M30B35 Swap FAQ

[kzolee]

If somebody wants to see how looks the E32/34 oil pan in E28 chassis:

(Sorry for the phone pics)









And the E32/34 manual transmission also fits:

[dave533i]

Sweet! It looks like sufficient clearance. Thus I won't have to buy an e28 oil pan. It is somewhat alarming how much of the motor sticks out forward of the mounts. It would appear front-heavy. I suppose there is no way around that.
Thanks for posting.

[AlpinaE24]

I just bought a B35 to strap all my alpina bits to, but first i need to swap out the E3 pan and sump for my E24 setup. I have read a ton of posts about this and just want to verify.

I can simply bolt the E24 pickup onto the B35 oil pump right? Or do i need to change out the whole pump? I have a 87/b34 pump that was on my M90...would I also have to change the sprocket and chain? Or just run the B35 sprocket and chain with tensioner?


Also, has anyone fabbed up a bracket to use a the B35 PS pump with the B34 pan? Seems easy enough

[Justin535turbo]

so im in the middle of this swap, actually in the home stretch. just did the C101 wiring connections last night. nobody has made mention of the relays in the harness up next to the DME connector. there are a few connections up there that look as though they should need to be taken care of. looks like main power input to relays and some grounds. it's up next to the ignition coil + and - . since nobody has made mention of them, i'd assume they don't matter. but im just making sure before i try to start this thing.

[Justin535turbo]

answer to my own question: YES!

as suspected, those are main power and some grounds for those relays, i believe one of them is the fuel pump relay, im not sure what the other one is. no start with them disconnected. add power and ground to them appropriately, and she starts! sweet. look like i've got some more wiring to run...

[Justin535turbo]

this thread is very helpful when doing this swap. I put about 200 miles on my car this weekend, 200 down, 1800 to go to complete break-in! it runs soo much smoother than the old B34 did. also, my "indicated" fuel economy went from about 23 to over 26. 23 used to really mean about 19 - 20, so im assuming 26 really means about 22 - 23. which isn't too bad! i'll take the increase in power, smother run, and better fuel economy any day! i will also post some pictures of some obstacles that i ran into not covered in great detail here.

[Brad D.]

this thread is very helpful when doing this swap. I put about 200 miles on my car this weekend, 200 down, 1800 to go to complete break-in! it runs soo much smoother than the old B34 did. also, my "indicated" fuel economy went from about 23 to over 26. 23 used to really mean about 19 - 20, so im assuming 26 really means about 22 - 23. which isn't too bad! i'll take the increase in power, smother run, and better fuel economy any day! i will also post some pictures of some obstacles that i ran into not covered in great detail here.

Good to hear! Make sure you post up the pics of your issues and how you solved the issue.

[tig]

This list should clear up just about every question of which parts you need, after using realoem and autohausaz for picture references, there should be no more excuses not to know which parts you need.

I wanted to track all the parts I need to either acquire, pull from my B34, or keep from the donor B35 so I took this MOST EXCELLENT post and turned it into a spreadsheet.

Hopefully this will help others. And hopefully this link to the web version of Excel works for you all.

Charlie's Excel version of Matt's Excellent List

[Justin535turbo]

ok, here's my small additions to this thread.

first off, the purge valve line. this line goes up to the intake boot on a B34. you need to run it over to the canister purge valve on the B35 which is on the other side of the engine under the intake manifold, i just used some plastic hose barb style connections and some fuel line. it only has fuel vapors go through it, no pressure at all. this is where i connected it.


#1 is where i connected the line, #2 and #3 is just showing the route across the bulkhead, #4 is the connection at the purge valve.


next is the ignition coil and wiring. #1 and #2 are grounds that come off of the B35 harness, i grounded them to the strut tower. #3 shows how i mounted the ignition coil. all i did was use adel clamps and went around the a/c lines right there, then sent bolts through the mounting holes on the coil. i wasn't sure how this would work, but its surprisingly solid and seems to work well. also keeps it far enough away from the exhaust so that it doesn't get too hot. #4 just shows the harness connection at the coil. I didn't have to modify the harness at all for where these are mounted/routed. you can of course modify the harness to reach down to where the factory coil mounts as well, but i thought i'd try this first. the other two unlabelled arrows just show the canister purge line mentioned above.


shot of the harness going through the bulkhead.


i took the 20 pin and engine/chassis harness connector bracket from an E32 and modified it to fit right here next to the expansion tank. #1 is the bracket. #2 is the 20 pin diagnostic connector. #3 is the engine harness to body harness connector that goes to the E28 C101 connector. #4 is the E28 C101 connector.


#1 is my modification to the expansion tank bracket to make room for the bracket/connectors. I had to move it over about an inch and a half. #2 is the canister purge valve, again mentioned earlier.


this is the intake i had to fab up. I still need to make a heat shield though.

I also was unable to get the B35 coolant temperature sender to work correctly. i swapped the wires as mentioned elsewhere, but it didn't work for me. so i just used the B34 temp sender. it has 2 wires coming off or it, and the B35 harness has 2 wires also. there is no polarity to these, just connect them both to the two wires in the B35 harness. I ended up taking my B34 block and rebuilding it with a B35 crank/rods/pistons and head/intake manifold, etc... basically making a B35 out of a B34 block. im about 350 miles into break-in and so far im really happy with it.

[Brad D.]

