engine change choices

[kylepiggy]

i have a 89 320 and would like opinoins for the best engine choice for bang for buck i dont have a massive budget for a v8 conversion or anything silly like that. would also like a semi straight forward swap. i was thinking on just fitting a 2.5 but was looking at maybe a 2.7 coz reading up on e30 wiki i can use my 320 head and also have the option to port it so i can use the 2.5 inlet and TB. what you guys think. would i feel the difference of a 2.7 setup using my head as opposed to just dropping in a 2.5 thanks guys

[GrindCulture]

Drop an M30 3.5 straight six, have a read up, there's loads of into here. That's by far the best bhp per ££ option. Either that or got for an M50 2.5 24v from an E36/later E34.

[zimmer-320i]

depends what the buget is a 2.5 stroker might seem a easier option but could be as expecive as a m50

[kylepiggy]

i just thought possibly a 2.7eta as i can use my head so i already have the top end sorted

[zimmer-320i]

but iirc you need custom fit pistons and im sure the b20 head isnt a wise option as the b25 head has bigger valves,
and eta cranks arnt cheap for a decent one, plus your always going to have 12v's
the 24v block has a better power delivery and hasnt got the m20 flatness
also i i though the block needs skimmign to be level with the pistons plus the pistons need the recesses cutr as the piston travels diffrently plus its less of a head jar as you may find your self rebuilding a 20 year old engine
were as a e36 engine is half its age and take to moddifying better ie cams exhaust etc

[leeparkes]

depends what the buget is a 2.5 stroker might seem a easier option but could be as expecive as a m50

+1
M50/M30 is a popular choice

[zimmer-320i]

also at the end of the day would you rather have a engine in bits having it machined whch can be costly and then have new gaskets seals, belts tensoners, heatbolts,

then the shopping list is a eta crank,pistons 2.5 engine in the first place then using your 2.0 conrods making that engine worthless

or a m50 were you need minamal wiring knowlage and then diffrent engine mounts and your in preety much.

and tbh as great and bullet proof the m20 is its a dead end with performance, best thing you could buy is a btb2 manifold and a remap getting proberly 20bhp and still having a 16-19 year old engine on 12v's and that would cost a good 900 quid
600 btb
300 at least remap

or a m50 which is around 500

plus if ya lasy you could start of buying this

http://cgi.ebay.co.uk/Modified-loom-for ... dZViewItem

and you would just then basicly plug and play

ask bob_s what he thinks of a m50'ed e30

[Bob_S]

I have arrived for ease of fitment put an m50/m52 in the ONLY custom part you need is the manifold/downpipe section welded up everything else is standard BMW stuff and can be done for sub £500.

Zimmer, fair do's that's the best post I've seen you post
by no means is the m50/m52 the ultimate engine for an e30 but it's by far one of the better £/performance conversions for sure!

[zimmer-320i]

thanks,
well i may of come across wrong but i dont mean to.

if i hadnt shunted the front end week back i WAS thinking of swapping enignes and nearly won a m50 non vanos for 250 but right at the end and i mean 20 seconds some one jumped in and i wasnt expecting it as it had me as only bidder and listing was a bit vauge!!
oh well lol
but yer if bmw made a m50 engine instead of making a new model beeing the e36 id have brought one of those, as the e36 looks are the only reason i wont buy one but i know the engines are exellent and strong pullers

[E30BeemerLad]

M50 makes a lot of sense both for the conversion and bits needed but also, you have to factor in how the car will behave down the line.

It's all well & good with the M30 anchor having more power & torque out of the box, but the newest 3.5 M30 has got to be over 15 years old and they do like a drink, so it would be the more costly proposition to run.

From what I have read, the M50 boys seem to enjoy reasomable fuel consumption as well as decent performance gains

[Alex]

if you can find a 2.7 bottom end, just swop that and keep your 731 (320i) head and fit a chip and thats basically it "i think"

[Theo]

I'd just fit a 325i engine. More specifically, the one I have for sale

[zimmer-320i]

but for maybe 150 more he has a 200bhp+ engine,
tho i wouldnt mind having the b25 shame im broke!

[Theo]

200bhp for £350 - please explain.

[zimmer-320i]

ok sorry 192 bhp and the m50 weve been talking about and before you say there is a m50 on ebay going for 370 unless its finnished already. ok its non vanos but not sure what diffrence single and double vanos there is

[mr_dink]

Taken from -

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

Retain the standard Eta bottom end untouched and fit a head from an E30 320i or 323i. This is the 731 head which has much bigger inlet ports than the 200/Eta. It has the same sized valves as the Eta which are 40mm inlet and 34mm exhaust. The combustion chambers are identical the Eta 200 head so by fitting a 731 head, you will retain the Eta compression ratio.


