The comprehensive DOHC engine swap thread.

[Mr.SWISS]

No, the booster just hooks up directly to the intake manifold with a single hose (and check valve).

The throttle body has three ports on the bottom. Two are for the coolant in/out for the throttle body heater, and the one on the far right goes to the electric valve (1 in attached diagram) that is connected to the charcoal canister.

Ok I hooked up the check valve last night and no real big change in idle. I installed it with the arrow going toward the engine. I still got a check engine light and kind of a lopy idle. :(

[DTRguy]

So I read this whole thread yesterday and I came away wondering a couple things. I am procurring parts for my winter project build.

1. Is the M20 tranny the same as the Getrag 260?
will that tranny/clutch support 600whp?
2. The E36 m3 tranny swap uses the E30 M3 driveshaft?
3. If I use a E28 535 diff... do I need different halfshafts for the splines or flanges?
4. Is there a preferred lightweight single mass high tq capacity clutch assembly for use on a E36 M trans?
5. Will an M50 non vanos head fit and work with a Vanos M52 block... as I have both and want to use the 2.8

I am really trying to get all of my ducks in a row so I can concentrate on the fabrication of the custom necessary items and the wiring up of my stand alone. I don't want to be stuck on an issue that I can figure out pre op.
Kevin

[FredK]

1. Is the M20 tranny the same as the Getrag 260?
Yes

will that tranny/clutch support 600whp?
I don't know

2. The E36 m3 tranny swap uses the E30 M3 driveshaft?
Yes.

3. If I use a E28 535 diff... do I need different halfshafts for the splines or flanges?
No, you use E30 halfshafts, but you'll need to swap the diff output flanges to the E30 ones (medium case diff only), because E28 flanges have a different bolt circle diameter. If you choose to use M Coupe / Roadster trailing arms and halfshafts for any reason (5 lug, larger vented rear rotors, etc.), you need to use the E28 output flanges.

4. Is there a preferred lightweight single mass high tq capacity clutch assembly for use on a E36 M trans?
M5 clutch. A lot of FI people do not use lightweight flywheels, they use the stock dual mass unit.

5. Will an M50 non vanos head fit and work with a Vanos M52 block... as I have both and want to use the 2.8
Yes.

Thanks for reading through this thread. It's a little disorganized, but will get you through a swap.

[DTRguy]

1. Is the M20 tranny the same as the Getrag 260?
Yes

will that tranny/clutch support 600whp?
I don't know

2. The E36 m3 tranny swap uses the E30 M3 driveshaft?
Yes.

3. If I use a E28 535 diff... do I need different halfshafts for the splines or flanges?
No, you use E30 halfshafts, but you'll need to swap the diff output flanges to the E30 ones (medium case diff only), because E28 flanges have a different bolt circle diameter. If you choose to use M Coupe / Roadster trailing arms and halfshafts for any reason (5 lug, larger vented rear rotors, etc.), you need to use the E28 output flanges.

4. Is there a preferred lightweight single mass high tq capacity clutch assembly for use on a E36 M trans?
M5 clutch. A lot of FI people do not use lightweight flywheels, they use the stock dual mass unit.

5. Will an M50 non vanos head fit and work with a Vanos M52 block... as I have both and want to use the 2.8
Yes.

Thanks for reading through this thread. It's a little disorganized, but will get you through a swap.

Thanks so much for answering these questions.

Makes me wonder... should I be looking into different trailing arms? I was possibly planning on doing a five lug swap to the rear only for power handling. This sounds as if I could get the whole shebang with half shafts and all with M coupe/roadster trailing arms and disks and such. I already have Big Brembo setup set asside for the front that needs a little modification to work.

Also, are there any advantages to the M52 head over the M50? Valve sizing, included angles, port shapes/sizes etc that you are aware of to make me want to rebuild the M52 head (at a considerable cost). The M52 head is crashed and there are some nicks in the piston tops that need smoothing out.

[FredK]

I am fairly certain there is no difference in the casting or finish machining between M50, S50US, M52, and S52US heads.

One of the few differences is that later model M/S52 engines only had one temperature sensor tapped into the head, whereas earlier engines and the M/S50 engines had a second temperature sensor port tapped into the head. You will likely need this second sensor port to fit the temperature sender to the dash.

The valvetrains are almost identical as well, but the S5x motors have conical valve springs that reduce mass.

[DTRguy]

good to know thanks so what then is your opinion about...

Makes me wonder... should I be looking into different trailing arms? I was possibly planning on doing a five lug swap to the rear only for power handling. This sounds as if I could get the whole shebang with half shafts and all with M coupe/roadster trailing arms and disks and such. I already have Big Brembo setup set asside for the front that needs a little modification to work.

[FredK]

Well, what kind of Brembo setup do you have? The key is to make sure you don't mess up the balance of the braking system by changing the caliper piston displacement too much. If you have an E36 front big brake kit, I'd say go for it.

