M50 swap - please run the rule over this plan

[green-blood]

hey

I've been offered a 1992 M50 from a 525 sport

basically we can park the car next to mine and have everything lifted, engine, rad, box (close ratio), loom, ecu...

Now this is to go into my tech1 sport, keeping my LSD.

Can anyone suggest where the major stubling blocks may be - exhaust??

thanks

[jaistanley]

If the diff is 3.64 ( I think they are in the MK1 sport??) then the gears will be a little short. It'll accelerate like a lunatic though!

Exhaust manifolds willl need to be fab'ed from some E36 328/323i ones. Exhaust is easy: Use an E30 M3 one.

Jai

[m-dtech]

i have an m50b25 from a 525i in my e30.

exhaust is a bit of a headache i modded an e36 m52b28 tubular type.
engine mounts are from an e36 m20b20 (i used m20b20 rubber mounts)
gearbox bmw 318is (retains ratios and i can use e30 diffs)
clutch,flywheel,starter motor is all m50b25.
propshaft is from e30 m20b25
brake servo is from a clio
m30 airbox

hope this helps.

there was no fabrication in the above other than the exhaust, everything bolts in nicely.

m

[Brianmoooore]

Pre vanos unfortunately, but still a worthwhile conversion. You'll need the alloy engine mounts of an E36 320 or 325, then it'll drop straight in.
The problem areas are the exhaust manifold fouls the exhaust manifold and the inlet manifold fouls the brake servo. Both problems and their various solutions are well documented in the archives.
Diff ratio will be too high if you use the M50 gearbox - you need something like a 3.15 ideally. Alternatively, an E30 box can be used, but it will be rotated in the car and cause other problems with the linkage.

[m-dtech]

Pre vanos unfortunately, but still a worthwhile conversion. You'll need the alloy engine mounts of an E36 320 or 325, then it'll drop straight in.
The problem areas are the exhaust manifold fouls the exhaust manifold and the inlet manifold fouls the brake servo. Both problems and their various solutions are well documented in the archives.
Diff ratio will be too high if you use the M50 gearbox - you need something like a 3.15 ideally. Alternatively, an E30 box can be used, but it will be rotated in the car and cause other problems with the linkage.

as he says but use the 318is box as you dont need to rotate it and you can use m20b20 manual linkages.

job done.

[green-blood]

thanks lads

a lot of food for thought there

I think I can get a decent swap on the diff, kinda wanted to retain the box with the engine as its got a new clutch on..... and we have a good prop fabricater on board....

so problems

exhaust !!!!!!!!
brake servo - scrappy
engine mounts - scrappy

[Brianmoooore]

You can get away with using a standard servo with a M50 if you move the servo and brake cylinder outwards until the edge of the servo is against the inner wing, and use a modified E34 brake pull rod.
Only took half a day to do, and retained full servo power.

[liam012]

are you serious brian?
your tec 1 is unmolestesd and a nice example
while this may be a good conversion for very little more power, and more drivability i dont know would i be so quick to do it if i had your motor
just my two cents.

oh if the tec1 engine and box is a begging let me know

[bam2002]

the brake booster from a e20 320 will work. It bolts up to the stock brake cylinder, but you will need to cut the threaded rod and re tap it. I hear you also can use one from an old 2002.

Everything I have read, stated for all the work involved, you will want to use a S50 or M52 engine. If you really are looking to make the car much faster.

OH i just realized this is all for LHD cars. So please enlighten me on the RHD . I would like to know how the cars differ. Sorry not to make things more confusing.

True is you use the e30 gearbox you will have to have it lean at a 18 degree angle. A custom trans mount will need to be made. Plus the shifter rod will need to be cut and rewelded.

B

[m-dtech]

difference in RHD vs LHS is that the steering column impeeds the use of the m50 manifolds and the rear header needs to be bastardised to fit.

gertag 240 on the 318is is different to the m20 boxes and dimensionaly the same as an e34/e36 box also does not sit at an angle.

i used clio servo and brakes are sharp as can be, deff better than standard.

[green-blood]

well my standard servo/clutch master arrangement is pretty rubbish anyway so no worries there

Still fancy dropping teh entire m50 lump/box in, will need mounts, but I'd like to keep it as a unit. I've no power steering on my tech1, i wonder will that help or hinder exhaust clearance

[m-dtech]

well my standard servo/clutch master arrangement is pretty rubbish anyway so no worries there

Still fancy dropping teh entire m50 lump/box in, will need mounts, but I'd like to keep it as a unit. I've no power steering on my tech1, i wonder will that help or hinder exhaust clearance

its not the pas pump that causes problems its the actual steering column coming from the car into the engine bay. pop the bonet and look at the exhaust manifold you wll see steering column on left.

[green-blood]

cheers.... I've a 6 branch on my m20 engine and it only just clears the oilf filter/column so this will be a similar headache!!!

actually I wonder would it be possible to modify the m20 6 branch!!!

[jaistanley]

That sounds like MUCH more of a headache! The head design is very different. You'll get strong money for your 6 branch which will pay for some parts or a guy to do the manifold mods for you.

Do a search for "M50 Developments". It's an illusive little bugger (normally a few pages in on the search) but all of the info you could need is in that thread though it's old so look at some of the more recent ones too.

You can use the diff from an E30 M3 or the MZCoupé/Roadster. They are all 3.15 or 3.25 LSD's. The prop from a 325i fits straight on then I think. Only the 5speed 328i/M3 and 6 speed need different or custom props. I'm with you: Forget buying another 318iS gearbox and swapping. Just sell your LSD for good money and get a 3.15 one.

Brake servo wise I think the M50 guys can just get away with the smaller servo (you'll get used to the slightly heavier pedal by the end of the first long journey). Us S50 boys have to move the thing over which is a pain in the jacksie but entirely possible.

Gear linkage: Fit a Z3 1.9 one while you're there.. Nice action, not to fast, not to slow.

You should consider doing an E36 power steering rack swap too whilst you're there. You dont want to mod a manifold (323i/328i steel one) then later decide to go E36 and realise it wont fit. Having no power steering with a heavier engine might be a pain.. My M20B25 engine'd 318iS has a failed power steering rack atm and is a complete pain in the rectum around town; I dread to think what my S50 engine'd car would be like.

Good luck mate.

Jai

[green-blood]

thanks man

Don't want to go to power steering, i like muy steerig as it is, other than at absolute parkin speed its fine, and I like that fast road speed weight - 40-70 on country roads

I'm definitely going for a 25mm e32master clylinder so that will help the brakes, just got to source a decent servo, golf gti been mentioned also

If I do this I am not breaking the m50 from its box and I've the offer of a diff swap so I think that makes most sense.

I suppose with a bit of a clean, my 6 branch should nab me 500 or so, which is plenty to be using for manifold parts.

thanks lads you are being very helpful