I'm going to 2.7 my Touring... Could you assist on planning?

[frankiej]

I've got a 320i head. It's my understanding that I still need a complete late series Eta block, Ant's 2.7 chip and a 325i Intake manifold and TB.

-Is this correct and am I forgetting anything?

-Will I have to swap my ECU to the B25 ECU, or will the chip handle that?

-Do I need a B25 MAF, or will the B20 MAF work?

-What kind of power can I expect?

Thanks for reading,
Aaron

[frankiej]

Bump... Ant, could you perhaps help me out? Onz...?

[oze30]

I was going to say I have everything here, but then noticed your in Italy!

Do you want a high comp motor or low comp-FI motor?

Hicomp you'll need early 325 pistons and get some machining done. Eta rods/crank/block

Low comp is leave everything as is and use the ETA bottom end. Not sure which head, but both 320 and 325 wil fit. I think 325 gives better performance as the valves and ports are bigger???

[daimlerman]

Frankiej,You have all the basic requirements.A 2.7 zone chip(I bought mine from the zone shop) will fit your 320 ECU,just like mine.As standard,you have an AFM (air flow meter) you will need a rubber boot to fit between this and your throttle body.Again,I got mine running with the 320 AFM.Do not forget that the 325 inlet/injectors/thottle body will need the larger capacity FPR(fuel pressure regulator)I did...and it took me a while to work out what was wrong.Expect around 180bhp,with a good,flat torque curve.Have a look for the results from the Evolve R/R Day held on 24Nov07,my graphs are there,the lower power 2.7.(Oakey's is the more powerful one)Do also check your crank for wear,the eta units are old now.I needed a crank regind and new rings.Have fun building it and good luck..oh yes,I am using the 320 clutch and gearbox,but swapped to a 3.64 diff.

[frankiej]

Do you want a high comp motor or low comp-FI motor?

Hmm... That's what I'm still trying to sort out in my head. I don't know if I'll be happy with the expected 180 (+ or -) HP that the high comp 2.7 will have or if I'll go insane and want to break 200 with the FI...

One MAJOR contributing factor is that I don't have access to a machine shop. So that will ultimately have a huge draw on which way I go.

[frankiej]

Frankiej,You have all the basic requirements.A 2.7 zone chip(I bought mine from the zone shop) will fit your 320 ECU,just like mine.As standard,you have an AFM (air flow meter) you will need a rubber boot to fit between this and your throttle body.Again,I got mine running with the 320 AFM.Do not forget that the 325 inlet/injectors/thottle body will need the larger capacity FPR(fuel pressure regulator)I did...and it took me a while to work out what was wrong.Expect around 180bhp,with a good,flat torque curve.Have a look for the results from the Evolve R/R Day held on 24Nov07,my graphs are there,the lower power 2.7.(Oakey's is the more powerful one)Do also check your crank for wear,the eta units are old now.I needed a crank regind and new rings.Have fun building it and good luck..oh yes,I am using the 320 clutch and gearbox,but swapped to a 3.64 diff.

Thanks daimlerman. I've got so much spinning around in my head about this.

So let me make sure that I've got this straight: For a low comp FI engine it's the B20 or B25 head on the Eta block with all of the 325i intake bits. And if I use the B20 head, I'll need a B25 cam. That's all?

And for the high comp NA engine it's Eta block with high comp pistons, Eta crank, Eta rods, and the B20 or B25 head with the B25 cam and intake bits. Correct?

If I were in the UK I would just swing by ATech and have a chat with Ant or maybe meet some of you fellas at the pub and write all of my bench racing notes on a napkin. I think that would be easier

[daimlerman]

frankiej,You have the right idea there.Be aware that if you use pistons other than eta you will need to have the top of the block surface ground(decked) to suit them.This then opens a fresh can of worms regarding the relationship of the cam to the crank and the need for a vernier cam wheel....the main difference between the heads is valve size,the 325 head has a slightly different shape chamber that is best suited to 325 pistons. You can fit the bigger valves to the 320 head,just need the seats opening out to match them,but do check for clearence between piston/valve before attemting to run the engine...the 325 cam is the cheap option,garrantees low down torque like I have,to increase power above 5000rpm you will need an aftermarket cam of some kind.Lots of options I know,but it does mean that you can build an engine that will do just what you require.

