Jump to content
Ultimate Subaru Message Board

EA81 engine masters, I have Q's.


Recommended Posts

I'm thinking of building a hot EA81. So I need some info.

1) can the EA81 be stroked at all? If so how much?

2) I'm looking for about 10.5:1 CR, what pistons do I need? And can I mill the heads to get it right where I need it? (I'm not sure what to do about pushrods if I mill the heads)

3)What brand/type of rings do U recomend?

Link to comment
Share on other sites

I was also thinking about building up and ea81 but have no idea where to start or what to use. Qman has about 150 hp out of his ea81 he said somthing about building it to air plane engine specifiations. I have no idea where to get the specification for the airplane engine though.

Link to comment
Share on other sites

1) I'm sure it could be stroked, but you'd have to find a rod that would work on your own, i don't know anyone thats stroked an EA-81

 

2) You might try www.ramengines.com they might have custom pistons, you won't be getting 10.5 with any subie pistons

 

2.5) You can mill the heads up to .030, any more than that and the intake won't fit anymore

 

3) for rings i'd contact either Ram /\ or Emily at CCR

Link to comment
Share on other sites

EA82 SPFI pistons will get the compression up to 9.5:1. With some milling, you can get more.

 

You should be able to compensate for some milling just by adjusting the valve lash differently.

 

I'd just go with OEM rings from a discount supplier. They don't fail very often, so I think they must be pretty good.

Link to comment
Share on other sites

I'm thinking of building a hot EA81. So I need some info.

1) can the EA81 be stroked at all? If so how much?

2) I'm looking for about 10.5:1 CR, what pistons do I need? And can I mill the heads to get it right where I need it? (I'm not sure what to do about pushrods if I mill the heads)

3)What brand/type of rings do U recomend?

 

if you decide to bore, I have a new set of .030 over ea71 pistons with rings. Repco brand. $70 shipped.

Link to comment
Share on other sites

I would LOVE to get my hands on the manifold I have seen here that is for the single side draft webber. That's what I would like to run, but I think I'm gona end up with a little 390cfm Holley 4bbl.

 

390 should work good.

 

I just pulled a 600 of my 82 Brat. it was a blast, but I need to keep the revs high....

 

http://www.ultimatesubaru.org/80s/mick/gallery/holley1.jpg

http://www.ultimatesubaru.org/80s/mick/gallery/holley2.jpg

http://www.ultimatesubaru.org/80s/mick/gallery/holley3.jpg

http://www.ultimatesubaru.org/80s/mick/gallery/holley4.jpg

http://www.ultimatesubaru.org/80s/mick/gallery/holley5.jpg

Link to comment
Share on other sites

That looks good, what manifold & adaptors wer U using?

 

I used the following

 

weber adapter

2 weber 1/2" spacers

standard 2->4 barrel adapter that I used a cone grinder to "widen" the 2 bbl holes inward to match the weber patter which is a bit smaller.

 

it's much nicer to drive around town now with a weber on it.

Link to comment
Share on other sites

  • 7 years later...

Tony... ive dreamt of building a monster EA81. Same lines your runnin.... 10.5:1 CR, cams, pistons, intake... etc.

 

But I also wanted to run EA81T heads that have the injector bosses for the MPFI. Forget about carburation, and then say hello to N.O.S!!

 

-Brian

Standard EA81 heads can be drilled and fitted with injector bosses if you want to run multi-port. This way you don't have to hunt down the almost impossible to find EA81T heads. Most machine shops should be able to do it. If you run in to trouble, RAM Engines can do it for you.

Edited by Crazyeights
Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...