How to: KA24DE swap into 720

[Crytek89]

Hey Guys,

 

I finished my KA24DE swap into my '84 720 KingCab (June 2017) and based on the information that I could find, the swap still proved to be an advanced undertaking.

 

With that said, this community has helped me so much to achieve the vision I pictured for my truck the day I first saw it - I knew it was going to need more power for my young 20's (and now 30s) self and the KA certainly provides that.

 

This guide is still a work in progress and as I begin my first few thousand kms in the truck I'm sure I'll be doing some editing (edited Feb/22) to make parts more clear and understanding. Please bear with me while we work on the best how-to guide we can for others to enjoy and reference.

 

 

 

 

 

 

 

 

 

Full story on the truck and rebuild of the engine itself: 
http://imgur.com/a/gBCD5

http://community.ratsun.net/topic/68278-1985-720-engine-swap/

Edited February 14, 2022 by Crytek89
Clarification; Grammar

[Crytek89]

Tools required

·        Engine hoist

·        Engine stand

·        Acetylene Torch

·        Socket set – Metric up to 27mm

·        Wrench set – Metric up to 24mm

·        Pliers, Vise grips; general hand tools

·        Stick welder and/or MIG welder

·        Vehicle hoist or alternative method to raise the vehicle (Jack/Jack stands etc)

·        Angle grinder

·        Table Vise

·        Wiring accessories

·        Timing light (recommended, not required)

·        Multimeter

·        Torque wrench

·        3/8 & 1/4 ratchet wrench

Edited July 23, 2019 by Crytek89

[Crytek89]

Parts required

·        KA24DE; block, head, intake, exhaust manifold, wiring harness, ignition coil, power steering reservoir (if applicable), all other stock engine accessories (Rebuilt recommended but not a requirement, conduct maintenance as required.)

·        D21 oil pan and 240sx oil pan

·        Power steering lines from 240sx (if applicable, or your local hydraulic hose store)

·        CAN/AM wiring box (icehouse)

·        KA24DE engine mounts ([2eDeye: IG Ratsun)

·        Heater Hose

·        Vacuum lines

·        High pressure (50psi min) fuel lines

·        Fuel Injection applicable fuel pump + filter (recommended: Walbro 255l)

·        Steel plates – ½" thick, 3x3" *

·        2.5in exhaust/steel pipe (Cold air intake)

·        10-gauge wire w/ inline fuse 70amp (wiring box)

·         Zip ties

·        1.5in diameter washers x12 

·        Z24 Throw out bearing

·        EGR delete plate

·        Dual core radiator (recommended) 

 

*Only required when lower engine mounts are old/sagging/worn out. If lower mounts are like-new condition, then this is n/a.

Edited February 14, 2022 by Crytek89
Clarified requirements;

[Crytek89]

Where to start?

 

 

 

You’d like to begin with ensuring you have all the required tools and parts listed above; this will include all your hoses, vacuum lines, accessories wiring parts etc.; Over preparing yourself is going to be the best strategy for this swap.

 

Start by taking photographs and tagging all your lines that will remain in the engine bay once you pull your old engine – this includes vacuum lines and existing wires.

 

Pulling the old engine should be straightforward – reference your Nissan FSM for engine removal.

 

Once the old engine is out you can begin reviewing how your new KA is going to fit. Take measurements and adjust or remove anything as needed to ensure your engine will go in smoothly. This would also be a good time to review any last minute issues or connect any accessories onto your KA which would otherwise be difficult later on. Installing the intake manifold prior is at your own discretion.
Be aware the KA starter bolted from the rear, so on your new one drill out the two holes on the starter so that you can thread them into the Z24 transmission.

 

If you previously had power steering this would also be a good time to remove existing power steering hard lines.

 

 

Be aware that due to the placement of the transmission in its stock location and size constraints, this guide will be purely for KA engines in which EGR is deleted. Swapping is possible with EGR intact, but a transmission adjustment or firewall push will be required.

 

 

 

All the vacuum lines on the rear of the KA and the EGR pipe from the exhaust to the intake manifold will need to be removed; this includes swirl valves and secondary butterfly valves on the intake manifold. EGR Block off plate is recommended otherwise you can simply bolt a piece of metal to the old EGR plate where the swirl valve connected.

