engine swap

E28 technical advice asked and given! Troubleshooting, modifications and more.
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moshik1958
Posts: 13
Joined: Mar 29, 2023 12:30 PM
Location: israel

engine swap

Post by moshik1958 »

hi
i am new here
my car is 728 e23 with L jetronic, "banana" intake manifold
my engine need to be replace.
the only engine i found here in israel is e32
m30b30 with motronic injection system
i will keep the L jetronic system and the intake manifold.
what other things i need to look for in this engine replace?
flywheel?
distributor?
engine mounts

i know its not an e23 forum but i search things in this forum and probably i can find help here.


thx for your help
Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: engine swap

Post by Mike W. »

Welcome to our group! No worries about it being an E23.

As you seem to well know, the basic engines are both M30s but there are some differences.

You may need to fabricate a motor mount adapter, but that's doable. We didn't get the late B30 here, only the M30B35 so I can't say exactly, but on the B35 the intake ports are a slightly different shape. Same bolt pattern, but you might want to play with the shapes and gasket a little bit.

Image

One big thing is you will need the adapter nut as the nose of the cam is different and doesn't have a provision to drive the distributor. It's part number 15 and labeled Hex nut. Yours will probably have a locking plate on it which you can reuse or just use locktite, but it's a big nut and has to be tight.
https://www.realoem.com/bmw/enUS/showpa ... Id=11_0387

Image

You will want to use most of your existing bolt on stuff like the flywheel and upper timing cover, fuel injectors etc. And of course don't forget a pilot bearing if you have a manual transmission car.

https://www.firstfives.org/ May be of some use, I'm a moderator over there. Not very busy these days but some searches might find more info than here as all the US E28s were Motronic and E12s were L jet and some have done M30B35 transplants.
moshik1958
Posts: 13
Joined: Mar 29, 2023 12:30 PM
Location: israel

Re: engine swap

Post by moshik1958 »

Hi
thx for the fast reply
the new engine came with distributor
(not the round looks like half banana )
if i understand from your answer
i cant use this distributor i need to use the old 1
and the old 1 will work only if i put the no 15 nuts in the end of cam.



thx
Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: engine swap

Post by Mike W. »

moshik1958 wrote: Mar 29, 2023 2:10 PM Hi
thx for the fast reply
the new engine came with distributor
(not the round looks like half banana )
if i understand from your answer
i cant use this distributor i need to use the old 1
and the old 1 will work only if i put the no 15 nuts in the end of cam.



thx
Correct, and you need to use your existing upper timing cover to use your old distributor
moshik1958
Posts: 13
Joined: Mar 29, 2023 12:30 PM
Location: israel

Re: engine swap

Post by moshik1958 »

I have a manual transmission
what is exactly the pilot bearing that i need to replace or check.
the new engine came with mounting arms for both sides
in this case do i need the adapter for those arms?
i have a lot of expirience in metal working it is possible to do it by myself?
do i need to put the old flywheel in the new engine.


thx
Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: engine swap

Post by Mike W. »

Manual transmission cars have a bearing in the end of the crankshaft that the input shaft of the tranny goes into because the engine and the tranny don't always turn at the same speed. Autos have the torque converter bolted up to the flywheel which is bolted to the engine and the nose of the torque converter is kind of a press fit in the end of the crank, because they do always turn at the same speed. You may have to remove a bushing before you can install the pilot bearing. Even if it happens to be the right size, you need a bearing in there.

Yes, you should use your existing flywheel.

The new engine might have the right mounting holes, but I doubt it. If you're good with working with metal, yes, you can definitely make an adapter yourself, I've done it a couple of times. I used 1/4", which is ~6MM steel. It needs to be strong, so bracing might be needed. You might be able to use your old mounts too, you'll just have to look at it and measure.
moshik1958
Posts: 13
Joined: Mar 29, 2023 12:30 PM
Location: israel

Re: engine swap

Post by moshik1958 »

hi
in the old engine the oil filter housing is facing down
in the new engine the oil filter housing is facing up
can i leave it facing up or replacing it with the old oil filter.
thx
Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: engine swap

Post by Mike W. »

Just keep the new oil filter assembly with the new engine.
moshik1958
Posts: 13
Joined: Mar 29, 2023 12:30 PM
Location: israel

Re: engine swap

Post by moshik1958 »

hi
i put the new engine in the car, kept the l-jetronic system.
distributor , engine mounts etc ok.
the ecu of the old engine provide a fuel amount for 2.8 l engine
the new engine is 3.0l
its enough fuel for the new engine?
the fuel regulator is 2.5 bar
if i put a 2.8 bar regulator it will solve the problem?
thx
Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: engine swap

Post by Mike W. »

It's got an AFM, which is an Air Flow Meter. Meaning it measures airflow, which is kind of self correcting. It injects fuel for a 6 cylinder engine based on the amount of air going thru. Now a 3.0 will draw more air thru than a 2.8, but the AFM sees the amount of air and gives fuel accordingly.

On US cars, late 70's, early 80's, BMW used the same AFM and ECU and injectors and FPR for 2.8 and 3.3 engines. And I bored out a 3.3 to a 3.5 of that era, used the same FI parts and it ran great. I mean it ran really well. And passed smog comfortably.

Use the same parts, you'll be fine.
szacsi72
Posts: 219
Joined: Nov 13, 2022 3:41 AM
Location: Hungary

Re: engine swap

Post by szacsi72 »

Since you are swapping the engine Anyway, I suppose keeping the car original is not your main goal.
In this case I would swap the engine 1:1 and also swap to the motronic unit. It is a more modern DME with better fuel efficiency and more perforance, and smoother running.
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