I recently completed swapping a four speed manual transmission into my originally automatic-equipped 240Z. I got much of the info to plan this conversion from this site, but found that there was no one thread or article that contained all the information that I needed. So to give back some to the group that has helped me, I decided to try to document the whole process in one place.

Disclaimer: While the basic process, theory and parts requirements should be valid for any S30, the exact details of my swap will apply only to my exact situation - installing an early four speed (Type A - F4W71A) into a left hand drive early '71 240Z (10/70 series 1). That said, much of this info should be a good guide for swapping any manual transmission from a 240/260/280Z or ZX (except the Borg Warner T5 from some ZX Turbos) into any automatic-equipped S30.

The car - 1971 240Z, HLS30-12746, 10/70 build date. Factory equipped with an automatic transmission.

The parts - Basic mechanical parts for the job:

• Manual transmission (your choice of 4 or 5 speeds)
• Rear engine plate from a manual transmission engine
• Pilot bearing (auto-equipped cars didn't have them)
• Flywheel (find one with bolts and a good ring gear)
• Pressure plate
• Clutch disk
• Manual transmission starter and solenoid
• Release bearing
• Bearing collar
• Clutch fork
• Clutch fork boot
• Rear transmission mount (not absolutely required, the one from the automatic will work)
• Shift lever
• Inner shift boot
• Slave cylinder
• Clutch hose
• Metal hydraulic line
• Master cylinder
• Pedal box assembly (or brake and clutch pedals)
• Various nuts and bolts

To finish the interior trim, you will also likely need a shift knob, outer shift boot, and possibly a manual transmission console.

Some notes on picking out your parts - a bit of attention to what you get can pay off big in saving headaches. For example, when you pick out your transmission try to get one that still has its original clutch fork and bearing collar. Make certain that your clutch pressure plate is for the same year/model as the bearing collar. Try to get a pedal box assembly from a similar year car as you are swapping into. While a 280Z pedal box will probably go into a 240Z (and vice-versa), there are differences between them. Using as many of the proper vintage parts as possible can make it go easier.

In my case, my car came with a proper vintage Type A four speed when I bought it. The clutch fork and bearing collar were still installed. But that was all I got, so the rest I had to hunt down separately. The clutch hydraulic parts (except the metal fluid line) should all be new, not used, as should the release and pilot bearings. The pressure plate and clutch disk should be either new or almost new. Don't waste your time using a half worn clutch.

Preparation - There are a couple of things that can be done in advance to prepare for the actual swap. One is to swap the pedals. The other is to pre-route the hydraulic line. In my case, the original pedal box had been buggered up by a previous owner who had routed the injection harness (for a poorly installed ZX injection system) through the clutch master cylinder hole in the firewall. So I had to replace the entire pedal box, but in many cases I expect that people can get by with replacing the pedals only. But it might still be best to acquire an entire pedal box so that you get the bushings, return springs, pedal stops, etc.

While replacing the pedals only should be fairly simple, replacing the entire pedal box would definitely be much easier if the dash was out of the car. Which was not the way I did it. Only one surprise here, the pedal box I got was for a slightly later model 240Z ('73, I think) and the hole in the brake pedal for the clevis pin (to connect to the pushrod) was smaller than the one that came out. This was pretty simple in my case, I just had to drill out the new pedal to the larger size. It would have been worse had it been the other way. So again, try to get pedal parts that are the same year as your car. Adjust the clutch pedal height as specified in the FSM. (In the case of my '71, the face of the pedal should be 8" from the floor.)

Once the pedals have been changed, you can bolt up your new clutch master cylinder, and then route the metal fluid line across the firewall. The reality here is that there is no good way to do this part while the engine is in the car. In my case, that's not too big a problem, since I plan to do an engine swap in a few months anyway. So my line is not routed as it should be. If you're not planning to pull the engine anytime soon, plan on an whole afternoon of crawling around back behind the engine to get it done right.

I don't know about the later cars, but on the Series 1 cars the metal tab that the metal line and the clutch hose clip to doesn't exist. Manual transmission cars have this tab welded to the right side frame rail. The tab itself is normally spot-welded to the frame rail and can be fairly easily removed from a wrecked manual transmission car with a hammer and chisel. But attaching it to your car is a different issue. This is another item that would be difficult to do with the engine in the car. So again I passed on that for now. When the engine is out, I will pop-rivet it to the frame rail, and then I'll have it properly welded when I have the car de-rusted and painted someday.

The swap - I did my swap with the engine in place. It could have been done by pulling the engine/transmission as a unit from the top, but since I did it the other way, all the following details will assume you are doing it the same as I did.

