Lets talk about engines!

[pac1982]

Right well by the end of the month my 318IS should be pretty much mint, re-spray will be done, new front wings fitted and new suspension and bushing fitted so its time to start looking at engines conversions.

I’m fairly handy with a spanner my self and with the help of my mate 10 apes we can do anything so top of my list is an M52 conversion but after looking in to this the complexity and cost has made me think that I may as well save up for an E36 M3 engine and make the ball ache much more worth while.

So in the meantime I want to know which 6 pot engines I can throw in to my humble 4 pot 318IS with little or no bother willing to go up to about 3.0L’s as it will still be my daily so don’t want to go for something really silly just yet.

So just to clarify what engines can I more or less throw straight in, don’t mind having to change my gearbox but don’t really want to mess around with custom exhaust manifolds and prop shafts just yet.

[pac1982]

Bump

[Jhonno]

M52... Cheap and easy

S50 is a completely different league of cost and difficulty

[pac1982]

From what I understand the M52 conversion requires a custom exhaust manifold and a custom prop is this correct??

I have asked before on E3024v.com exactly what is needed to do an M52 conversion but they seem to be quite a secretive lot

[Jhonno]

No, it requires a small tweak on the exhaust manifold, nothing expensive or difficult

No custom prop required, which prop you'd use would depend on your choice of box

We aren't a secretive lot.. BUT somethings get asked time and time again..

[pac1982]

No, it requires a small tweak on the exhaust manifold, nothing expensive or difficult

No custom prop required, which prop you'd use would depend on your choice of box

We aren't a secretive lot.. BUT somethings get asked time and time again..

I guessed that may be the case you must get umteen people everyday askng the same question but i couldnt even find a post on there that gave you all the details you needed to know prehaps you could point me in the right direction?

Also what box & prop would you recomend?

[E30BeemerLad]

M52 engine
use your is gearbox, fit M20 flywheel, clutch & starter
325 propshaft
use you iS rad for now with leccy fan
E34 sump, oil pickup & disptick
E36 engine arms
E28 M5 rubber mounts
320 gear rods
clio servo
Exhaust manifold will need some cutting
325 exhaust system

You're about there

[E30BeemerLad]

oh and a 325 diff

[pac1982]

oh and a 325 diff

Cant use the LSD from my IS then?

[E30BeemerLad]

you can but it'll be doing probably about 5k at 80mph

[pac1982]

you can but it'll be doing probably about 5k at 80mph

Ah not so good then on the plus side LSD's are worth a few quid so will pay for a few bits i need to do the conversion

[glenn]

i'm selling my S50 3.2 engine/box/ews etc ready to go into an e30.
pm me if your intrested

[pac1982]

to be honest mate i dont think i could afford it, my plan was to get the bits together as and when i could afford them and crack on with the conversion once i had everything, cheers for the offer though

[N00b]

M52 engine
use your is gearbox, fit M20 flywheel, clutch & starter
325 propshaft
use you iS rad for now with leccy fan
E34 sump, oil pickup & disptick
E36 engine arms
E28 M5 rubber mounts
320 gear rods
clio servo
Exhaust manifold will need some cutting
325 exhaust system

You're about there

Hi mate, can I just ask you to explain a couple of points in the above?
Am I correct in assuming that you mean E36 (any particular model?) engine mounts with the engine mount rubbers coming from an E28 M5?

Also, why do you suggest the 320 gear rods (linkage?)

Thanks in advance.

[N00b]

Hi mate, can I just ask you to explain a couple of points in the above?
Am I correct in assuming that you mean E36 (any particular model?) engine mounts with the engine mount rubbers coming from an E28 M5?

Also, why do you suggest the 320 gear rods (linkage?)

Thanks in advance.

Yes, e36 m52 mounting arms with e28 M5 rubber mounts.

Gearbox sits in a different place (further back) so you need shorter linkages.

As I understand it, the 50/52 block is the same design as the M20. Would this mean if you kept your original box then your existing linkage would be fine? Thinking about it though, I suppose you'd be better off using the newer gearbox.

[daimlerman]

As you would be starting with an iS you can use your existing gearbox,the M42 sits at the same angle.M20 sits at a different angle,meaning that 320/325 'boxes are not suitable.
The engine/'box(M50/M52/iS'box)will sit futher back in the 'bay than your iS motor does,so either you cut a fresh hole in your tunnel,build a new centre console to suit and change gear with your elbow,or read the advice given....320 linkage on 318iS 'box,320 propshaft.
A 4.1 small case LSD will have a short,but very entertaining life,a medium case 3.64 or 3.73 or even 3.91 would last longer.
Main issues are engine wiring and exhaust manifold.
A good read is E30beemerlads thread on his conversion.
A shorter version covering a lot of the issues is my thread 'Daimlerman's Folly' in the photo gallery,now many pages down the list!

[E30BeemerLad]

1st gear is quickly despatched in mine with the 3.91 LSD out back

[daimlerman]

M20 sits at a different angle,meaning that 320/325 'boxes are not suitable.

