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Ideas on Swaping a Weber Carb on EA82´s

WEBER EA82 EA81 JesZeK PCV Carburator Swap Honduras Loyale 2.7 Turbo

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9 replies to this topic

#1 Loyale 2.7 Turbo

Loyale 2.7 Turbo

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Posted 20 April 2007 - 04:03 PM

Ideas on Swapping a Weber Carburetor on a Subaru EA82 Engine


In this Writeup:


 Solving problems untold by the Manuals.


 Jetting for the EA82 to be used between Sea Level and ~ 6500 Feet (2000 Mts) Altitude.


 Proper PCV (Positive Crankcase Ventilation) Hoses Setup and installing an (optional) Oil Catch Can.


 A much better Adapter Plate than the one designed for the EA82.


 Intake manifold modifications (optional).


What to do with ASV, EGR, etc...


 ...and Much More!    ;) Pay attention to the "Important Notes" 



On early 2006 I Swapped a progressive Weber 32/36 Carburetor on my 1985 Subaru White Wagon (which isn't white anymore),, that swap job took much more things to do than what the Manual included with the kit, stated; so I'll explain everything needed to successfully do the Swap and I will add Photos, describing all the problems I faced and the ideas I had to solve them, here; Hoping that this writeup will Help you to Swap a Weber carburetor on a EA82 Subaru engine.


Many of the Ideas I'll explain here, might be aplicable to the older Subaru EA81 engine as well, almost everything except the adapter plate.


REMEMBER: Use this Ideas at your Own Risk!



First of All: the Redline-Weber K-731 Kit, which is designed to install a Weber carburetor on the Subaru EA82 carbureted Engines, comes with a Progressive Weber 32/36 Carb, an Air Filter Box plus its element, a Throttle Cable Bracket, some Gaskets and a two plate Adaptor, which consists on one Lower plate designed to be mounted directly to the intake manifold, and one upper plate, designed to be mounted over that first plate; this last one will have the studs which are intended to Hold the Weber Carb in place; and needs the Gaskets inbetween... Also it comes with a bag with different screws.


All those Weber carburetors that are Sold in USA comes with a sticker with a Statement that says something like: "For Racing -or Offroading- Purposes Only" due to Smog, pollution and other Legal Regulations that varies from State to State, so They're Not "Street Legal" on certain areas and that statement shall be placed on all brand new Weber Carbs, due to said Legal Regulations; so be sure that you are legally allowed to do this Swap on the Areal where you Live, prior to start.


There are many different Weber Carburetors' Designs on the market, however the two models used more often on Subaru Engines, are those who features two Barrels.


There are two variations of the two barrel design on Weber Carburetors, One design is known as the Progressive Models (Such as the 32/36 DEGV) and the other design is known as the Synchronous Models (Such as the 38/38 DGAS).


Each barrel has its own butterfly that opens / closes according to the Throttle position; if you want to be Sure which model do you have, just take a look at the Linkage that opens the butterflies between both Barrels, it is located behind the throttle plate: If Both Butterflies on both barrels, opens at the same time, always when the throttle position moves, it is a Synchronous Weber (Such like the 38/38 DGAS or a bigger numbered, like the 48, etc...)But if one barrel's butterfly starts to open only after the other one have already reached the half way open, then it is a Progressive Weber. (such like the popular 32/36 DEGV ).


The Synchronous Webers, such like the 38/38 DGAS are more used for Racing purposes due to the Higher Fuel usage (Both identical barrels works / opens at the Same Time, all the time), and thus means that if you use a Car with such kind of carb as daily driver, it will be a Gas guzzler, compared to the Progressive Webers, like the 32/36 like the one I Used, where you commute with only one barrel which is known as the Primary -Low- Stage (with a Smaller Jetting), usually; and the other barrel, which is known as the Secondary -High- Stage (with a Bigger Jetting) is used during deep accelerations only, so you have the Best Balance between Power and Fuel Consumption.


That been said, lets Begin to explain the Problems I Faced during the Swap Job, and How I Solved them.




~► First Problem: The Screws that Holds the Lower Plate.

The lower plate needs four screws to be Held properly in place, directly on the intake manifold; each screw has a cone shaped, flat top head, whose angle is approximately 60° and is designed to fit on the also cone-shaped openings of the Lower plate, letting the screws' Heads to be as Flat as the lower plate's Surface itself, and the inner angles holds that plate firmly in place. Those screws use hexagonal wrenches.


