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Ea71 mod advice... HELP!!!


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66 replies to this topic

#1 blownchevelle503

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Posted 13 January 2010 - 12:28 AM

I have a 1980 1600 4spd 4wd hatch. I plan on buying and installing, stripping, and refinishing the car this summer. I really want to do some internal engine work.

I plan on replacing the stock hitachi carb with a webber, I am looking for opinions of head, cam, piston, rod, and etc... configurations to get more tq, and hp, while still maintaining somewhat of a decent fuel mileage. maybe 12+mpg

from what I've heard, I could use ea82 heads, port and polish them, and get more hp, but I'm not sure if I'm only being told part of the story. can anyone give me some insight into the realm of ea engine building?

what resources and options can you give me?

what cams are available?

I'd like to have a really rough idle. none of that smooth garbage. I wanna feel the car.

I'd like to change the weight to hp ratio from 30+/- lbs per hp to something in the 20+/- lbs per hp. maybe not so extreme but something in the neighborhood, if its achievable.

Thank you all, look forward to hearing from you all.


Kyle B.

#2 cubastreet

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Posted 13 January 2010 - 12:52 AM

You can't put OHC EA82 heads on your OHC EA71.

You an drop an EA81 straight in there for an instant 10% increase in torque and HP. That's real cheap and easy.

Get a custom cam for a rough idle.

Put the EA71 pistons in an EA81 for higher compression.

Weber carb is good.

#3 blownchevelle503

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Posted 13 January 2010 - 03:49 AM

OHC means Over Head Cam, right? wouldn't that mean the cam is in the top of the head? but I dont have OHC I Have OHV right? since my timing chain is on the tranmission side of the motor, not a belt in the front like ea82 and ej motors. am I correct so far?

Don't get me wrong, im not debating whether or not the heads will fit.

I've heard 2 distinct rumors (I say rumors, because I don't have proof yet)

rumor #1. (came from a member of this forum) "you put Ea82 heads on an Ea71 for a 150hp increase" "It's a trick that nobody knows about, I can't tell you, cuz I don't know you well enough"

rumor #2. (came from a google search) use of high flow air craft heads on an Ea71 will increase the hp... not to 150, but definitely a substantial increase.

I've had 3 Ea82's and only 1 Ea71, I have never tore them apart, but I have removes the Ea82's from the vehicles, and know they look a lot different from the Ea71.

#4 The Beast I Drive

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Posted 13 January 2010 - 08:44 AM

you CAN NOT bolt EA82 heads to a 1600. I have had EA82's, EA81's, EA71's and EA63 (1400) apart, and I have looked closely at all these parts. Heres pretty much the jist of what you can and can't do.

you CAN bolt EA63 dual exhaust port heads to the EA71, with minor modification to the water jackets. This will increase the compression substantially as well as they are a better flowing head design, with a good P&P.

you CAN NOT bolt EA81 or EA82 heads to the EA71 block. The bores are spaced farther apart on these engines and nothing lines up even close. Not to mention EA82 are OHC and EA81 and older are all OHV.

There is no timing chain, its direct gear-on-gear crom the cam to the crank. You can get a reground cam from Delta Camshaft for under $70 shipped, with a torque grind, hp grind, or have them grind it to custom specs. Best bang for the buck.

You can pony up the enormous cash for EA71 aviation parts, but that stuff is not only insanely expensive, but also getting rare. EA81 and EJ22 are the "in" thing in Experimental Aviation motors, as far as Subaru power, and NOTHING made for those engines will swap to an EA71 (except EA81 distributor, with a minor mod)

If you want to stick with the EA71 your best and cheapest bet it order a new cam from Delta, have the heads shaved a couple thousandths to boost compression, have Jerry De Moss portmatch the heads and intake and polish them, as well as have him port and polish the venturis on your Weber. Convert to electronic ignition if you have points, and open the exhaust primaries to 1 3/4" diameter, and run them to an X pipe about under the front diff, then run duals from there. Have the flywheel lightened, turn up the advance a little, and you should be looking at around 90-100 HP (complete guesstimate) at the crank.

