eta motor

[Pat W]

would it practical to start a stroker motor with a eta or be eaiser to start with the m20b25?..

[nando]

B25, swapping cranks is easy but there is no magical way to change an e head and intake into an i head and intake. ;)

[Pat W]

yes but i thought that by using the e bottom end and the i head and what not you would basically have a 2.7i....now i know you need to run custom pistons or super eta pistons....
but this would be ideal because im planing on turboing it after stroking it....

comments

[Madhatter]

you dont really need to swap blocks though, like nando said, all you need to swap is the crank and rods / pistons (or go custom, or super eta, or whatever).

Both the eta and 325i blocks have the same bore size, the difference is the eta crank has a longer stroke.

[nando]

yes but i thought that by using the e bottom end and the i head and what not you would basically have a 2.7i....now i know you need to run custom pistons or super eta pistons....
but this would be ideal because im planing on turboing it after stroking it....

comments

no, because just bolting the i head on an e block gives you very low compression. you have to rebuild the bottom end anyway (with pistons made for the new bore/stroke), so just start with a B25 and find an e crank somewhere. much cheaper than finding an i head and intake.

the alternative "easy" way is to start with an 88 eta and changing it to an i cam etc. but you're stuck with 8.5:1 compression..

[EverWiser]

yes but i thought that by using the e bottom end and the i head and what not you would basically have a 2.7i....now i know you need to run custom pistons or super eta pistons....
but this would be ideal because im planing on turboing it after stroking it....

comments

no, because just bolting the i head on an e block gives you very low compression. you have to rebuild the bottom end anyway (with pistons made for the new bore/stroke), so just start with a B25 and find an e crank somewhere. much cheaper than finding an i head and intake.

the alternative "easy" way is to start with an 88 eta and changing it to an i cam etc. but you're stuck with 8.5:1 compression..

An i head on an eta bottom end will yield a CR of close to 8:1; I've heard some say 7.9:1. If you're planning to turbo it you would be in very good shape with that CR. As far as 8:1 being "too" low, not really. Although you won't put out as much total HP with a lower CR you will be able to run more ignition timing without detonation; especially on the pump gas that most of us can buy...Just my .02.