The Redline-Weber K-731 kit came with two different sets of screws to hold that first plate of the adaptor to the intake manifold, one set has the appropriate size and pitch of the Subaru's intake manifold's threads (1/4" ~ 6 mm), but the heads of those screws are very small, around the half size of the cone shaped openings at the first adaptor plate. The other set of Screws provided, are Bigger (5/16" ~ 8 mm) and their heads fills completely the cone shaped openings on the first adaptor plate; but their thread and pitch are bigger and will not fit on the intake manifold's threads.

It is impossible to bolt in a "safe" way, the lower plate to the intake Manifold using the thinner screws provided, but I bet that they included both sets, in order to let the Lazy mechanics to swap the carb fast and easy ... but those tiny screws will make the first plate to fit Loose, and develop vacuum leaks sooner or later.


So, some modifying job to the intake manifold is needed for sure: to re-thread the intake manifold's threads to the size of the bigger screws provided, in order to use them to hold the Lower plate properly, and firmly in place. That is what a true mechanic will do, to seek reliability.

I used the Bigger Diameter Screws, of course(But continue reading: in further posts of this writeup I'll show you a more safe & Definitive way to solve this problem)

To make those Bigger diameter screws to fit, You'll need to Drill and tap new Bigger Threads to the intake manifold, but Be Careful when doing that: The intake manifold is also a coolant crossover, so you must take the proper measurements to avoid drilling onto a water passage. I Kindly Suggest you to remove the whole intake manifold from the Engine, prior to do the rethreading.


Here you can see how the Intake Manifold Originally was, 

with the Craptachi Carb & Gaskets just Removed:


(Notice the Small threads on the Carb's Base)




So I took off the whole intake manifold to Drill the New Oversized Threads




From mm (around 1/4") to about 8 mm (around 5/16")



Also I Sent the intake manifold to a Machine shop, to polish the flatness of the Carb's base:




Here, you can see how the Bigger Screws Now fits perfectly on the Subie's Intake:



Then, I Washed clean the intake manifold using Household Detergents, to remove any debris:



Important note: All the inbetween gaskets should be placed completely Smeared (the two faces) with Shellac, because shellac is Coolant / Oil \ Gasoline Resistant (more info on Shellac ~►Hereother gasket makers will fail in that place.



~► Second Problem: To Seal the (Now Unused) Water Passage for the Old Craptachi Carb.

If this procedure is not done right, the cooling system will spill coolant on the intake manifold, right to the carb's base opening, so be Careful!

My first solution was to place the Gasket completely smeared with Shellac over that water opening, and also I cut in half the tiny Hose which supplies coolant for that Passage, and cap closed both ends of said hose, using screws and clamps... That worked fine for five years, but you must consider that there is still a coolant flow inside the water crossover of the intake manifold; so there still will be coolant flowing on that Area, even without said hose.

You might use Cold Welding Compound such like the 4 minutes "JB Weld" to fill close that opening ... as I wrote, I ran my subie for years with only a Shellac smeared gasket and a removed hose without problems, but that setup was about to Fail after five years. Continue reading, in further posts of this writeup I will show you another Idea which is a definitive and permanent solution for this problem.


After placing the Gasket, smeared with Shellac on both sides,

inbetween the intake and the first plate, I bolted it there:


(Notice the Bigger Screws and how their Heads fills the Plate's openings)





Then, the Upper plate went over that first one,

Also with a gasket smeared with Shellac on both sides, inbetween:





And Then you can place the Weber Carburator.



~► Third Problem: Power Steering Equiped Models.


If your EA82 engined Subaru, has a Power Steering Pump, the Choke's Spring mechanism on the Weber Carb, will hit the Power Steering Pump's reservoir ...  :( ... and even removing the Choke's Spring, the base for the said spring, impacts the bolt's head at the back of the power steering pump.



(the Choke spring was already Removed from the Weber Carburator)





Here at the Caribbean Tropics we don't need the choke too much, so my first solution was to Remove the Choke's Spring, but also I Needed to cut Half of the head from one of the Steering Pump's Rear Bolts, to prevent the Base for the choke's spring from hitting the power steering's back bolt. ... Another Solution is to Completely Remove the Choke's Spring Base from the Carb and its Butterflies (choke plates), so you'll not need to cut anything.  Continue reading, because in further posts of this writeup I'll show you yet another and better Solution I found, later.   :D 




Important Note: I did installed on the Weber Carb, the throttle's Cable Plate Taken From the old Craptachi carb,  plus the part of it that works with the Air Conditioner Accelerator Actuator, which with a simple twist on its metal plate (due to the new carb's different angle) I managed to made it work good.