I recall having the same issue with the b35 CTS for the gauge. IIRC, the wires in the connector have to be de-pinned and swapped in the plug.

[BuzzBomb]

Edit: Solved

[BuzzBomb]

As an addendum to those using the e24 B35 harness, who also are more inclined to use this chart by color and not pin number, there are a few differences between the e34 harness wire colors and e24 harness.
#2 = BU/VI (same as e28)
#7 = large GN (same as e28)
#8 = small GN *This needs to be spliced into #7 above or you get no + to represent "key on" to the ECU, meaning no start.
#10 = BU/WT (same as e28)
And some of the unused wiring is different than the chart, but aren't necessary to note.
Since a lot of people are more visual and rely on colors in a schematic, it's good to know these differences.

[kzolee]

I have replaced the fuel lines, but sometimes there was slight smell of gasoline in the engine bay.

I forgot one little piece



This is very underhand leak, because the fuel is dropping at the top of intake manifold, and evaporates on hot surface very fast.

[Justin535turbo]

I finally got around to finishing my intake for the car. I've got about $100 in materials into this one. It took much more fab work that I thought it would, mostly due to the heat shield. I'd recommend just buying the one for $225 from TCD. Which I swear I have seen on his website before, but now i can't find it...? I'm not normally a huge fan of cold air intakes, but the B35 AFM position made it an easy option. It makes a little more intake noise than normal. But im sure performance is negligible.

[viprojekt]

Hey all, I know I'm probably asking a stupid question here, but I have read through this thread a few hundred times, and I just wanted to double check before investing in the swap, are B32 and B34 motor mounts, harnesses and overall swap to B35 fairly equal? I have a '83 533i, and this thread seems to be all for B34. I'm new to wrenching on cars and I look forward to getting into working on my car! Thanks for any help.

Sean

[My528e.awesome]

I was told the b32 does very well with just the Motronic 1.3 swap. Someone correct me if I'm wrong.

[gmb49all]

I would recommend you start with the 1.3 swap first. If you dox it, and you find you still want more, than upgrade to the B35 - at least you'd have all the engine management stuff already in place.

A lot less work at first, and it sets you up nice for a b35 upgrade if you feel you want to try it....

[BuzzBomb]

Hey all, I know I'm probably asking a stupid question here, but I have read through this thread a few hundred times, and I just wanted to double check before investing in the swap, are B32 and B34 motor mounts, harnesses and overall swap to B35 fairly equal? I have a '83 533i, and this thread seems to be all for B34. I'm new to wrenching on cars and I look forward to getting into working on my car! Thanks for any help.

Sean

it looks like all you'll have to do it fabricate the adapters for the mounts like others have shown on this thread. Besides that, no worries.

[9mil]

Read through the thread and still can't wrap my head around my dash temp sensor not working. I have tried a couple of gauge sets none seem to work correctly at all- I have another one coming to make sure it isn't my old junk / si board issues.
Using MS so I can see the temp on my TS dash so at least I'm not totally screwed - but this brings up my point.
I have an e32 179 harness and I only have one temp sender connection and it connects fine- I haven't cut anything to adapt it to the m106/b34 gauge sender unit. I get CT (appearntly) from this connection so I am hesitant to butcher it and redirect the signal to my dash.

Anyone messed with this? I am having some tach issues too- so I'm not all convinced it isn't the gauges.... But I don't see how they can be connected to both (without yet another wire bypassing my goathumper apadpter board and butcher the plug to go to the b34 sender)
Did that make sense?

1987 e24 5spd - m106 turbo with FMIC with later model e32 motronic 179 harness with BIMMER guy c101 plug and goathumper adapter board to MS1

Thanks!

[BuzzBomb]

bummer guy c101 plug

I just gotta assume that this is a typo and you're not being disrespectful.

[9mil]

Absoulutly a typo. Posting from phone.
He has been great - no disrespect at all... Ill edit.

[9mil]

Got the alligator clips and leads out and did some playing around.
Temp gauge will work with b34 temp sends grounded on one spade and the other to the #4 pin in the c101.... Leave the one in the b35 harness alone, feeding the MS...

Just incase some other poor bastard is searching

[anton-sa]

hi there
would you guys say its feasable and/or do-able to
buy a e34 535 in manual form with lsd. and swap the entire lot over into my 86 520i ?

e28's are so so scarce, especially in my country (south africa) where we only got them from late 85 to 89. we had the e12/8 here till late 85. which is basically a e12 chassis with e28 bits.

anyhow, to get my "foot in the proverbial e28 door" i had to settle for a neat/clean/straight 520i 86

[kzolee]

You can swap the engine and transmission, but you will need a driveshaft, custom engine mounts.

The diff internals are interchangeable with the 520i.

The output shafts on the 20i are weak for M30 power. You will need the bigger output shafts, the rear drive flange from an E24 or E28 525/28/35i.

[tig]

i took the 20 pin and engine/chassis harness connector bracket from an E32 and modified it to fit right here next to the expansion tank. #1 is the bracket. #2 is the 20 pin diagnostic connector. #3 is the engine harness to body harness connector that goes to the E28 C101 connector. #4 is the E28 C101 connector.


#1 is my modification to the expansion tank bracket to make room for the bracket/connectors. I had to move it over about an inch and a half. #2 is the canister purge valve, again mentioned earlier.

What happened to your main relay and fuel pump relay?