The comprehensive DOHC engine swap thread.

[TeXJ]

I'm in the middle of the same swap (g260/m52b28) and have everything else put back together, just have to put it back in the car now.
I used the Garagistic trans mount brace to account for the 10% twist of the tranny.
Also had a machine shop shave down the m20 single mass flywheel. I'd have to look up how much they shaved off.
Clutch and TOB were both M20 parts as well as most of the other components needed. I can get you my parts list if you want as I also went in and refreshed some of the transmission components.

Did you stay OBD2? What are you doing for the FPR if you went OBD1? (Fuel Pressure Regulator)

[schmidty]

Thinking of using my existing G260 on my M52b28.

I know I will need to modify both the shift selector rod and trans mount.

Can I use the M20b25 single mass flywheel, clutch, TOB, etc ?

Anything else I'm overlooking?

I'm in the middle of the same swap (g260/m52b28) and have everything else put back together, just have to put it back in the car now.
I used the Garagistic trans mount brace to account for the 10% twist of the tranny.
Also had a machine shop shave down the m20 single mass flywheel. I'd have to look up how much they shaved off.
Clutch and TOB were both M20 parts as well as most of the other components needed. I can get you my parts list if you want as I also went in and refreshed some of the transmission components.

[bradmer]

Thinking of using my existing G260 on my M52b28.


I know I will need to modify both the shift selector rod and trans mount.




Can I use the M20b25 single mass flywheel, clutch, TOB, etc ?


Anything else I'm overlooking?

Below is from the swap notes I have culled from r3v 24v swap posters who were gracious enough to post their experiences. Unfortunately I did not save the posters information for credit where it is due.


"The pilot needs to match the trans. ie ZF is an e36 328/m3, so purchase the pilot for that.

Starter needs to match ring gear on flywheel. So purchase the starter for the FW you have.

Slave matches trans.

TOB matches clutch set (BTW m50/s50/m20/m42 use the same depth). *note* "some" people had issues with the dual mass m20 to SM conversion on the TOB. The only DM m20 FW I have seen is the late eta.

The m20 FW has a large protrusion on the engine side that will contact the RMS housing on a 24v (or m42), so you can either shave the FW, shave the RMS housing, or some people put the bolt ring on the back of the FW (the 6 bolt ~3mm thick ring that goes on the clutch side of the FW normally)."


I have the G260 trans with 99 S52 motor, I used the aluminum cup / rubber transmission mounts on the 15* transmission bracket I purchased from a forum member, the delrin tranny mounts were way to harsh of a ride. Also not all of the tranny bolts mate up to the motor, just the 5 or 6 larger bolts if I remember correctly, none of the smaller bolts align.
I lightened the flywheel to 11.5 pounds when the machine shop shaved the back of the SM flywheel to clear on the engine side and it now r3v's gloriously.
I didn't do the rear seal and wish I had.

Good luck!

[Panici]

Thinking of using my existing G260 on my M52b28.


I know I will need to modify both the shift selector rod and trans mount.




Can I use the M20b25 single mass flywheel, clutch, TOB, etc ?


Anything else I'm overlooking?

[KIRIEIW]

What throttle cable are you guys using for your S50/ M50 swap cars? I purchased a e34 throttle cable already/ installed it on my car but it's so damn long.. On top of all this I'm not even sure if it's going to work with my OBD1 throttle body (my stock S50 throttle body) since no one ever makes it clear if the e34 throttle cable is compatible with both OBD1 and OBD2 engine swaps. I plan on installing the engine this weekend and want to have everything on hand.

Edit: e34 cable works perfectly with a OBD1 S50 throttle body.

[mtech325]

I have a question about wire harness and ecu flash.

I have an e30 with a frankenstein s52 swap = m50 head and m50 block bored to 3.2, s52 pistons, s52 crank, s52 headers, s50 cams. Obviously OBD1. This setup had a flashed ecu by TRM.

My piston rings are fried (tired engine) and I am putting another s52 in.

The S52 comes with harness, ZF tranny, and all accessories.
I am going to:
M50 manifold swap, but I am wondering if I can use my old engine's m50 wiring harness on the S52? I want to avoid paying again for another e36 to e30 wiring harness adapter and the very expensive TRM flash again for this new harness.

I think I can use the old harness and ecu, but I might have to change all the engine sensors (crank position, cam position, etc) which connect to the m50 harness to the m50 type. Is this correct?

I would rather avoid the $600 TRM ECU cost and the $200 wiring harness adapter cost again.

Assuming your M50 was a Vanos engine, you should be able to swap everything over to the S52 to convert it to OBD1. I recently did a similar swap (M50 to S52), and I was able to reuse the same wiring harness and harness adapter. I used the same ECU as well, just swapped out the chip for the S52 tune.

