The comprehensive DOHC engine swap thread.

[Van Westervelt]

e21 booster. nothing to custom is required. run all e36 from the manifolds back.

typo. all depends on if you want to go single pipe, aftermarket cans or all oem.

[85Ecoupe]

thanks, so the only thing i need thats different to mount it is e28 535i mounts, i can use the e36 arms? (i know bout the tranny bracket is needed too)

[etxxz]

e36 arms.

btw to clear above posts. e21 does require shaft modification/shortening/welding.

85coupe: stock tranny bracket if going with e36 ZF trans or modified e30 bracket with e30 trans or unmodified e30 bracket with proper transmission mounts.

[85Ecoupe]

Im going to use the Getrag 260

i heard there is a guy on here who makes tranny brackets for 75 bucks, i think ill do that.
Also i may use treehouse racings booster knowing that it is the right dimensions for the swap without having to make any custom adjustments to it. Unless i can find a different booster that wont have to be modified in any way....

BTW how much does the 260s flywheel need to be shaved to work? and can i just use a new sachs clutch and pressure plate?? the one in my car is the original so im going to replace it.

P.S. about the wiring, how do i connect the e36s engine harness to my cars harness? i have the square connection not round.

thanks

[hoveringuy]

Speaking of wiring... I pulled my M50 last week and it had two (2) X20 connectors and the diagnostics connector. I know what the diagnostics is for, along with the main X20 that had the important stuff, but what is the second X20 for? It had about 8 smaller wires. What do you do with it?

Hoveringuy

[nismoman]

im just kidding about making the harness for you my starter turns over but i have no fuel. lol , yes there is no info on how to wire mine and your cars up on here, every body has info on how to wire a 325i or a 325 e with the circle c101 lug but as far as the square 85 e and the c104 plug under the dash no body knows, i have my c101 sorted out i believe but im having trouble figuring out the fuel pump. i need to know what goes to the c104 connector as far as wire colors. i m going to give it a try again tonight because from the schematic it looks like i need to hook a green power wire up to the c104 connector so that might be my problem and also i need to know which wire on the m50 is the cranking signal and does that go through the dme or the c101 because if the fuel pump doesnt know the engine is cranking then it wont work ,

[diegom6]

getting the e34 oil pan and dipstick are necessary, as well as the sump tube. IF you do use an m50 from the e36 you have to remove the oil baffle as the e34 oil pan has it built in. there is a support for the e36 oil tube that is attached to one of the main bearings. If you opt to remove the bolts and the main cap you have to get new bolts and be sure to get the cap back on the same way it came off. or you can di it the easy way and bend the bracket until it breaks off, I would not attempt to cut it because where do the shavings go?

While you have the pan off make sure you oil pump nut is VERY tight!

To digress a little, what ever flywheel you use you have to match it to the starter.

you need e28 535 engine mounts, the green rubber ones. e36 engine brackets. You can use the e36 power steering pump and all. My e30 hose had a bango fitting on the rack side and a sort of nut typ fitting on the pump side, well the e36 pump requires a bango type. I looked over to my m10 power steering pump and it already had the adapter I needed so I could use the e30 hose I had recently replaced.

IF you have a 89+ car your cooling system will work, if not get a e36 radiator and 89+ surge tank and hook it up.

If you want to stay with a clutch fan you have to use the e30 one, it goes right where the e36 one comes off.

When you buy the engine, make sure they are sending you a complete running engine, includign the AFM as well.

Cannot think of anything else right now, but I do remeber The Euro Depot sells a e30 "kit" for like 2800. They also have low mileage engines.

What is the baffle? I'm planing to put a S50B30 us version m3 in a possible 318 86' (gotta confirm first if it's a 318 or a 325i) and we don't have any used e34 m50 oil pan-dipstick available over here. What are the modifications necesary to run the stock m50 e36 oil pan and oil dipstick?

Thanks,

-Diego

[etxxz]

the "baffle" is a splash guard "tray" right under the crank that kees oil from exesively going in there. it simply unbolts but you do NEED the e34 oil pan, there's no way around thisone...unless you want to fab one.

[diegom6]

the "baffle" is a splash guard "tray" right under the crank that kees oil from exesively going in there. it simply unbolts but you do NEED the e34 oil pan, there's no way around thisone...unless you want to fab one.

