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KA24DE in 280z with stock transmission vs swapped transmission


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Hey Guys!

I am new here and I have a 1978 280Z.  It has a blown head gasket which I am in the middle of replacing, that and the timing chain.  After doing that I am thinking about swapping in a KA24DE.  I can get an engine,  harness, and ECU for about $300 at a local pick and pull.  What I am wondering is weather I can put the KA24DE in the Datsun with the stock 4 speed manual transmission.  I have read on this forum that the KA can fit in the 5 speed but is tilted the wrong way.  I am guessing that the KA will also bolt right up to the 4 speed?  I am pretty good at fab work and have my schools shop to work in.  I can also get a 5 speed from a 280zx or from a 240sx on craigslist, although the 240sx trans would require a custom shortened driveshaft and I am trying to do this on the cheap (or maybe could I just move the engine and trans forward 2 inches?).  My preferred method is sticking with the stock trans and bolting up the KA, could I do this and make a custom oil pan to accomadate for the odd angle?  Or would I have to tilt the stock trans?





Ps.   The reason that I am doing this is because I would like the MPG and reliability of the KA.

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...or just replace the headgasket and enjoy the MPG and reliability of the L28...


You will want to swap the transmission with it, as it has reliability and strength upgrades, as well as proper internal engine oil drainback. Also, the manifolds being on opposite sides of the engine will make it easier to use the KA bellhousing tilt. Use the stock driveshaft with the dust collar removed, move the shorter engine up 2 inches and be done with it...will drive exactly like a stock L28 and get about the same gas mileage.


Also, easy placement...just bolt the KA trans up to the stock transmission mount and you're located front-to-back. NBD, drive it home in a single day in the workshop.

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The L28 will have comparable mpg to the ka. If you still insist to put the ka in, then put it in with a ka tranny. The tilting you are referring to is if you bolt the ka tranny to an L28. If you think about how the engine is sitting in a 240sx, the tranny sits right when the ka is tilted. so just put the ka in with the same tilt.

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If I bolt the KA tranny to the stock transmission mounts would it sit 2 inches up or would I have to shorten the drive shaft for that?  Also would the shifter sit in an alright position, or would I have to cut into the tunnel to make it fit?  I am not adverse to cutting but I would like to shifting to feel normal.  One of the reasons I want to do the swap is because of aftermarket part availability, for the KA I can usually get performance parts on craigslist. Does the KA use the same slave piston as the stock trans or would I have to mess with that as well?  I do not mind messing with that much because I have to do clutch hydraulic work anyways 'cause the car has been sitting for a while.  I am at school right now so I have to go now.  Thanks for helping me guys, never done a swap before and am looking forward to it if I do end up doing it.  

Edited by ChickenCoupe
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When he says it sits 2 inches up, he means that the engine won't be as close to the firewall. It will sit closer to the radiator support. Won't really affect anything other than center of gravity since the S30 bay is so damn long.


The KA tranny is almost identical in length (if not the same) to an L series tranny. If you bolt the ka tranny using the L mount, then you will be able to use your stock driveshaft. You may need to cut the hole a little wider, but I highly doubt that. 


You would use the slave that is design for the KA tranny. I think it's the same as an L slave so the clutch line should work. If not, it would cost like $20 to make a custom SS line from the clutch hardline to the slave cylinder. 


What KA parts can you get that are easier to get than L series parts? if you're keeping it NA then basically you're only really looking at headers, which you can get for an L28 no problem. 

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I was hoping to build up a turbo in the future. I was thinking that the KA would be cheaper to do that.  I was thinking about an l28et but I really wanted to make my car different just cause, although I do really like straight sixes as well... I might change my mind when i get that l28 running (probably get it done this weekend) but I am not sure.  I guess the money that I spend on the KA could be spent putting a turbo on the L28.   I will think about it,  couldn't start looking for the motor in a yard til this or next weekend anyways. Thanks again for all of the help with this, this is my first Datsun or Nissan and I'm still learning about 'em.
off topic but does anybody know if the 280zx mustache bar and the 2 link mounting braces (I think that is what they are called, anyways #2 and #5 in the pic below) will fit my 280z?  there is someone on craigslist that has 2 280zx parts cars (one manual 5 speed non turbo and one auto turbo) and I cannot find any s30 parts cars.


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It will cost nearly identical for any HP level below 300hp. I converted my L28 to turbo, and I'm currently putting together a kit for my soon to be KA-T s13.


The only, price difference, and I mean only, it the engine management. For sub 300 you can use a simple RS enthalpy or similar chipped tune, while for an L28 you should almost immediately go to a standalone to save teh trouble unless you want a stock power L28 (or only a little above)


Unless you get a major deal on someone parting out their KA-T or selling as a group you won't be saving more than maybe a few hundred dollars.


Turbo headers:

KA $150 new Isis, L28 turbo mani $100 used (will support 300hp all day)


Turbo: Stock t25 from an SR $150, stock T3 from a ZX $150 (if you go brand new garrett, a T28 will be like $300 less than a T3)




SR20 370cc injectors $100, Turbo L28 injectors $100 (if you go with something larger, you can probably find sets of injectors for either an SR or RB for pretty much teh same price)



Stock KA intake free if you have one, Stock L28 turbo mani $100 maybe



There is no such thing as a real ready made kit, so you will probably buy an intercooler sized to fit, then some pipeing you can cut up to fit. Will cost the same with either engine.



Stock ones should run you less than $40


Exhasut piping:

Will pretty much be custom either way so roughly the same price


Fuel system:

Should get a new walboro and FPR for both cases, will cost the same


Just for reference, I honestly think the KA is worse than the L28 and I've owned both in NA form. Then again if it turns out your engine is fubar, then whichever one you can find for cheaper locally would be the better deal. you just need to fab some motor mounts for the KA and it will fit.


To answer your quetion: the 280ZX does not have a mustache bar, that's from a 280z. The 280zx is a completely different suspension. You should put a want add up on this site, zcar.com, and classicz.

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Okay thanks! I will finish (hopefully) the timing chain this weekend and hope that the head gasket was the only thing wrong with it. The car was sitting for about 15 years before I got it and It was momentarily a parts car (that's where the mustache bar went) and i am not sure of the condition of the motor, I did a comp test and cylinders 1 and 2 were both at 60 so I guessed it was a head gasket and jumped into replacing it. If it turns out that there was something else I will probably just drop in whatever I can find like you said.

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  • 2 weeks later...

As far as choosing between ka and L series engines stock the L series has a little more power but not much. As for a turbo build if your looking for 400+hp ka is better you won't have to worry about snapping crankshafts. But the ka weakness is it's rods pistons and head gaskets. So keep in mind that if your going to boost the stock ka with no internal work then your not going to make much above 240hp without risking blowing it. The L series however can and will make 300hp with little to no internal work reliably.

Edited by Driftinrican
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As for a turbo build if your looking for 400+hp ka is better you won't have to worry about snapping crankshafts.

I've never heard of an L6 snapping a crankshaft.  I get most of my information from the world-wide web though.  Do you have any examples?  And I've read about quite a few L6 head gasket problems.  Some pictures or links would be interesting.  Always looking to learn something new.

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