A/T to M/T Swap
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From: Seattle
A/T to M/T Swap
Alright Guys, after many months of planning, struggling, and wrenching I have finally gotten my automatic 1982 Rx-7 fully manual swapped and back on the road. I have had a lot of questions along the way so I am making this to document every issue I have ran into along the way and what you need to take into account if you are considering doing an automatic (A/T) to manual (M/T) swap on your Rx-7.
The first thing I want to say is YOU CAN DO THIS. It might seem like a daunting process but it really can be straight forward if you do your research and plan accordingly.
Now, you could go about this swap in two different ways. You could just swap transmissions. Taking the old auto out and putting the manual in. This could be a good choice if you only have a transmission and your engine is already in good health. The second option would be to change both the engine and the transmission together. Option 2 was better for me because I already had a lower mileage engine and manual transmission ready to swap in and my current engine needed a rebuild. I will be explaining my process which was swapping the whole drivetrain.
Parts List
Here I will list the bare bones things you will need. Manual Drivetrain, If you pull this from another vehicle it will include the new engine, and transmission and everything that is involved. (Clutch, Flywheel, Pressure Plate, Clutch Slave Cylinder, and the Manual Starter.) There might be a couple smaller things depending on your situation but the drivetrain is the biggest cost here. Along with these things you will need a Clutch Master Cylinder (with a hard or a soft clutch line) and a Manual Pedal set. You might also need a drive shaft from a manual transmission car but in my case that was not necessary because the auto and manual drive shafts were the same length.
When i researched how to put the pedals in most people said to buy the whole assembly for a couple hundred dollars but I already had the long bolt and spacers I needed as well as the clutch pedal, so I bought a manual brake pedal to complete the set and I put that in the car instead of buying the whole assembly.
Interior
The first thing I would do is the interior, removing the auto shifter, shifter trim, and starting the pedals. This part of the project was probably the most frustrating part of this whole process for me. Take the seat out so you can lay down and maybe bring a pillow because you might be under the dash for a while. If you follow the brake pedal you will find the long bolt it rotates on. On the passenger side is where the bolt slides in and there is a nut on the driver's side. Once you get it out you will need the manual pedals, which includes a longer bolt, spacers and the two pedals. Don't forget the springs on both of the pedals.
Another thing you could do while you’re under the dash is to take off the two bolts holding on the clutch master cylinder block off plate. On these Rx-7s there is no drilling required to install the clutch master cylinder, just remove the plate and install the clutch master cylinder.
Engine Prep for Removal
The first step is getting the old automatic stuff out. Take the hood and the radiator out so that you will be able to have the room to pull the drivetrain. Also disconnect the engine harness and hoses. If I had one tip to help this run way smoother, LABEL EVERYTHING. It will make installation SO much easier so please, please label it.
Once most things are disconnected you will have to disconnect the cables on the carburetor. These were a struggle for me and I ended up taking the carburetor off whichmade disonnecting the cables is easier. Make sure if you remove the carburetor to tape off the ports because you don’t want anything falling in there. It will be a pain to get out. After you do all of that in the engine bay move to under the car. The next step is to remove the driveshaft and the exhaust. Make sure when you take off the driveshaft, you mark how it is mounted so that you can mount the driveshaft exactly as you took it off. Once that is off, disconnect the headers from the rest of the exhaust and you are ready to pull the engine.
Engine removal
I will not be going into super detail here as there are many other guides that go into a lot of detail when it comes to pulling an engine and transmission. When everything is disconnected connect the cherry picker to the engine and start to lift it so that there is no slack in the chains. Then unbolt the two engine mounts and the transmission mount and pull the engine out.
Engine Prep
Now is the time to take everything from the working engine and put it on the engine connected to the manual transmission. Take everything, headers, intake manifold, spark plugs, fan, and transfer it over. In my swap, my car originally had a Front Mounted Oil Cooler (FMOC) and the new engine going in was an 83 with the Beehive Oil Cooler. I chose to keep the FMOC and if you are in the same situation, don't worry I will talk about that process later. While you have the engine and tranny outside of the car, it would be a good idea to replace all of the mounts. Also don’t forget new gaskets where needed. Once the engine is ready reinstall it in the car.
Engine Installation
Everything here is pretty straightforward except for the transmission mount. The manual and auto transmission are the same length so the shifter goes right in the proper place but the mount for the manual is further back on the car. I found a company selling manual transmission mounts but I am not able to confirm it would actually fit for this application and it is not cheap running around 400$ for a simple mount. So either you could buy this mount or fabricate your own.
Neutral Safety Switch Bypass
When I had everything ready to go and I turned the key over nothing happened. It was a no crank no start even though the battery was fully functional. I knew it was a problem with the Neutral Safety Switch and after a while of scratching my head I finally was able to make it work. Because the Neutral Safety Switch is connected to the automatic transmission there will be an open four pinned connector hanging out in your engine bay. It should have four wires you can use to identify it, BY (Black with Yellow stripe), BW (Black with White stripe), GY (Green with Yellow stripe), and RW (Red with White stripe.) Although none of those really matter except for the signal wire, BY, which should be the top left pin if the connector is facing you. To Bypass the Neutral Safety Switch, you will need to run a wire from this signal wire on the Neutral Safety Switch connector to the signal wire connection on the starter. Once you do this you should be able to start the car up, BUT make sure it is always in Neutral because if you're not careful the car WILL start in gear and destroy stuff.
