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EA81 high performance


archemitis
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Hey everybody, its been a while, 50s chevys and a new wife has taken me away from subarus for a while, but its good to be back, looks like alot of things have happened, allied ups and downs, sjr has some great looking stuff, and ej plates are easy to get?!?!?!

Up untill now i've always ran ea82s or er27s in my 86 hatchback but im so tired of EFI im going old reliable with pushrods, carburetors, and a 5 wire engine compartment.

a few years ago there was all kinds of info on here about upgrading ea81s but it looks like the ej swap has taken over and theres not tooo much info on here anymore.

Is an ea82 manifold and/or carb an upgrade for the ea81?

If i go with the dvg weber carb is an ea82 manifold better?

Are there any cams that arent geared just towards high rpm airplane engines?

How can i get more compression with stock pistons(not ea71s)? does decking the head mess with pushrod length/adjustments in hydrolic lifter motors?

Are the small valve heads more or less desirable for low to mid range performance, compared to larger valve heads?

solid lifters better than hydrolic?

 

im not trying to get as much power as my old 2.7 but i gotta have more than the 65 or so the ea81 puts out...

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Is an ea82 manifold and/or carb an upgrade for the ea81?

The EA82 carby manifold is, the factory EA82 carb isn't. More emissions garbage.

 

If i go with the dvg weber carb is an ea82 manifold better?
Yes.

 

Are there any cams that arent geared just towards high rpm airplane engines?

Yes! Search for Delta Camshaft, they have several grinds for the EA81 these days.

 

How can i get more compression with stock pistons(not ea71s)?

The SPFI EA82 pistons have 9.5:1 compression and a slightly better design from what I'm told. The EA71 pistons are only 9.0:1.

 

does decking the head mess with pushrod length/adjustments in hydrolic lifter motors?

After a certain point yes. I think you can get away with some VERY minor decking, but then the intake manifold will not line up.

 

Are the small valve heads more or less desirable for low to mid range performance, compared to larger valve heads?

NO!!! :Flame:SMALL VALVE HEADS!!! The intake passages are already poorly designed, why make it worse?

 

 

solid lifters better than hydrolic?

If you can get this little engine to spin fast enough, then yes. Otherwise, why would you want to adjust your valves?

 

im not trying to get as much power as my old 2.7 but i gotta have more than the 65 or so the ea81 puts out...

The engines with the larger valves were rated at 73HP @ 4800rpm and 94LB/FT @ 2400rpm. Ever thought about an EA81T?:cool:

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check out ram performance engines. they mainly deal with aircraft engines, but will also work with you to make a streetable ea series engine. they are the only company i know of that actually makes stuff specifically for the ea81 engines. get in touch with them and talk to Ron, i think.

 

i am looking at getting their master rebuild kit with the high comp pistons and hot cam, ect... either way, it should be fun when i get it all together.

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  • 2 weeks later...
The EA82 carby manifold is, (more performance)

What all is needed from the EA82 for the swap, minus the intake of course? And does anyone have the vacuum diagrams for an EA81 and 82? I have an 86 EA82 carby mani that I'd like to use on my performance EA81 build going in my Brat but cannot find good vacuum diagrams for either. It would be nice to see what all the metal lines under the mani's are for and what is required for smog and accessories. Any help would be greatly appreciated, and yes, I read the SPFI Swap Manual but I'm not going SPFI and want to make sure I don't forget/ miss anything. Thanks.

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You don't want all that vacuum junk cluttering the motor. Ditch the metal lines underneath the manifold. You will still have plenty of vacuum connections for other necessary stuff. You can plug the disty vac line into the Weber vac port. You are getting the Weber, right?

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No, I was going to use the original EA81 Carb until I was told it wont fit. I need to pass Cali's dreaded SMOG Nazi's :mad: otherwise I would go Weber. But, luckily on another post I made, someone has a SPFI setup they are selling and I'm buying it Friday :banana: . So looks like I'll be going SPFI sooner than I thought :headbang: .

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What all is needed from the EA82 for the swap, minus the intake of course? And does anyone have the vacuum diagrams for an EA81 and 82? I have an 86 EA82 carby mani that I'd like to use on my performance EA81 build going in my Brat but cannot find good vacuum diagrams for either. It would be nice to see what all the metal lines under the mani's are for and what is required for smog and accessories. Any help would be greatly appreciated, and yes, I read the SPFI Swap Manual but I'm not going SPFI and want to make sure I don't forget/ miss anything. Thanks.

 

the ea82 manifold kinda fits, but it looks like it will limit my disty adjustments, and a water line had to be relocated, it'll work for now but,

as far as my motor goes, i've started to put together a dual carb setup.

 

Im going to use two 39 millimeter constant velocity side draft kehein carbs, with a balance tube between the two. once i make the manifold i can deck the heads as much as i want, as long as i "adjust" the pushrods correctly, and watch for piston to valve clearance.

my pushrod 1200cc harley makes 86 hp to the wheels, with one 39mm carb. when it was a 883cc it put down around 60hp.

half of my 1.8 ea81 is 900ccs so if i could squeeze even close to 60 out of each side... wahoo!

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