I have used a e30 260 getrag box behind my M52, just had to twist the standard 325 linkage slightly and make a new gearbox mounting crossmember, have the standard 325 prop as well. I used the box because of the overdrive 5th. 4.1 lsd would make 1st gear a waste of time, I eventually settled for a 3.46 lsd as even the 3.64 made 1st too lively for my liking.

As you can see, there are several routes you can take doing the conversion.

Sure,but you have knowledge/skill/means to modify in this way.
I found the BMW parts bin to be an easier option!
I have tried a 3.45 diff,and found I was spending more time in 4th,and no gain in fuel economy on the motorway to balance it.

[E30BeemerLad]

1st gear is quickly despatched in mine with the 3.91 LSD out back

Must be fun, cruising must be busy. How are you enjoying your M52? You certainly had a marathon journey doing it..!!!!

Yeah it is busy, 70mph = 3k.

60 is just obtainable in 2nd

No regrets so far. I need to iron out the niggles like vibrations and the PAS pump seems to kill the revs down when at idle and also it holds the revs up when you go to change gear. But instead I keep driving it, spent 2 years laying underneath it and can't be arsed jacking it up again

[dazleeds]

need to get a drive in yours lee


fairly sure i will m52 my next e30 assuming its worth the effort


can the m52 box not be used?? i guess not but cant be arsed to read a full thread right now to find out

[daimlerman]

Standard crossmember in front, modded one rear.

Lovely bit of fabrication there,Danthe (I think,or Randomdave) did something very similar to enable the stronger ZF 'box to be used.
My feeling is that the Getrang 240 was designed for 320/323 so was drawn up with 150bhp in mind,I would expect a 'safety margin' of at least 50%,so should not explode with until,what,225bhp is being put through it....or about what a cammed M52 is capable of....
Anyone else thinking along the same lines?

[Gunni]

M20´s 260 Getrag box lives happily in cars with 700NM´s.
So it´s not going to have problems in anything that has less.

[daimlerman]

M20´s 260 Getrag box lives happily in cars with 700NM´s.
So it´s not going to have problems in anything that has less.

Erm,yes,I agree the 260 'box is a lot stronger,built with 170bhp in mind!
I am questioning the strength of the smaller 240...

[pac1982]

Sorry to change the subject a bit but if i wanted to drop a normal E30 325 lump in would i still need to change my prop in my IS??

[leeparkes]

Sorry to change the subject a bit but if i wanted to drop a normal E30 325 lump in would i still need to change my prop in my IS??

Yep, you will need the 325i one

[pac1982]

So one a 325 prop is in place i would be able to fit any 6 pot that was origianly fitted in an E30?

[daimlerman]

320i uses a version of Getrang 240.
325i uses Getrang 260.
Front prop lengths vary to suit the different 'boxes.
325i has a lot of detail differences compared to the lesser models in the range.
A lot of these differences were carried over to the cabbie and touring,as these two versions were added after the basic saloon was in production.

[Gunni]

No the260 is also the M30 box.

[N00b]

M52 box definitely can be used, but it has a 1:1 5th so you need to find a 3.15 or taller ration diff or it will rev its tits off.

That was my problem here, diff ratios like that are generally only found in the older e28's but in the large case only so cant be used in the e30, hence going for the e30 box with overdrive 5th.

If lower ratios were available in the E30, can't you just swap the crown wheel and pinion on your own diff? That's what determines the ratio, right? (getting too technical for me now, lol)

[daimlerman]

M52 box definitely can be used, but it has a 1:1 5th so you need to find a 3.15 or taller ration diff or it will rev its tits off.

That was my problem here, diff ratios like that are generally only found in the older e28's but in the large case only so cant be used in the e30, hence going for the e30 box with overdrive 5th.

If lower ratios were available in the E30, can't you just swap the crown wheel and pinion on your own diff? That's what determines the ratio, right? (getting too technical for me now, lol)

E30 was fitted with two sizes of diff case,we refer to them as 'small' and 'medium',because the 'large' was fitted to E28 and the equivalent '7' series cars.
E30 diffs come in a range of ratios from 3.15 to 4.45.Most people can find something suitable here.
The problems arise when you require to use a ZF gearbox from an E34 or E36,because these use a direct 5th gear,the Getrang 'boxes that E30 comes with use a direct 4th gear,with 5th as an overdrive.
I mentioned that E30 uses two diffs,yes,they are interchangeable!How do you tell them apart?
'Small' has 6 bolts holding the rear cover on,'medium' has 8 bolts holding the rear cover on.
Ratio of the diff will be stamped on a tag attached to the upper r/h bolt.
Now,certain E28 models used 'medium' diffs,ratios such as 3.09 and I think 2.89 can be found.These will fit E30,but the diff will need to be 'dressed' with at least the comparable output flanges and possibly the back plate as well.I have never needed to use an ex E28 diff myself.
Crownwheel/pinion sets from one size of diff will not swap into a different size casing.