Early Model 318i (M10) 24v Swap Nuances

[bakedfool]

I have a 1984 318i that started life with the m10 engine. In the distant future I will be embarking on a 24v swap, using an m50b25. Those that have completed this swap could you chime in on the differences compared to the later model chassis?

This is what I have gathered so far, noticed, and completed.

- Radiator mount from the M10’s is different. Lower mounts sit different and lower. The upper mount (17111709347) is missing one hole that may just need to be drilled, assuming that the slotted mount on the passenger side is in the correct location.

- Once using a late model 325/E36 radiator an expansion tank will need to be added as m10 engines didn’t have one. Are the mounting points there on the driver side for the expansion tank on these early model cars?

- The coding plug on the odometer needs to be changed to that of a 6 cyl E30

- Small case differential should be changed to a medium case.

- Front strut housings are 45mm compared to the 51mm found on later cars. Is this worth changing?

- Rear Drums should be converted to disc brakes by installing complete trailing arms with disc brakes.

Anything else I am missing?
So far I have installed a medium case diff, pulled the m10 engine and auto transmission, and I am starting to prep the engine bay as I noticed the difference in the radiator mounts found on most swap pics. Thanks

[82eye]

- Radiator mount from the M10’s is different. Lower mounts sit different and lower. The upper mount (17111709347) is missing one hole that may just need to be drilled, assuming that the slotted mount on the passenger side is in the correct location.

probably need the lower mounts and possibly sheet metal.

- Once using a late model 325/E36 radiator an expansion tank will need to be added as m10 engines didn’t have one. Are the mounting points there on the driver side for the expansion tank on these early model cars?

set it up for the later 6cyl cooling system as the early stuff is nla and hard to source.

- The coding plug on the odometer needs to be changed to that of a 6 cyl E30

use a 6cyl cluster, coding plug, and wiring.

- Small case differential should be changed to a medium case.

should also upgrade to the 6cyl heavier half-shafts.

- Front strut housings are 45mm compared to the 51mm found on later cars. Is this worth changing?

m10 struts and springs won't support the weight of the m50.

Anything else I am missing?

engine harness and c101 wiring. front 6cyl subframe. upgrade to later fuel system. single in-tank pump and pump upgrade. e34 oil pan and pick-up. bunch of small stuff.

an m10 is the hardest donor car to start with for the swap and the most expensive proposition.

[bakedfool]

engine harness and c101 wiring. front 6cyl subframe. upgrade to later fuel system. single in-tank pump and pump upgrade. e34 oil pan and pick-up. bunch of small stuff.

Is the front subframe really different? I’ve read that a few places too but then others chime in and say that it’s not.

As for the fuel system, I haven’t pulled the fuel pump carrier but any insight on how to mount the new pump in there? I have a good used E46 325 Bosch fuel pump laying around, I assume this would suffice if I can get it to mount in the E30’s carrier.

I think the radiator stuff will be the most tough for me as I don’t have the ability to weld yet, so getting those mounts modified and the bracket for the expansion tank will be tough.

[82eye]

Is the front subframe really different? I’ve read that a few places too but then others chime in and say that it’s not.

m10 will work if you can fab and weld. 6cyl subs have plug and play support for the swap. m10 does not.

As for the fuel system, I haven’t pulled the fuel pump carrier but any insight on how to mount the new pump in there? I have a good used E46 325 Bosch fuel pump laying around, I assume this would suffice if I can get it to mount in the E30’s carrier.

most just use a later style e30 single in tank pump hanger and mod in a higher flow pump. the e46 stuff is useless.

I think the radiator stuff will be the most tough for me as I don’t have the ability to weld yet, so getting those mounts modified and the bracket for the expansion tank will be tough.

early 6cyl e30's now upgrade to the late cooling system so it should be doable. there will be radiator options you can use or mod in.

[bakedfool]

m10 will work if you can fab and weld. 6cyl subs have plug and play support for the swap. m10 does not.

Do you know what specifically needs to be modified on the m10 subframe.

I really thought it would work as I recall reading this thread about it and someone mentioning s50 swapping a euro 1983 318i with no issues.

https://www.r3vlimited.com/board/forum/e30-technical-forums/24v-engine-swaps/m50-52-s50-52/159124-m50-into-1984-318i

[2mAn]

an m10 is the hardest donor car to start with for the swap and the most expensive proposition.

BUTTTT… the 84/85 cars are a few hundred pounds lighter so I say go for it. Mine weighed 2400# in street trim post 24v swap

[bakedfool]

BUTTTT… the 84/85 cars are a few hundred pounds lighter so I say go for it. Mine weighed 2400# in street trim post 24v swap

Do you have any insight using the m10 sub frame or fitting a late model cooling system into a 84/85? Got a pic of your engine bay?

[Chilezen]

I can't speak for M10 cars, but I can speak for an early model.
I am a fabricator by trade, so I was able to make/modify things on my own that other people probably can't.

1- Yes, you need to fit a late model cooling system / an E36 radiator. My original core support was damaged in a crash so I completely rebuilt mine with tubing, making my own brackets to support the radiator. I recommend you analyze a late model car to understand how they are held together normally.

2- I cut and welded on a bracket to hold the front of the expansion tank. I drilled a hole in the wheel arch to become the stud that holds the other end of it.

3- Yeah probably.

4- Yes

5- Most aftermarket kits are designed around the larger housings.

6- Uhh I suppose? Not directly related to the engine itself, but, at that point, you're buying an entire 6-cyl rear subframe, which has your diff, half shafts, and brakes. Might as well modify the trailing arm brackets to allow for rear toe/camber adjustments.