So start by getting the car up off the ground. I pulled the front wheels up on ramps, and jacked the rear up and placed it on sturdy jackstands. Disconnect the battery and remove the starter. Since the starters are different between automatic and manual transmissions, I used the auto starter to start my "unused parts" pile. Then drain the transmission fluid, and remove the transmission fluid cooler lines.

After the fluid is mostly drained, you should remove the lower flex plate cover to gain access to the bolts which attach the flex plate to the torque converter. There are four of these bolts, and you'll have to turn the engine using the crank pulley bolt to get to them all. I did not drop the exhaust on my car, but depending on how yours is routed, you may have to do so. Disconnect the shift linkage and remove the driveshaft.

While it is not entirely necessary, it can be handier to disconnect and remove the dipstick tube and metal vacuum pipe to the intake manifold. Be sure to plug the vacuum fitting on the manifold, as you won't need it anymore. Also disconnect the six wires to the transmission - one pair (kickdown switch) on the left side, and two pair (reverse light and neutral safety switches) on the right side. Disconnect the speedometer cable also.

Now place a jack or something under the oil pan to help support the engine, and a transmission jack under the transmission itself. (There are other ways to do this if you don't have access to a true transmission jack, but they aren't as fun. Try to rent or borrow a real transmission jack.) Unbolt the rear crossmember from the car and the rear mount and remove it, catching the small metal plate that may have been installed between the crossmember and the rubber mount. Let the rear of the transmission drop down a bit and remove the four bolts from the bellhousing to the rear of the engine.

Slowly pull the transmission towards the rear of the car. As the transmission separates from the engine, the torque converter will do one of two things - it will either stay on the input shaft and come out with transmission, or it may stay stuck to flex plate like mine did. Watch the torque converter as you go and be prepared for fluid spills or for the converter to fall. Note - the converter is full of fluid and is heavy!

OK, it's out. Now it's time to prepare for the new transmission. Go inside the car to unbolt and remove the shift linkage plate from the tunnel. Then go back under the car. Unbolt the flex plate from the end of the crankshaft. You will need to figure way to hold the crankshaft from turning to do this, I wedged a prybar into the ring gear and against an engine bolt. Remove the flex plate along with the spacer plates on both sides of it, and also the rear engine plate. Install the pilot bushing into the end of the crankshaft. Drive it in carefully, trying not to smash the end of it. Test it now using the clutch line-up tool (or spare transmission input shaft), so that you can use a file or something to clean up any damage from driving it into place before the flywheel is installed. (Much easier to get to now.)

Put the manual transmission rear engine plate in place (on the engine dowel pins), and then install the flywheel (which I hope you had resurfaced already). Note that (at least for my Series 1 car) the flywheel bolts are longer than the flex plate bolts, so try to get the matching bolts with your flywheel. The flex plate bolts are not long enough. When torquing the flywheel bolts down, you will again have to find some way to keep the crankshaft from turning. There are special tools available for this, or you can get creative. (I was creative.)

Using your line-up tool, install the clutch plate and pressure plate to the flywheel. At this time (while the engine is out) is the time to prepare the wiring as well. The kickdown switch wires (on the left side of the tunnel) can be ignored. I taped them up out of the way. On the other side of the tunnel, identify the two wires for the neutral safety switch, and splice them together or make a jumper wire to connect them to each other. (On my car, these two wires were both black, and both had female bullet connectors.) The remaining two wires are for the reverse lamp switch. (On my car, these were both red with black traces and both had male bullet connectors.) Verify that the connectors for the reverse lamp switch on your transmission are compatible with those of your car's wiring harness. Mine were not, all four connectors were male bullets. Now is the time to deal with this, not when the transmission is in place.

Now time to ready the transmission itself. This is a great time to replace the rear seal, as well as the obvious time to refresh any of the clutch actuator parts that may be needed. Again, make certain that the clutch fork matches the transmission, and replace the fork dust boot unless it is really good already. The release bearing and collar should be properly fitted to the fork, and the slave cylinder should be mounted to the bellhousing. Bolt the rear transmission mount to the tailshaft housing, but do not bolt the crossmember to the mount. Lastly, put the transmission in gear, don't have it in neutral.

Time to put the transmission into the car. Again, it is best to use a transmission jack to do this. Get it lined up and try to slide it up to the back of the engine. Never let the transmission hang from the input shaft, always support it from the bottom. If the transmission won't slide up easily, slide the driveshaft part way into the tailshaft and use it to spin the transmission to try to get the splines on the input shaft to match the splines in the clutch disc. (This is why you want it in gear, not in neutral.) Don't try to force it, if you can't get it to mate after several attempts, drop the transmission back down to re-check the set up with the clutch line up tool.

