E30 M52 Swap

[Rohil 30]

Hi guys,

Just wondering how many of you guys have done a M52 swap on your E30's. Im seriously looking into it, ill put up the E46 hopefully this summer and get it sold so i have a bit more to play with when it comes to this. I have been reading around and i doubt i can do this with the resources available to me, but it would be ideal and make a great project. Problem is, it cant be off the road for long!

I have decided first step is to get the M20 currently in there manual converted with a Getrag 260 which can later bolt onto the M52. I have also asked about a ljet to motronic swap, but is it best to just leave this till the engine swap time comes around? I couldve bought a manual E30 and skipped one step and saved a bit of money, but im in too deep now. I like this car way too much to even consider getting another just to make this whole process easier.

I just need to look around for a M52B28, the plan is to get that and slowly work on it, then when the time comes hand it over to someone to do the swap. Although what would be ideal is, have someone that has done the swap show me and i would love to work alongside to see what is actually needed and how it all goes together. I feel confident in doing everything BUT the wiring which seems like the worst part. The car will be a DD and it would be nice to have a bit more power and reliability than the ghost kms M20 currently floating around in the front of the ol' 323. Thought about a stroker for it, but the M20 is getting a tad old and tired now, i have been babying it since i got it, but thats been about 3 months out of close to 30 years of unknown history. And reliability is key, the M54 in the E46 even though its just the baby B22, has an awesome feel and sound. And has been pretty reliable so far, touch wood. And no, no boosting please.

Sorry that this has been less of a question and more wanting opinions/guidance/experiences from people who have done the swap. I just want to know what its like to live with and what in entails. As much forum surfing as i do, its all overseas and it would be nice to have some Kiwi input on the matter. Rough costs/time, any information you or anyone can provide would be greatly appreciated.

Thanks in advance!

[will 169]

I have done several conversions. There is no one way of doing them so you need to decide which route you want to take. Most of the conversion uses OEM bits, which ones depends on which route you take. There is some fabrication always necessary i.e. exhaust. Wiring is not difficult but your 323i is a little more complex than a later model.

The first part you need to locate is a sump, normally from an e34. Stay clear of any later e46 motor as they use CAN BUS and that makes life VERY difficult in the wiring dept. Stick to using a M52B28 from an e36. You must get the motor with MCU and loom (it does not matter if the loom is from an auto), and also the EWS box, key with chip and the ring antenna. You can get the ECU reflashed to remove the EWS but that is just another expense which is not necessary IMO.

You can use the G260 box and e30 flywheel but the standard e30 clutch is not up to it. You will also have to modify the gearbox mounting crossmember and the shift rods when installing it behind the M52 as the motor sits at a slightly different angle. The advantage in using the G260 box is that it has an overdrive 5th which means you can use a standard 3.46/3.64/3.73 etc e30 ratio diff (whichever grabs your fancy..!) Using the e36 box with 1:1 5th means you need to source an e30 188 diff in the 2.93/3.25 range and those are not easy to come by. Propshaft will depend on what e36 box you use. The e30 m40/42 box can also be used and has an overdrive 5th but is not as strong as the G260. Giving it too much jandal might shorten it's lifespan..

Normally you use the e36 radiator with an electric fan up front. You can fit a viscous fan but this requires careful planning as clearances are tight. (I run viscous in my e30 cab with no issues, also have electric installed as a backup but it has never switched on except when I use the a/c.)

While you are at it, replacing the e30 rack is a good thing to do. e36/e46 racks can be used, which one depends on what ratio you want and how much you want to spend on it.

There are lots of other bits that need doing but these are the bigger ones. Other things like suspension, brakes, mounting rubbers need checking/upgrading as necessary depending on what you have/find when you go through the car.

Done properly, the m52b28 conversion is totally reliable and transforms the e30. The ali block means it is lighter than the m20 so handling is improved. IMO it is the best bang for buck conversion you can do to an ageing e30.

[Rohil 30]

Thanks man! Yeah i should start sourcing the parts slowly, the E34 sump, pickup and dipsrick is needed right? Im sure i can rustle up the help to drop the engine in there, its just wiring that im sketchy on. I really do want to get this done, the M20 is slowly dying on me and having a M50/52 B25/28 i think would really just make it a perfect car. Thanks for all the help so far!

If anyones done the swap keep the tips coming!

[e30ftw 410]

Will has summed it up quite well. I went with a G240 from an e30 m40/m42. This gearbox combo doesn;t require any shifter or cross member modification as it sits on the right angle and fits using E30 320i shifter / driveshaft. I find it takes the abuse quite well... IMO it is perfectly fine for a daily.

M20 flywheel, Get the rear side skimmed as it slightly grazes the pan - best to get it lightened while you are at it.

If you can get all the EWS, go that route. i went with an EWS deleted ECU, Very simple to get it working like this but it does add a bit extra for the convenience!

[Ahmedsinc 414]

There's an M54B30 - E30 build on R3V which makes for very interesting reading if you're wanting to do something a little different.

If you buy a bare engine I have a set of M52 tubular factory headers for cheap if needed

[Rohil 30]

I have looked into this quite a bit over the last couple months and theres a M50B25 for sale from an E34 at the moment. But as my luck has it i cant pick it up right as uni starts in a week or two so thats a shame. For a daily driver i have also looked into going to a M20B25 instead. I figured it might be safer to stick with an engine i know and can work on. But a 24v conversion will happen eventually. I shall start collecting parts as soon as i can!

Cheers for all the help so far!

[KING_POM 10]

sorry to revive an old thread but Im also doing this conversion soon. i have a g250 box and a M52B28 coming from japan. how much performance gains would i expect if i fit a set of S5x ITBs and a decent exhaust manifold?

Edited August 27, 2015 by BADassE30

[e30ftw 410]

From memory Kerry's M52tub28 was like 240rwhp with S50 ITB's, Locked VANOS and a Link ECU I believe? Do a search on this forum you might find out for sure.

[hybrid 1043]

Not too much without bigger cams, some head work and tuning. Not saying its not worth it, but the gains are minimal without the reason for doing it in the first place. Exhuasts and intakes are only needed when the things inside demand it.

It will however sound awesome so thats a good enough reason to do it.

[thorburn 121]

is importing euro motors etc from japan cheap?

[DeadlyPixels 6]

I'm curious about this too. If you pick up a wrecked E36 from Turners/Manheim Auction you can get a M52B28 for incredibly cheap. Admittedly you have to deal with parting out the rest of the car but it is still a good way to find a motor. I would think shipping alone from japan would make it an expensive by the time you got it here.