1990 D21 KA24E into 1984 720

[frankendat]

I have been a hard line lover of the Z24 and still believe it is a worthy motor, but an opportunity has presented.

 

The plan, as of today (if this doesn't jinx it) is in the next week or so, to travel to a semi remote location and remove parts from a 4wd 1990 D21. The D21 has the KA24E and axle code CA41 (so 4:11's) It has the 71C transmission with the integrated transfer case.

 

I have a 4wd 1984 720. My 720 has the Z24 and axle code CA41. It has the 71B transmission with the divorced transfer case.

Additionally, I have a 71C from a 2wd D21, and multiple KA24E ECU's, harnesses, and throttle bodies (Although the plan would be to yank the motor complete with all accessories attached.

 

Travel to and from the D21 will be a pain and staying on site is not an option. The truck will be scrapped after I take what I want. I envision more "cutting out" and less "taking out". There is said to be a crane on site to lift the motor. Absent better ideas, my thought was to set it on a couple tires in the back of my (full size) pickup and use ratchet straps to keep it in place.

 

My questions for the Ratsun Brain Trust:

1. What items are MUST grab to make a swap happen?

1a. What items should I avoid hacking off when removing the engine?

 

2. What items are NICE to grab and make a swap happen?

 

3. What items are GOOD to grab, if there is time, or for spares?

3a. Are the 1990 CA41 4:11's an improvement over my 1984 CA41 4:11's

 

4. There is a very good chance that this will be a one man show. I have never worked as a professional mechanic and engines I have pulled in the past, have been accomplished a little here a little there. I am hopeful that the ability to cut drivelines or cut the transmission housing off, cut motor mounts etc. will expedite this engine snatch/parts grab. Think it could be done in a day or two? (sun up-sun down)

 

 

[bottomwatcher]

Grab all the sensors. Something that doesn't look important might be and if everything is up for grabs grab it.

[datzenmike]

You can cut the rad hoses and just replace them. Sawsall the exhaust down pipe but keep as much as is prudent... You will need to join to your Z24 pipe. Keep the throttle cable the Z24 one may not reach. The EFI wiring is mixed in with the engine harness, might take all day to disconnect and pull everything through the firewall. Perhaps cut the engine and the ECU free and join them later at home? Get engine brackets and rubber mounts they might fit the 720. Keep flywheel and the release bearing and collar from the transmission.

 

The rear differential can't be removed like the H-190 unless you remove the entire axle.

 

 

 

 

 

 

[frankendat]

2 hours ago, datzenmike said:

You can cut the rad hoses and just replace them. Sawsall the exhaust down pipe but keep as much as is prudent... You will need to join to your Z24 pipe. Keep the throttle cable the Z24 one may not reach. The EFI wiring is mixed in with the engine harness, might take all day to disconnect and pull everything through the firewall. Perhaps cut the engine and the ECU free and join them later at home? Get engine brackets and rubber mounts they might fit the 720. Keep flywheel and the release bearing and collar from the transmission.

 

The rear differential can't be removed like the H-190 unless you remove the entire axle.

 

Excellent! I have a KA24E harness already. I talked to a gentleman who said always replace the release bearing when changing transmissions. Was this bad, or unnecessary advice? Have you ever heard of someone cutting the transmission free? Unbolting bell housings was rough on my 620 and on my FJ40. Since I'm in scrap it mode, I have been looking for shortcuts. Sawzall to the aluminum transmission bellhousing came to mind. OR Sawzall the front fenders inner/outer to expose the engine.

When I mentioned trading axles, 84 CA41's w/ 90 CA41's I was talking about the complete units. Would there be a benefit? Should I wait and if swapping swap for a R200 HB233 combo? 

 

 

 

 

 

 

[frankendat]

3 hours ago, datzenmike said:

You can cut the rad hoses and just replace them. Sawsall the exhaust down pipe but keep as much as is prudent... You will need to join to your Z24 pipe. Keep the throttle cable the Z24 one may not reach. The EFI wiring is mixed in with the engine harness, might take all day to disconnect and pull everything through the firewall. Perhaps cut the engine and the ECU free and join them later at home? Get engine brackets and rubber mounts they might fit the 720. Keep flywheel and the release bearing and collar from the transmission.

