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ea81's.. why'd they change em


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74 replies to this topic

#1 torxxx

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Posted 19 January 2004 - 01:45 PM

From what I've learned here, every speaks pretty highly of the ea81 and lack of timing belt..

Why did subaru change it to a less stable timing system?

sucks you gotta change t-belts now every 40-60 thousand miles.

#2 subarubrat

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Posted 19 January 2004 - 01:53 PM

To boost timing belt sales.

I agree Subaru should have stuck with OHV pushrod to include the EJ series.

#3 calebz

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Posted 19 January 2004 - 02:25 PM

More power.

I happen to like my OHC motor

#4 torxxx

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Posted 19 January 2004 - 02:33 PM

caleb - I love mine too... it just seems too problematic compared to the ea81

#5 calebz

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Posted 19 January 2004 - 02:40 PM

Mine has never given me any problems with timing belts.. closest thing I have had to a timing problem is when the ignition module in the dizzy died.. that was about a pain in the ass to diagnose..

I mean, sure, you hear 100 people every year complain about timing belts.. what you don't hear is the other 1,000,000 people that don't have any problems.

Timing belts were a natural progression of things.. do you think the STi would be pushing 300+ hp on an OHV EA81 derivative?

Whwn Saab went from OHV to OHC, people complained too.. but they didn't complain about the 20-30 increase on HP.. And no car maker that I know of has ever reverted to OHV after introducing an OHC motor.. there has got to be a reason..


i suppose it all just depends on what you want from the motor..

#6 torxxx

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Posted 19 January 2004 - 02:42 PM

true about the STi

did soob ever put a timing chain on any of their engines?

#7 subarubrat

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Posted 19 January 2004 - 03:18 PM

The EJ series could have produced the same yeild on OHV pushrod. There is no reason why their couldn't be a 300Hp OHV pushrod in the STI. If you don't think pushrod engines can make big power dig around a bit and you will fins pleanty of examples.

#8 calebz

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Posted 19 January 2004 - 04:49 PM

I didn't say that they can't.. In my experience, OHC engines make the horsepower easier.

#9 richierich

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Posted 19 January 2004 - 04:52 PM

Subaru changed the from the ea81 motor because of emissions. They were unable to get a the HP they needed with all the smog devices that they had on them. The only reason they could keep the BRAT and hatch back is that it was such a small part of sales. They ran the ea81 motor in other countries into the late 90's. But they did not have smog restrictions.

I would see there would be a problem with a 300hp pushrod motor, I would think that it would bend the push rods pretty easy.

Timing chains have their problems as well. Nissan was plagued with timing chain problems (tensioners, pulleys, noises) in the 90's.

The new Legacy timing belts are rated out to 105k. And by that time they usually have a front oil leak anyways.

The GL/Loyale problems is that there is two of them, and that means twice as many problems.

#10 subarubrat

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Posted 19 January 2004 - 04:58 PM

We have pushrods that hold up against spring tensions our engines would never see at over 10 grand RPM.

But I think we all agree that timing chains are evil and at least we never went there.

#11 torxxx

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Posted 19 January 2004 - 04:59 PM

you guys sayin a 300 hp pushrod 4 cylinder or just 300 hp pushrod in general?

Arent the early 80's Ford and GM motors pushrod?
GM's 454 was over 300 hp

#12 archemitis

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Posted 19 January 2004 - 05:12 PM

bottom line is pushrods are ghetto old technology. domestic motors are not a good example of what can be done with pushrods. they have used them forever. they just keep piggybacking new technology ontop of their old short blocks.

the ea82 is the same size(bore and stroke) as the ea81, and it makes something like 15 more horsepower.

all you gotta do is change the belts, and thats not hard. i will trade an ea81 for an ea82(engine) any day. and have, for good reason. better mpg and more hp right off the bat.


the new 6 cylinders use a chain to keep the engine short enough to fit against the radiator.

ohc is the only way to go!
you ever see a ford guy swithcing a overhead valve motor for a flathead motor?

#13 subarubrat

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Posted 19 January 2004 - 05:24 PM

The flow capability of a OHV Vs OHC engine are a totally different animal than comparing OHC to a flathead. Cam profile and slight compression increase can make the 15 Hp difference between the 81 and 82. Between EA81 and EA82 I would choose the 81. However I did choose the ER27 over both of them for the raw dispalcement and power potential. So clearly I am not saying OHC is worthless. However I would prefer to see the ER27 in OHV pushrod format.

#14 torxxx

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Posted 19 January 2004 - 05:27 PM

Originally posted by archemitis

you ever see a ford guy swithcing a overhead valve motor for a flathead motor? [/B]



I'd love to see anyone come out with a flat 8 cylinder. Could you imagine the horses you could get outta that thing....

I'ma make me one. one day, oh yes...

#15 GeneralDisorder

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Posted 19 January 2004 - 05:32 PM

Better HP? Nope - EA81's have been taken to 200 HP.

Better mileage? Nope - I've seen EA81's get up over 35 MPG.

Emmission? Nope - doesn't matter how the valves open - you can strap the SPFI to an EA81 and have the same emmisions equipment as the EA82....

You can make pushrods that are plenty strong enough for 300 HP - it's just a matter of making them from the right material, and making them thick enough.

What everyone has failed to see is the accesebility of the overhead cam design. Your entire valve train is accesible right there in a small, removable engine peice, and is thus easily serviced. The EA81 has the disadvantage of having part of it's valve train inside the engine casing, and is much more difficult to service should something go awry.

There is less moving parts in an overhead valve system - Subaru actually simplified things.

