Reversed head swap question

[danval]

Hey guys.
So, I'm pretty familiar with the "I" head on the "e" block. Ive Done it myself. My question is, can it be done the other way around? Having an "e" head on an "I" block? First, I'm not looking for performance or anything. I just need to know if it's doable. Thanks in advance.

[Cabriolet]

no, you will have inference issues

[jlevie]

Can it be done, yes. But understand that you will see a significant power loss because of the cam and smaller ports and that you will have to use a self imposed rev limit of 5400rpm. Anything above that risks valve to piston contact and loud noses that will scare the horses with subsequent expensive repairs.

I suspect fuel economy will suffer because the DME is not expecting the characteristics of that head. All in all, a really, really, bad idea.

[danval]

no, you will have inference issues

Cabrio, can you be more specific? Thanks

[LJ851]

no, you will have inference issues

Cabrio, can you be more specific? Thanks

Should you really trust the guy who can't spell interference?

[danval]

Can it be done, yes. But understand that you will see a significant power loss because of the cam and smaller ports and that you will have to use a self imposed rev limit of 5400rpm. Anything above that risks valve to piston contact and loud noses that will scare the horses with subsequent expensive repairs.

I suspect fuel economy will suffer because the DME is not expecting the characteristics of that head. All in all, a really, really, bad idea.

My only concern was valve to piston clearance. The only "I" I'm leaving is block (with internals of course). Head, intake, DME and harness will be from the "e". That's why I said inverted stuff, because it's like an 2.7i swap (which I'm currently running on my e30). Thanks again

[danval]

Should you really trust the guy who can't spell interference?

I was actually trying to figure out what was I missing. :s

[LJ851]

jlevie is rarely wrong.

[bmwm42]

My only concern was valve to piston clearance. The only "I" I'm leaving is block (with internals of course). Head, intake, DME and harness will be from the "e". That's why I said inverted stuff, because it's like an 2.7i swap (which I'm currently running on my e30). Thanks again

Stupidest swap award candidate

[danval]

Stupidest swap award candidate

Thank you! :D

[jlevie]

Why would you want to do this? Even if you had those parts just laying, they could be sold for close to what an M20B25 head would cost. And if buying the parts by the time you are done the cost would be more than that for the right head. In addition to the head, intake, harness and DME you'll need the injectors, FPR, AFM, transmission, flywheel, and timing reference sensors from an M20B27 engine.

[digger]

ive never tried it but i always thought the dome on the B25 piston would hit the flat squish band on a 200/731 head. the 885 squish band is angled the same as the dome on the B25 piston.

[crazyman]

Yeah the first time the pistons come up and hit the head (which they will) boom goes the weasel. The i engines have domed pistons with matching domed combustion Chambers in the head, eta's have flat top pistons with matching flat combustion chamber in the head. Put a flat head on a engine with domed pistons and the first time you try to fire it, it will end badly.

[danval]

Why would you want to do this? Even if you had those parts just laying, they could be sold for close to what an M20B25 head would cost. And if buying the parts by the time you are done the cost would be more than that for the right head. In addition to the head, intake, harness and DME you'll need the injectors, FPR, AFM, transmission, flywheel, and timing reference sensors from an M20B27 engine.

Jlevie, it's not that I want to do this, or like other people are "assuming". I didn't come up with a brilliant idea and want to do it. Like you said, I have the parts (all of them) just sitting around and wondered if it could be done. I know theres knowledge here so that's why I asked. Now that I have the knowledge and understanding, I can see that it's not possible/worth it. Thanks again to all who helped. After all, that's what forums are for right?

[danval]

ive never tried it but i always thought the dome on the B25 piston would hit the flat squish band on a 200/731 head. the 885 squish band is angled the same as the dome on the B25 piston.

Thank you, that's what I was thinking. Clearing issues.