Beehive to FMOC Swap
My Rx-7 originally came with a FMOC (Front Mounted Oil Cooler) and the engine and transmission I was swapping in was from an 83. In 83 Mazda changed to the Beehive design which places the Oil Cooler right below the Oil Filter, on the top of the engine. From what I had researched many people agreed that the FMOC was more efficient than the Beehive so I decided to keep the FMOC. The first step is to start removing the Beehive stuff from the engine. Start with the Beehive pedestal, there should be two 10 mil bolts holding it to the engine. There will also be oil cooler lines you will have to disconnect to get this off. In place of this you will need an Oil Pedestal from an 82 or earlier car. After you have attached the Oil Pedestal the next thing will be the oil cooler lines. There will be one place at the Front Left of the engine and one place at the Left Rear of the engine, near where the starter is. These will be really large bolts and it may require two wrenches to get them off. In place of them you will need either OEM 82 Oil Cooler Lines or aftermarket AN lines. I went with the OEM route as it was free but AN lines would probably be the best way to go because used OEM lines could be worn or close to failure. Once you have removed the beehive lines, replace them with the FMOC lines. Make sure you get these tight because if they leak once you start it, it will be difficult to tighten it more.
If you are doing this swap and have any questions shoot me a message I'd be happy to help
The first thing I want to say is YOU CAN DO THIS. It might seem like a daunting process but it really can be straight forward if you do your research and plan accordingly.
Now, you could go about this swap in two different ways. You could just swap transmissions. Taking the old auto out and putting the manual in. This could be a good choice if you only have a transmission and your engine is already in good health. The second option would be to change both the engine and the transmission together. Option 2 was better for me because I already had a lower mileage engine and manual transmission ready to swap in and my current engine needed a rebuild. I will be explaining my process which was swapping the whole drivetrain.
Parts List
Here I will list the bare bones things you will need. Manual Drivetrain, If you pull this from another vehicle it will include the new engine, and transmission and everything that is involved. (Clutch, Flywheel, Pressure Plate, Clutch Slave Cylinder, and the Manual Starter.) There might be a couple smaller things depending on your situation but the drivetrain is the biggest cost here. Along with these things you will need a Clutch Master Cylinder (with a hard or a soft clutch line) and a Manual Pedal set. You might also need a drive shaft from a manual transmission car but in my case that was not necessary because the auto and manual drive shafts were the same length.
When i researched how to put the pedals in most people said to buy the whole assembly for a couple hundred dollars but I already had the long bolt and spacers I needed as well as the clutch pedal, so I bought a manual brake pedal to complete the set and I put that in the car instead of buying the whole assembly.
Interior
The first thing I would do is the interior, removing the auto shifter, shifter trim, and starting the pedals. This part of the project was probably the most frustrating part of this whole process for me. Take the seat out so you can lay down and maybe bring a pillow because you might be under the dash for a while. If you follow the brake pedal you will find the long bolt it rotates on. On the passenger side is where the bolt slides in and there is a nut on the driver's side. Once you get it out you will need the manual pedals, which includes a longer bolt, spacers and the two pedals. Don't forget the springs on both of the pedals.
Another thing you could do while you’re under the dash is to take off the two bolts holding on the clutch master cylinder block off plate. On these Rx-7s there is no drilling required to install the clutch master cylinder, just remove the plate and install the clutch master cylinder.
Engine Prep for Removal
The first step is getting the old automatic stuff out. Take the hood and the radiator out so that you will be able to have the room to pull the drivetrain. Also disconnect the engine harness and hoses. If I had one tip to help this run way smoother, LABEL EVERYTHING. It will make installation SO much easier so please, please label it.
Once most things are disconnected you will have to disconnect the cables on the carburetor. These were a struggle for me and I ended up taking the carburetor off whichmade disonnecting the cables is easier. Make sure if you remove the carburetor to tape off the ports because you don’t want anything falling in there. It will be a pain to get out. After you do all of that in the engine bay move to under the car. The next step is to remove the driveshaft and the exhaust. Make sure when you take off the driveshaft, you mark how it is mounted so that you can mount the driveshaft exactly as you took it off. Once that is off, disconnect the headers from the rest of the exhaust and you are ready to pull the engine.
Engine removal
I will not be going into super detail here as there are many other guides that go into a lot of detail when it comes to pulling an engine and transmission. When everything is disconnected connect the cherry picker to the engine and start to lift it so that there is no slack in the chains. Then unbolt the two engine mounts and the transmission mount and pull the engine out.