If you want to build an EA81, you can have a cam ground from Delta, and install either 1600 pistons or EA82 non-turbo pistons in the block. The EA71 pistons should give you 9.5:1 compression, the EA82 pistons should get 9:1. Have the heads and intake P&P and the carb to match, lightened flywheel, etc. 1 7/8" primaries and an x pipe and you should be good for about 100-110 HP (also complete guesstimate), more if you have the heads shaved some to boost the compression more.

If you find a pair of 1400 heads with the dual exhaust ports (one on the front of each head, one on the back) get the water jackets machined to fit and use those on the EA71 block to oget even higher compression and better flow.

-Bill

#5 GeneralDisorder

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Posted 13 January 2010 - 01:14 PM

The top-mount starter EA71 is a very poor platform to start with. Not that it's a bad engine per-se, but it's very dated and entirely unsupported. You can't even buy head gaskets for it from Subaru anymore. CCR doesn't rebuild them, and most parts are becomming scarce and/or are out of production.

It can't be mated to a transmission that can handle much more power, and additionally the single-range 4 speed that's in there is a worthless POS of a transmission - no low range, very poor gearing for performance, and they suffer from syncro and reverse gear failure - especially if driven hard - even with the stock engine.

You are starting out with a 64 HP engine and your expectations are wildly out of line with the platform. The 1980 body will take a lot of modifications to turn into anything decent. They have a bad wireing setup to start from - external VR, and they have an engine bay mounted fuel pump so there is no return line to the tank which makes fitting any form of fuel injection a real nightmare.

If you want something decent to start with you need to find an '82 to '84 EA81 powered hatch. Pull the engine and do an EJ22 swap. Instantly doubled performance, availible transmissions to meet any demand you could want.

The only way to get the EA71 to a decent power range would be to completely rebuild it with performance components and then turbo it. Even then you *might* not make stock EJ22 power though. I can get an EJ22 - the whole donor car with wireing, etc. for around $250 if you give me about a month to search one out. That might buy a used Weber carb in decent condition for the EA71 :rolleyes:. It's just not economically viable.

And yes - you can't put EA81 or EA82 heads on the EA71. They aren't even close. Like Bill - I've built and rebuilt my share of EA's. About the only thing that swaps between the 71/81/82 is the pistons and the distributors (some with modification).

GD

Edited by GeneralDisorder, 13 January 2010 - 01:22 PM.


#6 MilesFox

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Posted 13 January 2010 - 01:38 PM

you can bolt in anea82 motor, go with an spfi block, ea71 pistons, and an ea82 carb intake with weber carb

#7 GeneralDisorder

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Posted 13 January 2010 - 02:01 PM

EA71 pistons are not better than the EA82 SPFI pistons. They would lower the compression and thus be worse for performance. Besides the ring sizes the EA71 pistons are only about .005" taller than the EA81 pistons makeing for about 9:1 comp. ratio using the EA81/EA82 stroke..... The EA82 SPFI is already 9.5:1.

GD

#8 blownchevelle503

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Posted 13 January 2010 - 11:55 PM

I was just trying to clear up the rumors I've heard.

I'm not trying to get a million horsepower. I'm trying to get something more than what I have, I'm really tired of the EJ22's, granted they have a bit of stock power, but they are worthless, problematic, and high maintenance.

I have had my fair share of EJ22's. so far I've had a water pump explode, timing belt jump 2 teeth and run like garbage. and my personal favorite... I had one throw a rod through the top of the block at less than 120K. engine was full of oil, clean oil, no knocking, rattling, or pinging until it happened.

I just cant kill this EA71. I've blown head gaskets on 2 spfi EA82's.

so lets restart this whole thread...


I am sticking with my EA71, I CANNOT PUT EA81/82 HEADS ON IT.

I CAN have delta regrind my cam.

I can use EA63 Heads if I can find them.

I can buy a weber.

I have used NGK Iridium Plugs w/premium gasoline w/octane booster,

just the NGK's made a night and day difference.

Premium Fuel makes a noticeable difference.

I bought a distributor from a guy on here, he claimed it was for my motor, the plugs were the same, now It wont time to factory specs or run decent without idling @ 1700rpm-2000rpm... speaking of which, it says unhook and plug the vacuum advance hose... WHICH ONE?

#9 cubastreet

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Posted 14 January 2010 - 02:48 AM

Don't know what ea81 prices are like where you are, but I bought two a while back for less than the price of a pair of headgaskets or a cam grind. One decent one and one spare for parts. Hard to get cheaper power than that.