 

 

 

 

1. You can either block off this plate and retain the cast piece, OR

2. You can remove this and create a block off plate on the manifold itself.

 

 

 

Prep the KA with the intake manifold and exhaust manifold removed* prior to installation for ease of access connecting the engine mounts.

Install the KA into the engine bay with the passenger engine mount attached and small pieces of plywood under the cross member and connect the engine to the transmission (you can do this with the transmission out of the vehicle but I left it in place to save on time).

 

To ensure the mounts are set properly, slide between 5-6 washers under them to raise the mounts up slightly upon installation, otherwise they will be at a 30° angle to the stock rubber mounts.**

 

*Intake manifold can be installed prior, but will increase the difficulty of installing the engine mounts.

**Only applicable if lower engine mounts are old/sagging/worn out, otherwise disregard.

Edited February 14, 2022 by Crytek89
Clarification; grammar; image added;

[Crytek89]

Engine (loosely) installed - cont.

 

 

 

Your next steps will be to install your alternator, power steering pump (if applicable), belts and exhaust manifold.

 

You can also connect your power steering lines from the KA if you have them (I cannot confirm at the time of writing on whether the KA p/s lines will connect to the 720 power steering as I used custom ones and re-threaded it.)

 

You can now re-install your radiator and positioning how you’d like it to sit in the vehicle, ensure you have enough clearance if you’re going to use a clutch fan.

 

Connect your heater hoses, alternator wiring, oil pressure wiring and starter wiring.

 

Be aware the alternator, oil pressure and starter wiring will connect to the existing 720 wiring and NOT the wiring on the KA harness – you will need to change over the plugs from the KA harness to the 720 harness.

 

 

There is also a PCV/Breather Separator on the block that originally fed back into the intake manifold you can either reconnect this once your intake is installed or put a hose on with a bolt to seal it off.

 

Once this is complete you can now install the intake manifold to the head and bolt it in place if not previously done; It is a tight squeeze, I recommend using a universal style socket to better torque the bolts into place.

 

Now you can connect your fuel lines – reference your 720 FSM on which one will be feed and which will be return to connect to your intake manifold. Now, I recommend taking a break from the engine bay and removing your old fuel filter and fuel pump with the new one, located on the passenger side just before the rear wheel; being that the filter and pump are located below the tank, in terms of height, put a pair of vise grips on the fuel line before the filter to ensure it’s not going to soak you. You will also need to remove the old line from the pump to the hardline with your new 50psi hose.

 

Moving back to the engine bay you may now install any other accessories you have left including your spark plugs, plug wires, ignition coil and power steering reservoir.

 

At this point you should begin to see how your engine is finally going to look as a finished product.

 

Finally, we can start on wiring the engine – using the harness you received with the KA, start with the injectors and connecting/bolting it down – this will be your base point on where all the other wires are going to go – 99% of these will easily find a home to connect to and within an hour you should have all your plugs connected.

 

Next, you may move onto the wiring of the CAN/AM box and I recommend checking out Icehouse’s thread on how to wire it, although here are some photos of mine wired up – there will only be 2 plugs you will use from the KA harness.

 

 

 

 

Finally we can begin all the final bits such as your cold air intake, exhaust downpipe and any other tweaks, zip tie lashings etc. you’d like to make.

Edited February 14, 2022 by Crytek89
Images added; Clarification; Grammar

[Crytek89]

Additional modifications required:

 

The KA is not a *direct* fit into the 720 as I'm sure many other people have figured out - while it will bolt to the 5 speed transmission (FS5W71C), your oil pan will require major modification to work and this will impact how you will need to approach adjustments on your truck itself.

 

This section will highlight what those additional modifications will be and how to best ensure their proper application to best prepare for your swap.

 

 

Oil pan:

The Oil pan as we know won't work - both due to the sway bar and steering linkage and due to the Z24 oil pan not being long enough for the block. You will require the D21 (KA24E) oil pan as well as your KA24DE oil pan. The other option is simply removing your sway bar, however this is not recommended, nor endorsed.

 

 

Start by ensuring that both your oil pans are clean of any residual oil or debris - this will include both the inside and outside - I recommend using a wash basin and wipe clean with shop towels/rags (relatively clean ones).

 

 

1. With your KA24DE oil pan - you're going to want to cut a straight line ½" above the bolting lip. This will result in you being left with the part which will eventually bolt to the block.

