The comprehensive DOHC engine swap thread.

[Mr.SWISS]

You must have bought the blue temp switch (for ecu) instead of the brown temp gauge sender.

Looks like a light brown or dark yellow. So what year is the single pin from?

[BigD]

Looks like a light brown or dark yellow. So what year is the single pin from?

09/1985 up

[Mr.SWISS]

09/1985 up

I robbed the one from the eta for now and it works. I also bought a new DME temp sensor. The eta will get a new one when it comes in tomorrow.

[BigD]

Guys, I can't find the answer by searching, I've tried many times.

What is the thread size of the brown coolant temp sender? I bought a set thinking that it's M12x1.5 and it's 1.5 but it sure ain't M12, more like M17... Also if you know off the top of your head, the final bit size.

[Mr.SWISS]

Guys, I can't find the answer by searching, I've tried many times.

What is the thread size of the brown coolant temp sender? I bought a set thinking that it's M12x1.5 and it's 1.5 but it sure ain't M12, more like M17... Also if you know off the top of your head, the final bit size.

I have no idea. I thought you didn't have to tap the head on the S52 that there was another way? If you must take it to a machine shop and give the guy a 6 pack to find the thread size. Prolly will take him all of 10 min, or have a shop do the tapping. Can't be that much.

[BigD]

I have no idea.

Wonderful. Does anyone know?

[Lobstrosity]

Wonderful. Does anyone know?

I also don't know. Just thought I'd throw that out there. Although, it looks like it may be M14, same size as the power steering banjo bolts?

I just rethreaded the temp sender to M12x1.5 so that it will thread into the throttle body coolant output from the head, instead of tapping a new hole.

[BigD]

I also don't know. Just thought I'd throw that out there. Although, it looks like it may be M14, same size as the power steering banjo bolts?

I just rethreaded the temp sender to M12x1.5 so that it will thread into the throttle body coolant output from the head, instead of tapping a new hole.

Well I have to drill a new hole anyway since mine's a 98 but I figured someone who's done it would remember. It's not a huge deal, when I finally get around to it I'll just take the sensor with me to the hardware store but I didn't think such a simple question would be so difficult to answer.

[BigD]

Coolant sensor problem solved. I don't know why no one else suggested this, Lobrosity is absolutely right... if you're not using the throttle body warming circuit... use the hole! I rethreaded the M20 sensor, no engine drilling.

(messed up the focus but you get the idea...)

[Lobstrosity]

Coolant sensor problem solved. I don't know why no one else suggested this, Lobrosity is absolutely right... if you're not using the throttle body warming circuit... use the hole! I rethreaded the M20 sensor, no engine drilling.

(messed up the focus but you get the idea...)

Nice and tidy :-)

Now I just need to find a clean solution to blocking off the metal throttle body heater line on the metal obd-II coolant spider hose deal. Bolt in a hose works for now, but is hardly elegant.

[Court M3]

ok been reading this thread for the last few months and still unclear on a few things. Just got a 95 m50 engine and wiring harness from a 325is

Will an e30 dogleg tranny bolt up to the M50?

Will I need to change the driveshaft?

harness will work with no probs right?

[Jean]

From the way I understand it, getrag 260 will bolt up to m50 and you won't have to run a custom length drive shaft, the tranny will be at a different angle and you'll need to fabricate your own lower tranny bracket (look at the thread here on the forum as someone is making them for this task to make the job easier).

[RyanZ06]

Is this list still an accurate list of everything I will need to get my S50 into my E30? I am about to start the swap and I will have no longer than 1 week to get it all done :hitler: so I'm trying to make sure I have EVERYTHING i need. There is a BMW junk yard local to me, but they charge $$$$ for everything... So i'd prefer to shop there only "last minute".


Thanks!

E30 M50 ENGINE CONV PARTS LIST

"1. E30 88' radiator, I used the e36 unit with the lower mounts raised
2. E30 88' radiator over flow tank
3. E30 M20 fan, poss. w/clutch
4. E28 533i motor mounts w/ 5mm spacers or e28 m5 mounts with out spacers
5. E34 throttle cable
6. E21 brake booster w/ modified shaft, to 15mm or 325IX/e32 735 without mod to the shaft
7. E34 M5 or 25mm brake master cylinder w/ additional brake line used for the 325ix booster
or a e32 735i with the modified 320i booster
8. E30 325 trans X-member
9. E28 m5 or two 320i trans mounts/ which are cheaper
10. E30 M3 driveshaft or i used the front of the e36 mated to the rear of my e30 M3 have it rebalanced
11. E30 diff. w/ 3:25 ratio or E28 533i w/ 3:25 LSD
12. E30 318 ECU mount
13. E34 oil pan
14. E34 oil pickup
ect. ect.
15. E36 m3 exhaust manifold
16. M50 radiator hoses
17. E36 M3 Motronic
18. OBDI intake manifold
19. OBDI throttle body boot
20. E36 alloy mounting arms
21. OBDI wiring harness DO NOT BUY silver label “413” motronic, it has EWS (security),
it can only put into original chassis
22. the engine harness and the ECU are all E36 M3.
On the standard E30 with M20 engine fitted, you have the large round plug (C101) up on the firewall next to the brake booster.
This plug has 2 parts. One half is connected to the car wiring, and the other is connected to the engine harness.
When the M20 was removed, the engine side of the plug was removed with the engine. Now I have the S50 half of the plug in its place. Although similar in appearance, it will not plug directly into the E30 half of the plug.
I removed the E36 engine half of the plug, and replaced it with an E30 one. This then allows the 2 parts to screw back together. All you need to make sure is that you have the correct wires connected to each other. Its not just pin 1 to pin 1 and pin 2 to pin 2 etc (although some of the wires do actually connect this way).
This plug connection is the only point where the E30 & E36 wiring interface with each other. The rest of the E36 M3 engine harness is totally self contained.

[RyanZ06]

Just read this whole thread..

Sounds to me like it's not possible to put my OBD2 M52 into my car without converting to OBD1 :( Is that true?

Will I be able to swap my steering rack once the M52 is in place? I have to move forward with my motor installation due to time constraints, and I do not have a steering rack yet.

[asubimmer]

I have a m50tu w/ the getrag 240 on it (m42 tranny). The stock shift lever carrier and selector rod were quite a bit too long and I was told that I needed a m20 selector rod and carrier. I picked one up local and I just finished putting it on and it seems like its almost a tad too short? The shift lever was moved to the VERY front of the hole in the floor. But w/ the z4 3.0l lever I still can go through all the gears w/out a problem. Is this common?