 

The rear differential can't be removed like the H-190 unless you remove the entire axle.

 

 

 

 

 

 

Is it really this easy? 

 

[]2eDeYe]

Take as much as you can fit in your ride back home. 🙂

Getting them out is pretty easy and quick, getting them back in on the other hand....

[datzenmike]

You need a fuel tank with the in tank high pressure pump for the KA EFI.

 

Optional...

 

Get the front calipers/rotors and hubs for spares or casting deposits.

You have to remove the radiator anyway so if not leaking keep it as well.

 

[Wildcat Walker]

I did a KA24DE swap in a 720 several years back. Wiring it up was NOT like wiring an SR or KA swap into a 620 or 510. Sure the engine harness remains the same, but the chassis and Z24 engine harness on the 720 is much more complex. There may be a write up out there now but there wasn't at the time. I spent a few days in the garage scouring over wiring diagrams, labeling, testing, splicing, and wrapping. In the end the only issue was I forgot to provide 12V+ to the coil packs, but that was easily remedied. Just know, the wiring is not hard if you can solve problems, but if you easily lose focus or lack patience, you're gonna have a hard time. 

[bottomwatcher]

Good call on the downpipe Mike. When the ka goes in the 720 the downpipe goes directly into the frame. This means a ridiculous amount of pie cuts and welding. If it is rusty? I really haven't found a good source for a new one.

[frankendat]

22 hours ago, bottomwatcher said:

Good call on the downpipe Mike. When the ka goes in the 720 the downpipe goes directly into the frame. This means a ridiculous amount of pie cuts and welding. If it is rusty? I really haven't found a good source for a new one.

I missed the downpipe post, do you mean the downpipe on the gas tank? Do you have (or know of) pictures of this procedure?

[bottomwatcher]

No from the flange at the bottom of the exhuast manifold. The ka dumps the exhaust directly to the frame.

[frankendat]

Met the D21 owner today and purchased it. Much like hunting, I waited and scouted and waited and investigated; took the shot, and the work begins. I didn't count the sale as finished until today, after money was exchanged and documents signed. 

 

1. In the threads about KA swapping a 720, I don't recall the exhaust pipe into the frame. Is that considered the way?

2. Are there easier methods than pulling the bed, to reach the gas tank? (To remove the tank in a Dodge, I took a grinding wheel and cut a square out of the bed. The after midnight operation on the side of the hwy was successful and the wave of sparks from the wheel kept the area illuminated. The sparks, also, keep me alert, focused and awake, trying to think of ways not to die. )

3. Still curious if the 90 D21 CA41 axle/diff is the same as a 84 720 CA41 (besides 6 years younger)

 

If there is a part of a 1990 D21 that your looking for, hit me up and deals will be made. 

[datzenmike]

RE: exhaust pipe into the frame. Weird but I think what's meant is the pipe doesn't clear the frame and has to be cut and welded.

 

 

The 4wd C200 in the 720 were two pinion, the D21s were 4 pinion through '93 when replaced by the H-233 same as the VG

The 2wd were all H-190

[frankendat]

5 hours ago, datzenmike said:

RE: exhaust pipe into the frame. Weird but I think what's meant is the pipe doesn't clear the frame and has to be cut and welded.

 

 

The 4wd C200 in the 720 were two pinion, the D21s were 4 pinion through '93 when replaced by the H-233 same as the VG

The 2wd were all H-190

I kept imagining the pipe running in the frame the frame becoming the exhaust tube. The pipe bending or cut spicing to clear the frame rail and run the exhaust like a regular exhaust sounds better and sounds easier.

 

Is it true that a 4 pinion is better than a 2 pinion and an H-233 better than a 4 pinion? I like the H-233 replacing the middle without messing around with shims and such, as I understand it the H-233 is used for the rear is there a similar style of diff/axle (replacing middle) for the front? The R200?