So the Intake Manifold + Adaptor Plates + Weber Carb ended looking in this Way:




(Yes: Those are my dirty Hands)



Once installed, the EA82 Engine started at the Very First Try and Purred like a Kitten...


a Boxer Kitten! ...  :D ... you know.




The Weber carb reveals somehow the Hiding potencial of the engine, and the Boxer Rumble Sound of the Carburated EA82's at its Best! ... While lets you Clean the crowded engine bay, removing lots of unused smog stuff. It is a Win-Win Deal for sure.


I Noticed a Huge Improvement inmediately! ... Summarized in a quicker Engine Response and Faster Acceleration, smoother Idle and a really noticeable Better Low end torque. 


Fuel Consumption remains close to the Stock Specs... (if you drive carefully) ...but the Weber swap could make you to want to keep the gas pedal floored ...  :o ... in that case, fuel consumption will increase for sure   :burnout:

Edited by Loyale 2.7 Turbo, 30 September 2015 - 12:36 PM.

#2 Loyale 2.7 Turbo

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Posted 07 September 2011 - 12:34 PM

Almost Seven Years have been Passed Since my Weber Swap and I've Learned Lots of Things from my Experience that I want to Share Here.

First of All, the K-731 Kit is a Great kit but the Two Plate Adaptor Sucks! ... :angry:
 ... I Understand that they wanted to Keep the Whole thing Stock Looking but by using that low two-plate adaptor, the Choke had The above described problem with the Power Steering equiped Models: Not only the Whole Choke Hits the Rear of the Power Steerin' Pump, but even removing the choke, its base Hits one of that Pump's Screws.


As I wrote, I had to Cut that Screw's Head to allow the Weber Carb


to Completely Sit on that two plate Adaptor.






And I Had to Completely remove the Choke.

(Thanks God it isn't Needed here at the Caribbean Tropics)










I've sent it Brand New, including the Butterflies and Hardware


to a Great Friend and USMB Member in Australia.






Also, if you Need to Take out often the Weber Carb to do a Cleanup, etc, 


Probably This is Gonna Happen:





After all those years of Use, that happened to my Two Plate adaptor, even if I removed the Carb Carefully only a couple of times before; this breakage is due to the Angle of the Tool,  forcing to Remove the Nut at that Point behind the Power Steering Pump's reservoir, it makes some extra effort to the Weak aluminium material of that Plate because the Carb sits too Low.

So, I Searched locally at all the aftermarket stores in my area, and also all across the internet, and I Found a Way Better Adaptor to Fit the Weber 32/36 carburator to the EA82 engine's intake manifold; it was Originally Designed to be used on certain Datsun Vehicles that came factory with a 1600 engine which featured a Hitachi Carburator that has the Same measurements on the Mounting Base (identical size) as the factory Subaru Hitachi Carburator.


The Adaptor is Made by "Trans-Dapt" Model Nº 2107


and is a Strong, Thick Single Plate adaptor; as you can see:





I Obtained it at amazon.com, Here you can see it when it Came by Mail:









And here you can see the Old Two-Plate (broken) Adaptor Vs the New Single Plate Adaptor:





The New Single Plate Adaptor is much Taller than the Double Plate older one, So it Solves the Problem of the impacting Screws / Choke while it Raises Up the Base to install the Weber Carb. That also makes an Easier Reach to the Screws that Holds the Carb, in case you want to Remove it for Servicing / Cleanup, so no more Forcing angle tool anymore.

The Trans-Dapt 2107 adaptor Directly Bolts in the EA82's intake Manifold without any Problem, you can use either the Original Subaru Thin Screws or the thicker diameter ones, but is Better idea to Bolt it Using the Thicker Screws as I Explained above.




Important NoteNone of the Adaptor Plates I show in this writeup, will fit on the EA81 nor any other Subaru Engine's intake manifold, those are specific for the EA82 engine only.

Edited by Loyale 2.7 Turbo, 03 April 2013 - 12:44 AM.

#3 Loyale 2.7 Turbo

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Posted 07 September 2011 - 12:55 PM

--► Fourth Problem


This one occurs only when you Switch to that Single Plate Adaptor, Because it Raises Up the Weber Carb, you Won't be able to continue using the 2½" tall Air Filter Element anymore, Because now it will Rub the Hood, Unless your Subie has installed a Lift kit that Dropped the Engine Crossmember 1½"






The Solution: you Must Switch to the Shorter 1¾" tall Air Filter element.