 

2. Next, on your D21 oil pan - do the same however measure 1 ½" from the lip and make an even cut all the way around.

 

3. On the D21 oil pan the lower portion will not have enough height to clear your new rear sump setup - begin by cutting directly where the sump of the oil pan meets the lower portion in the middle. This will leave you with a large, rectangular shape open. This opening should begin at the front and bottom of the sump, and extend all the way to the front of the oil pan and come down to meet the lip. 

I highly recommend doing this prior to installing the engine, or if available, a spare KA block.

 

 

(HQ Image w/o indications: https://i.imgur.com/VnFkw5y.jpg + https://i.imgur.com/uKMF52F.jpg)

 

Now you should have 4 pieces that you're going to join together.

 

Begin with welding the KA24DE lip to the D21 pan. 

Make sure your placement is correct to ensure this will be a rear sump setup to clear the cross member. If possible, bolt to a spare block to prevent warpage, or hold down on a table with vice grips. 

 

Only weld the outside of the pan itself, the inside will not require it and doing so will lead to problems when you make up your rear sump.

 

Ensure your pan is clear of any debris from welding/grinding prior to any fitment to the block itself - you can wash it, or blow it out with compressed air.

 

Continuously check to see how the pan measures up with how your intended rear sump pickup will be installed. You will want to review how you're going to create your rear sump to ensure you have enough clearance when you weld the final piece to the oil pan.

 

 

Rear Sump:

Begin by taking your old KA24DE oil pick-up and cut off the pipe connecting to the oil pick-up leaving about 1" of pipe to work with remaining.

 

On the crank girdle you will notice further down there is a bolt hole where it will now connect to your rear pickup. For easier reference you can bolt it to the girdle to swivel and review the angle of the pick-up tube.

 

Where your previous sump connected to the oil pump cut off the pipe leaving approx. 1/4"-1/2" of pipe remaining - cut at a 30-40° angle towards the rear.

 

Next purchase the same diameter steel pipe (do not use the old EGR pipe, there's too much carbon) and begin reviewing how you're going to join the two pieces - I recommend using the acetylene torch with some wire much the same way you'd use a soldering gun.

 

Upon each weld you make on the rear sump - air cool for 20-30sec then dunk in water to retain steel strength.

 

Once fully welded up and keeping as low as possible for the oil pan clearance remove your new rear sump and check for vacuum to ensure there are no leaks.

 

 

Oil Pan pt.2

Now that your rear sump is finished have it bolted to the block and place your new oil pan over top as it would when fully finished.

 

You can now see how you're going to weld on the final piece to ensure you have a fully operational oil pan - you can weld it either as a full piece or cut into 2 pieces length-wise to achieve this.

 

Check for leaks with a bit of gasoline in the pan - once confirmed, clean the pan once more and attach to your block.

 

 

Updated Photos coming soon. Oil pan photo pre-frame swap.
 

 

Engine Mounts

 

The engine mounts I used, I purchased from ]2eDeYe and was very pleased with the overall build quality.

 

Initially I had issues with these mounts, however that was due to the fact that my lower mounts were old and worn out.

I have since upgraded my lower engine mounts and have reverted any previous modifications to ]2eDeYe's mounts.

 

 

I will retain the below photos for the time being, however I will be updating these with the current placement in the near future (Jan/2022)

 

Drivers side engine mount:

 

Passenger side engine mount:

 

You can also see from this image how the washers raise the mount up to be square on the existing 720 pad:

 

Edited February 25, 2022 by Crytek89
Clarification; Grammar; Image added; Links added;

[flatcat19]

TL;DR. Send pics.

[]2eDeYe]

Three are pics for you in the first post :lol: 

 

 

Nice write up  :thumbup:

[Charlie69]

What you have is a 720.  The hard body is the next generation Nissan truck (D21).  The 720s ran from late 1979 to early 1986.  The hardbody ran from late 1986 to 1997.

[Crytek89]

What you have is a 720.  The hard body is the next generation Nissan truck (D21).  The 720s ran from late 1979 to early 1986.  The hardbody ran from late 1986 to 1997.

Thanks Charlie, edited ;)

[]2eDeYe]

I haven't had anyone have to modify my mounts like that. Can you tell me what drove those modifications? 

