EA71 vs. EA81 pistons; differences and compression increase?

[Guest Brettm57]

I've seen on some different websites that EA71 pistons will interchange with EA81 pistons, and give an increase in compression. My question is, what exactly is the difference in the pistons, and what is the compression ratio with the swap? Does it create any valve clearance problems?

[Guest archemitis]

i have read the same thing... maybe the airplane guys are the ones to ask. my ea81 could use about 10:1:D

[Guest GlCraigGT]

there are people here using ea71 pistons in a ea81, I belive the increas is from 8.7:1 to 9:1

[Guest RTFMharpua]

I don't think there are any valve clearance issues either because you can still mill the heads with the ea71 piston swap.

[Guest jcdenton]

are the EA71 pistons the 1.6L pistons?

[Guest GlCraigGT]

Yes

[Guest Brettm57]

So then is the wrist pin height the same between the 1600 and 1800 pistons, and the 1600 connecting rods shorter than 1800 rods to make the deck height right? If the gain in compression ratio is only 0.3, It sounds to me like that must be it. Are the 1600 pistons domed at all? Doing some quick math, milling the heads about .015" would make the same compression increase. Can anyone verify this for me?

 

Thanks.

[Guest GeneralDisorder]

but if you mill the heads much, the intake will not fit. Not impossible to fix, but the 1600 pistons do allow you to keep the stock heads. Which is nice if you ever want to replace one.

 

GD