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What drivetrain?


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EA81 and EA71 heads dont interchange, there is more space between the cylinders on the EA81s, I checked all this out yesterday after I pulled the heads off my 1400, i had some pre-'80 EA71 heads laying around, as well as some EA81 heads to compare, and I plan on using a Post-80 block for the 1400 heads to go on (has about 12,000 on the bottem end) and from the measurements i took, everything should swap to it.

 

I believe the EA63 cam will work with the EA71 block, but that matters not, because custom cams will be ground. The valve configuration in the 1400 heads is the same as the 1600 heads, its the exhasut ports and the combustion chamber size that are different

 

-Bill

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Now there you go trying to tempt me with that turbo motor! Don't think the thought didn't cross my mind! :grin: So it would seem the best course of action would be the early EA71 with the 1400 4 port heads and reground EA63 cam. Mods to be possible high compression pistons (if the 1400 head swap doesn't raise it), larger valves (cost dependent) with some port work, lightened flywheel, custom stainless headers and a sidedraft weber. Sounds like a workable plan! Just need to find an EA71 now! :lol:

 

BTW, what would the best header design be? I would think you would want all primaries to be equal length (stock is short/long) with a relatively short length under 36" prefferable. I would guess it would need be of a "tri Y" variety as a 4 into 1 design would probably have undesireably long primaries for good top end power. I would think 1 1/2" primaries into 1 3/4" 2 into 1 collectors for the left/right banks, then 1 3/4" into 2" collector for the connection to the exhaust system. That should be more than sufficient for the power this combo will produce. It's speculation at this point but sounds good. :-\

 

Mark

Flywheels... I have no idea, i've yet to see a lightweight flywheel setup for these drivetrains. Heck, i've yet to find a "new" flywheel anywhere!!!

 

For the clutch, i've seen some ACT stock-replica clutches, but nothing really performance related that I've seen, which sucks. (although I might have missed something somewhere...)

 

For exhausts, Subaru actually had a "Sport" header setup for the 4-ports. Here is a good photo showing the difference:

 

ff1exhaustphotochop.jpg

 

However, I also layed out a couple other ideas about how to run the exhaust:

 

ff1mufflersetups.jpg

 

It sounds like you have more experience with the technicalities of exhaust systems though! LOL!

 

BTW, in regards to transmissions, I made this nifty chart awhile back, bu tit doesnt include the 5-speed FWD transmissions. I actually found an 82 FWD with that tall gearing that i'm going to try to use in my FF-1, but it would be a direct bolt in for your car:

 

fwd4speeds.gif

Edited by Kostamojen
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Here is an informative webpage:

 

http://www.economysuperstar.com/milesfox/subaru/service/glossary-index.htm

 

So the "fat-case" EA71 is the one that isn't compatible and is basically an EA81, but the 80-82 EA71 is basically the same as the pre-70 EA71 but with the internal coolant passage? Is that correct everyone?

 

Oh and for kicks, here are the power #'s for the EA motors over the years (according to Subaru, through lots of tiresome ressearch that I previously did):

 