[Crytek89]

I haven't had anyone have to modify my mounts like that. Can you tell me what drove those modifications? 

 

Rather than pulling both the transmission and the engine I simply pulled the engine and put in the KA. I believe most who have used the mounts on the 720 pulled the transmission along with it and while that will allow the mounts to line up, causes the transmission to shift off it's original mounting points by a few degrees.

 

I personally didn't want to mess around with transmission removal so I just put in the engine and had to adjust that drivers side mount to work.

[]2eDeYe]

That makes sense then :lol: 

[Evo Chico]

I am considering dropping a Frontier ka24de into my z24/Weber powered '86 720 and mate it to the L4N71B auto trans I installed a few years ago. From what I see the mechanical installation may not be so much of a hurdle but the wiring puzzle has got me feeling squeamish before I even start!  I don't suppose any of those little boxes are around anymore or is there an alternative?  I'm considering just keeping my fine running z24 but that extra 40+/- horses would be nice!

[Lockleaf]

Send a PM to Icehouse for a can/am wiring box.

[Charlie69]

Nice write up.  Pictures would be a big help.

 

Went to both imgur links posted above and both links have the same content, engine build pictures.  Is there a link to pictures of the actual swap.?

[tgaydos]

now that it's been awhile how's the truck running/driving? i've heard of many having oil starvation issues with swapping/cutting the oil pan. i'm looking to do a ka in my truck. 

[Crytek89]

On 5/12/2018 at 7:45 AM, tgaydos said:

now that it's been awhile how's the truck running/driving? i've heard of many having oil starvation issues with swapping/cutting the oil pan. i'm looking to do a ka in my truck. 

 

I had to replace the front main seal last month (August 2018) but other than that I've had no issues to speak of with the swap.

Still slowly working on a few things (fuel consumption) and probably going to install an aftermarket fuel rail with pressure regular to assist in that regard.

[tgaydos]

that's awesome, i ended up getting a single cam ka for mine out of a 92 pickup, hoping to drop it in and get it fired in the next week or so. 

[Crytek89]

Nice! At least with that you're not worrying about the oil pan, should give it some pick-me-up!

[Charlie69]

Excellent additions to the original write up!

[720_potter]

bro, ive been looking for someone to look off of for this engine since I wanted to do the same thing but everyone told me to do a ka24e swap from the hardbody truck. im so excited now to start my build seeing that you did it, and it inspires me to do it more now.

[AtomChurch]

I am also curious to why you needed to modify the motor mounts

.. You seem to understand how and why to modify things specifically, hence the the oil pan being so well designed. 

 

However, what clearance did you need to make for the brackets you bought?

[]2eDeYe]

On 6/23/2017 at 8:27 AM, Crytek89 said:

 

Rather than pulling both the transmission and the engine I simply pulled the engine and put in the KA. I believe most who have used the mounts on the 720 pulled the transmission along with it and while that will allow the mounts to line up, causes the transmission to shift off it's original mounting points by a few degrees.

 

I personally didn't want to mess around with transmission removal so I just put in the engine and had to adjust that drivers side mount to work.

 

 

5 hours ago, AtomChurch said:

I am also curious to why you needed to modify the motor mounts

.. You seem to understand how and why to modify things specifically, hence the the oil pan being so well designed. 

 

However, what clearance did you need to make for the brackets you bought?

 

 

It's always best to install the engine and transmission as a package. Once they are positioned and all mounts are installed loosely you can then tighten everything up. 

Not doing that can result in bolts not going in and fighting one side or the other.  

It also helps to use brand new rubber mounts and with the 720 mounts you have to grind off the little clocking nub. 

[Crytek89]

6 hours ago, ]2eDeYe said:

It's always best to install the engine and transmission as a package. Once they are positioned and all mounts are installed loosely you can then tighten everything up. 

Not doing that can result in bolts not going in and fighting one side or the other.  

It also helps to use brand new rubber mounts and with the 720 mounts you have to grind off the little clocking nub. 

 

For most applications I certainly recommend installing as a package, the reason I installed separately is that I heard of issues with the transmission not being proper positioned after installing with the KA.

 

Absolutely recommend new rubber mounts if you can find them - it'll be something I'll have to replace in the future as when I swapped my engine none of the parts places in my area had them available.