Transition to M30B35 big time novice

gdub0717

gdub0717

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I need input!
Although I went and bought side drafts (same boat as markos) the thought of a higher displacement motor and long term reliability as driven me to consider a M30B35 motor.
My e9 already has a 5spd.
I have a lot to learn but this purchase me force that learning curve.
I have the opportunity to purchase a mostly complete and running 1992 750il.
I have the room can part it out some then hopefully get some money back.
1. Is the motor worth the effort? I would likely rebuild it.
2. Are there any other parts I should take for the e9 beyond the motor and head?
3. Need to figure what car I should get for the intake, ecuand harness to make the car period correct.
4. I need to continue to read and learn about efi on this forum among other sources.
5. Is the rear end of any value? (Thinking about recouping the cost)
6. Is this thought over the top?

Input and comments are welcome. Thanks!
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The m30b35 is a common enough substitute engine, harness and ecu. It is normally combined with an intake of a jetronic engine from the late 70’s so that it resembles a 3.0 csi
Not any instructions out there that I know of for doing the job but honestly I have never looked.
It’s a big job that requires a ton of work.
Done right it’s easily a 15k job. Most people end up refreshing all the components in the engine bay while they are at it.
Parting out an e34 is something that I think you would find regrettable. Take what you need from the junkyard and leave the rest. The tow to and from your garage is likely more than any money you would get from any parts you could sell.
 
A M30B35 is the best option IMO if you're looking for an engine upgrade. I don't know if you're looking to upgrade the B35 while rebuilding it (cam, high CR pistons, headwork, exhaust, MS), but anyway it's a step up from the B30.
I don't have much info since I haven't started my own swap yet, but here are a couple of threads that I found after a short search on the forum, might be useful. I'd say you have alot of the info you need on this site if you take the time to search, as the info is quite spread out in all kinds of threads.

https://www.e9coupe.com/forum/threads/3-5l-transplant-from-a-1989-e34.5865/#post-35888
https://www.e9coupe.com/forum/threads/3-5-donor.5534/
https://www.e9coupe.com/forum/threads/m30b35-swap-questions.10683/#post-68683
https://www.e9coupe.com/forum/threads/b35-l-jet-motronic-conversion.6737/#post-41818
https://www.e9coupe.com/forum/threa...ing-pump-and-engine-mounts.21056/#post-153498
 
Are you going to put the carbs on the B35? That's what I did, and I'm swapping in a different B35 this week. I found a 91 at the local Pick-n-Pull with a really clean motor so I grabbed the long block. I'll make some plates out of flat stock to adapt the motor mounts and drop it in.
If you are running carbs and a conventional distributor you will need an adapter nut for the cam so your distributor drive will work and you will keep the drive housing from the old motor. You need to plug the hole in the small chamber of the oil filter boss and re-use your old filter housing. You will need an electric fuel pump as there is no place for the mechanical pump on the B35. I used the lift pump from an E24 as my pump and it provides 3# to my Webers.
 
Don, reference to the 750il was just mentioned as the car i am getting the motor from. Should have just said, 'getting the M30B35 from an e32.'

Thanks for the your input. I may just get the car, Pull the motor, ecu, and harness next spring. Then take it to the junk yard. Hassle, but can get everything I want from a known, complete car. Do the work at my own pace. Good idea to drop it at the junk yard pull the motor and take it. But, I am slow and want to make sure I get everything I need.

Wont bother with trying to part out. The kid(18 years old) is taking some of the body parts anyway to sell once I get it to my house.
Wish my son was as driven to make a few bucks!!

Gransin,
Thanks for the info. Have reviewed 2 of the forums you mention. Will read them all thouroughly.
From those threads i will come up with a plan for getting the intake to be period correct. Will go to the junk yard for those parts. Sounds like would be the best option.

Mike,
I am going FI. If I am going to go through this motor replacement I figure FI is my best bet to add value and overall reliability.
I love side drafts but this plan seems to make the most sense.
 
gdub0717 said:
Don, reference to the 750il was just mentioned as the car i am getting the motor from. Should have just said, 'getting the M30B35 from an e32.'
Click to expand...