Both are "Standard" Air Filters for the Weber Carbs and are easy to Find, usually The Taller one is Widely used in Weber Swaps while the Short one is Widely used in VW Bugs.

Edited by Loyale 2.7 Turbo, 30 March 2013 - 05:31 AM.

#4 Loyale 2.7 Turbo

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Posted 07 September 2011 - 01:24 PM

After that many Years of Driving my Subie with the Weber Carb, I have removed it for Cleansing few Times. The First time was due to an "Error" done by a friend who was "Helping" me to do a Paint Job, he "Mistakenly" poured Paint Thinner in the Carb and somehow melted the Acceleretor Pump's Diaphragm:





I Found one Brand New locally, on a E.M.P.I. Rebuild Kit.





I've Taked out the Weber and Deeply Cleaned it:
















(I'll use simple mathematics: I don't want to give Scientifically accurate and detailed calculations here, it is not necessary)



The Original Hitachi Carb that came Stock on my Subie (Mine is 1985 California -Yes, USA- Version) came Stock Jetted as Follows: 116 in Low -primary- Stage and 160 in High -secondary- Stage, for a Grand Total of 276.


My New Weber Carb which Came in the K-731 Kit Already Jetted for the EA82, came with 140 in Both Low -primary- Stage and 140 in High -secondary- Stage ... the Weber Carb's Grand Total is 280, Very close to the Stock Hitachi's Grand Total.



Since I did the Weber Carb Swap in my Subie, I Noticed that the Lower Range RPM's had an increased Torque, the engine developed an overall faster acceleration, but the High Range RPM's Behaviour seems to be Almost Equal to the Stock Hitachi Carb behaviour: both carbs gave the Same Feeling at Higher Rpm's.


So, Thinking about the Increased Air Bleeding Capabilities & Size of the Weber Carb, also thinking about the 140 / 140 Jets and the Feeling it Gave in Both Stages, I Realized that the People at Redline-Weber Sets their Carbs for Applications at the Average Use, Because the Weber Carb's Grand Total of 280 is Very close to the Hitachi Carb's Grand Total of 276 ... Despite that the Weber is Really Bigger and more capable...


People at Redline-Weber did increased the Low -primary- stage jetting but they decreased the high -secondary- stage jetting, comparing to the stock Hitachi Carb's jettings; and that explains somehow the increased low end torque given by the Weber Carb as it came jetted... So, I wanted to gain the Same improvement found in the Low -primary- stage, on the High -secondary- stage too.


So, I Re-Jetted my Weber.




First I tried with Many Different Jettings and did Test Drives in Many Different Situations and circumstances, in Order to Get the Best Performance Without Getting the Mixture too Rich or Flooding, nor letting my Subie to Swallow more Gas unnessesary...

After All that Weekend's Tests, I Left the Weber's Low Stage as it Came: 140 without Modifications as it already develops the Best performance in Low -primary- stage.


While the Best Performance at the High -secondary- Stage was Gained with 162 ...  :o ... So Now my Subie has 140 on Low -Primary- Stage and 162 on High -Secondary- Stage, for a grand total of 302.




comparing it to the 276 of the Stock Craptachi Carb... it only increased 26 points.





Seems like the Weber's Air Bleedings already came set to Handle the increased amount of Mixture very Well... but if I Drive with Full Pressed Gas Pedal it will Use a Li'l Bit more Gas than Before, but Believe me: it is Almost unnoticeable and giving a such Small engine a Li'l more Power, really Worth it.




Important Note: I Changed the Distribuitor's dual port Vacuum advance, for a Single Port unit: it works much Better with the Weber's single vacuum port for that distribuitor's advance. In the Photo below you can see the removed two port vacuum advance, and the Box with the Part Number of the Single Port vacuum advance.






Both Vacuum Advance units are intended for the NIPPON-DENSO Distribuitor, found on the 2WD (FWD) EA82 carburated engined subarus; those aren't intended for the Hitachi Distribuitors found on the 4WD (AWD) EA82's






The Only Few Moments when I Feel a Li`l bit of Flooding, are when the Subie is First Started Cool early Morning and Only if I Press the Gas Pedal too Deep... but my Weber Carb Does Not have Choke at All, also that Behaviour shows only for the Very First Minute or Two after Startin` the Engine, then Dissapear.

One Last experience: My Subie's Sparkplugs comes in Light Reddish Colour, they're Not Blackening. :)

Edited by Loyale 2.7 Turbo, 03 April 2013 - 12:50 AM.