That means I need yes or yes a e34 M50 oil pan for do this conversion? That sucks, not so much or none avilable over here used, of corse.

ABout the stock brake booster? I have seenakgmotorsport sells this part but modded to make it fit, does omeone know what it's done to make it fit the stock booster?

Thanks,

-Diego

[Black Power]

anyone know how to get my tach working correctly for an e30 m3? i messaged the guy on here that makes the kit to do it, but has not received a response in over a week.


also which short shifter do most people go with. do a stock z3?

[kevdeno]

for sure.!! ive to figure out qhere to hook up my input signL FOR SPEED,(CRnking signAL, so my fuel pump will come on line.

nismoman, could you elaborate?

I've got a 1992 M50 (non-vanos) that cranks, main relay turns on, but for some reason the fuel pump relay (and unknown third relay) doesn't turn on. I know the brown/green ground trip wire going into the fuel pump relay is all that's missing, as I've tested it.

Are there specific sensors that have to be hooked up and sending a signal in order for the computer to turn on the fuel pump?

Thanks

[owenjm]

E30+m50

I am familiar with E30s not so much other models. I have been driving myself nuts reading this thread and looking up model #s to note what all of you are saying. What I have is an 87 325is, I also have a 94 525I thats wrecked I want to put the running gear out of the 525 into the 325. I do not recall anyone mentioning using the 525 gearbox in the conversion. But this thread is so long it is like reading a novel. My retention is not what it was years ago. any help is appreaciated.

Thanks Owen

[Van Westervelt]

anyone know how to get my tach working correctly for an e30 m3? i messaged the guy on here that makes the kit to do it, but has not received a response in over a week.

also which short shifter do most people go with. do a stock z3?

On the Tach, there is a plug that is specific for what RPM range that tach is, 8k, and the size of your engine, 4cyl. The problem you have is that you are sending the tach and plug a 6 cyl signal. I dont know the details, but you have to adjust it electronically, like the aforementioned control unit.

I had an m3 tach in, and took it out for this reason. I put in a 325i tach with 325i coding plug, and it reads accurate. My redline is at 7200 which is where the tach runs out. No biggie to me.

Shifters are all based off preferance. I use the UUC Evo3 shifter.

I am familiar with E30s not so much other models. I have been driving myself nuts reading this thread and looking up model #s to note what all of you are saying. What I have is an 87 325is, I also have a 94 525I thats wrecked I want to put the running gear out of the 525 into the 325. I do not recall anyone mentioning using the 525 gearbox in the conversion. But this thread is so long it is like reading a novel. My retention is not what it was years ago. any help is appreaciated.

Thanks Owen

You do not use the 525 gearbox. Either use your 325i 5 spd tranny with, or get an e36 (92+ 325i) tranny.

I would recommend keeping your current tranny and using it. Benefits from doing this are you keep the driveshaft stock, your differential will also be appropriately geared. Only things you would have to change then are shaving your flywheel, twisting your shifter linkage, and supporting the 10-15 degree shift in tranny location. I would also recommend a fresh clutch.

[diegom6]

On the Tach, there is a plug that is specific for what RPM range that tach is, 8k, and the size of your engine, 4cyl. The problem you have is that you are sending the tach and plug a 6 cyl signal. I dont know the details, but you have to adjust it electronically, like the aforementioned control unit.

I had an m3 tach in, and took it out for this reason. I put in a 325i tach with 325i coding plug, and it reads accurate. My redline is at 7200 which is where the tach runs out. No biggie to me.

Shifters are all based off preferance. I use the UUC Evo3 shifter.

You do not use the 525 gearbox. Either use your 325i 5 spd tranny with, or get an e36 (92+ 325i) tranny.

I would recommend keeping your current tranny and using it. Benefits from doing this are you keep the driveshaft stock, your differential will also be appropriately geared. Only things you would have to change then are shaving your flywheel, twisting your shifter linkage, and supporting the 10-15 degree shift in tranny location. I would also recommend a fresh clutch.

Shave the flywheel? Need to be done because won't fit something? I fso, how many mm?? Or it's done to get the new clutch in place with a fresh surface of the flywheel only?

[Van Westervelt]

The e30 m20b25 flywheel does not clear the e34 m50 oilpan. So you either trim back the oilpan, or remove the lip off the engine side of the flywheel. I would always go the flywheel route as you are netting a lighter flywheel in the process.