The comprehensive DOHC engine swap thread.

[Mike B.]

The Euro engines also require US M/S50 oil pumps, at least the S50B32's, due to their dual pick-up pumps.

They also cannot use the brake boosters you have listed due to the size of the intake. The simplest options are a Geo Metro booster / Master cylinder, or manual brakes.

I would also like to add that Porsche 924/944 boosters are a much better solution than the 320i boosters. They bolt up to the stock location, have the same thread pitch as the E30 clevis, and the shaft just needs to be cut down a few inches to fit. No re-threading necessary.

[Teaguer]

Thats a nice quick compact list .
But I noticed one or two things right away when reading through it .

1. Engine Variants :
The nonVanos M50b25 was first available in the US in model year 1991 E34 525i .
2. Notes :
Also where you say the E36 mount arms are relevant only if you have an E34 you might want to also include the E39 in there since its also a donor for the M52 .

3. Clutch Variants :
The E30 single mass flywheel is NOT 11lbs .
Its just under 20lbs ...more like 19lbs .

[Mr.SWISS]

The Euro engines also require US M/S50 oil pumps, at least the S50B32's, due to their dual pick-up pumps.

They also cannot use the brake boosters you have listed due to the size of the intake. The simplest options are a Geo Metro booster / Master cylinder, or manual brakes.

I would also like to add that Porsche 924/944 boosters are a much better solution than the 320i boosters. They bolt up to the stock location, have the same thread pitch as the E30 clevis, and the shaft just needs to be cut down a few inches to fit. No re-threading necessary.

Yea but how do they feel or perform? I had a 944, I remember the pedal being kinda stiff. Kinda like what mine is now.....

[nholm325e]

does the e21 320i brake booster studs line up to the e30 master cylinder holes??

[FredK]

does the e21 320i brake booster studs line up to the e30 master cylinder holes??

yes.

Also the 944 booster doesn't feel too bad with a stock E30 MC and stock E30 brakes. There's not a huge amount of brake assistance, but I can hit the brakes pretty hard and get the ABS to fire without ridiculous amounts of leg power. This is on street tires and stock Pagid pads.

[kylebes1]

is a 944 booster cheaper? I don't understand the advantage if not.

I had 318i solid rotors with my m50 and teh e21 booster. it stopped fine.

[FredK]

slightly. It's like $110 with a core charge of like $20. The 320i booster is $140 plus a core of $40. Used, it makes no difference.

Also the input rod is 12 mm in diameter on the 320i booster, so in order to get down to 10x1.5mm threads, it's a lot more involved. You have to cut and weld or grind the shaft down and then thread it.

The 944/924 booster have 10 mm diameter input rods so all you have to do is cut the rod a few inches and add like 3/4" more threads on a 924 booster.

[SchnellerVert]

here is a good UK board

http://www.e3024v.com/board/

[nholm325e]

I know this has been told many times but im having trouble finding it, how long should the threaded rod end of the e21 booster be approx?? (7 or 8mm or somethin like that)

Thanks Nick

[gregslow318i]

hello making my first post in the place where I have spent the most time larking I am in the planning process for swapping a m52 in to my early 318i (1985) and I see all the diy wiring guides for the late e30 that have the c101 connectors but I was wondering can someone point me in the right direction on how to do the wiring of my car since it does not have a c101 deal
also I have seen the pinout on the this site but is it the same for my car http://www.akgmotorsport.com/e30convpins.html
and is the connector that they are referring to the one that is next to the main fuse box under the hood ?
also if anyone has pics of an early 318i swap the would be sweet but if any one has pics of the wiring on a early 318i swap that would be the $#%&
thanks in advances
also I need be you can e-mail them to me
nitroman12@gmail.com

[500ke30]

It's been mentioned twice in this thread but hasn't been answered (at least I don't think so)

Why do you have to convert the OBDII engines to OBDI?

[B3M2W5]

Here's a diagram for the m20 plug, more are coming...

Does any one know if this will be the same Pin and wiring set up for an 87' 325e with the 2.7l motor. Is it all the same for the M20 motors or could it be diff for the E motor?
I just dont wana dive into this wiring and then come up with "Oh shit the 2.5 and 2.7 motors are diff for the plugs."

[B3M2W5]

It's been mentioned twice in this thread but hasn't been answered (at least I don't think so)

Why do you have to convert the OBDII engines to OBDI?

You dont have too its just better for performance.
The OBDII set up is more constrictive with the air intake and the emmisions i beleive. Converting the engine back to OBDI yeilds more HP in the end yet i am under the impression that is still keeps the small torque gain that OBDII had over OBDI with the engine being bigger.
Altho i could be worng on this theroy, some one slap me if i am miss informed.

[etxxz]

after 3days of reading, behold the 59th pg!!

^^ my research suggests that the ONLY gains from the OBDI conversion comes from the intake Manifold for which you do not *NEED* to convert to obdI in order to swap it. there's a few hoses that you need to re-route and custom make cheaply with Advance Auto parts. i'll have to see when my S52 gets here

see:

http://www.midnightautowerks.com/Installs/95intake/install.html

There's a $400 "kit" that looks like:

http://m50manifold.com/images/stories/Pic_7.JPG

or $360 ($200minus manifold)
http://koperformance.com/BMW/product...ds/11-61-1-735-

i'm atempting an obdII swap since i have all the ews stuff (minus antena ring) and dont feel like dumping extra money for the obdI conversion...i'm pretty sure i'll be posting more often when i start getting my hands dirty.

...i have like 4pages of tightly packed hand notes, reference to links, electrical [holy wiring discrepancies batman!], parts lists etc etc etc. thank for this thread ppl...but someone should seriously summarize it.

[nholm325e]

I have a 87 325e and i noticed that some of the wires change color from one side of the C101 connector to the other side.

Ex. For pin 2, Oil Level Static is green/yellow on one side of the C101 connector but then it changes too Blue/Yellow

Take a look at the C101 connector on your car right now and im sure you will find a few wires that change colors from one side of the C101 connector to the other side.