The comprehensive DOHC engine swap thread.

[grinchxvx]

I have a few questions and rather than start a thread I decided to post it here.

My m52 came out of an auto car, can I just cut the auto trans TCU and pull all the wires out from there?

Is there anyway to jump the Started wth the motor out of the car to do a compression test? Also what should cold numbers be for a good motor?

Where's the best place to send me ECU for ews delete etc? All the threads have links to places that don't do them anymore it seems


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[Maxeastman]

N00b questions

looking at a S50 this week for $1500. i have put together a pretty good list but i do have some specific parts questions...

1. do you use/can you use the e36 power steering pump with the e30 steering rack?
2. if I will be using the e30 trans (1990 325i so i think its the 260) what flywheel and clutch should be used?
3. can i use the stock master cylinder with the 320i booster?
4. what does "e34 oil pickup" mean in terms of what actually needs to be bought? the whole pump?
5. does the AKG wiring harness adapter make the e36 ecu, e30 wiring and the s50 harness plug and play?

I know there's tons of literature out there and ive been reading a lot... but there's almost too much to look at, especially when your questions get specific...

[kronus]

Im guessing most people just go through the wiring and delete all the auto trans stuff?

yup. delete the auto computer plug and all the wires that come from it.

Wondering if anyone can provide some pointers on what parts are needed and should be bolted to the m52 before putting it back in the car?

all the wiring can be installed after, as can the water pump and such. if you're replacing the idler and tensioner, you can't do it with a radiator mounted, so do it before then. pretty much everything else that's not the long block can go on after installation.

[grinchxvx]

Ripped my friends s50 out of his m3 today and noticed there was TWO X20 connectors Besides the fuse box. Didn't realize one was for the auto trans until I asked around as no 24v swap threads mention it. Im guessing most people just go through the wiring and delete all the auto trans stuff? Just a heads up so no one else wonders about it all day like I did




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[schmidty]

Hey 24v experts :)

Wondering if anyone can provide some pointers on what parts are needed and should be bolted to the m52 before putting it back in the car? (and what things can wait until after you have the engine back in).

Obviously I'll have motor and trans mounts, new transmission brace for g260, e34 oil pan/dipstick.

Do I need to mess with anything related to wiring/ecu, coolant lines, etc... before dropping the engine in? Or do I just button that all up afterwards?

Main reason I am asking is because the car is at a buddies shop (where I have access to an engine hoist, lift and air tools) so I'd like to just do what's needed to drop the engine in, and then I can take the car back to my place a finish everything up in my garage (where I'll be able to work on it more frequently).

Thanks,
Ryan

[mjweimer]

Hey folks - first post so bear with me. Got my hands on a "lightly rolled" '97 Z3 2.8 auto trans for a great deal and plan on transplanting the engine in to my '90 325iS. Here are my plans so far:

2.8 engine
E34 oil pan, dipstick assembly and level sensor
E28 motor mounts
OBD2 wiring with PnP harness adapter from Andrew325iS
G260 trans, flywheel, driveshaft, etc with modded trans mount and linkage
Either the stock Salisbury 3.73 LSD or the Z3 Torsen 4.10 LSD
Exhaust TBD but would like to use as much of the stock pieces from the Z and E30 as possible

Some questions:

Looking for some good info on what can be removed from engine to simplify the install. I assume that the air pump, post cat o2's are first on the list but can other items get removed without much trouble (no smog testing in my state). For the record, I plan on getting a proper ecu flash to delete EWS and whatever else I come up with from this list.

Should I mod the dipstick tube to run the CCV or delete CCV altogether?

Any other gotchas on doing an OBD2 swap I should be aware of before diving in?

S52 cams, OBD1 intake worth it?

Use the remote fuel pressure regulator or find an early M52tu fuel rail with integrated FPR?

Would really appreciate hearing any tips, tricks and links from the OBD2 swap folks. I have read through this entire thread and have not seen much on the OBD2 stuff.

Thanks!

[e30sforlife]

When using the getrag 260 for the tranny, can you use the e30 ltw flywheel? Those with the aluminum flywheel, does it make driving the car a pain? What clutch should you use?