I’m guessing his point was that the 750il never came with a B35. Probably just some badge engineering on that 735i. :)
 
Don, reference to the 750il was just mentioned as the car i am getting the motor from. Should have just said, 'getting the M30B35 from an e32



Nope
750il has a v12 engine
 
Just this weekend I was trying to convince my buddy not to swap in a B35 (while also sending him links to cheap e34’s). Anyway, I suggested that he read this thread. It’s obviously mostly e28 related but there is some good info in there.

http://www.mye28.com/viewtopic.php?t=60306
 
Sorry, it is is a 735il.

Markos, I will read the info in the link you sent prior to purchase. Want to make sure I am heading down the right path.
 
you want to put one of these in an E9!? It's going to be tight!

It's tight in an E38
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sfdon said:
It’s a big job that requires a ton of work.
Done right it’s easily a 15k job.
Click to expand...
Don, going through this myself, I get the impression that, while the motor swap is fairly straight forward, most of the work/cost is in converting from carbs to FI. Parts, plumbing, electrical, tuning, etc.. Would you agree with that? If yes, this would mean that, if one has carbs, going to a b35 motor while retaining the carburators would be quite a bit less expensive. True?
 
Bmachine said:
Don, going through this myself, I get the impression that, while the motor swap is fairly straight forward, most of the work/cost is in converting from carbs to FI. Parts, plumbing, electrical, tuning, etc.. Would you agree with that? If yes, this would mean that, if one has carbs, going to a b35 motor while retaining the carburators would be quite a bit less expensive. True?
Click to expand...

There is no tuning with fuel injection- it’s in the computer from BMW.
The intake, harness, injection all ad up though to thousands.
 
gdub0717 said:
I need input!
Although I went and bought side drafts (same boat as markos) the thought of a higher displacement motor and long term reliability as driven me to consider a M30B35 motor.
My e9 already has a 5spd.
I have a lot to learn but this purchase me force that learning curve.
I have the opportunity to purchase a mostly complete and running 1992 750il.
I have the room can part it out some then hopefully get some money back.
1. Is the motor worth the effort? I would likely rebuild it.
2. Are there any other parts I should take for the e9 beyond the motor and head?
3. Need to figure what car I should get for the intake, ecuand harness to make the car period correct.
4. I need to continue to read and learn about efi on this forum among other sources.
5. Is the rear end of any value? (Thinking about recouping the cost)
6. Is this thought over the top?

Input and comments are welcome. Thanks
Click to expand...

That's quite a few questions, but I think I get what you are after. I did this swap about 10 years ago so I'm about as rusty on this as a rear wheel well. I'll go through them one at a time:

1. You get a good bit more torque through the range, more horsepower, and more fuel economy. Not a bad package depending on how you mix and match. Why rebuild, though? The bottom end on the M30 is quite stout and frequently doesn't need internal work. At most, I'd do a leakdown and compression check to see if you need to open it up, unless you know it has been abused or the coolant looks like a milkshake.
2. That depends on what you want to do. If you convert to FI from the car (Motronic 1.3 BTW, not a bad setup) there's a lot to take. If you just want the mechanical bits, you will have to make some changes and swap parts between the old and new engines, such as the dizzy drive nut, valve cover, and upper timing cover.
3. Period correct EFI would be one of the jets, which are all more difficult to maintain and source, as well as not as, well, "good" at running the engine. I ended up just going full Motronic 1.3 so I wouldn't have to deal with all that.
4. Always a good idea to learn more, but what do you want to know in particular? The different systems (L-Jet, D-Jet, Motronic 1.0, Motronic 1.3, MegaSquirt, etc.) all have different hardware and quirks.
5. I don't remember if all the E32s got large-case diffs; not super useful to you unless you do an E28 rear subframe swap.
6. A 3.5 swap is pretty direct, as far as these things go. You are upgrading the engine to the same basic type with technical revisions and more displacement. You could make it more complicated by trying to use a M90 block with a B35 crank, custom pistons, and a M88 head if you wanted to get crazy.