#5 Loyale 2.7 Turbo

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Posted 07 September 2011 - 01:28 PM

After that many Years of Driving my Subie with the Weber,  I Know that I'll Never go Back to the Craptachi carburetor Anymore.  I'm More than Satisfied with the Weber Carb ... th_dance9bh.gif ... So I Decided to make my Swap job, more "Permanent"

Here I Will Explain some Modifications I Did to the EA82 engine's intake manifold, but I Clarify that those mods are Not Nesesary, I Just Did them to make things Stronger and get Rid of Possible Future Failure points.

Right after obtaining my Brand New Trans-Dapt 2107 adaptor, I Removed the intake Manifold and the Weber Carb. Also the old and Damaged Twin plates adaptor and the Gaskets Between.




The Gasket under the First plate Held good there closing the Water Passage intended for the Old Craptachi Carb, but it had more than Six Years there and was About to Fail, Even if I have closed the Water Hoses as you can see:





So, in the Following posts, I'll explain the Modifications I've Done to my Subie's intake manifold:

Edited by Loyale 2.7 Turbo, 03 April 2013 - 12:52 AM.

#6 Loyale 2.7 Turbo

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Posted 07 September 2011 - 03:35 PM

First Step:

I Wanted to Remove and Completely Erase those Unused Water Passages, So I Took the intake Manifold to a Professional Shop in order to Cut the Water inlet Hose and Permanently Fill with Aluminium Welding of the Same Quality as the intake, the Tiny Hole and the Water Passage.

Then I Asked them to Bolt on the Trans-Dapt 2107 Adaptor, which is made of good quality Aluminium, Directly to the intake manifold, without Gasket and then Completely Weld it to the intake with same good quality aluminium.

So the adaptor is not only Held in place by the Bolts, but completely Welded with Aluminium; Making it to be a Solid One-Piece with the intake manifold itself; also doing that does Eliminate permanently the Need of a Gasket between intake manifold and adaptor plate, so it also erases a Future Gasket Fail Problem, or a vacuum leak / coolant leak problem.




Also I asked them to Close the hot Water Outlet passage


that came from the Heather Tube, with Permanent Brass Welding.




Edited by Loyale 2.7 Turbo, 30 March 2013 - 06:04 AM.

#7 Loyale 2.7 Turbo

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Posted 07 September 2011 - 03:59 PM

Second Step:

Since I Changed my EA82's Heads for the Third Gen EA82 Heads
(The ones with Surrounded EA82 Logo, as Explained ~► Here) the New Heads came Without EGR Passages. (it is Known that the EA82 had a EGR Design Flaw, after all, the EA82 was originally intended to be a ~►  2.0L engine) The EGR Stuff isn't Needed anymore.

So I Asked them at the Shop, to Close Weld with Aluminium Filling, the EGR Valve place, the EGR Pipe and a unused Vacuum Port that was aside the P.C.V. valve inlet.




When it came from the Aluminium Welding,


Once again I Washed the intake manifold Throughly


with Household Detergent, in order to remove any debris.




Here you have a Closer View of the Aluminium Welding,

Note: There's No Hot Water inlet anymore!







Third Step: (optional)

I Checked the Aluminium Fillings and I Noticed Very tiny Holes that made me Think if one of those could Lead to a Vacuum Leak... So I Covered completely all the Aluminium Fillings with the Strongest "Cold Welding Compound" I could find, in order to Completely Seal the intake.


I Think that this step isn't really Necesary, but Doing that gives me "Peace of Mind" that nothing could fail about those Weldings.



Edited by Loyale 2.7 Turbo, 31 March 2013 - 03:14 AM.

#8 Loyale 2.7 Turbo

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Posted 07 September 2011 - 04:13 PM

Putting all Together:

The E.M.P.I. Rebuild Kit that I Obtained locally, had the Accelerator Pump Diaphragm plus all the Gaskets and a Temperature isolating Plastic Spacer, which is used as a Sandwich Between two Gaskets; so the Carb will Run Cooler:)




I Kindly suggest you to smear a thin layer of Shellac on each gasket's sides, it is the only one that could be in contact with Gasoline without Problems. Forget about others like Silicones.


This is How the Whole thing Looked Like, just before reinstall it on the EA82 engine:





 Gasoline Tank Lines are Three:


- The 5/16Main fuel supply line is the "Fuel Delivery" to the Carburator.


- The 1/4Secondary Line is  the Gas Tank's "Vent Line"


- The 3/16" Third line is the "Fuel Return" to the Gas Tank.