From here you can open up the tops of the inlet ports using a 325i inlet manifold gasket as a template to accept a 325i inlet manifold, or you can use the 320i/323i manifold with or without a 325i throttle body. It will be a bit flat at the top end without one though. You are not likely to get past 180 bhp but it will be pretty torquey.

Decking the block or shaving pistons is only neccesary with 325 parts.

OP can bolt his 320 head onto a complete eta engine, 325 inlet/ecu/loom etc. Check the wiki page.

[mr_dink]

ok sorry 192 bhp and the m50 weve been talking about and before you say there is a m50 on ebay going for 370 unless its finnished already. ok its non vanos but not sure what diffrence single and double vanos there is

vanos is variable cam timing.

Single on the inlet cam only, boosts torque.

Double vanos is on both inlet and exhaust cams.

The vanos on the exhaust cam is mostly there to improve emissions IIRC.

[zimmer-320i]

fook i didnt know it was that simple my apologise,

so to re-cap its a eta bottom end block pistons and then a 320 head with 325 inlet and tb

what needs to be done fuel and timing side??

[zimmer-320i]

sorry also how easy is it to fit that sprigot ring?

[mr_dink]

I would read the wiki page here mate -

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

I'm just getting my info straight from there.
It says the 320 head is a bolt on so this is the simplest way to do it, but your engine will make more power if you use 325 head with or without matching pistons as the 325 head has bigger valves and flows more.

More than 1 way to skin a cat as they say.

I'd read the page mate cos there's no way I'm going to be able to explain it better than Andyboy!

[mr_dink]

Spigot bearing goes where then input shaft of the gearbox inserts into the engine.

Not sure if you have to press it in or what though

[zimmer-320i]

yer ive read it

so if the 320 and 325 heads are the same apart from valve sizes surely a 325 head can be bolted straight on, i know some one who has a 525e just sitting in a yard this is y im so "whats this whats that"

[mr_dink]

Yeah the 325 head does go on and as you've got one it makes sense.

If you get the eta bottom end complete and bolt your head and the rest of the 325 ancillariess on (inlet/injectors/loom/ecu/afm etc) then all you need is a 2.7 chip.

If you're going to go for it I'd start a new thread and get advice from people who've done the build, as I haven't!

[zimmer-320i]

ive got a 320!
but im wondering if the 325 head fits ill start a new thread

[leeparkes]

Spigot bearing goes where then input shaft of the gearbox inserts into the engine.

Not sure if you have to press it in or what though

you need to use a suitable sized socket and lightly tap it in.

[Brianmoooore]

320 and 325 heads have completely different combustion chambers, as well as different sized valves.
IF you can find a 525e bottom end in good order, just swap a 731 320 head onto it, with a 325 inlet system and a suitable chip (I think Ant does one), you will have an engine that produces slightly more power than a good M20b25, but with loads more torque.
A worthwhile modification to a 325, but a total transformation for a 320!
If your 525e bottom end needs a rebuild, forget it, and go for a M50B25 vanos. You won't be disappointed!

[kylepiggy]

been reading into the m50 would love to but dont have the time or money i just thought it would be easier to do the eta as i have the whole top end just need the eta bottom end and 325 inlet TB and Injectors. once bits are sourced i could probably do it in 1 day and would be cheaper. just the whole having to fabricate a manifold for the m50 dont have them sort of skills and to get some 1 else to do the conversion will be expensive.

[zimmer-320i]

ar i see, cool so whats there when the auto box is connected? i persume the shafts has its own bearing??

[Brianmoooore]

ar i see, cool so whats there when the auto box is connected? i persume the shafts has its own bearing??

The torque converter has a somewhat rude shaped projection on the flywheel side, that locates into the hole in the end of the crank.

[zimmer-320i]

thanks

[zimmer-320i]

been reading into the m50 would love to but dont have the time or money i just thought it would be easier to do the eta as i have the whole top end just need the eta bottom end and 325 inlet TB and Injectors. once bits are sourced i could probably do it in 1 day and would be cheaper. just the whole having to fabricate a manifold for the m50 dont have them sort of skills and to get some 1 else to do the conversion will be expensive.

check my thread out may help you got a link there for the spigot ring etc and a few qestions awnsered

http://www.e30zone.net/modules.php?name ... 76#1335676