Engine conversion do i go for 2.5 or 2.7? - With pics of 2.3

[DAZ1985]

The head gasket on my e30 2.3 has jus gone and i was thinking about just putting another engine in as the 2.3 felt under powered.

The car was originally a 316 that had been converted to a 2.3 before i brought it. It has all the 2.5 rear beam and i believe the loom,ecu and injectors are 2.5 items already.

I have dont engine swops before but im new to e30's. Would i be right in thinking its a simple swop as most of the 2.5 stuff is already thier.

Any help,tips or advice would be helpful. Thanks in advance

[daimlerman]

Any engine in mind?

[DAZ1985]

Well i was thinking a 2.5 but i've been offered a 325 and a 525e engine but i want a simple swop as i've only got 1out of 3cars road worthy at the moment

[daimlerman]

Now you are talking!! Take the 525e short motor and fit the sump pan from your 2.3. Fit the head from the 2.3 as well,do make certain that it is flat...you will end up with about 180bhp...and 2.7 ltr...have a read of Andyboy's sticky in the conversions section for more info.,but you have the basis of a very nice motor.The standard 323i cam is the most agressive of the standard cams.

[Alex]

keep the 323i engine i know there nothing special but there rare

[daimlerman]

keep the 323i engine i know there nothing special but there rare

What is rare about an 80mm bore with a 325 crank?

[Alex]

keep the 323i engine i know there nothing special but there rare

What is rare about an 80mm bore with a 325 crank?

im guessing parts arnt rare then, but the combination is

[daimlerman]

323i was short lived and replaced by the much better 325i,but the OP has all the proper bits to make a good,suprisingly quick,2.7....go for it.

[DAZ1985]

I was told that the 2.3 engine was out of a 5 series?

I've got a few pictures that ill upload in a moment

[DAZ1985]

[daimlerman]

All the M20 based 6 cylinder engines have the same external dimensions,it is the insides that vary.They all mount the same way,so can be swapped easily.Be aware that induction systems are specific to capacity and valve sizes and cylinder heads do vary.Agood mix of the bits you already seem to have would be; 525e short motor,323 head and cam,325 inlet and associated bits.Use the alloy E30 sump,and I would suggest a medium case(8 bolts to rear cover)diff.Use the 325 engine loom and management(contact Ant at A-tech for a suitable chip)to upgrade to the later electronic ignition and fueling.This mix will give an engine that will pull strongly in all gears from little more than idle speed.overtaking HGV's on single carriage way roads in 5th is very safe,my car will accelerate from 55mph to more than 80mph in 5th in the distance it takes to pass the truck.Have fun....

[DAZ1985]

So in a list all id need is?

525e block
323 head and cam (currently on the car)
325 inlet and tb
e30 alloy sump (currently on the car)????
325 loom and management (currently on the car)
chip from A-tech

[Alex]

So in a list all id need is?

525e block
323 head and cam (currently on the car)
325 inlet and tb
e30 alloy sump (currently on the car)????
325 loom and management (currently on the car)
chip from A-tech

yep pretty much

[DAZ1985]

along with?

gasket kit
head bolts

[--alpina--]

Just a question, how much BHP would you get using the 323i head over the 325i head? also the ports are small including the valves on the 323i head, wouldnt you lose power in that department?



Cheers


j

[DAZ1985]

Good question that is

[Alex]

the 325i 885 head will be better but im sure you need to do work to it to fit, where as the 731 320/323i head goes straight on with a chip you have an instant 2.7

the 525e bottom end with 731 head will be fairly torque'y

[--alpina--]

Alex, the 885 head fits on the 535e block effortless, no need to do work to it to fit!!!


j

[Alex]

Alex, the 885 head fits on the 535e block effortless, no need to do work to it to fit!!!


j

you mean 525e

i thought the compression ratio was too low or something

[DAZ1985]

How can i identify what head its is on what i've got now? Im assuming thiers some numbers stamped on it? Can they be seen with the engine still in the car?

