SMG to 6MT Conversion

[sapote]

I re-read your post in the thread: https://nam3forum.com/forums/forum/m...ent-pin-spring

I realized I misunderstood your statement, I thought you were agreeing that it isn't the best option. Instead of running the spring you would stick a wine cork in the transmission, does a wine cork degrade in trans/atf fluid? You really are holding firm onto this idea that you don't need one of the gate detents. Have you tried this? I really feel like you are spreading misinformation by saying "do this..." when you have no idea if it'll work or not. I don't claim to know everything but when I propose something either I have done it and no the results OR I state that it may or may not work. There are plenty of guys reading these forums and not realizing the information is untested then get themselves into trouble. I appreciate you trying to help the community but from my end some of this is a disservice.

Transmission gate detent is not rocket science. I had carefully studied the design and proposed that there is no need to have the 5/6 gate detent. All 4-speed boxes have zero detent on the ¾ gate (unless the Reverse is on the right side of ¾), including the popular Porsche 901 box I have, so if we think shifting from 3/4 to 5/6 is just like on a 4-speed box from 1/2 to 3/4, then perhaps the idea is nothing new at all. I have not tested this idea on the 420G box but no reason to think this doesn’t work. It has a solid stop at 5/6 (edited to correct 4/5)gate so how can one not able to find the gate at the far right without the detent pin?

As about the wine cork as a backing piece behind the sealing cap, that was just some colorful language to brighten the day, although I’m sure it won’t dissolve in dinosaur oil; the dinosaurs didn’t. Btw, the sleeve is still in there and will not let the cap backing into the tranny. Of course for the new conversion, no detent pin for 5/6 and no hole and sealing cap needed.

[RaliusM3]

All done. Just needs a bath now, and a good bleed of the brakes. But I was able to drive it in to work. The cheap clutch I got is a bit rough but it shifts fine and the headers I put on have a good sound. I cheaped out on some things but in the end still put over $8k into parts. I did subframe reinforcement, suspension, Z3 rack, headers, vanos rebuild, rod bearings, smg to manual, water pump, soft top gear and latches, diff input seal, rear main, front main, timing chain, timing guides, short shifter kit, coding and flashing, and probably some other things all on weekends in the span of 6 months in my tiny condo garage. Now to ship it to Hawaii when I move there next year. Thanks for the help and this thread!

[RaliusM3]

Bit of an update after a week of driving:

i rebuild the vanos and did timing chain and guides while doing rod bearings, kept getting a code for the exhaust vanos (I went with the upgraded hub that has cylindrical tabs). Timing looked perfect at first but after popping valve cover it was actually off by a tooth on the hubs so I had to pull vanos and move the hub by a tooth. After that, no vanos codes.

i am getting 1 code consistently, error 80 “switch chain adhesion” meaning clutch is slipping. I’m attributing this to the SMF and clutch setup I installed. The clutch doesn’t slip but does seem like the engagement is off somehow like maybe the slave is actuating early (but the pedal does have a tiny bit of dead zone at the top). 3rd gear was a bit grindy and other gears very notchy, feeling like the clutch is off a tiny bit. The shifter leans like 2 deg to the right. I did have the shift selector rod on the wrong side but changing it did nothing. If I find the gears right it shifts just fine no grind. I did change the oil to Royal Purple Synchromax which does seem to help. Would really like to get an opinion on whats up with the shifter being off a tiny bit. The cruise does work since I used the brown clutch switch that came with the pedals i got. If the transmission dies I won’t support getting another, I am a CNC engineer by trade and have already found examples of a transmission adapter plate to use the 6-speed that is mated to an N54, I forget the name. I’m sure there will be a few more things to machine in the process but that will be my plan of action over the next few years.

the car dies sometimes which I believe is due to the fact that I hand rebuilt the TB actuator. Once the dme adapts it no longer dies. If i delete adaptations then it sometimes dies again when coming to a stop. Doesn’t seem to be any air leaks.

the soft top latches I got, I messed the left one up and am waiting on more. I should have checked the magnet clearance from the hall sensor.

the subframe plates from Turner really seem to stiffen up the car. Funny enough, after changing every bushing in the rear to Poly and going with Tein lowering springs and Stagg struts, the car creaks FAR less than it did before getting into this project.

the Z3 rack I threw on is way too “floaty” for me and I will probably change it.

the megan racing headers I put on are great, bit noisy but everyone loves the new sound.

I do all of my own flashing and coding and often use my weekends to flash and code peoples bmw’s E and F series out here in Seattle, meaning I was able to handle the software side pretty easily. One thing though, the DSC was looking for the SMG ecu even after changing the VO and coding it. I had to go in and change an option but now the car has zero warning lights.

I did all this work over a span of about 6 months, I saved money where possible and am so happy with the outcome. That said, I will never attempt a project like this again without a lift and bigger place for all my tools. Happy to answer questions for the next person that goes this route.