Probably easier to get parts for, no mods necessary. Can probably sell your ea71 too. No brainer.

#10 kiwi subbie

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Posted 14 January 2010 - 04:23 AM

Double up

Edited by kiwi subbie, 14 January 2010 - 04:31 AM.
Double up


#11 kiwi subbie

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Posted 14 January 2010 - 04:28 AM

Im also pretty sure that the EA63 heads only fit to the earlier EA71? top-mount starter? like what is fitted to a gen 1 brat or 1977ish 1600 car etc

I think its the same EA71 that GeneralDisorder was talking about before.. in the Quote below


The top-mount starter EA71 is a very poor platform to start with. Not that it's a bad engine per-se, but it's very dated and entirely unsupported. You can't even buy head gaskets for it from Subaru anymore. CCR doesn't rebuild them, and most parts are becomming scarce and/or are out of production.



#12 blownchevelle503

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Posted 14 January 2010 - 10:41 PM

I do have the top mount starter version of the EA71. its a very young car compared to the other subies I've had, I got this car with 113,xxx original miles, I'm the 3rd owner, I have all of the maintenance and tire records, it even had the tires on it from 1989 when I got it. she now has 137,xxx on it. I've added an overflow reservoir from a 93 legacy.

I've only had a few minor issues with her.

clutch, v-belt, distributor bearings were gettin dry so I replaced it, and my fan control switch just went out. I did a quick fix and grounded the wire so the fan comes on with the key. I got her august, 2008, she has yet to break down on me.

my reasons for not going with a different motor have nothing to do with my mechanic abilities. my theory is "If I'm going to increase the hp to that of an EJ22, I might as well get a better platform, drop in a EJ20TT, upgrade the suspension, get urethane bushings, coilovers, racing clutch, air fuel controller, turbo timer, etc..."

I might as well buy a fully modded sti. or drop in a chev 350.

a lot of you might think I'm trying to polish a turd. and maybe I am, but this car is worth it in my eyes.

I'm shooting for a 25-35hp increase. if I have to build an EA81, I will, but that's as new as I'll go. I don't want any turbo, or nitrous cheater power. I want actual power.


so new questions, what can be done to an EA81? how much power am I looking at?

#13 cubastreet

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Posted 15 January 2010 - 12:54 AM

drop in a chev 350.

#14 corvette6698512

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Posted 15 January 2010 - 01:25 AM

So you are trying to get a 45% increase from an ea81? Good luck. Remember, just like any engine, the ea81 is a giant air pump, the more air and fuel you pump, the more power. Bigger cam, porting, higher compression, better carb, Etc.. I still don't know about getting that much out of an ea81. Let me know what you figure out, I want a 110hp ea81.

#15 AWD TURBO!

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Posted 15 January 2010 - 03:54 AM

[ATTACH]7264[/ATTACH]

this looks cool

#16 blownchevelle503

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Posted 15 January 2010 - 03:56 AM

you said you wanted to see a 110hp ea81, lol

#17 blownchevelle503

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Posted 15 January 2010 - 03:57 AM

well we can slice it like this, the ea82 was what, a 90hp engine? aint the ea81 & ea82's 1.8L motors?

ok, so the saying goes "There's no replacement, for displacement" it works for cars as well as guns.

so theoretically speaking... you can shave the heads, grind the valves, port and polish the heads, put a custom cam in it, and if one were so inclined, one could stroke the crank. is this possible in subaru engines? according to ccr, boring the cylinders is not an option due to heat dissipation issues.


I looked at ccr's website, to me, (judging by the picture) the ea81 looks like a ea71 with the starter located off to the side a bit, im sure the insides are differnt, but the outside looks quite similar.

#18 GeneralDisorder

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Posted 15 January 2010 - 11:49 AM

You think the EJ22 is worthless, and high maintenance?

You're nuts kid.

The EJ22 is very little more maintenance than an EA pushrod. Timing belt and associated components every 60k. That's about it. No valve adjustments every 15k, no leaking cork gaskets.

And it's worth the 2 hour timing belt job every 60k for TWICE the HP and better mileage.