X    Displacement    Engine code    Horsepower (HP @ rpms)    Torque (ft lbs @ rpms)    Compression    Features    Years        Modelsx    1000        EA52        55 @ 6000        57 @ 3200        9.0:1        2bbl OHV    1966-69        10000    1100        EA61        62 @ 6000        63 @ 3200        9.0:1        2bbl OHV    1970-71        FF-11    1300        EA62        61 @ 5600        65 @ 4000        9.0:1        2bbl OHV    1972        1300G1A    1300        EA62A        80 @ 6400        73 @ 4000        9.0:1        2bbl OHV    1970-71        1300G1B    1300        EA62S        93 @ 7000        76 @ 5000        10.0:1        2bbl OHV    1970-72        1300G Sports2    1400        EA63A        80 @ 6400        76 @ 4000        9.0:1        2bbl OHV    1972-75            2A    1400        EA63S        93 @ 6800        80 @ 4800        10.0:1        2bbl OHV    1972-75        GSR2B    1400        EA63A(4port)    61 @ 5600        69 @ 3600        9.0:1        2bbl OHV    1973-74    2C    1400        EA63A(2port)    58 @ 5200        68 @ 2400        9.0:1        2bbl OHV    1975-76        FWD2D    1400        EA63E        56 @ 5200        67 @ 2400        9.0:1        2bbl OHV    1975-76        4WD3    1600        EA71A/G/T    67 @ 5200        81 @ 2400        8.5:1        2bbl OHV    1976-79        3A    1600        EA71W        65 @ 5200        80 @ 2400        8.5:1        2bbl OHV    1976-79        4X43C    1600        EA71        68 @ 4800        84 @ 2800        8.5:1        2bbl OHV    1980-82    3D    1600        EA71        69 @ 4800        86 @ 2800        9.0:1        2bbl OHV    1983-84    4    1800        EA81        72 @ 4800        92 @ 2400        8.7:1        2bbl OHV    1980-82    4A    1800        EA81        73 @ 4800        94 @ 2400        8.7:1        2bbl OHV    1983-84        Brat/2dr GL4B    1800        EA81        82 @ 4866        103 @ 2800        9.5:1        2bbl OHV    1985-87        4DR/Wagon DL4C    1800        EA82        94 @ 5200        101 @ 2800        9.5:1        SPFI OHC    1985-87        3dr/Wagon/4wd(notCA)4D    1800        EA82        90 @ 5600        101 @ 2800        9.5:1        SPFI OHC    1985-94        3DR/4DR/Wagon/Loyale4E    1800        EA82        85 @ 5200        101 @ 3200        9.0:1        2bbl OHC    1987        4WD (not California)4F    1800        EA82        84 @ 5200        101 @ 2800        9.5:1        SPFI OHC    1987-89        4DR 2WD4G    1800        EA82        97 @ 5200        103 @ 3200        9.5:1        MPFI OHC    1987-91        XT5    1800 Turbo    EA81T        95 @ 4800        123 @ 2000        7.7:1        Port Inj.    1983-84        All Turbos5A    1800 Turbo    EA82T        111 @ 4800        136 @ 2800        7.7:1        MPFI OHC    1985-86        All Turbos5B    1800 Turbo    EA82T        115 @ 5200        134 @ 2800        7.7:1        MPFI OHC    1987-90        All Turbos

Edited by Kostamojen
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Ive thought off doing some thing on a 1400 coupe for exhaust same as number 1.

After I restore my GSR, I will try look around for another GSR and try do the GSR heads on the 1600 motor and maybe turbo or supercharger.

or fit a 1800 RX motor in if I could find one.

is all the ea81s the same block? or or is it like the early EA71 and later EA71 fat block

Edited by kiwi subbie
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Thats some good info there, and I will be double checking the early and later style EA71s I have to make sure for certain that the heads will swap.

 

As for the EA81, the only differences in those were the heads, early EA81s have small valves and solid lifters, later EA81s had bigger valves and solid lifters, and the 85+ EA81s had hydraulic lifters and bigger valves.

All EA81 heads are interchangeble though, all the blocks have the same dimmensions.

 

What would be kindof interesting would be to see if Fat case EA71 heads would fit an EA81, and if there would be anything to gain from that...

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Must say this is a great thread!!

 

I want to do this conversion too - 1400 heads and cam with the 1600 block. I already have the EA63 (1974 GL coupe), EA71 (1976 GL coupe) and a twin carb manifold for EA63. Just need to get organised!!

 

Originally I wanted to keep the coupe stock, however I recently brought a 1974 DL sedan. One 'old lady' owner since new with only 85 000 Km, so might as well 'go for broke' with the coupe :grin:.

 

Time to collect more stuff - gaskets and such!