Things to note with the S52 is that the stock crank sensor is at the back of the block, so you'll want to leave it there to keep the hole plugged, otherwise the OBD1 crank sensor provision is still present at the front like the M50. The Vanos solenoids have different cable lengths between OBD1 and OBD2, but they swap easy with a 32mm wrench. The last bit is the need for an adapter fitting to make the OBD1 coolant hose work, as the S52 uses a coolant pipe. Hopefully this helps.

[cocofunk]

I have a question about wire harness and ecu flash.

I have an e30 with a frankenstein s52 swap = m50 head and m50 block bored to 3.2, s52 pistons, s52 crank, s52 headers, s50 cams. Obviously OBD1. This setup had a flashed ecu by TRM.

My piston rings are fried (tired engine) and I am putting another s52 in.

The S52 comes with harness, ZF tranny, and all accessories.
I am going to:
M50 manifold swap, but I am wondering if I can use my old engine's m50 wiring harness on the S52? I want to avoid paying again for another e36 to e30 wiring harness adapter and the very expensive TRM flash again for this new harness.

I think I can use the old harness and ecu, but I might have to change all the engine sensors (crank position, cam position, etc) which connect to the m50 harness to the m50 type. Is this correct?

I would rather avoid the $600 TRM ECU cost and the $200 wiring harness adapter cost again.

[TeXJ]

Thanks for the reply.

Where is the o2 sensor at?
It was originally just reading one of the banks from the stock exhaust. So I got some long tube headers and straight piped the car. The exhaust shop put the o2 sensor after the collectors.


have you smoke tested the intake & checked for exhaust leaks?
Yes, I've checked it and then had another mechanic check for leaks. I have also replaced the o2 sensor that is there.



Right now the car is at the shop and the guy said it needs both O2 sensors to read correctly. From my research on this swap, I wasn't really able to get the answers about how many o2 sensors are needed.

[Caperix]

I have a m52b28 from a 1998 328i car in my 1990 325iS. The PO did the swap and ever since I've had it, it has had some running issues and the o2 sensor(Lambda Control 1 code 1222).

I have just one o2 sensor in the exhaust as the PO said there is only need for one. Is that true or should I have two o2 sensors?

I'm running the red label 413 dme, obd1 swap

Where is the o2 sensor at? 413 only uses 1 mounted at the y pipe so it reads both banks. The m52 exhaust uses 4 o2 sensors, 2 at the headers and 2 behind the cat, if it is only using 1 o2 in the header you are missing reading half the engine. Code 1222 looks like it is a lean mixture fault, have you smoke tested the intake & checked for exhaust leaks? My 95 m3 used to set a lean code on long highway trips, it was fixed with a fuel filter & new o2 sensor.

[TeXJ]

I have a m52b28 from a 1998 328i car in my 1990 325iS. The PO did the swap and ever since I've had it, it has had some running issues and the o2 sensor(Lambda Control 1 code 1222).

I have just one o2 sensor in the exhaust as the PO said there is only need for one. Is that true or should I have two o2 sensors?

I'm running the red label 413 dme, obd1 swap

[eternal24k]

Those with AKG poly motor mounts, anyone ever wrap with a heat shield on the exhaust side? If so, what did you use?

[Metallated]

Question. Would cutting the extra wiring connectors from my my s52 harness and heat skrinking them be a bad idea? Connectors like sap, rear o2 etc..
I want to cleanup the harness of unnecessary connectors I won't be using.

I think that would be a great idea.

I also have a quick question. I've done some reading and know I need to rethread the brown top temp sensor but I haven't been able to find the exact thread. Anyone know what they've used successfully?

[UgkNW*]

Question. Would cutting the extra wiring connectors from my my s52 harness and heat skrinking them be a bad idea? Connectors like sap, rear o2 etc..
I want to cleanup the harness of unnecessary connectors I won't be using.

[wworm]

Technically you could use it, but the way the spider hose or coolant pipe for the m52 exits the block works a lot better with a late model m20 expansion tank since both sit on the driver's side of the car (You'll also want the late model m20/e36 6-cylinder radiator too). Otherwise you would have to run a long hose all the way back to passenger side where the pre-88 expansion tanks sit.

As for the shift linkage, you'll want to use the carrier and selector rod from an e36 m3 or e36 328.

thanks bro!

[mtech325]

ive got an 87 325 (eta) and im swapping in a 96 m52b28 with the zf320 trans. Can I use the stock radiator and overflow? which shifter linkage will I need to use?

Technically you could use it, but the way the spider hose or coolant pipe for the m52 exits the block works a lot better with a late model m20 expansion tank since both sit on the driver's side of the car (You'll also want the late model m20/e36 6-cylinder radiator too). Otherwise you would have to run a long hose all the way back to passenger side where the pre-88 expansion tanks sit.

As for the shift linkage, you'll want to use the carrier and selector rod from an e36 m3 or e36 328.