[frankiej]

frankiej,You have the right idea there.Be aware that if you use pistons other than eta you will need to have the top of the block surface ground(decked) to suit them.This then opens a fresh can of worms regarding the relationship of the cam to the crank and the need for a vernier cam wheel....the main difference between the heads is valve size,the 325 head has a slightly different shape chamber that is best suited to 325 pistons. You can fit the bigger valves to the 320 head,just need the seats opening out to match them,but do check for clearence between piston/valve before attemting to run the engine...the 325 cam is the cheap option,garrantees low down torque like I have,to increase power above 5000rpm you will need an aftermarket cam of some kind.Lots of options I know,but it does mean that you can build an engine that will do just what you require.

The machining is where the hang up is at. I can't afford machining here. It will be MUCH less expensive to build the low comp engine and turbo it than it will be to build the high comp engine and have the block decked.

It's a 3MM shave off the block for the high comp, correct? I would rather build the high comp engine, but I can't afford the costs of machining here in Italy. I don't have a problem with turbo, I would just rather not have to wory about poping head gaskets and such as this is my daily driver and I want the most reliable power that I can have.

I spoke to a fella yesterday who builds engines for ralley and up hill racing. I explained to him that all I wanted for him to do is deck the block 3MM. He was quoting me more than 1,000 Euro... I wanted to hit him in the face. He also said that he wouldn't deck the block unless I let him do some work to the head. He insisted that I MUST put bigger valves in and that would cost another 1,000 Euro. Again, I wanted to hit him in the face.

In closing: I HATE THE US DOLLAR!

[daimlerman]

Looks like you will take the same route as me,standard eta short motor with 320 head.This will give a good reliable engine with good torque.Do check the crank for wear,though.Machining costs seem very high,I paid £25 for a head crack test and skim at my local engine building place.Seem to remember that someone built a low compresion 2.7 with the intention of using a turbo,and they used 325 pistons.This gave,IIRC,a CR of about 7.1. That option would let you use 325 pistons and the big valve head from a 325 without having the block decked or the snags with cam positioning....not done it myself as I cannot fabricate an exhaust manifold to drive the turbo!!

[frankiej]

Now I'm a bit confused. If I just drop a B20 or B25 head on an Eta block; do I have to deck it. I thought that I wouldn't have to deck it if I wanted a low comp engine.

[daimlerman]

The difference is in the pistons.The 325 piston crown is nearer to the gudgen pin.This means that it does not reach the top of the bore.I do not know the exact measurement,as blocks/pistons can vary a little. The general advice is to build up one piston/rod/crank assembly and measure yourself at TDC.The other point to remember is that the piston top is shaped differently between eta pistons and 325 pistons,eta pistons best suit the 320/323/eta head. If you are going the turbo route I am lead to belive that a low comp. ratio is better,you can achieve this with the 325 pistons on the shorter eta rods.Then you can use the 325 head with the advantage of bigger valves.Another plus is the increased valve/piston clearence....hum...I am talking myself into a turbo here!! So the short answer to your question is,...no you do not need to deck the block of an eta short motor to fit either head.You only need to deck the block when 325 pistons are used.

[Templ8e30]

Fitting a 320i head onto an eta bottom end gives the highest compression of them all. The 320i head has the same combustion chamber volume as the eta head so will retain the original compression.

No decking required if using a standad eta bottom end.

Best method for power is:
325i head and facelift 325i pistons
Decked eta/325i block
Eta crank
Eta/320i conrods
Cam of at least 260 degrees duration
Vernier cam pulley to correct timing
325i inlet manifold and injectors /afm etc

Best method for torque is :
320i head
Standard eta bottom end
Standard 325i cam
320i inlet bored out to take 325i throttle body or 325i inlet
325i injectors and AFM

Or you could build a 2.8:
325i head/late pistons
325i block
320i conrods
M52 328i crank
325i inlet/injectors/afm etc
No decking involved

Cheers,

Iain T

[daimlerman]

It has occured to me overnight that 325 pistons may need machining to clear the crank at BDC.The eta pistons have a scallop on the bottom edge.....the 2.8 build that Iain mentioned is the way forward,but you need a spacer machining for the front of the crank.....