As I pointed out - your EA71 is a very bad place to start. You have no transmission options and it will be almost impossible to find a replacement top-starter 4 speed when you blow the thing up.

You need to swap it out to at *least* an EA81 and associated side-mount starter transmission to insure you will have availible parts to keep it on the road. The EA71 is a dead platform as is the top-starter transmission. They are good for Museum restorations - that's about it.

Think of it as your first performance upgrade - the EA81 will net you 10 HP instantly.

GD

#19 blownchevelle503

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Posted 16 January 2010 - 12:49 AM

hmm, lets see, timing belt every 60K with ej22, or timing belt every 20 billion miles with ea71... thats a hard choice to make... oh wait, its not!

#20 corvette6698512

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Posted 16 January 2010 - 02:07 AM

I think you would be happy with a ea81 and the mods you listed above. You probably wont get 110 hp, but even if you got 90 or 95, that would be a night and day difference from the old worn out ea71.

#21 blownchevelle503

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Posted 16 January 2010 - 02:58 AM

I'm really starting to sway toward the ea81, the ea71 I have is far from worn out, she's just a baby. but I'm sure my hatch would greatly appreciate the ea81. I know I'd appreciate not getting my a$$ handed to me by a chevy sprint (geo metro).

I had my @$$ ridden by a 1986 chevy sprint the first night I got this car. I burried my speedo at a whopping 85mph, lol. he overtook me, and I tried to keep up, but I gave in. I'm mean to my cars, but not that mean.

so now that I'm gonna go with the ea81, do any of y'all know where an oregonian can find the block, heads, good cam. and do we have a price list?

#22 GeneralDisorder

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Posted 18 January 2010 - 12:26 AM

You will have to get them from a junkyard or donor car - EA81 parts are not simply picked up from a catalog. Major components like blocks and heads you will need to source used and rebuild or have rebuilt. Delta cam has grinds for the EA81 - they will regrind your core. Price is under $100 to have the cam ground. The rest of the stuff is going to depend on where you pick up the parts from.

Timing belts are nothing to be afraid of. Belts are availible for the 22 that last 105k even - replaced twice in the life of the engine. No big deal at all.

EA71/81 are just as much maintenance keeping the seals from leaking, and the valves in proper adjustment.

I've owned more than you have ever seen of both. Torn them up/down/sideways and rebuilt a number of them from the ground up. Hands down the EJ22 is the better engine. I'll take the t-belt motor any day for the ability to swap cams easily, more power and more potential for power. The maintenance is a lot less on the EJ's simply because you aren't dealing with a carb that wants attention all the time. Instead of random failures that leave you frustrated and unhappy you have controled, scheduled down-time that is actually very simple and pleasureable.

GD

Edited by GeneralDisorder, 18 January 2010 - 12:29 AM.


#23 blownchevelle503

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Posted 18 January 2010 - 01:54 AM

not afraid of t-belts a bit. I'd just rather have something a bit more solid, I know we are dealing with non-interference engines, so im not worried about that, I just don't like the ej22, you aren't gonna be able to change my mind.

ram engines sent me a reply, they have an ea71 for $850 with "88hp and 95 lbs. torque. These hp figures are with different carb, headers and the distributor curved."

so you guys are telling me its basically impossible to do. and ram engines did it. they also say they can give me more hp if I want different internals.

I checked my local wrecking yard, and they have several ea81's and ea82's plus a plethora of 5spd dual range 4wd trannys. so they aren't really that hard to come by.

#24 blownchevelle503

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Posted 18 January 2010 - 02:01 AM

You are starting out with a 64 HP engine


Engine Specifications: EA-71
Displacement: 1595 cc/97 cu in.
Aspiration: 2-bbl Carburetor
Compression Ratio: 8.5:1
Horsepower: 68 at 4800 RPM
Torque: 85 at 2800 RPM
Spark Plug Type: BP6ES
Plug Gap: .032 inches

#25 GeneralDisorder

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Posted 19 January 2010 - 01:03 PM

It depends on the year. Later EA71's were more powerful.

It just isn't worth it. For $850 I can buy a couple EJ22 donor cars and have more power and more reliability. There is no Subaru engine more solid. Period. Plus it will get better mileage.

Never said it was impossible - I said it wasn't worth it. And it isn't. Not in a car anyway. Aircraft...... different story.

GD




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