[bottomwatcher]

Don't worry. The exhaust into frame will become obvious when you install the engine.🤔

[datzenmike]

Four pinion spreads the load better. The H-233s are all 4 pinion.

 

The D23 and WD21 use a shortened R-180 or R-200 front differential, so won't fit the 720.

[frankendat]

6 hours ago, datzenmike said:

Four pinion spreads the load better. The H-233s are all 4 pinion.

 

The D23 and WD21 use a shortened R-180 or R-200 front differential, so won't fit the 720.

Au contraire monsieur datzenmike, the R-180 or R-200 will fit a 720 with a custom front driveshaft. Will it not?

[datzenmike]

What I said was still true. Let me rephrase "It's not a 'drop in' swap." By your reasoning a 426 Hemi fits a 720. Anything can be made to fit with a wire feed wrench.

[frankendat]

2 hours ago, datzenmike said:

What I said was still true. Let me rephrase "It's not a 'drop in' swap." By your reasoning a 426 Hemi fits a 720. Anything can be made to fit with a wire feed wrench.

"wire feed wrench" I like it. I too, enjoy the "will this work?" posts, as with enough time and/or enough money anything will work. I only responded to your last, because we discussed this in another thread, that the later model "better" axles are able to be swapped into an 720, so long as you:

 

1. Relocate spring perches 

2. Understand additional width

3. Length change on front driveshaft

4. (pending) ujoints?

 

According to the door tag the 1990 has 4:11's, same as I have now, but six years newer. I am pulling the bed for scrap and for access. (I might not scrap it, if the bed hard to wrangle solo). Sounds like "grab'em" is the name of the game. As for the body, the driver's door is shot, passenger door looks alright, front fenders look ok as well as grill. I'll put up an ad in the "parts" section 

[bottomwatcher]

Well if you can grab the fuel tank it should be larger and has the fuel injection pump located in it. Quieter than an add on external pump. If you grab the bracket that holds the tank it should be any easy retrofit. I have not done this myself but it is on the list.

[Stoffregen Motorsports]

Keep it simple and try to connect the fuel tank as it was in the donor truck. Don't short cut any return lines or breather hoses. If it has an EVAP line, run it up into an EVAP can, (which you can buy generic, think Dorman) or up into a breather valve or even into the filler neck.

 

Wiring - I would use the entire D21 harness and integrate it into the 720. No, I haven't actually done it on a 720, but I have done it on other vehicles. It's sometimes easier to connect the old gauges, tail lights, turn signals, etc to the new harness than it is to weed out the two harnesses and integrate them into one.

 

It's always easiest to swap with a donor vehicle handy.

[bottomwatcher]

The hardbody engine harness and chassis wiring are supposed to be one loom and difficult to separate. That was the reason the 240sx intake with its stand alone harness for the engine was popular. You are chasing down a wiring and intake offered only 89-90. That's 34 Years ago. That being said FB marketplace has some local to me now I just need to resist the hoarding gene. 

[frankendat]

Still trying to make best use of what I have horded over the years. I have multiple intakes and multiple heads and a couple different harnesses, but this is my first Nissan swap. Using KISS, transferring from the donor to the 720, as directly as possible appears the way-unless great minds differ?

[bottomwatcher]

https://www.facebook.com/share/jcPKnKBM1gCaNhjJ/?mibextid=kL3p88

 

Thankfully this sold and I think the price was a little high but this manifold, engine harness, ecm and can am box and you would have a running kae 

[frankendat]

4 hours ago, bottomwatcher said:

https://www.facebook.com/share/jcPKnKBM1gCaNhjJ/?mibextid=kL3p88

 

Thankfully this sold and I think the price was a little high but this manifold, engine harness, ecm and can am box and you would have a running kae 

I admit that I am new to fuel injection and often go down avenues trying to save a buck or two that wind up costing more in the end, but I have multiples of the parts mentioned in that ad. The only part that I am not 100% sure on is the "can am box", but that might be confusion in terminology.