    (Yes, the Return line on EA82 Carbureted models has a small diameter but is enough)


I only hooked the main fuel delivery (5/16") line to the carb, closed the return and left the vent line open with a short 1/4" hose, but I attached one of those mini air filters to it, in order to prevent debris to getting into it; those two unused lines hangs next to the Brake's Booster, hiding there and the Subie worked Flawlessly like that for nine years.


Then, I had the idea to remove the straight fuel inlet fitting from the Weber carb, and place there the "Y" shaped fuel inlet fitting from my old craptachi carb, which has an Straight 5/16" inlet, and a smaller 3/16" return line; in order to reconnect the closed Return line (3/16") to the fuel tank, with the idea of helping the Weber's Float to do easier its Job. The thread's size and pitch are Equal between the Weber and the craptachi Carburetors.


Closing the Return and the Vent Lines, or Hooking a "T" between them is a Dreadful idea; it will made a strong pressure buildup on the Tank and its lines / Hoses and in my own humble opinion, could be Dangerous, especially during hot weather days.





Differences on those lines, between the Carbureted EA82's and the EFi EA82's: You must be Aware that in the Carbureted EA82's, the Main Fuel delivery line (5/16") comes alone to the engine's bay, from above the Frame Rail, down under the Master Cylinder; and the other two lines (Return and Vent) comes together, above the Brake's Booster; that setup is Different on the EFi EA82 counterparts; because on those, the Main fuel delivery line and the vent line, comes together above the brake's Booster, while the Return line comes down, from above the frame rail, and has an increased diameter.


That information will help those who wants to install a Carbureted EA82 on a Body that came from factory with an EFi EA82 or Viceversa.

Edited by Loyale 2.7 Turbo, 30 September 2015 - 10:14 AM.

#9 Loyale 2.7 Turbo

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Posted 07 September 2011 - 04:46 PM

The Hoses Mess and the  P.C.V. - A.S.V. - E.G.R.  Systems:


- A.S.V. = "Air Suction Valve"


The Purpose of the A.S.V. system is to put some fresh air onto the Exhaust system, to aid to the Catalytic Converter to work as it Should; the two Small Black Boxes on it (one per side of the Engine), are intended for Noise reduction.


- E.G.R. = "Engine's Gases Recirculation"


The Idea was to put part of the Exhaust Gases, onto the Air / Fuel Mixture at the Intake Manifold, but the Design of it for the EA82 proven to be Defective and Harmful for the Engine, affecting one cylinder directly; So it was not available on the State of California; Also the Subaru Engineers Sealed its Passage on the redesigned Third Gen EA82 Heads. You can see Pictures of the Three (3) different EA82 Heads, ~► Here.


P.C.V. = is the "Positive Crankcase Ventilation"


This is the only one that is Really, Really Needed for the engine, So you need to properly Understand the reason why the P.C.V. system exists and how it Works:

Why? ... The engine needs an air Flow in and out of the Crankcase, not only to facilitate the crank's spin movement and release internal's pressure, but mainly to take the harmful acid vapors Outside; so routing those thru the P.C.V. valve at the intake Manifold, makes possible that said vapors could be sucked by vacuum and Burned along the Air / Fuel Mixture on the Cylinders during their normal cycles.

This is How it Flows: To Coordinate the air flow direction with the Crank spin, the Passenger's side (R) Head does "Suck" Fresh air, while the Driver's Side (L) Head "Expels" that air along the Harmful Vapors. All that throught the 5/8" Openings on the Top of Each head. The Impulse that circulates that air, comes from the intake manifold's Vacuum, thru the P.C.V. Valve.

So, very Basically you'll need:

  • First: To plug a 5/8" Hose from the Passenger's Side (R) head opening, to the Air Filter Box, so it can Breathe Fresh, Filtered Air for the system. This side has the incoming air.
  • Second: To plug another 5/8" Hose from the Driver's Side (L) head opening, to the P.C.V. Valve at the intake manifold, so its vacuum will move the air and take out the Harmful vapors to get Burned in the Cylinders. This side has the Outgoing Vapors.


Warning! ...  :excl: ... Said P.C.V. Setup needs a  "Presure Relief Detour"  on that second hose, to Relieve the Suction from the P.C.V.'s Valve, in order to Avoid sucking oil out of the valve cover.


To do So, you just Need to use a 5/8" Detour "T" but with one Size Smaller (3/8") on the Driver's Side (L) Hose and route that Smaller opening to a Filtered Fresh air Source; preferably at the Air Filter Box. (but it could go to an independent air filter as well)


This very Clear Picture Belongs to Kanurys from his EA82:




Please, note the Detour "T" placed right after the P.C.V. Valve at the intake manifold and how its detour is routed to a new (added) small opening at the Air Filter Box's Base.