[frankiej]

Ahhh... So there is machining involved in the 2.8 build? I knew it sounded too good to be true I just want to build something that will give me more than what my thirsty for no reason B20 has to offer without having to do any machining.

My only other option, I believe, would be to work out a deal with another Zoner on your side of the water to help me get any machining done and then have the worked over bits shipped to me. That's a lot of hassle for someone though.

I have a fella offering some possibly valuable bits for 150 bp. That doesn't seem too bad to me considering that IF I can find a B27 and B25 engine, they will cost around 600 Euro a piece! I might not need all of the bits, but he wants to get it all out of his shed.

It's a full eta block / crank / rods / pistons
PLUS Early 325 rods and pistons (for High comp 2.7)
PLus a spare bare 325 head (no cams/followers and unsure its condition)
Fuel Rail and inlet manifold from 325

I thought that I knew what bits I needed for sure to build something, but now it's becoming a bit unclear.

[frankiej]

I just want to say also; thanks a lot to everyone that is pitching in on this. I really mean it when I say "thank you" for helping me out. I have very limited resources where I'm at and most of them, I'm starting to realize, are in the UK. Thanks fellas, I honestly really appreciate the help!

-Aaron

[Templ8e30]

For a 2.8 build, early high comp 325i pistons will need to have the skirts machined to clear the crank. Facelift low comp pistons have shorter skirts anyway so no machining needed.

Cheers,

Iain T

[frankiej]

For a 2.8 build, early high comp 325i pistons will need to have the skirts machined to clear the crank. Facelift low comp pistons have shorter skirts anyway so no machining needed.

Cheers,

Iain T

How is your 2.8 build going?

[Templ8e30]

It isn't at the moment, I've been waiting for a crank for ages. I had one reserved at quarry motors but another employee sold it to someone else. I have another one lined up but need to raise more funds to pay for it

Cheers,

Iain T

[antony]

Hey, I'm doing a 2.7 aswell, and I was wondering if you need to change the sump, or is the 525e one alright?

[Templ8e30]

The 525e sump will fit but doesn't hold as much oil or have the oil level sensor arrangement.

Cheers,

Iain T

[daimlerman]

You will need the E30/M20 type water pump as well,I found out the hard way....the eta water pump has different outlets,not suited to the reduced space in 'proper' BMW's....

[frankiej]

Well damn, those are some good bits of information! Thanks fellas!

[Andyboy]

There are two Eta engines; early ones up to August 1985 are 11.0:1 compression. later ones are 10.2. The 325i head will fit straight on without problems. The compression ratio will be 10:4 on an early Eta engine or 9.4:1 with a later one. Both CR's are fine.

The 320i/520i/323i (E30) head is the '731' from the casting number. The chamber volume is identical to the Eta head. The Eta head is actually the same head from the E21 320 and 323i but with three cam bearing oilways undrilled. Therefore fitting a 731 head to an Eta will retain the Eta compression ratio. The slightly smaller valves and inlet ports will increase low speed torque but won't help top end power. But an E30 drives very well with the 731 head.

The Eta inlet manifold is no good - and the injectors are useless and are the same as the 320i - no good for an engine with 700cc more. You will need a 325i inlet manifold. injectors and throttle body plus 325i air flow meter. The 325i ports are a different shape to the 320i but they are easily modified with a griding stone and a drill. Just use a 325i inlet manifold gasket to mark out the areas to be ground away - just just want to smooth away the bits that stick out.

Early 325i pistons will foul a 2.7 crank. The later ones (8.8:1 compression) from the plastic bumper 8/87 onwards cars do not. It's nice to use 325i pistons but not essential. Eta pistons work okay.

[Andyboy]

For a 2.8 build, early high comp 325i pistons will need to have the skirts machined to clear the crank. Facelift low comp pistons have shorter skirts anyway so no machining needed.

Cheers,

Iain T

Early pistons with the 9.75:1 compression give a compression of exactly 10.8:1 with the 84mm stroke and 10.4 with the 81mm Eta crank. Using later short skirt 8.8:1 piston you have 9.75:1 as a 2.8 and 9.4:1 as a 2.7. This is assuming you have a standard unskimmed head and are using a standard head gasket.

You need to shave 12mm from an early piston and have them balanced.