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My exhaust plan would be most like #3. Exhaust systems are a little like black magic in that there are so many variables involved. In a nut shell, too small and you restrict power. Too large and you can also lose power and low end torque. It will also make it louder. The header has probably the biggest effect on power production and curve. Just based on potential HP of a NA motor, 1 1/2" primaries should be fine. Now, where the primaries join is where I need to do some research. I am thinking of stepping them up to 1 3/4" there, but 1 1/2" will still provide enough flow for 2 cylinders so I don't know. I do know that for an engine producing 100-120 HP, a 1 3/4" exhaust size is reccomended to keep flow velocity up, which will help low end torque, fuel economy and keep it quiet(er). So from where the headers merge, most likely under the trans, I will run a 1 3/4" exhaust size back to a 2" muffler. I would like to use a single in/dual out muffler so I can do a dual exhaust tailpipe like #4, probably with 2" tailpipes so there is no backpressure issues. For the flywheel, I was talking more along the lines of just lightening the stock one, as I kinds figured there wouldn't be a readily available (or cheap) aluminum one. I have an aluminum flywheel in one of my Datsuns and don't really care for it for street use. Sure it makes the engine rev up a lot quicker, but it makes it very easy to stall and makes the engine feel harsh (hard to describe). I would imagine there should be no issue with a stock clutch at the power levels we are talking. I sure wish I was a little more knowledgable on Subie engines to help out a bit more on this concept engine, other than asking questions. Now, if you need guidance on Datsun engines, I can help there! :lol: Leeroy, I think there is noting wrong with modding, with bolt on items. It helps "personalize" your car. So long as it can be returned to original (as with bolt on changes such as manifolds), it's all good in my book! Throw the original motor on the shelf and drop in that hot rod engine. :banana:

 

Mark

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thats sitting on stock 93 lego mounts.(notched holes in crossmemeber(1/4 in or so per side) no trans on it the crank pully would sit a little higher with the trans in and the axles are within 1/4 of being in the right spot for the front wheels.(liveable) its amazing that from the engine mount to the center of the front stub axle didnt change hardly at all over the years even though the bell housing and engine depths changed drasticaly...

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thats sitting on stock 93 lego mounts.(notched holes in crossmemeber(1/4 in or so per side) no trans on it the crank pully would sit a little higher with the trans in and the axles are within 1/4 of being in the right spot for the front wheels.(liveable) its amazing that from the engine mount to the center of the front stub axle didnt change hardly at all over the years even though the bell housing and engine depths changed drasticaly...

So really, all you need are modified valve cover gaskets and stiff engine mounts? I'd think that would be easier to do than "notching" the frame.

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Here is an informative webpage:

 

http://www.economysuperstar.com/milesfox/subaru/service/glossary-index.htm

 

So the "fat-case" EA71 is the one that isn't compatible and is basically an EA81, but the 80-82 EA71 is basically the same as the pre-70 EA71 but with the internal coolant passage? Is that correct everyone?

Aparently this website is only partially correct... The 1983 EA71 is the same as the 1980 model, so the 83 is not the fat-case EA71.

 

And actually, I just checked the 85-89 manual, and the crank/rod/pistons are the same all the way from 80-89 on the EA71. But the head and case part number does change from the 83 to the 85 year (fat case?)

 

What is the exact width of an EA81 short block? 13.5" or 14"?

Edited by Kostamojen
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I was talking to Jerry the other night when i picked up a Fat case bellhousing and a full set of flat top EA71 pistons, and it looks like the 85+ EA71s were also HYDRAULIC LIFTERS... which I would assume means they have bigger valves in the heads... BUT, for a hi-po motor, adjusting the valves after evey oil change really isnt that big a deal :banana:

 

I have to get out there and check out that post-80 block and make certain that the heads will interchange, Ive been busy last couple of days, so I havent been able to... And if you need a block, let me know if you can make arrangements and I can get one to you, I guess I could do like last year, send it back with Brian at WCSS? Ill have to make sure i have a good one though...

 

Also, something to look into, we need some stronger connecting rods, I have a stock EA71 here that threw a rod, so maybe we need to see if there are some H-beam or other rods out there that might work and are stronger than the stock pieces, if one of these can break in a stock 70-ish HP motor, who knows what can happen with almost double the power... :eek:

 

Does anyone know anything about Kryo-treating? I think some info on this would be good, and Im also really thinking about having the pistons either kryo treated or ceramic coated, I figure Ill be pushing close to 11.5:1 compression with shaved heads/block, flat top pistons, and the much smaller cc of the 1400 heads... Im gonna want to reduce heat-fatigue/damage as much as possible...

 

-Bill

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I don't remember if Brian is going to WCSS again this year, i'll have to ask. He asked if I was going and I told him the FF-1 wasn't ready yet, duh, LOL!

