325i 885 head modification to increase compression

[dougs87325is]

Stroker SUPER GHETTO 2.7

Im in the process of swapping my 86 eta 2.7 block to put in my 87 325is.Im thinking on trying to have the combustion chamber welded and filled in where the dome is on the i head. I think this is very doable. Im wondering has this ever been done to a 885 swap, all stock ETA parts?

I have had heads welded and they are solid.

[Mossman]

ughhhhh what about where the valvey things are? I think a better option, not sure if it's good, but sounds better to me, would be a pretty considerable deck, I think 0.040" nets you a 1 point bump in compression. So yeah....deck a lot and if necessary get valve reliefs milled into the pistons.

[dougs87325is]

Forgot to add that I still want to Turbo Later on. I want to try and see how much hopefully reliable horsepower I can get when its all put together.

[1craze30]

get an m50, then turbo. head work is $$$$$$

[evandael]

If you want tarbo, just live with the low compression until then. I think its best to just leave the combustion chamber alone, sometimes just increasing the compression ratio doesn't have the desired effect.

Messing with the "squished" area in the combustion chamber can result in an engine that runs worse, pings badly, or just generally does not generate power as effectively as leaving it well alone.

[dougs87325is]

I want to try this, I think it might be 100 bucks to have the areas on sides of chambers welded( where the dome starts), not much material needed, increase cc of chamber. Then you grind it as even as you can get it, mill it. Im thinking when I turbo it, I can come back later and grind that material away.

[SpecM]

increase cc of chamber. .

you mean, DECREASE the cc of the chamber? I bet you don't even know what cc means.

what you're talking about sounds like a very bad idea

[dougs87325is]

spec, have you ever built a motor? Im talking about filling in areas on the combustion chamber to decrease the chamber, right. I Cant change the dang title, know how to do that? Thanks for catching that tho.

A machinist would know what Im talking about and trying to do I guess.

[dougs87325is]

Im a NOOBIE

[jasonsnoddy]

Im a NOOBIE

i noticed you are from mexico, is your e30 a truck

[george graves]

Good thread. Great thread.

[dougs87325is]

Jason that's not even right.It's supposed to be New Mexico. The other thing I don't know what your talkin bout. I was seriously close to turning the Eta into a pick-up, amazing, your a mind reader. Props

[jasonsnoddy]

Jason that's not even right.It's supposed to be New Mexico. The other thing I don't know what your talkin bout. I was seriously close to turning the Eta into a pick-up, amazing, your a mind reader. Props

my humble apologies, good sir.

[E30Nova]

This thread reminds me of that build thread in Mexico where the guy had an Evo (or some Mitsubishi I think) and the "builder" drilled holes in the pistons and carved patterns into the combustion chambers for extra horsepower. :rofl: :rofl:

Matt

[Adrian_Visser]

This thread reminds me of that build thread in Mexico where the guy had an Evo (or some Mitsubishi I think) and the "builder" drilled holes in the pistons and carved patterns into the combustion chambers for extra horsepower. :rofl: :rofl:

Matt

Lol I recall watching some news segment on tv about some dude in India of all places who carved designs in the combustion chambers of rickshaw engines and swore it made them run better.

OP welding and grinding your combustion chamber isn't a good idea.