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1985 720 KA24DE Build


Atma

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So let me preface with: This is my partner's build, but he doesn't really do forums so I'll attempt to document it here.

 

Vehicle: 1985 Datsun 720 King Cab 4WD

Motor: 2002 Frontier KA24DE

Wiring Harness/ECU: 2000 Frontier KA24DE

 

We scored an entire Frontier wiring harness w/ manual ECU out of a 2000, everything forward of the taillight harness so we're sitting pretty there.

 

So this all started with a desire to do an L28ET swap, but, well, we're not quite up to extending the frame rails.  Which led us to a KA24DE.  Looks, from reading the forums, pretty straight forward on a 2WD.  On the 4WD, the oil pan is going to be a pain that requires custom fabrication so far as we can tell.

 

Where we are right now: BHG Z24 out and torn down for inspection/parting out, KA24DE ordered and awaiting arrival via freight.

 

Pictures so far: https://imgur.com/a/SNwOnS5

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Another decision made: Getting the manual steering rack and intermediate shaft so that we can avoid having to plumb power steering with the swap.  Working on that today.

 

Plus the motor will be here on Monday 7 December!  Progress is being made.

 

If anyone needs Z24 partout parts please contact me!  We've got a whole Z24 we need to make go away and would rather not ditch it for scrap.

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Have you looked at electric power steering? A prius/yaris steering motor might be a great option.  They can be fitted under the dash or out on the engine bay, anywhere along the steering shaft you can fit it.

 

Those are becoming really popular swaps, lots of info out there on using them.

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The KA has landed!  Fresh off the slow boat from Jersey comes a 140k mile specimen...which doesn't look too horrible all in all.
 

Mechanically it looks pretty complete.  All the brackets are there, although the power steering pump's pulley is fragged, but we're not keeping that system either so that really doesn't matter.  The a/c ompressor bracket is bent so we'll just have to use the Z24 bracket.
 

No exhaust bits came with it, and the EGR pipe was chopped so we're kinda forced into getting the blockoff plates for it regardless.  This also means having to find a header that will fit in the 720 without fouling against anything.
 

Obligatory head casting and block serial number shots, because why not document Everything™ while we're here?
 

The oil pan is definitely from a 2WD Frontier, so kitbashing a pan between the Z24 sump and the KA24DE mount has to happen.  Unless by some miracle the 4WD KA24DE oil pan can fit around the 720's front diff, but just from looking at pics I doubt it can.

 

Images can be found at https://imgur.com/a/QpuHdpa

 

So, open questions raised by this:

• What exhaust header can we use that will fit around the differential, steering shaft, etc?

• That 'little' problem of the oil pan, so far I don't see any other 4WD D720 KA24DE swaps so I'm hoping I've just missed a thread and someone has done this

 

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  • 1 month later...

Alright, slow updates but we're still working on it.  As far as I can tell this may be the only KA into a 4WD 720 that's been done.  The wife is going to have to kitbash the timing section of the KA oil pan to the rest of the Z24 pan.  Thankfully the Z24 sump bolts perfectly to the truck KA and the Z24 pan bolts right on except for the timing area.

 

So then we're going to cut each and weld them together to get one oil pan that will fit around the front diff and bolt to the KA.  Pictures and walkthrough will come once we work through it.

 

Other thing we're working on is swapping the lower section of the steering column and the steer box for a manual one -- keeping the top part to keep tilt steering.  Using it as an opportunity to replace that old u joint while we're at it.  Wouldn't bother otherwise but this simplifies the swap.

 

 

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  • 4 months later...

Steer box swap was a bust -- the power steering had an entirely different set of links.  So that sucks.  But found a friend rebuilding a manual steering 720 so gave the box to him; not a total loss.

 

On the other hand, the oil pan was a great success.  It seals and it's beautiful after powder coating in a metallic version of Nissan Blue.

 

GD4HIYr.jpeg

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Looks like you did a great job of mating the stock nap 4x4 pan to the ka pan! Do you have any pictures of the oil pickup tube? I am guessing it needed moding. I am currently trying to do the same swap in an 85' as well. Any pics of the oil pan fabbing and oil pickup would be greatly appreciated!

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Actually, the Z24 pickup bolts right up to the KA24DE bottom end and everything fits properly!

It's pretty amazing how similar these motors are in the bottom end; honestly I think that's the saving grace of even attempting a swap like this.  Wife is credited for all the work though, I've never lifted a welding tool before.  She's the one that did all that. (=

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  • 3 weeks later...

85' 4x4 720 here, I'm looking to do exactly what you are doing. I didn't expect the power-steering to be a problem though. It would be nice to keep but wouldn't mind that sacrifice.  Doesn't the Z24 pacesetter header bolt up to the KA24DE? I think I read somewhere it might be true.

 

@Atma

 

So the Z24 pan actually bolts right up to the bottom of the KA24DE? 🤯

 

If that's true, this swap will happen a lot quicker haha.

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I wouldn't think any napz intake/exhaust manifolds bolt up to the KA24DE...

 

Also Atma was saying that the oil pickup tube bolts onto the KA24DE block, not the oil pan. You have to cut the bottom part off the old 4x4 napz pan and weld it up to the flange of the KA24DE. 

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@Logical1

 

AH yeah, sorry I was thinking of the SOHC KA24 has the same exhaust stud patterns.

 

Oh okay, thanks for clearing that up. 

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  • 2 months later...

The KA oil pan will need to be modified to clear the front 720 differential. Perhaps a KA 4x4 oil pan? would be a good place to start?

 

Both the 720 with Z24 and the KA engines both came with 5 speeds. The KA will bolt to the 720's 5 speed but a KA 5 speed is stronger. Either will work but will require the drive shaft to be either lengthened if a truck or shortened if a car transmission

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Ok, to clear up the oil pan issue.

 

The magic is that you use most of a Z24 4WD oil pan, with the exception of the nose.  To cover the timing chain section on the KA24DE you need to cut the nose off the KA24DE pan and weld it to the Z24 oil pan -- otherwise they fit up nicely.  You also have to use the Z24's oil pickup, which bolts up just fine as well.

 

Good luck!

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