Thank you.

Aaron

im using fidanza lightweight flywheel part #195321
with a sachs s52 clutch kit i got off rock auto
m20 pilot bearing
s50 throw out bearing
g260 trannny
any m50/s50/m52/s52 starter works
(ive got an m52 one)
drivability is great, little to no rev stick at 2k-3k and feels great. idle is a bit low though but i have the miller war chip so i can easily adjust idle speed and stuff like that. i highly reccomend it.

[exhaust]

I kind of have the opposite question.
I have an 87 325is I'm wanting to swap a M52TUB28 into.
Can I use the the stock e30 transmission?
I've read that some modification needs to be made to the cross member and shift linkage but don't know what exactly?
...and if there is anything else that needs to be modified or purchased?

Im also wondering what all is needed for the cooling system? I'll have a full e36 donor car. Do I need anything besides an electric pusher fan? And what is everyone using for that? SPAL?

To answer the transmission question, yes you can use the G260. You need an adapter to tilt the G260 ~10 degrees to mate up to the M52. Here is what I'll be using for my S52/G260 build:

http://store.garagistic.com/bmw-performance-parts/bmw-motor-swap/getrag-260-e30-transmission-brace

I'd recommend refreshing the G260 while it's out. Here is a link for what parts you'll need:

http://www.r3vlimited.com/board/showthread.php?t=295325

As for the linkage, you'll need to twist the shifter arm ~10 degrees in the opposite direction of the cross member adapter in order to keep it centered. You can either heat it up and bend it or find an aftermarket version. I don't have one bookmarked but I'm sure they are out there.

I can't answer your cooling questions as I've got to many of my own!

[Gaboer]

I was pulling out the engine and noticed my O2 sensor was zip tied to my battery tray. OBD I cars if I recall only have 1 O2 for both, but my exhaust runs 1-3/4-6 dual pipes all the way to the muffler. Previous owner said the car ran strong even without the O2 sensor. Is this something I need to worry about?

[schmidty]

I just bought a M50B25 TU from a 94 325... I have a 91 318is... Can I use the tranny and driveshaft from the same e36 325? My tranny just blew today so it's time to get serious with this swap.. Please help!

I kind of have the opposite question.
I have an 87 325is I'm wanting to swap a M52TUB28 into.
Can I use the the stock e30 transmission?
I've read that some modification needs to be made to the cross member and shift linkage but don't know what exactly?
...and if there is anything else that needs to be modified or purchased?

Im also wondering what all is needed for the cooling system? I'll have a full e36 donor car. Do I need anything besides an electric pusher fan? And what is everyone using for that? SPAL?

[Gaboer]

Ah sounds good, I ended up deciding to go and just use the X20 lines, and run them to my C104 instead of messing with the DME. My best friend knows how to solder and such made me this

[luckysnafu]

Found out that pin 1 doesn't exist on my S52 loom, guess I don't need the oil level sensor lol. Anyways, I just thought, is the DME pinout for the S50 and S52 the same? I just wanted to make sure that the DME pinout for 74/17 are the same since your thread was for an M50 engine.

No, they are not the same! S50 is OBDI and S52 is OBDII. You'll want to check wiring diagrams for your specific engine when making your harness. Check the wiring diagram links in my sig.

[Gaboer]

Found out that pin 1 doesn't exist on my S52 loom, guess I don't need the oil level sensor lol. Anyways, I just thought, is the DME pinout for the S50 and S52 the same? I just wanted to make sure that the DME pinout for 74/17 are the same since your thread was for an M50 engine.

[NeverEnough02]

Saw your thread, that was really helpful.
So this is what I have right now, does this look good?

What I'm wondering is for the tech, do i use pin 20 on the X20, or do I just directly wire it to my DME?

There is mention that there are different methods for the late model. Mine was tapped into the DME harness because I had the 3 prong plug as pictured. If you do not have that plug you may have a different resolution. But yes, the C104 to DME you listed is accurate.

[Gaboer]

Saw your thread, that was really helpful.
So this is what I have right now, does this look good?

What I'm wondering is for the tech, do i use pin 20 on the X20, or do I just directly wire it to my DME?