There are threads here about which brake master/booster to use, I personally recommend getting a Euro E90 booster.
I didn't know there was a difference in the front subframe for an M10, I'd be surprised to learn if you're correct on that. Reinforcement plates welded on that would also be a good idea.
There's a lot to this swap, you only mentioned a few things, so, it's really up to you to look through all the threads with great info scattered about. You'll find stuff about the oil pan, transmissions, driveshafts, throttle cables, ECU and reprogramming, A/C, etc.

upgrade to later fuel system. single in-tank pump and pump upgrade.

Ignore this advice. You don't need to do this. Stock dual pump setup is fine.

[bakedfool]

I can't speak for M10 cars, but I can speak for an early model.
I am a fabricator by trade, so I was able to make/modify things on my own that other people probably can't.

1- Yes, you need to fit a late model cooling system / an E36 radiator. My original core support was damaged in a crash so I completely rebuilt mine with tubing, making my own brackets to support the radiator. I recommend you analyze a late model car to understand how they are held together normally.

2- I cut and welded on a bracket to hold the front of the expansion tank. I drilled a hole in the wheel arch to become the stud that holds the other end of it.

3- Yeah probably.

4- Yes

5- Most aftermarket kits are designed around the larger housings.

6- Uhh I suppose? Not directly related to the engine itself, but, at that point, you're buying an entire 6-cyl rear subframe, which has your diff, half shafts, and brakes. Might as well modify the trailing arm brackets to allow for rear toe/camber adjustments.

There are threads here about which brake master/booster to use, I personally recommend getting a Euro E90 booster.
I didn't know there was a difference in the front subframe for an M10, I'd be surprised to learn if you're correct on that. Reinforcement plates welded on that would also be a good idea.
There's a lot to this swap, you only mentioned a few things, so, it's really up to you to look through all the threads with great info scattered about. You'll find stuff about the oil pan, transmissions, driveshafts, throttle cables, ECU and reprogramming, A/C, etc.



Ignore this advice. You don't need to do this. Stock dual pump setup is fine.

Thanks for the in depth reply. I have a Euro E90 booster going in today actually.

I am aware of all the typical 24v swap parts and have the E34 pick up, oil pan, dipstick, etc. My main question/concerns pertain to these super early model 4 cyl cars that haven’t been very well documented swap wise. I’m hoping as Ingo thru the process to get that sorted out for anyone else.

I also got my engine mounts mocked up. I am using BMW 11811132793. They were green on the product pics, but showed up in black/grey from ECS tuning.

One thing I noticed about them is the unthreaded part of the stud on the engine mount is taller than the thickness of the E36 engine arm. Therefore the nut won’t thread all the way down and snug up to the motor mount. Atleast on the one engine arm I mocked up on it.

I’m wondering if these are the right ones? I know some people have mentioned various sized spacers on these swaps on the motor mount but didn’t know they were necessary for it to snug up.

[bakedfool]

E90 Booster in! Need to clean up the brake line T but just wanted to get everything mocked up.

Heres how my engine bay is currently sitting.



Chilezen are these the same lower radiator mounrs you saw on your early model car?

Part of me was hoping a couple of the threads I read about the late model radiator sitting in these bumps are true. Then I would just need to hopefully add a second hole up top here for the typical radiator mounting bracket.

[82eye]

BUTTTT… the 84/85 cars are a few hundred pounds lighter so I say go for it. Mine weighed 2400# in street trim post 24v swap

what all is different to lose the 400lbs?
other positives also include being the cheapest e30 to get into, and hand crank windows if you have a stripper model. i'd do it for the hand cranks alone ...

[reelizmpro]

While newer healthy dual pumps work fine on an S52 swap, if one starts to go bad (usually the transfer pump) you will be starving the engine without realizing it and eventually leave you stranded. It has happened to me a couple of times in different cars. The single high flow fuel pump upgrade (including hoses) is something I would definitely do with the swap, especially if it's an early 318i and you don't know how old the pumps are. The cost is minimal for the peace of mind. It's just like the other things (actually the fuel pump is more important) you are upgrading...the struts and rear diff/axles/brakes. You don't have to but it's a good idea to upgrade them now than have them fail later on, leaving you stuck on the side of the road.

[bakedfool]

While newer healthy dual pumps work fine on an S52 swap, if one starts to go bad (usually the transfer pump) you will be starving the engine without realizing it and eventually leave you stranded. It has happened to me a couple of times in different cars. The single high flow fuel pump upgrade (including hoses) is something I would definitely do with the swap, especially if it's an early 318i and you don't know how old the pumps are. The cost is minimal for the peace of mind. It's just like the other things (actually the fuel pump is more important) you are upgrading...the struts and rear diff/axles/brakes. You don't have to but it's a good idea to upgrade them now than have them fail later on, leaving you stuck on the side of the road.

In your opinion, would you just get a late model drop in ? Or Would you rather fit a higher flowing pump into the carrier?

[reelizmpro]

I would get an aftermarket high flow (190lph or so is fine) TRE or Walbro pump and retrofit it to the existing carrier. The late model 325i carrier doesn't have the fuel return port and the connector is different.

[2mAn]

Mine was already M20 swapped when I bought it, along with the later strut housing and rear trailing arms.

if you search for “aluminum monster” you should be able to find the thread for the car. I had a separate thread specifically for the headaches of my aluminum M52B28 swapped in the 24v forum. It was during the photobucket days but I spent way tooooo much time going back and updating as many pics to my Flickr but some are still lost. Hopefully you can find what you need in there