DATSUNgeo Posted June 30, 2022 Report Share Posted June 30, 2022 Greeting guys. I just located a KA24E for my 1973 620 swap. My 620 is currently an automatic and I would like to keep it automatic so the wifey can drive it. Should I just look for a KA24E automatic transmission? Which automatic transmission would be easiest to find that would work? I have the motor mounts pictured below but I looks like I would need a transmission support too, right? I believe a member here make them, could someone direct me to him and provide me a user name? Thanks guys, much appreciated! 1 Quote Link to comment
datzenmike Posted June 30, 2022 Report Share Posted June 30, 2022 Steve... https://ratsun.net/profile/38-2edeye/ ... makes and sells quality KA swap engine brackets and transmission mounts. Not sure if the standard and the automatic mounts are compatible though. Contact him by private message. Three automatics. I guess the RE401A (240sx or 2wd D21 pickup) automatic for a KA would be the most compatible arrangement. However they may require some electronics connection to the KA's engine management system or emissions controls. Something to look into. The car transmission and later trucks use an electronic speedometer that won't work the 620 speedometer. I don't know the length of this automatic, and assume car and truck are the same length, but I doubt it will match the 620's automatic. Because the KA and Z series share the same transmission bolt pattern, a Z series transmission for a 720 truck should work also. Your 620 automatic is a 3N71B. The 720 also used an upgraded 3N71B so cooling lines and shifter should match up well. The 620 length I'm not sure of, could be 26" or 31.5" . The 720 automatic is 31.5" so if that matches then no driveshaft modifications needed. The 720 automatic from '83 has the locking torque converter. I would get the 3N71B flexplate from the Z24 just to be sure the torque converter bolts up. There is another automatic used by the Z24i used in the early '86-'88 D21 pickup. This is the L4N71B which is stronger and does away with the locking converter and adds an overdrive 4th gear that is engaged or locked out by a switch on the shifter handle. This transmission is definitely longer than the 3N71B. Quote Link to comment
bilzbobaggins Posted June 30, 2022 Report Share Posted June 30, 2022 It would be pretty sexy to convert it to column shift as well. Quote Link to comment
datsunrides Posted June 30, 2022 Report Share Posted June 30, 2022 Should be able to swap on a Z series bell housing to your existing transmission. Where this gets a little tricky is the torque converter bolt up. The KA flex plate is closer to the block and the hole in the crank is different. Don’t remember exactly what I did, but I think I documented this in a build thread on my 521 years ago. I believe it was Project FTO. Quote Link to comment
DATSUNgeo Posted July 1, 2022 Author Report Share Posted July 1, 2022 Well it’s full steam ahead…! I bought/traded my L16 and $200 for two KA24E engines, and a wire harness. Thanks for the help. I will look for a KA or Z series transmission. 1 Quote Link to comment
datzenmike Posted July 1, 2022 Report Share Posted July 1, 2022 The '73 flex plate will never bolt to the KA engines. You could maybe make this work with an L or Z series and probably the KA flex plate but the little L16 automatic is a little light for a 150 hp engine. Get a Z24 or KA automatic and swap it in. Quote Link to comment
DATSUNgeo Posted July 4, 2022 Author Report Share Posted July 4, 2022 Thanks Datzenmike. After doing some reading I have two 240sx KA24E engines. I also have one wire harness but no ECU. I’ll get the ECU and transmission from the same vehicle so they match. Quote Link to comment
DATSUNgeo Posted July 6, 2022 Author Report Share Posted July 6, 2022 (edited) I have some pictures here of a possible candidate. It's off a 1989 240SX. Is it possible for anyone to know if this transmission will work with the KA24E by the making on it? Thanks for all the help guys. Edited July 6, 2022 by DATSUNgeo Added a picture. 1 Quote Link to comment
datzenmike Posted July 7, 2022 Report Share Posted July 7, 2022 The '89 through '90 240sx (S13) was KA24E powered.... so YES it will fit a KA24E. There are some electronic connections to the engine through the ECU. In other words, I believe some of the shifting is controlled by the ECU to reduce emissions. You would probably need an automatic ECU I'm guessing. This is why I mention a Z series 3N71B. No electronics, fits KA engines. 1 Quote Link to comment
DATSUNgeo Posted July 7, 2022 Author Report Share Posted July 7, 2022 Thanks Mike! I’m getting such a good deal on this and it comes with everything, shifter converter and flex plate for $200 obo. They converted the car it came out of to a manual transmission. I have a friend that has done several 510 swaps helping with the ECU and wiring. Quote Link to comment
]2eDeYe Posted July 7, 2022 Report Share Posted July 7, 2022 Hello, I make the mounts you have. I also have a crossmember but the auto is bulky and the crossmember needs modified. It has been done though. Quote Link to comment
DATSUNgeo Posted July 7, 2022 Author Report Share Posted July 7, 2022 20 minutes ago, ]2eDeYe said: Hello, I make the mounts you have. I also have a crossmember but the auto is bulky and the crossmember needs modified. It has been done though. I’ll PM you, thanks. 1 Quote Link to comment
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