Important Notes:


Let me explain this with complete details: The Smaller diameter detour, placed with a 3/8" out "T" on the Driver's side, is intended to avoid High pressure "Sucking" from the P.C.V. valve, and thus means to prevent oil to getting sucked and sent to the intake manifold, especially under hard acceleration, which could lead to have oil getting burned on the mixture at the cylinders, creating white smoke clouds, dirty sparkplugs, etc... the usual "Worn Engine" symptoms you know.


It is better to use a smaller (maximum of 3/8"~ minimum of 5/16") diameter detour Directly to the air filter's box, because:


If you use a 5/8" detour (same Diameter as the rest), the P.C.V. valve most likely will suck fresh air thru it (Shorter travel), instead the Driver's side Head, and the whole P.C.V. setup will not make any sense, turning that system onto a completely Useless mess of hoses; because in that case, very few to none crankcase fumes will go to the intake manifold thru the P.C.V. valve, to get burnt.


This equals to install small air filters on each head's opening and the P.C.V. valve, is like leavin' those open... That turns the P.C.V. system completely Useless for sure.


 That smaller diameter detour shall be routed Directly to a fresh filtered air source, Never to the Other Head's Hose; in order to prevent a recirculating phenomenon where both sides moves air from each other and a very small to none amount of Harmful vapors goes to the intake to get burned.



Additional info:


In my Case, My EA82 engine has over 300 K Miles of Hard, Rude Driving; Mainly off-road on (My Li'l Country) Honduras So it has a Problem: it trend to Has some Oil Blown-by on the outgoing Harmful Vapor thru the Driver's Side 5/8" Hose.

So in my case, I decided to place an
Oil Catch Can to Separate Oil from the Fumes, between the Driver's side Head Hose (L) and the P.C.V. Valve, I obtained this one:







Let me emphasize that Once the P.C.V. System is Properly set, and the three (3) Needed vacuum lines are in place, as I will detail how to, on the Next post; you could Get Rid of Everything Else on the Vacuum Hoses mess, including the E.G.R. system, the A.S.V. System, its Hoses and the two small Black Boxes, which are one per side of the Engine. (Deleting the A.S.V. system includes to Block the Exhaust openings.)


You won't believe the large amount of useless crappy stuff I Removed from the Engine's Bay, It ended as a Huge Box full, including the Small metallic vacuum lines' set, the Thermo-Vacuum Switch, the Carbon Canister, all the "Spaghetti" of Hoses, the E.G.R. System, the A/C accelerator Actuator, Sensors, wirings, the A.S.V. system, Hoses, the Craptachi Carb, the old Air Filter Box, etc...


Also my "BumbleBeast" runs without Both Cathalytic Converters, as you can see ~► Here.

Edited by Loyale 2.7 Turbo, 29 July 2015 - 11:46 AM.
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#10 Loyale 2.7 Turbo

Loyale 2.7 Turbo

    The Mighty "BumbleBeast"

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Posted 07 September 2011 - 05:22 PM

Remember: Japanese cars uses milimetric measurements, so the factory size for the main PCV system's Hoses, is the milimetric equivalent to 19/32" (~ 15.1 mm)  I used 5/8" in evaporative systems' rated Hose, 5/8" = 20/32" (~ 15.8 mm) with perfect results.




5/8" is easier to find than 19/32" and gives more room for the fumes to move freely.


So, I'll refer to all the hoses in inches only.




To do the proper P.C.V. Hoses Connections, I needed:

1. Enough 5/8" Hose (more than 4 foot needed).


2. Enough 3/8" Hose (Less than 1 foot needed).

3. One Lightweight Plastic 5/8" Tee with a 3/8" detour opening.


(the 3/8" detour is very important, do Not use an equal diameter tee)




4. One 5/8" Lightweight Plastic Elbow to Use at the Air Filter Box,

(instead this Heavyweighted brass one I did before)





I obtained an Aluminium Elbow for the P.C.V. Valve:
(it is Not necessary, could be Directly Connected, but I Like it)




5. Add a New 3/8" Opening, welding a Plug with Brass, to the Air Filter Box Base. 


I took a Photo of it, to show you the two openings, which are intended for:


 The one on the Left was added by me; is for the "Pressure Relief" detour. 