Eventually the transmission should slide up to the engine, rotate it back and forth a bit until the dowel pins line up. Put one or two of the bellhousing to engine bolts in lightly, and then bolt the rear crossmember into place. (Remember to use the metal plate between the crossmember and mount if there was one there originally.) Put the remaining engine bolts in, and tighten all four to spec. Note here that I had to get new engine bolts for mine, as the bellhousing flange on the Type A four speed is much thicker than the automatic, and requires a longer bolt. In my case, the bolts I used were 10 mm x 1.5 x 60 to 65 mm thread length. Since the holes in the block are blind (don't go all the way through, but have a bottom), the bolts can't be too long or they'll bottom out in the holes. Remove the transmission jack and the support from under the engine.

Re-install the driveshaft, connect the reverse switch wiring and the speedometer cable. Fill the transmission with oil! Install the shift lever and inner shift boot. (Since I was installing a Type A transmission into my Series 1 car, I did not have to enlarge the hole in the tunnel. If you are installing a Type B or a five speed in a Series 1, the tunnel modification should have been done earlier when the transmission was out.) Install the small bolts that hold the lower part of the rear engine plate to the lower bellhousing. If your slave cylinder has the adjustable pushrod, adjust it now.

Connect the (probably new) clutch hose to the slave cylinder. Note here that I ran into a snag. The hose to slave cylinder connection is not a flare fitting, but requires a copper crush sealing washer. In my case, neither the hose nor the cylinder came with the washer, and I had to go hunt one down before I could finish the job. Learn from my experience, make sure you have one before you need it.

When the slave connection is tight, connect the other end of the hose to the metal fluid line. Fill the master cylinder with clean fluid and open the bleeder on the slave. Let the fluid 'gravity bleed' for a short time, then close the bleeder. Keep watching the fluid level in the master cylinder during all this to make sure you don't introduce more air. Top off the master cylinder and bleed the slave manually once or twice to ensure that you have all the air out.

Almost done! Install the starter and re-connect the battery. Get the car back on the ground, put it in neutral and start it. With the clutch pedal depressed and the engine running, carefully try to shift through all the gears, making sure there are no grinding noises, and that the shift lever moves into each gear normally. If that tests out OK, put it in reverse and move the car just a couple of feet, noting how the clutch feels. You don't want it to be grabby, or feel like it is slipping. Now into first, and come back forward a few feet. Do that back and forth a couple times. If that all goes well, buckle up and go test it!

I think that's it. I hope I didn't forget anything important, and I also hope this might help people planning for a similar swap.

Okay so I bolted up the tranny and everything slides right in except for the tranny x-member. Did I miss something because the tranny x-member will not bolt up. And I will need to cut a bit of my shifter housing off. I'm using a 280Z 4spd tranny. I think I'm going to need custom tranny x-member made or something. What a headach!!! Sorry for hijacking this thread Arne.

Since I now have a second 240Z that is a manual transmission car (a later '71 that I'm parting out), I have had a chance to learn a bit more about the differences, other than what I mentioned in the original article. As is the case with the original article, the details here are based on early 240Zs. Some of this will likely apply to later cars as well, but YMMV.

Bodyshell - I have found a few other differences in the bodyshell, in addition to the presence of (or lack thereof) the bracket for the clutch hose on the framerail. One is a mounting point on the inside of the firewall above the throttle pedal for the "kickdown" switch. (More on the switch itself later.) Manual transmission cars do not appear to have this mounting tab. But the manual transmission cars do have a rectangular clutch pedal stop (about an inch high) on the firewall, that is missing on some or all automatic cars. Also, the automatic cars have four holes with captive nuts at the four corners of the shift lever opening (to retain the automatic shift selector) that the manual cars don't have.

Wiring - Both the engine compartment and dash harnesses are different for the automatics, the rear body harness is the same. The dash harness has extra leads for the "kickdown" switch, as well as an extra dash illumination bulb for the shift selector. In the engine compartment harness, the lead from the ignition switch to the starter solenoid is routed through a neutral safety switch on the automatic before it gets to the starter. (These are the leads that must be connected together.) The reverse light switch leads may have different connectors than on a manual car. And lastly, there is an extra relay on the left inner fender in front of the coil and near the radiator support. More on this below.