[DTRguy]

It is off of an Audi TT I believe 312 MM or 328mm there is a company in Germany that offers the same setup for consumption. I am following their lead and I got the calipers and rotors off of a client's project car CHEAP so I will make that system work. I need something more substantial for the velocities I intend to make this car go. If Bias becomes an issue I will most likely be installing an adjustable brake bias valve.

[BUDNUNTA]

New question.
Are all Non Vanos ECUs the same. Will an e34 ECU work with an E36 motor/ harness. Id imagine they do but just wanted to be sure.



Hunter

[Van Westervelt]

They are not all the same no. Although there is some cxross compatibility.

[nholm325e]

Where do i tie in the vaccum line for the brake booster on the engine??

[Van Westervelt]

Where do i tie in the vaccum line for the brake booster on the engine??

There is a port just to the right of the throttle body. Plugs straight in.

[Court M3]

Searched, but couldn't find answer. Will the S50 bolt right up to an e30 tranny?

[Teaguer]

Searched, but couldn't find answer. Will the S50 bolt right up to an e30 tranny?

Yes using the e30's Getrag 260 is the most common trans to use with a 24v swap .

Using the e30's trans eliminates the need to buy a 24v trans and elimnates the need to source a different driveshaft .
Also you can usually keep the same diff ratio since the e30's trans has a overdiven 5th whereas the 24v trans are a 1:1 fifth gear .

The trans will be rotated slightly at 10deg angle however .
This is why people bend the shift lever or cut and reweld the shift linkage to compensate .

[kylebes1]

This is information I have gathered in my own experiences. If there are errors let me know, I will verify your complaining and change it if I want. This is intended to be a parts list and not an instruction manual. You should have a general idea of how a car works and how to work on it before you take on this conversion. This conversion is a 6 on a 1 to 10 scale. If you have all the parts, a lift and necessary tools this should take no longer than any other engine replacement. Labor should be between 12 and 15 hours at any competent shop.
Good luck!

All information is for use at your own risk.


Parts:

Double Over-Head Cam Inline Six

Variants

1991-1992 m50b25,
1993-1995 m50tub25, tu in this cause means the addition of VANOS
1996-1999 m52b28,
1995 s50b30,
1996-1999 s52b32,
1995 Euro s50b30, ITB
1999 Euro s50b32, ITB

Notes:

Of all the engine’s listed above, all 1993 and up have VANOS.
1996 and up have OBD2, and smaller intake runners.
Euro s50 variants are actual “M” engines. Solid lifters and ITB.
Euro engines require a standard m50 oil pump to work with the e34 pan
All require
e34 oil pan, pickup, oil pan gasket, dipstick, and dipstick tube
E28 535is engine mounts
E36 engine mounting arms- only relevant if your engine is from an e34 or e39

Transmission

Variants

1987-1991 e30 325 Getrag 260, five speed with overdrive
1992-1999 e36 325 and 328 five speed, no overdrive
1995-1999 e36 m3, ZF five speed with overdrive
1999 Euro m3, ZF six speed with overdrive

Notes:

Your transmission choice can affect your differential and driveshaft selection.
Non m3 transmissions require 1984 to 1991 m20 driveshaft
M3 five speed transmissions require e30 m3 driveshaft, or swap transmission output to that of an m20
ZF six speed, I have no information at this time
E36 transmissions allow the use of e30 trans bracket, mounts, and e36 shifter.
E30 transmission requires some fabrication to trans bracket, mounts and e36 shifter.

Clutch

Variants

1987-1991 e30 325, single mass flywheel
1992-1999 e36, dual mass flywheel
1992-1999 e36 m3, larger diameter friction surface

Notes:

Non M3, E30 and E36 clutch components are interchangeable.
Flywheel requires matching clutch slave, and starter.

Brake booster

Variants

E21 320i with shaft shortened approximately 7 cm and rethreaded
2002, custom modification that I am not familiar with.
Euro engines require added clearance, so the two above will not work.

Cooling

Variants

1988-1991 e30 radiator and overflow
E36 radiator and 1988-1991 e30 overflow

Notes:

Due to limited space and arguable added benefit I would convert to an electric puller fan with thermostatic switch.
It has been discussed that the smaller, 318is radiator can be used.
Lower temp coolant thermostat is also a must.

Wiring Harness

Variants

1991-1992 e34
1992 e36
1993-1995 e34
1993-1995 e36
1996-1999 e36
1996-1999 e39 no information at this time

Notes:

1991-1992 harness will not have VANOS wiring
E34 harness is 2 to 3 inches shorter at ECU. May or may not matter in mounting
1996-1999 OBD2
Treehouse Racing sells a harness adapter for your project.


You can email me with questions. I like a challenge.

Kyle Taylor
KyleTaylor@PMcar.com