[tlow98]

Bit of an update after a week of driving:

i rebuild the vanos and did timing chain and guides while doing rod bearings, kept getting a code for the exhaust vanos (I went with the upgraded hub that has cylindrical tabs). Timing looked perfect at first but after popping valve cover it was actually off by a tooth on the hubs so I had to pull vanos and move the hub by a tooth. After that, no vanos codes.

i am getting 1 code consistently, error 80 “switch chain adhesion” meaning clutch is slipping. I’m attributing this to the SMF and clutch setup I installed. The clutch doesn’t slip but does seem like the engagement is off somehow like maybe the slave is actuating early (but the pedal does have a tiny bit of dead zone at the top). 3rd gear was a bit grindy and other gears very notchy, feeling like the clutch is off a tiny bit. The shifter leans like 2 deg to the right. I did have the shift selector rod on the wrong side but changing it did nothing. If I find the gears right it shifts just fine no grind. I did change the oil to Royal Purple Synchromax which does seem to help. Would really like to get an opinion on whats up with the shifter being off a tiny bit. The cruise does work since I used the brown clutch switch that came with the pedals i got. If the transmission dies I won’t support getting another, I am a CNC engineer by trade and have already found examples of a transmission adapter plate to use the 6-speed that is mated to an N54, I forget the name. I’m sure there will be a few more things to machine in the process but that will be my plan of action over the next few years.

the car dies sometimes which I believe is due to the fact that I hand rebuilt the TB actuator. Once the dme adapts it no longer dies. If i delete adaptations then it sometimes dies again when coming to a stop. Doesn’t seem to be any air leaks.

the soft top latches I got, I messed the left one up and am waiting on more. I should have checked the magnet clearance from the hall sensor.

the subframe plates from Turner really seem to stiffen up the car. Funny enough, after changing every bushing in the rear to Poly and going with Tein lowering springs and Stagg struts, the car creaks FAR less than it did before getting into this project.

the Z3 rack I threw on is way too “floaty” for me and I will probably change it.

the megan racing headers I put on are great, bit noisy but everyone loves the new sound.

I do all of my own flashing and coding and often use my weekends to flash and code peoples bmw’s E and F series out here in Seattle, meaning I was able to handle the software side pretty easily. One thing though, the DSC was looking for the SMG ecu even after changing the VO and coding it. I had to go in and change an option but now the car has zero warning lights.

I did all this work over a span of about 6 months, I saved money where possible and am so happy with the outcome. That said, I will never attempt a project like this again without a lift and bigger place for all my tools. Happy to answer questions for the next person that goes this route.

incredible amount of work! Nice job. Love the kiddo shot - I’m in a similar boat with my son and this car. He loves working on it haha. I’m also in a similar boat with a motor rebuild in jack stands - yay!

thanks for the update - all these details and solutions help everyone.

[sapote]

1. Timing looked perfect at first but after popping valve cover it was actually off by a tooth on the hubs so I had to pull vanos and move the hub by a tooth. After that, no vanos codes.
2.i am getting 1 code consistently, error 80 “switch chain adhesion” meaning clutch is slipping. I’m attributing this to the SMF and clutch setup I installed.
3. the car dies sometimes which I believe is due to the fact that I hand rebuilt the TB actuator.
4. 3rd gear was a bit grindy and other gears very notchy, feeling like the clutch is off a tiny bit. The shifter leans like 2 deg to the right.

1. Wonder why you didn't detect this off-timing when doing the final check before close up the valve cover. Nothing should have moved since the vanos was bolted down.
2. How does the DME know that the clutch is slipping? If gear is 6th and clutch slipping then DME calculation based on wheel speed and rpm could erroneously become 5th instead, and 6mt cars doesn't know what gear engaged (slipping clutch can confuse the DME's calculation). So I think error 80 decimal means clutch switch issue.
3. Engine stall could be due to the clutch switch bad/wrong as in (2)
4. This could mean the gate selecting arm (in the bellhousing) is not set properly -- the big coil spring end wasn't bent correct or the spring anchor pin hole was drilled a bit off. This can cause the gear selector rod touching both 3/4 and 5/6 forks, and the notchy feel. You should have check the shifter (on the tranny) position when the tranny was on the floor. The bellhousing has to be removed again to correct this.

[RaliusM3]

1. Wonder why you didn't detect this off-timing when doing the final check before close up the valve cover. Nothing should have moved since the vanos was bolted down.
2. How does the DME know that the clutch is slipping? If gear is 6th and clutch slipping then DME calculation based on wheel speed and rpm could erroneously become 5th instead, and 6mt cars doesn't know what gear engaged (slipping clutch can confuse the DME's calculation). So I think error 80 decimal means clutch switch issue.
3. Engine stall could be due to the clutch switch bad/wrong as in (2)
4. This could mean the gate selecting arm (in the bellhousing) is not set properly -- the big coil spring end wasn't bent correct or the spring anchor pin hole was drilled a bit off. This can cause the gear selector rod touching both 3/4 and 5/6 forks, and the notchy feel. You should have check the shifter (on the tranny) position when the tranny was on the floor. The bellhousing has to be removed again to correct this.