....(This will be explained below)


 The one on the Right, is the straight 5/8" opening, which goes to the above

....described Elbow(Also this will be explained below. Keep Reading)







6. Enough Clamps, for each Hose's end.  :D 


7. New intake Manifold's Gaskets and Bolts.




I Reinstalled the intake Manifold using the Original Subaru Gaskets.


Prior to Install them, I Smeared both sides with a Light Coat of Ultra Cooper Silicone:






Forget About Crappy Aftermarket gaskets and you'll Avoid Future Problems.


Also I changed the Worn-out Old Screws that held the intake manifold in place,


with Newer ones (Found at the Local NAPA)which are Steel reinforced and Rust proof,


which are 8 mm X 80 mm X 1.25 Pitch:




In my Case I added an (optional) Oil Catch Can.   :D 



As I wrote in previous posts, and in other threads:


My White Wagon isn't White AnymoreI Painted it in Yellow Colour as I explained hereLighter tone than my Other Yellow Wagon (the Dead 2.7)but this one has Black Stripes, and many mods...



Now you will See how all this Stuff ends Together...

P.C.V. Hoses Goes as Follow:

(Remember: these explanations are referenced for the LHD models)



First - The Driver's (right) Side Head Opening, goes to the P.C.V. Valve at the intake Manifold, use enough 5/8" Hose, but you must place the "T" with the 3/8" detour for the "Pressure Relief"  inbetween, then place enough 3/8" Hose, directly from said "Tdetour, to the added 3/8" Opening on the Air Filter's Box base.



(In my case, the Oil Catch Can is in that same 5/8" hose Route as well, if you don't need one, use a Direct Hose)






Last - The Passenger's (left) Side Head 5/8" Hose goes directly to the Air Filter Box.







► Vacuum Lines Goes as Follows:


  1. Use a Vacuum Hose, from the Front of the Weber's Right Port, to the Advance on the Distributor. (this is a Progressive Vacuum Port)
  2. Use the Proper Vacuum Hose, from the intake manifold, to the Brake Booster.
  3. Use another Vacuum Hose, from the intake Manifold, to the A/C vacuum accumulator Bottle.



Important Notes:


The accumulator bottle under the Windshield, at the engine bay, behind the Passenger's side strut Tower (on LHD Models) is used to provide stable vacuum for the A/C buttons on the Dashboard and also for engaging the 4WD mode on the models equiped with Push-Button transmission. So, if your subie doesn't have that kind of Transmission nor A/C, you can simply omit to connect that third vacuum line.


The E.G.R. System: Is it necessary? ... Well, the answer will depend on your area's Laws against pollution and what will be needed to stay in the car in order to pass emmissions; but that E.G.R. design is unhealthy for the EA82, that is the reason why the Subaru Engineers removed it from the third gen Heads.


But if you want to keep it and make it work as close as it should, the front of the weber carburetor has two pipes that provides vacuum, the one on the Right side which is Progressive, is intended for the distributor's advance; while the pipe on the Left side, provides vacuum until the engine is at higher RPM's, when the Secondary (high) stage of the carburetor is activated; so it is intended to be hooked at the E.G.R. Valve.


So, you can run a fourth vacuum line directly from said front-left port on the Weber Carburetor, to the EGR Valve at the intake manifold, to make the E.G.R. system, operative.


The A.S.V. System needs to be Removed, so the rest of the Openings on the Exhaust, shall be Closed, otherwise your engine bay will become Noisy from exhaust...


 Don't forget to cap Close all the unused ports at the intake manifold:excl: 




After all that, the engine Runs Flawlessly, Stable and Reliable!






And This is How my Weberized EA82 Subaru Wagon Looks Now:




Named: The





Here's the Build Thread:


~► http://www.ultimates...e-bumble-beast/


(Click on the Link above, or in my Signature, for more Writeups like this one, and Downloadable Files)




This is a Video of the Weber Carburetor, Working on my "BumbleBeast" Subaru:




Feel free to ask Any questions regarding the Weber Carb Swap,


on its Discussion Thread, which is Here:


~► http://www.ultimates...1-to-27-loyale/


I Hope This Write-up will be Helpful.  ;) There are interesting comments regarding this writeup, on Facebook, like this one:
If you find this writeup Useful, let me know by hitting the "Like" Button below.

Kind Regards.

Edited by Loyale 2.7 Turbo, 26 April 2015 - 01:51 AM.
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Also tagged with one or more of these keywords: WEBER, EA82, EA81, JesZeK, PCV, Carburator, Swap, Honduras, Loyale 2.7 Turbo

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