 

Anyway, I'm surprised to hear about the conrod failing. They don't seem to be a weak link after seeing them in the other motors, but i'll have to check and see what other engines used those, maybe there is a "stock" upgrade availible. Aftermarket wise, someone might be able to make a few sets for us I presume.

 

As for the pistons, custom would probable be the best bet there, custom pistons especially simple ones like these should be doable. I've heard of the coatings for the pistons before, but I haven't done a lot of ressearch with those.

 

Personally, I wasn't going for an uber-compression engine, just something that had better flow to match the carbs i'll be using. But I figure some of this stuff might require upgrading if there are issues like those conrods...

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One thing that should help prevent us from losing a connecting rod is have the rotating assembly ballanced, to like 8,000 rpm. That and Jerry said polishing the rods is supposed to make them stronger too... I need something that can handle the high compression though, i dont think stock rods will do it :-\

-Bill

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I was talking to Jerry the other night when i picked up a Fat case bellhousing and a full set of flat top EA71 pistons, and it looks like the 85+ EA71s were also HYDRAULIC LIFTERS... which I would assume means they have bigger valves in the heads... BUT, for a hi-po motor, adjusting the valves after evey oil change really isnt that big a deal :banana:

 

I have to get out there and check out that post-80 block and make certain that the heads will interchange, Ive been busy last couple of days, so I havent been able to... And if you need a block, let me know if you can make arrangements and I can get one to you, I guess I could do like last year, send it back with Brian at WCSS? Ill have to make sure i have a good one though...

 

Also, something to look into, we need some stronger connecting rods, I have a stock EA71 here that threw a rod, so maybe we need to see if there are some H-beam or other rods out there that might work and are stronger than the stock pieces, if one of these can break in a stock 70-ish HP motor, who knows what can happen with almost double the power... :eek:

 

Does anyone know anything about Kryo-treating? I think some info on this would be good, and Im also really thinking about having the pistons either kryo treated or ceramic coated, I figure Ill be pushing close to 11.5:1 compression with shaved heads/block, flat top pistons, and the much smaller cc of the 1400 heads... Im gonna want to reduce heat-fatigue/damage as much as possible...

 

-Bill

 

My old 1987 omega wagon had HYDRAULIC LIFTER EA71 it went good.

never had the head off so cant tell you if they are bigger or not?

 

Ive only seen one ea71 that thrown a rod.

it had the oil drained from it, coolent drained.

reved to the maxium....

and that still ran for about 15mins lol

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I have not seen a stock Subaru rod in about 20 years, but *usually*, with other japanese engines I have worked with, the rods are stout enough to handle increased performance (Honda's excepted. They are pretty weak). Polishing the beams, shot peening them, and ARP bolts should help with the durability quite a bit. Balancing a performance engine is always a good idea, as usually you are changing enough parts that the original balance will not work as good as it can. It will make the bottom end last much longer. As for the cryo treating, my take is it would be overkill for the level of power we can reasonably expect to make. However, it's not that expensive so...... The thermal coating however is kinda pricey for the benefit it may have. My belief is a properly machined and assembled STREET motor would see little advantage for the ceramic type coatings. 11.5:1 is pretty stout compression to run. Are you planning to run a race gas blend to control detonation, or other means? I built an engine once with 10.5:1 compression and the thing would ping on pump gas unless I cranked back on the timing, which reduced power. It was downright horrible when the ambient temps got above 85 or so degrees. Was almost undriveable without race gas/ avgas blended @ 50/50 it would ping so bad. That fuel is not cheap! * this was a cast iron american V8. Aluminum dissapates heat better, so you can run a little more compression before detonation sets in*

 

Mark

Edited by Datsunrides
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I checked through some of the parts for the EA71 shortblock to see whats still available from Subaru.

 

Aparently, there are THREE pistons still in the country... Sucks that its just 3 though, which means its not a full set :mad: There are 3 in the standard size, and 3 in the +.50 size...

 

Headgaskets are still availible.

Piston rings are not availible.

Rod bushings ARE availible still.

Rod bearings (standard size only) are still availible.

Main bearings are no longer availible :-\

Water pumps are still availible.

Flywheels are not availible :(

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