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1985 720 engine swap


Crytek89

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Hey Guys,

 

First time poster, been on here browsing for a little bit before I decided to make an account.

 

I'm doing a KA24DE swap on my 720 and wanted a place to post updates and get feedback/assistance (looking at you Datzenmike) :P

 

 

A little backstory to start.. I moved to VanIsland and my gramps asked if I wanted a pickup that he purchased from his friend for $300, came with an '83 parts truck with a running engine and quite a few spare parts. I had never previously owned a Datsun/Nissan before but I liked the look of the truck and the price was awesome.

 

Didn't do much work to it until a year later and after getting a decent job started to think of a vision for it.

 

Currently has new Tires/Rims, NRG steering wheel w/ quick release, new Shift knob.. couple other goodies.

 

 

v5VBv7Qh.jpg

 

a1GNmjvh.jpg

 

First KA I picked up - was a rebuild with a blown crank (Bushing was never installed on piston #2)
9Xeulbjh.jpg

 

L3kjtmwh.jpg

 

Second KA, currently in the machine shop getting the head re-done. (slightly blurry, sorry)

CrjNcWYh.jpg

 

I'll post updates as soon as I can. Aiming for the swap in February/March.

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Welcome to Ratsun Crytek.

 

I don't often see a 720 round here, and none as nice looking as yours. Has an '83-'84 bed on it I see.... fits and look alright.

 

I see both KAs are from S13s or S14s. Car KAs have floating piston pins while the D-21 Hardbody truck engines do not. The floaters have a bushing on the rod that the pin slides into. Truck rods have press in pins.

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Thanks Mike,

 

Yeah it was kept in a garage for a number of years before I took possession of it, I know my gramps replaced the box on the truck at some point.

 

Both of the KAs are S13s, fingers crossed I get the parts back tomorrow.

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  • 2 weeks later...

So I just got word back from the shop - I had two KA24DE heads, one was better than the other. They recommended to redo the valves, seats, springs, re-plane the head and clean out all of the exhaust/intake ports for a grand total of about $650, taxes in. (CAD)

 

Hopefully it doesn't take too long and then rebuilding can finally begin.

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  • 2 weeks later...

Hey guys,

 

been a bit since an update - Valve cover and intake manifold is back from my friends welding shop - all sandblasted down and cleaned up.

I'll have it sent to his dad's power coating shop to have painted next.

 

Front valve covers are back from the machine shop. Still collecting funds to have the head re-done.

 

Still deciding whether or not I'm going to replace the pistons or not..

 

obiB6Emh.jpg

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  • 1 month later...
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  • 3 weeks later...

isn't there an oil pan clearance issue with the 240 KA that it's a front sump oil pan. Or would it be a tight fit? I just here from other people that oil pan clearance is kind of an issue.

 

You are correct, the stock KA oil pan won't clear. I have two options that I'm considering.

1) cut the stock oil pan and weld on a portion to clear

2) cut the stock oil pan and make it thinner with a secondary tank to use as overflow.

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Supposedly generous girdle grinding will allow use of the truck pan, if you feel like it

 

Hm.. could, would be a lot of work to ensure it doesn't mess up the main bearings through. I'd rather leave in place and just mod the Oil strainer if I can and have the oil pan itself welded to fit.

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Another update though:

 

All the other parts are purchased:

Water pump, Belts, Sensors, thermostat etc.

 

Block is in the shop getting rebored with new pistons. Connecting rods are in, thankfully, good shape.

Bearings are all getting installed and I have my grandfathers shop "booked" for mid-june for the swap!

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Few things remaining to purchase, hoping to get some insight on one of them.

 

  • Clutch - looking at a 225mm Exedy stage 2
  • Rad/shroud - Still thinking on this one, but leaning towards a Mishimoto w/ a fan shroud.
  • Fuel Pump - I believe it needs to be at least 32psi, no idea where to get one to fit the truck though..
  • Cold air intake - may have my friend weld me one up, still deciding.
  • ARP head studs.

 

Also found an RB20 single turbo for about $200 that I may pick up for use in the future.

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Clutch - Google "white bunny clutch" basically a d21 ka flywheel for 240mm Clutch surface with a z31? Turbo clutch and/or pressure plate. I dont recall the exact details.

 

Radiator - stock will do pretty well for a good while, but mishimoto is good stuff.

 

Fuel pump - look up fuel pressure on the z24i that came in 86 720s. If flow is sufficient, buy a fuel pump for that truck. But really, any inline fuel pump would be fine.

 

CAI - a true cold air that pulls air from outside the engine bay might be worth the effort.

 

ARP - great product, nothing wrong with using them at all

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Clutch - Google "white bunny clutch" basically a d21 ka flywheel for 240mm Clutch surface with a z31? Turbo clutch and/or pressure plate. I dont recall the exact details.

 

Radiator - stock will do pretty well for a good while, but mishimoto is good stuff.

 

Fuel pump - look up fuel pressure on the z24i that came in 86 720s. If flow is sufficient, buy a fuel pump for that truck. But really, any inline fuel pump would be fine.

 

CAI - a true cold air that pulls air from outside the engine bay might be worth the effort.

 

ARP - great product, nothing wrong with using them at all

 

 

Yeah I saw some discussion on using a D21 Flywheel for the greater surface area - still have yet to decide what I'm gonna do there.

 

Reason I'm wanting to replace the radiator is I plan on using electric fans and the rad is showing signs of aging - it's the original that came with the truck.

 

Hm, I guess so.. I'll keep looking around and see what I can find.

 

I plan to route the cold air from the intake manifold down the passenger side front fender area, I'll throw on a protector cover over the air filter itself, should be okay.

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  • 4 weeks later...

New update!

 

Block and Head are back from the shop finally.

 

New pistons, re-bored, re-surfaced the block.. all that good stuff.

Pics to come tomorrow when I'm back home, just have to paint the block and re-assembly can finally begin!

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