :burnout:

 

Kind Regards.

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First Subaru Twin carb engines were in the 1400 GSR coupe and GS Coupes from 1st December 1972 these were the EA63 type Engines in a more sporting Variant.

 

The EA62 was available with twin carbs (in the FF-1) which pre-dates the introduction of the Leone in 1971/2.

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I heard a Rumor about the Subaru FF-1 Star with twin Carbs and Disc brakes; I took a Ride once on a FF-1 Coupe, it had not the twin carb setup...

 

I Believe those came in different trim levels and variants for different markets.

 

EA62 1.3L OHV Water-Cooled Flat-4

 

Displacement: 82 mm x 60 mm, 1268 cc

Power: 80 bhp (60 kW) @6400 rpm, 73 ft·lbf (99 N·m) @ 4000 rpm with 9:1 compression and dual two barrel carburetors

 

~► http://en.wikipedia.org/wiki/Subaru_G

 

Kind Regards.

Edited by Loyale 2.7 Turbo
To add the Web Link.

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