2.7 stroker

[lovnbmws]

Its a belt, not a chain. All M20 motors use a belt for the cam.

Jon

My bad, I was having flash backs of my first m10 rebuild. ;)


There have been many discussions regarding the eta/euro 323 head swap. In fact just a couple weeks ago someone was trying to sell the same head on this forum.

http://www.r3vlimited.com/phpBB2/viewtopic.php?t=16605

http://www.e21bmw.net/graymarket/library/327i.php

[EverWiser]

FWIW...Using the i head on the eta block without changing pistons will drop your CR to about 8:1 but, provided you get around the rev limiter, the higher RPM you can run the engine up to will still gain you more HP on the top end than you can get with the stock eta with its 9:1 CR. Exactly how much more, I don't know but since HP is a function of RPM, being able to rev higher and breathe there will make more HP. Also, with 8:1, you wouldn't have to worry very much about pre-ignition (detonation). Also, you would still keep most (not all because of the CR) or your bottom end torque and at a lower level than where the 2.5 i makes it. Just my .02...

[ultima]

Yeah, but is it worth it? I don't think so. If you're going to go through the trouble, then you need to do it right. I've got an 88 325 and will be swapping in my M20B25 soon. Then I'm going to build the 88 super eta engine into a stroker. With an 88 325, you already have the domed pistons in the block. There's already an "i" head with it, so all you've got is less work than is normally needed with a regular eta.

[lovnbmws]

Yeah, but is it worth it? I don't think so. If you're going to go through the trouble, then you need to do it right. I've got an 88 325 and will be swapping in my M20B25 soon. Then I'm going to build the 88 super eta engine into a stroker. With an 88 325, you already have the domed pistons in the block. There's already an "i" head with it, so all you've got is less work than is normally needed with a regular eta.

The relative “worth” of any project is entirely subjective based on an individual’s wants, needs, and resources. For example: I have a complete and running 81 euro 323, 86 325es, and the desirable half of a b25; all currently collecting dust. “Is it worth it” to pull the two cars apart and for the out of pocket price of a gasket set build myself a stroker? Maybe… Considering I’m currently in the process of swapping an m30b35 into my 87is, maybe not. If I was to build a stroker it probably wouldn’t be worth it, at lest for me, to go tracking down a super eta.

Just my $.02 ;)

[Axxe]

Is it possible to use the ETA crank with I pistons in an I block?

[Mot]

Guys, Pm Oh2Fly on this board, He is Dave Lumbra owner of 2002restorations in eugene. Im picking up his 323i which has this swap done. Eta block/323i head.. Heres a qoute from an email he sent me

Hi Tom, I adjusted the valves today, then checked the compression for grins.
It is 200,200,205,205,200,200. That's just what I was expecting. Compression
ratio is about 9.8:1

It is possible you just have to do it right.

[decay]

9.8:1, huh? higher than i thought... good to know.

[da breeze]

323i head on eta block!

Hey all im preety new to the site and i guess new to bmw technology aswell, i know the basics but nothing to technical!, anyways to my point in this tread some of you have been talking about a 323i head conversion onto an eta block, few things i have realised, (to fill you all in i recently pusrchased a 86 325e and it had a "i" instument cluster put in until last week i went on the assumtion that my car was still a eta ust with the converted cluster and the cluster was faulty because i could take the car to 6500 - 7000rpm without the usual stop dead ETA revlimiter cutting in) Anyways last week i went to a Bmw mechanic and found that i am actually running a "eta" bottom end with a "e21 78' 323i" head in my car. Now to clear some things up for people thinking of doing the conversion few things i wanna point out: (This just being what i know/have been told) When doing the conversion im not sure what pistons im running havn't dug into my enigine yet, But putting a E21 323i head on the Eta block is not very performance enhancing, due to the fact that the e21 head has smaller ports that the e30 323i head and when put on the eta bottom end air flow is restricted that much the performance is not very noticable. Computer also need to be changed, Use a later model 323i head with bigger post if you are going for this option but i was told that due to the compression change with the head conversion that unless you are running 98% octane fuel the car will ping like crazy just due to the compression being higher/lower.

I found my intrument cluster is reading right and the limiter is now at 7500rpm (Tested by mechanic) And does rev harder/longer than a usual eta engine but up to a point. I am heading back to mechanic to talk about 325i head conversion he said it can be done so i will wait an see. One more thing I was also told i have an e30 m3 diff in my car which has been rebuilt and the ratios are 3.15 to increase the bottom end power so how much effect that would have with the head conversion i am not sure due to all this being done by the previous owner. If Anyone has the ratios of a normal e30 m3 could you let me know. Any more questions i will try and help you with if i know or when i find more out my engine. sorry bout the long post!

Mark :)

[nefarious7907]

i was pretty sure that you could use an ETA crank on the 2.5 and still use the 2.5 pistons and rods just swapping to the ETA crank. I know it is not as fun as putting the I head on the ETA but I am pretty sure that this would work comments welcome.

[decay]

i was pretty sure that you could use an ETA crank on the 2.5 and still use the 2.5 pistons and rods just swapping to the ETA crank.

uhm, no.

visualize what you're talking about.

if you want to use b25 pistons with an eta crank, you need custom rods that are 3mm shorter, otherwise the pistons will hit the head.

[EverWiser]

i was pretty sure that you could use an ETA crank on the 2.5 and still use the 2.5 pistons and rods just swapping to the ETA crank.

uhm, no.

visualize what you're talking about.

if you want to use b25 pistons with an eta crank, you need custom rods that are 3mm shorter, otherwise the pistons will hit the head.

EXACTLY, What He Said!^^^^

[Axxe]

i was pretty sure that you could use an ETA crank on the 2.5 and still use the 2.5 pistons and rods just swapping to the ETA crank.

uhm, no.

visualize what you're talking about.

if you want to use b25 pistons with an eta crank, you need custom rods that are 3mm shorter, otherwise the pistons will hit the head.

Thanks for the info. I looked up all the specs a few days after posting, and realised it would be a major fuck-up.

[e30bimmerdude]

So basically if you want something fun.. right off the bat go with the 323i head, but for a turbo project would you guys suggest going witht the 325i components to drop the comp ( i have a 85 eta by the way), because its my understanding that with any blower, turbo, or nitrous motor you want low compression Correct?... thanks fellas

[nefarious7907]

So basically if you want something fun.. right off the bat go with the 323i head, but for a turbo project would you guys suggest going witht the 325i components to drop the comp ( i have a 85 eta by the way), because its my understanding that with any blower, turbo, or nitrous motor you want low compression Correct?... thanks fellas

the idel compression for a turbo or any boosted motor is 8.5 which would be really close but then you have to think about the strength of the stock pistons.

[nefarious7907]

I have an 2.7 ETA engine I am trying to figure out how to get some bang for my buck here, the 2.5 M20 runs around 550 for a complete engine and manifolds with less than 100k on it. Going to turbo it, really want the displacement, need the 7000 revs, want to do for less than 2k