where does the 2.7 engine come from?

[e30-EVN]

Mate, they wouldn't even see it coming! That's the best bit

[e30-EVN]

Funny as since this thread has been posted a mate has rung me tonight to ask me to build him an m20 stroker 2.7

So as I understand it....... If he gets me a 525e lump
Scrap the top half
I can use the whole eta bottom end (rods same length as 320 ones??)
Have 2mm shaved off the eta block
Bolt his pre facelift 325i head to it

And that makes a 2.7..?....

Is shaving 2mm off the block nessesary?....

Ant

[CHR1S1990]

no need to shave the block if youre using the standard ETA block and 325i 885 head, only needed if you plan on using 325i pistons does the block need decking

[e30-EVN]

Ok thanks for clearing that up mate, what sort of compression ratio will that give us?? 9 or 10?

[CHR1S1990]

all here in the wiki mate

http://www.e30zone.net/e30zonewiki/inde ... ding_a_2.7

depends on which ETA block you can find

early block > 9/'85 (11:1 CR) stamped 27 6KA (large freeze plug) or similar will give around 10.1:1
later block (10.2:1 CR) stamped 27 6EB or similar will give around 9.4:1

again, skiming the head/thinnest head gasket will increase the CR even more

[e30-EVN]

Right then, thanks again.

Of interest, how much would one charge someone to complete this build? He's not good at this thing so it will be me doing the work for him (drop car to me and have it back a 327i)

[CHR1S1990]

not an easy question to answer - depends how far you strip the engine down. Cheapest way would be to find a known good eta engine/block, and bolt a known good 885 head straight on without touching the bearings/rings etc

[e30-EVN]

Prob go with the "find a good eta bottom end and bolt his good 325i head to it" tbh, save cost for him but at the end of the day I've still gotta rip his m20 lump out, take head off, build 2.7 and then put it back in......

What you reckon?

[m_jermyn]

Prob go with the "find a good eta bottom end and bolt his good 325i head to it" tbh, save cost for him but at the end of the day I've still gotta rip his m20 lump out, take head off, build 2.7 and then put it back in......

What you reckon?

You can either use the 885 head or the 731 head.... Despite what people say there is very little difference between the heads. They share the same size ports the only difference is the size of the valves.. 885 valves are a little bigger.

885 has bigger valves and lower compression (hardly any difference 3cc chamber size)

731 smaller valves higher compression.


Worth noting that the 885 head is well know for cracking and the 731 isnt. 885 head is expensive 731 is cheap


And before everyone says that the 2 heads are miles apart I have had both side by side and they are not

[DanThe]

2.7 donk here Ant just needs freshening up

[Kieran_n22]

Wow some quite complicated talk going on here. I don't understand the calculations and stuff, I need to learn. I might just try get a bottom end from a 525e. Are these 12v or 24v? If its expenisve or hard to find I'll just look at doing a 24v conversion

[m_jermyn]

12v

^^^^ Danthe has one available it seems

[e30-EVN]

Yes he does and I'm waiting for him to ring me back as my mate wants it

[Ajsingh]

My 2.7 is:

885 '325i' head fully reworked
Eta bottom end (untouched)
325i inlet with injectors & TB
Lightened flywheel

And its a lovely motor to drive with a nice amount of torque.. Keeps up with e46 325's which is a great feeling...