I personally believe Subaru went with the overhead cam design because the engine is more easily tuned, and cams can be changed out, etc without removing the engine frorm the car - this has many benifits for rally teams, and race teams where modifications need to be done quickly.

Now - having said this - I still will run my EA81 - because Subaru didn't get the timing belts right on the EA82 - the EJ's are better from what I understand, and I may eventually get one. For me - I can get just as much HP from an NA EA81 as anyone else can from an NA EA82. By simply adding a Weber, and a high flow muffler, I'm already higher than a stock EA82...... Also - EA81's are cheaper to buy, run and maintain.

GD

#16 archemitis

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Posted 19 January 2004 - 06:50 PM

ok, since i have never seen a 200 hp ea81 or even a 100 hp ea81s numbers i tend to disagree. look over that other post that has real numbers for an ea82 with a turbo. pretty low compared to what everybody has been throwing around this forum.

#17 Meeky Moose

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Posted 19 January 2004 - 07:04 PM

well i have to side with the ole ford sittin in the driveway .. its got more than 400 HP its got pushrods, and it'll spank any wrx that steps up.. haha..

so timing belts or not, it just depends on how big the engine is.. the 4cylinders are easier to design small, get lots of hp/rpm's with timing belts...

so show me a big v8,10,12 whatever that has timing belts.. ya won't find it...

#18 Meeky Moose

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Posted 19 January 2004 - 07:05 PM

ohh and if ya wanna talk mileage, the ford gets 12mpg.. the little junkyard hatch with 200K on it went 140 miles on 3 gallons of gas.. believe that one or not.. hard for me to believe but it did..

for subarubrat: it went from ruckersville to manassas and back on 1/4 tank.. lol i think thats like what 40mpg?

#19 archemitis

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Posted 19 January 2004 - 07:09 PM

but the only reason v8s dont have ohcams is because american iron sux. just imagine an ohc 327 with 32 valves. no not a cadillac motor. it would rule.

#20 beauregaardhooligan

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Posted 19 January 2004 - 07:14 PM

EA81s are approved for aircraft use because there is no belt to break.
Generally speaking, the gear drives have more power loss due to friction, but hydraulic lifters can float at high rpms.
At least the EA82s are a non-interference engine.

#21 subarubrat

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Posted 19 January 2004 - 07:31 PM

for subarubrat: it went from ruckersville to manassas and back on 1/4 tank.. lol i think thats like what 40mpg?



That sounds real close to 40mpg. My BRAT stock got well into the 30s. Of course now it gets low teens but I am OK with that.

#22 Meeky Moose

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Posted 19 January 2004 - 07:37 PM

ahh don't feel bad my lifted hatch get like 12 or 14, lol i don't drive it much.. 120-130 or so miles and that puppy is empty..

#23 bushbasher

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Posted 19 January 2004 - 07:41 PM

-ea82s make higher rpm easier, because of less reciprocating mass in the valvetrain. there are less parts, the camshafts are easy to get at. an ea81 with 200 hp is so loaded with aircraft parts theres no way you could compare it with a stock ea82. You could go further in an ea82 with that much money in aircraft parts. You can still get high rpm with ohv, but you need springs that are stiffer, and your valvetrain is going to wear out alot faster with that kind of stress on it, and the beefier you make the parts the more spring you need. There is a reason why modern performance engines use ohc or dohc. Also I dont see why it is such a big deal to unscrew the plastic cover and put new timing belts on every 100k km? Its well worth it to me considering I get fuel injection and a higher hp motor.

#24 dave valiant

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Posted 19 January 2004 - 08:00 PM

I love my over head valve engines. I might have a dinosaur mentallity but I wont own OHC powered cars. I had one once a Nissan pickup had to change the chain gears tensioner and guides. Cost me over $200. and 10 hours of my life I'll never get back. As far as power the most powerful perfomance engine out there is an OHV. They dont have any longevity but what engine would making in the area of 7000 HP.

#25 GeneralDisorder

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Posted 19 January 2004 - 08:33 PM

There have been V8 OHC engines - the Ford 427 "cammer" - around 1964 vintage I believe. It was conceived to tear up the hemi's of the day - which it did nicely being that it puts out 657 HP with dual four barrel carbs..... completely unsuitible for street use - only 50 were made, etc, etc.

And yes - the EA81's producing 200 HP are aircraft engines - but the discussion wasn't about that - it was about being able to get a pushrod 4 cylinder up to high HP.

The EA82 isn't rated at higher HP than the EA81 because of it's OHC design. It has a bigger carb, bigger intake, and a redesigned head with bigger valves. Besides that it's a measly 15 HP. I can guarantee that I would eat an EA82 any day with a Weber, and striaght pipes on a well running EA81. The OHC has nothing to do with the higher HP numbers. Not to mention that the EA82 cars are heavier than the EA81's - eating up most if not all of the advantage they had to begin with.

Both are well designed engines, and I've seen both go well past 7k rpms - that's way past their power curve, so it really doesn't matter if the EA82 can go "faster" than the EA81 now does it?

I guess I'm saying that the EA82, while a good engine, was the first of it's kind for Subaru. They eat timing belts like candy, and are not particularly better than an EA81. I wouldn't trust an EA81 at 200 HP, nor would I trust an EA82 at 200 HP - your money would be better spent on an EJ engine.

The reason the aircraft guys use the EA81, and spend $10,000 or more building them up is BECAUSE they are OHV - timing belts CAN break, and that's a bad thing at 20,000 feet. Need I say more?

GD




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