eta stroker questions

[jaysee]

hey have a few questions. wanting to build a stroker for track use
have stock eta engine i know that the eta pistons dont match well with the 885 head because it has bigger and domed chambers.
so heres my question:
im wondering if it would be possible to keep the stock eta pistons and deck the head slightly to decrease the chamber size for a better compression ratio. and if so how much would i be able to remove without worrying about the valves and pistons touching, thx

[acolella76]

In short: leave the head alone. The bump in CR won't be worth possibly destroying your engine. The 2.7i CR is ~ 8.4:1 vs stock 325i 8.8:1. Not a difference worth worrying about. There are other things the engine needs (like a cam, headers, and a good tune) that will make a bigger difference than the compression ratio.

[jaysee]

it will get all that, just hard to cefer through all the mixed things ppl say. i fuigured wial the engines being built if it were possable it would be easy to do. anyway. you think the valves would touch the pistons?

[MR 325]

The head can only be decked so much, they have thickness indicators on them. You can have a little extra decked off with no issues but it's really not even worth doing that. If it were me I'd leave the meat on the head in case I have to deck it again in the future.

[Chuckcruzin1986]

885 Head milling

hey have a few questions. wanting to build a stroker for track use
have stock eta engine i know that the eta pistons dont match well with the 885 head because it has bigger and domed chambers.
so heres my question:
im wondering if it would be possible to keep the stock eta pistons and deck the head slightly to decrease the chamber size for a better compression ratio. and if so how much would i be able to remove without worrying about the valves and pistons touching, thx

I have heard this over and over, you can't mill the 885 head. I milled mine .050", installed super eta pistons in my 2.7 bottom (and milled more valve clearance in the pistons). I also installed an adjustable cam gear. My engine screams and I haven't started to tune it

So, this is the end of "you can't mill the head on a M20" or is it?

I am not an expert, but it is a done deal.

Chuck

[acolella76]

No one said you CAN'T mill a head. Just that you can't mill the the head past a certain point.

I think milling the head is a bad idea. If you want to bump the CR, buy a thinner MLS gasket. That way the head is not ruined.

Again, there are more important things that you need to do to a 2.7i to make it 'scream' than just decking the head a little bit to get a .1:1 CR bump.

[Chuckcruzin1986]

More to do

No one said you CAN'T mill a head. Just that you can't mill the the head past a certain point.

I think milling the head is a bad idea. If you want to bump the CR, buy a thinner MLS gasket. That way the head is not ruined.

Again, there are more important things that you need to do to a 2.7i to make it 'scream' than just decking the head a little bit to get a .1:1 CR bump.

I did a lot more :yawn:

It is that all I hear is that you can't mill the head on a M20 but a few thousands and that is the issue that I was commenting on, not what other options there are for performance.

Chuck

[Northern]

If you're going all out, why not just get SETA pistons, or better yet, swap the m20 altogether?

[devon.818]

why not machine block, o-ring block, stock HG, arp studs, and 15lbs of boost? can people do that? would that mean something awesome?