[Alex]

you have the 731 head found on all 320i and 323i

[DAZ1985]

Fair enough, im new to the e30 world. Im a vauxhall man at heart lol

[Alex]

vauxhall

im currently driving a corsa and i hate the damn thing, its unbelivably S L O W and made of cheese

[DAZ1985]

Funny you say that i've got a corsa as well but its got a cav turbo nugget in it so it doesnt hang about lol

[Alex]

whats that the 2.0 16v

i bet it shifts, shame the power goes to the wrong wheels tho

[DAZ1985]

Its the turbo one to much power for the wrong wheels yeah.had it r/r at 270bhp and 275ft/lb of torque so its abit of a hand full.still puts a smile on my face but torque steer aint as fun as rwd sideways lol

[--alpina--]

Sorry yes 525e, typing error,



j

[daimlerman]

The 731 head(320/323) has combustion chambers the same shape as the eta 200 head.This is what makes it a better head with a stock eta short motor.There is room for the valve seats to be cut back to take the bigger 325 valves The 885 (325) head has a chamber shaped to suit the odd crown of the 325 piston,this makes it less suitable,although this combo is being used by chromiebabe.My 2.7,with a standard 325 cam in a standard 320 head gives 178bhp,with 190ft.lb. of torque from 2000rpm up to 5300rpm...these engines are all about torque,this is what fires it past the trucks,big bhp numbers are for bragging about down the pub.

[DAZ1985]

Is the exhaust manifold the same?

[--alpina--]

Cheers daimlerman, also is there a big difference between the 2.5 and 2.7 by how much bhp?

Also the 731 head (inlet and outlet) ported and polished out to the 885 spec is it expensive, cos i have a 325 head slapped on my block but have often thought to get hold of a 731 head and get work done to it so i could retrieve some lost bhp that the car could squeeze out via the cylinder head, i have a spare 885 (2.5) head which i was thinking of getting some work done to it but its just sat in the garage.. so need to try get a 731 head and see.

The block is a 325 with eta crank, and the pistons are from the early eta 1981 which then is a higher comp pistons 11:1 ratio..

But with the 885 head i wont get that comp ratio!! BUT if i fit the 731 head will i get the fullest 11:1 ratio?


cheers


j

[DAZ1985]

I've also been offered a complete 325 engine so i would also like to know the differences between a 323, 325 and 327 power and drivability wise as im on a budget and it may work out better for me to just go for the 325 lump

[daimlerman]

this is very much a 'basic' 2.7,around a 5% increase in bhp,but a 325's torque curve will follow the power curve,mine is almost 'flat'. The car is graet fun to drive quickly,will overtake safely in 5th,climbed mountains in Scotland at least one gear higher than the 325's on last zone roam and returns a regular 34.5mpg,this rises to the 36mpg mark on a long motorway trip(not many motorways in Lincs.)With the parts available for an engine like this,you will be daft not to go for it.

[--alpina--]

so the 2.7 makes approx 178.3 bhp? so no way hitting the 200 bhp mark So whats the alpina`s c2 2.7 all about?.... how is it possible to take the car to 220bhp?

I thought maybe at least the 200 mark...


j

[DAZ1985]

Im goin ring the guy thats got the engine later see what price he can do it for. Just got no space at home for taking out the engine and re building it up. A few of my mates have got units its just if they have the space for me thier. With the car being an already converted 316 with a rust free shell what would it be worth with a 2.7? I wouldnt be wanting to de value the car

[daimlerman]

so the 2.7 makes approx 178.3 bhp? so no way hitting the 200 bhp mark So whats the alpina`s c2 2.7 all about?.... how is it possible to take the car to 220bhp?

I thought maybe at least the 200 mark...


j

Again,bhp is the fiqure you brag about down the pub,torque is the weapon that pulls you past the trucks!! 200bhp is achevable,so is 400bhp,so is 600bhp,BUT,every 10bhp from around the 180bhp mark with an M20 as base will cost an extra £1000.Alpina claimed 237bhp for their C2,just wait to see Simon13's rebuild costs!!Any advance on £6000?