A slight note is that you would need some motor mount adapters to make this particular block fit, as the bolt holes don't quite match the original mounts. Carl Nelson sells some adapters.
 
Thanks for all the input.
Still in the process of making a definitive plan.

1. Will not rebuild the motor initially. Car sounds, drives and runs well. Has almost 200k. But, this is the best and most cost effective plan. Bought the whole car for $400(delivered) less a number of body parts. Will put in my yard remove the motor and harness in my own time. Then I will tow it to a junk yard.
I understand the pan and oil pump will have to be changed and pay special attention to bolt head interference.
Period correct valve cover will also be changed over.
2. Motonic 1.3 will be used. That is what is already set up. Minimize the changes!
3. Will go to junkyard and pull the intake from a 5 series. There is a 79' 5 series just arrived in the last few weeks. Hope the intake is still on it. We will see!?
4. Will just keep reading. Would like to keep the current intake for the 1st phase but don't believe the 3.5 intake will clear the brake booster. Right?
5. Rear end it not going to work and will not bother with any other parts. May throw it on craigslist and if someone wants parts will let them come and remove the part to get a few bucks back on the car purchase.
6. Will minimize changes to the motor and efi system. I am sure my troubleshooting skills will be severely tested before I am done.

Will use the Mike Goble method for the required engine mounts.
Any additional comments ideas are always welcome.
 
gdub0717 said:
Thanks for all the input.
Still in the process of making a definitive plan.

1. Will not rebuild the motor initially. Car sounds, drives and runs well. Has almost 200k. But, this is the best and most cost effective plan. Bought the whole car for $400(delivered) less a number of body parts. Will put in my yard remove the motor and harness in my own time. Then I will tow it to a junk yard.
I understand the pan and oil pump will have to be changed and pay special attention to bolt head interference.
Period correct valve cover will also be changed over.
2. Motonic 1.3 will be used. That is what is already set up. Minimize the changes!
3. Will go to junkyard and pull the intake from a 5 series. There is a 79' 5 series just arrived in the last few weeks. Hope the intake is still on it. We will see!?
4. Will just keep reading. Would like to keep the current intake for the 1st phase but don't believe the 3.5 intake will clear the brake booster. Right?
5. Rear end it not going to work and will not bother with any other parts. May throw it on craigslist and if someone wants parts will let them come and remove the part to get a few bucks back on the car purchase.
6. Will minimize changes to the motor and efi system. I am sure my troubleshooting skills will be severely tested before I am done.

Will use the Mike Goble method for the required engine mounts.
Any additional comments ideas are always welcome.
Click to expand...


1. If you plan to run Motronic 1.3, that poses some complications for your plan. One of the major improvements of the system is the elimination of the distributor and integrating spark distribution into the front timing cover. That upper front timing cover does not play nice with the original valve cover, as I recall, as they had to move a couple bolts around. Additionally, the AFM for Motronic 1.3 uses a couple of posts embedded in the valve cover for placement.
2. If you are going to use Motronic 1.3, that includes the intake manifold, unless you want to go the full sfdon route (I think it was sfdon, I've been away a while) and rebuild the harness and injector systems around a L-Jet manifold. It is not trivial. When faced with the same choice, I used the Motronic 1.3 manifold (has 3.5 cast on the plenum instead of 3.3/3.5) and changed the brake booster to a 2002tii unit to clear the new intake manifold.

Basically, if you are going to use Motronic 1.3, you have to use all of it, rather than pick-and-choose what you want, unless you want to build it like sfdon. That also means you need to use the M1.3 harmonic balancer and crank position sensor system.

You will also need to fab up a conversion for the pedal, because the stock carb system is a "push" while the Motronic is a "pull". I did it with some random parts, not too difficult, but something to be aware of.
 
I didn’t have the issues you described when I did my b35 conversion. I used a valve cover with the filler in the rear, there are no bolts needed on these for the AFM (some covers have studs and such but don’t look correct). I used the e12 stub manifolds, C runners (actually e21 in my case), log plenum and fuel rail, my injectors didn’t need adapters. I did not have to change the pedal actuation, just a longer vertical rod slightly bent to clear the manifolds.
 
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