1. I used the amazom special timing kit that lots of people had complained about. Actually, I believe it was my fault somehow because I do think I may have tried to line up the slots with the old markings for some reason. It seemed correct but also at the end of its travel for the exhaust hub. My first time doing that repair.
2. DME apparently reads something from the sensor. There is no CEL and the cruise works so I’m not going to care about it and may figure out how to suppress it.
3. pressing the clutch even a tiny bit does raise the rpm to 1k. I personally think I didn’t set the actuator stop screw correctly.
4. It sucks but I’m probably not going to do anything about it. It was a conversion done by Lang and I didn’t notice anything at first. Actually, I couldnt find a good price on an oem shifter arm so I went with a cheap short shift kit. The correct one is on it’s way. If the hole is drilled off center then I won’t be able to fix it anyway right? There does seem to be more travel from “center” ie 3rd gear to 1-2, than 5-6, but only a small amount. Again, my plan going forward will be to go with a different transmission in the future.

[sapote]

I used the amazom special timing kit that lots of people had complained about. Actually, I believe it was my fault somehow because I do think I may have tried to line up the slots with the old markings for some reason.
3. pressing the clutch even a tiny bit does raise the rpm to 1k. I personally think I didn’t set the actuator stop screw correctly.
4. If the hole is drilled off center then I won’t be able to fix it anyway right? There does seem to be more travel from “center” ie 3rd gear to 1-2, than 5-6, but only a small amount

1. Using the old mark on the hub slots is not enough resolution, and so the error. When I did mine I use the drill bit as the pin that fitted in the cam hole, with carpenter square and a caliper to set the cams timing. The drill bit is not 90* to the head top surface. I do have the data used for my method.
3. Do you have DME with stock tune, or non-stock tune? I don't think pressing on the clutch pedal should raise the rpm, as this would wear the synchro faster.
4. If indeed the spring anchor pin is off center, the problem can be fixed by bending the spring straight end piece,

[lemoose]

I was haunted by the car dying when i came to a stop issue after my swap- it is indeed related to your clutch switch- however its a programming issue. You need to reconfigure your dme according to your clutch switch/gps configuration. The ecuworx mss54 tool does this out of the box now. You could also do it yourself though with a hex editor- but the location for this string varies based on a myriad of things like your dmes hardware, software, and firmware versions if i recall correctly

[tlow98]

I was haunted by the car dying when i came to a stop issue after my swap- it is indeed related to your clutch switch- however its a programming issue. You need to reconfigure your dme according to your clutch switch/gps configuration. The ecuworx mss54 tool does this out of the box now. You could also do it yourself though with a hex editor- but the location for this string varies based on a myriad of things like your dmes hardware, software, and firmware versions if i recall correctly

if you are not using a GPS sensor I’m assuming this applies, as well? As in, something will need to be done?

is there a best practice that gets you to the right answer or is a guess and check experiment?

many thanks!

[lemoose]

if you are not using a GPS sensor I’m assuming this applies, as well? As in, something will need to be done?

is there a best practice that gets you to the right answer or is a guess and check experiment?

many thanks!

when i came across this possible solution, i called the shop to see if they used the gps but no one remembered 😒 so i had to play around with it till it was right. My guess is that the shop didnt use the gps and therefore had to disable it in the dme. So if you kept the gps i would guess that you dont need to change anything.

[sapote]

when i came across this possible solution, i called the shop to see if they used the gps but no one remembered 😒 so i had to play around with it till it was right. My guess is that the shop didnt use the gps and therefore had to disable it in the dme. So if you kept the gps i would guess that you dont need to change anything.

The GPS sensor and the clutch switch are connected in series, and so the DME doesn't know which one opens the circuit (GPS is open circuit when in Neutral, clutch switch is open when pedal pressed down, so either one open will let the EWS to crank the starter).

[S3diment]

Just received this one in the mail from FCP:

https://www.fcpeuro.com/products/bmw...le-61319122700

The PN on the switch is 61-31.9122700.9

However the switch itself is black. Any thoughts? Will try it regardless.

[George Hill]

I have one of these "new" 700 switches as well, pn# on it is 61-31.9122700.9 and dated 070422, it is black in color.

I have not had a chance to test it in a car yet, but looks favorable.

[S3diment]

Just received this one in the mail from FCP:

https://www.fcpeuro.com/products/bmw...le-61319122700

The PN on the switch is 61-31.9122700.9

However the switch itself is black. Any thoughts? Will try it regardless.

Just tried the 700 black switch. Car shifts much better than before. No RPM dips. However CC does not work. Will be investigating further with the computer.

[LuLu]

Don’t use a donor bell housing - see my post about the damage it can cause. Convert your BH to match.

Old thread, having struggle to find the old post. In short why shouldn't you use another bell housing. I'll explain my situation I have a 04 M3 manual, with 4th gear syncro on it's way out I think. When engaging gear you feel a click and when clutch is released it grinds. Well I have bought a smg gearbox so I am sure synchros are good, and wanted to swap bell housing. Taking the manual one and putting it on the smg one. Should I be careful?