Mechanical - Under the hood, the automatics all had a radiator with integral transmission cooler in the lower tank. The fittings can be ignored or capped off when the manual transmission is installed. (In fact, these days many aftermarket replacement radiators on the market are fitted with the cooler so that they can be sold as one-size-fits-all.) There is also an extra vacuum fitting on the balance tube, that goes to the transmission modulator. This port will need to be plugged or capped off.

And then there is the ignition. The automatics came with a dual point distributor, instead of the single point unit on the manual transmission cars. And this is where a whole lot of the differences are related. You see, the dual point unit was not designed for performance or reliability, it was designed to give more ability to vary the timing advance curve. Under normal driving, one set of points would be used. Under full throttle, the above-mentioned "kickdown" switch (which actually has absolutely nothing to do with transmission kickdown) energizes the relay near the coil, which switches the ignition to the second set of points. That second set has a slightly different static timing, which effectively changed the advance curve.

This could cause problems during ignition swaps, if not taken into account. It might be considered less than optimal for the ignition to cut out whenever the throttle was opened wide, which could happen if the ignition were re-wired incorrectly!

i was wondering how much did all this cost for the swap ? and was it really worth it ? thanks.

cause i'm deciding to buy a 240z auto cause it has some rust . or should i just wait for a 4spd.? man im impatient

Thanks for the thread builder. it will def help if i decide to get it

thanks man.

Arne;

Mechanical - Under the hood, the automatics all had a radiator with integral transmission cooler in the lower tank. The fittings can be ignored or capped off when the manual transmission is installed. (In fact, these days many aftermarket replacement radiators on the market are fitted with the cooler so that they can be sold as one-size-fits-all.)

I could not find a new manual only radiator. Settled for auto because it is new and less cost then getting mine redone. But, will keep this core for a while incase someone needs it.

i was wondering how much did all this cost for the swap ? and was it really worth it ? thanks.

cause i'm deciding to buy a 240z auto cause it has some rust . or should i just wait for a 4spd.? man im impatient

Thanks for the thread builder. it will def help if i decide to get it

thanks man.

Cost? - That can vary a lot. Many of the parts needed will be used. So it depends on how much you can find the parts for. In my case, the 4 speed came with the car. All of the various used parts cost me less than $200 total. New clutch pieces probably another $200. Call it less than $400 for the whole job.

Worth it? - That also depends. If you want a Z with a manual transmission, there are only two options. Buy a manual car, or buy an automatic and convert. If you can find a manual car in equal condition for no more than $500 more than an equal automatic, it's a wash.

But frequently, the automatics are considerably cheaper than an equal condition manual car. Also, many of the automatics are in much better condition than a manual car, as they seem to have had much easier lives.

If you are looking for a restoration project, you should probably wait for a manual car. But if you want a Z for a fun daily or weekend driver, converting a nice automatic can be a viable option.

Cost? - That can vary a lot. Many of the parts needed will be used. So it depends on how much you can find the parts for. In my case, the 4 speed came with the car. All of the various used parts cost me less than $200 total. New clutch pieces probably another $200. Call it less than $400 for the whole job.

Worth it? - That also depends. If you want a Z with a manual transmission, there are only two options. Buy a manual car, or buy an automatic and convert. If you can find a manual car in equal condition for no more than $500 more than an equal automatic, it's a wash.

But frequently, the automatics are considerably cheaper than an equal condition manual car. Also, many of the automatics are in much better condition than a manual car, as they seem to have had much easier lives.

If you are looking for a restoration project, you should probably wait for a manual car. But if you want a Z for a fun daily or weekend driver, converting a nice automatic can be a viable option.

Thanks Arne. I think i'll convert the auto then. im not looking for any restorations. thanks and ill use the guide here that u made. wish me luck! haha :laugh:

Arnie - Thanks for the great article - I am just getting started - Question - did you have to Drill the hole in the firewall for the clutch master actuating rod to the clutch pedal? In my 73 240 the bolts are there for the master but no hole for the rod - If so what size? Thanks

Here is a link to some pics that may help while you're working the swap.

http://www.classiczcars.com/forums/showthread.php?t=20794&highlight=auto+manual

What a thread, Im just about to start the conversion.

I had a guy who claims to be a Z expert, say I needed to cut the drive shaft to get it to fit in between the manual gearbox and the diff. I guess this is not the case since no one has mentioned it.

Thanks for all the info

Edited August 29, 200816 yr by DC871F

If all you are changing is the transmission type (and not converting to the T5 from the late ZXT), the driveshaft you now have from your automatic will work fine.