Engine Prep
Now is the time to take everything from the working engine and put it on the engine connected to the manual transmission. Take everything, headers, intake manifold, spark plugs, fan, and transfer it over. In my swap, my car originally had a Front Mounted Oil Cooler (FMOC) and the new engine going in was an 83 with the Beehive Oil Cooler. I chose to keep the FMOC and if you are in the same situation, don't worry I will talk about that process later. While you have the engine and tranny outside of the car, it would be a good idea to replace all of the mounts. Also don’t forget new gaskets where needed. Once the engine is ready reinstall it in the car.
Engine Installation
Everything here is pretty straightforward except for the transmission mount. The manual and auto transmission are the same length so the shifter goes right in the proper place but the mount for the manual is further back on the car. I found a company selling manual transmission mounts but I am not able to confirm it would actually fit for this application and it is not cheap running around 400$ for a simple mount. So either you could buy this mount or fabricate your own.
Neutral Safety Switch Bypass
When I had everything ready to go and I turned the key over nothing happened. It was a no crank no start even though the battery was fully functional. I knew it was a problem with the Neutral Safety Switch and after a while of scratching my head I finally was able to make it work. Because the Neutral Safety Switch is connected to the automatic transmission there will be an open four pinned connector hanging out in your engine bay. It should have four wires you can use to identify it, BY (Black with Yellow stripe), BW (Black with White stripe), GY (Green with Yellow stripe), and RW (Red with White stripe.) Although none of those really matter except for the signal wire, BY, which should be the top left pin if the connector is facing you. To Bypass the Neutral Safety Switch, you will need to run a wire from this signal wire on the Neutral Safety Switch connector to the signal wire connection on the starter. Once you do this you should be able to start the car up, BUT make sure it is always in Neutral because if you're not careful the car WILL start in gear and destroy stuff.
Beehive to FMOC Swap
My Rx-7 originally came with a FMOC (Front Mounted Oil Cooler) and the engine and transmission I was swapping in was from an 83. In 83 Mazda changed to the Beehive design which places the Oil Cooler right below the Oil Filter, on the top of the engine. From what I had researched many people agreed that the FMOC was more efficient than the Beehive so I decided to keep the FMOC. The first step is to start removing the Beehive stuff from the engine. Start with the Beehive pedestal, there should be two 10 mil bolts holding it to the engine. There will also be oil cooler lines you will have to disconnect to get this off. In place of this you will need an Oil Pedestal from an 82 or earlier car. After you have attached the Oil Pedestal the next thing will be the oil cooler lines. There will be one place at the Front Left of the engine and one place at the Left Rear of the engine, near where the starter is. These will be really large bolts and it may require two wrenches to get them off. In place of them you will need either OEM 82 Oil Cooler Lines or aftermarket AN lines. I went with the OEM route as it was free but AN lines would probably be the best way to go because used OEM lines could be worn or close to failure. Once you have removed the beehive lines, replace them with the FMOC lines. Make sure you get these tight because if they leak once you start it, it will be difficult to tighten it more.
If you are doing this swap and have any questions shoot me a message I'd be happy to help
Last edited by Fizzpop; Aug 24, 2022 at 02:11 PM.
Senior Newbie Member
Joined: Jun 2017
Posts: 1,051
Likes: 89
From: Downey California
Is there a right way to do that neutral saftey switch ? The ability to start it in gear is a no no for me esp if some one who doesnt know accidently trys to start your car and grenades everything .
Use the manual trans harness and make the connection to the main wiring harness at the firewall.
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Joined: Jun 2017
Posts: 1,051
Likes: 89
From: Downey California
What is the Harness ? Dumb Question . I have a new old stock wiring harness that conects all the emissions system . And then I have all the wires that run under the dash from a 80' . Both were stick.
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From: Seattle
Proper Clutch Safety Switch Wiriing
I actually did not use the harness as I havent been able to find it for sale yet. If you did want to do this correctly I suggest custom wiring if you cant get your hands on a harness like me. For this you would buy a Clutch Safety Switch (CSS) and you would wire it straight from the Neutral Safety Switch (NSS) to the Clutch Safety Switch. The Signal Wire on the NSS will be BY (Black Yellow) on the 1982 model. Wire that to the By (Brown w/ yellow stripe), although it is listed as Br in the wiring manual, on the CSS. Then connect the Ry (Red with yellow stripe to the starter signal wire connection. This Circuit should in theory be open with the clutch not depressed and when you depress the clutch it should close the Circuit allowing the car to turn over. I did not have the time to do this because I had to move for school a couple weeks after I started this project so I am not sure if this will actually work. If you do try it though let me know how it goes! @Frogman
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Joined: Jun 2017
Posts: 1,051
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From: Downey California
i have no plans on doing the swap at the moment , I will when my auto goes bad eventualy. I have a stage 2 kit so that will not be replaceable. The funny thing is this trans is preety much indestructable unless you force it without fluid. When the fluid drops bellow a certain point the trans neutral drops and when it does go into gear it engages so hard the rear tires spin. I know why we love sticks , my mustang was a stick but honestly I love my 7 with the auto , I couldnt imagine daily driving with the stick in this traffic to be honest.
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