Milling heads on EA82 OHC

[Mike Moore]

How Much can be milled off he heads on a EA82 OHC and how much will it change my compression ratio. Not looking for speed but more power I live in some real mountian country.

Thanks

Mike Moore

[Snowman]

I would advise against milling because it changes the cam timing (I believe retarding it), and if you removed enough material to give a noticable increase in compression, the timing change would negate any power gain.

 

If your car is carbureted, you can put in pistons from an SPFI engine to raise the compression ratio from 9:1 to 9.5:1.

[idosubaru]

i don't think that's a good idea either. depending on age/condition replacing head gaskets and having a complete valve job done may give you what you're after. i did an EA82 a couple years ago for a guy...i actually recommended him not even paying for all the work but he wanted it so i did it. i was surprised how much it helped. he had the heads ported and polished and high performance cams installed but i would guess just the new valve job and head gasket and complete tune up probably gave the best results really. the head shop even told me not to port and polish the heads, wouldn't notice much of anything unless we were planning on further upgrades.

 

and like he said depending on your motor, upgrading to higher compression may help or just have an EA82T installed if you're looking for more power.

[MilesFox]

swap yer carbs to spfi blocks

 

i would port the heads

[fj401968]

Interesting, I was not aware of the compression ratio difference between carb'ed and fuel injected ea 82s. Is this why my '87 carb'ed Soob runs better (no knocking) on 85 octane fuel than did my '88 with SPFI which seemed to want higher octane fuel?

 

Tracy

 

I would advise against milling because it changes the cam timing (I believe retarding it), and if you removed enough material to give a noticable increase in compression, the timing change would negate any power gain.

 

If your car is carbureted, you can put in pistons from an SPFI engine to raise the compression ratio from 9:1 to 9.5:1.

[Snowman]

Interesting, I was not aware of the compression ratio difference between carb'ed and fuel injected ea 82s. Is this why my '87 carb'ed Soob runs better (no knocking) on 85 octane fuel than did my '88 with SPFI which seemed to want higher octane fuel?

 

Tracy

 

Very possible. The SPFI engine doesn't have a knock sensor like the other injected soobs. It also may have had excessive carbon buildup or the timing was advanced too far.