81 datsun 720 4x4 fix up!

[El_Roy]

Truck KA would be easier. You can run a carb (even your old one) and an L20B distributor. No need for EFI electronics to work with that CAS or high pressure fuel pump.

I'm trying to locate one but not having any luck! But ok good to know!Thank you!what else would I need to swap?the ecu?

[datzenmike]

Well you are swapping an EFI engine into where a carb engine was. There is no support for the EFI so if keeping it you need to wire the EFI's ECU box and wiring in. This would include the exhaust manifold with the O₂ sensor, the CAS and a EFI high pressure fuel pump. Then there's the incompatible 240sx oil pan that won't fit a truck. The Hardbody KA is much closer to a fit. The 240sx clutch is 225mm while your truck was 240mm... I think the Z series flywheel will fit the KA engine.

[El_Roy]

Well you are swapping an EFI engine into where a carb engine was. There is no support for the EFI so if keeping it you need to wire the EFI's ECU box and wiring in. This would include the exhaust manifold with the O₂ sensor, the CAS and a EFI high pressure fuel pump. Then there's the incompatible 240sx oil pan that won't fit a truck. The Hardbody KA is much closer to a fit. The 240sx clutch is 225mm while your truck was 240mm... I think the Z series flywheel will fit the KA engine.

If I can put my original carb on the new engine that is what I will do. The less I have to modify the better.so will I have to get a different oil pan?and ok so I will keep the original flywheel

[datzenmike]

The car (240sx) oil pan is front sump and won't clear the 720's front steering and cross support. In addition the car KA has a crank girdle that forces a deeper pan to clear it. The  truck KA has no crank girdle and is a closer fit with a rear sump similar to the 720 and has an intake manifold that just needs a home made adapter plate for mounting a carb.

[El_Roy]

The car (240sx) oil pan is front sump and won't clear the 720's front steering and cross support. In addition the car KA has a crank girdle that forces a deeper pan to clear it. The truck KA has no crank girdle and is a closer fit with a rear sump similar to the 720 and has an intake manifold that just needs a home made adapter plate for mounting a carb.

Will I be able to use this engine that I found? Or should I keep looking around?

[datzenmike]

It can be fitted but more work as noted. The D21 Hardbody is easier to fit a carb to.

[El_Roy]

It can be fitted but more work as noted. The D21 Hardbody is easier to fit a carb to.

Would it be cheaper and easier to just rebuild the original motor?

[bottomwatcher]

Yes way cheaper and easier. You looked at Crytek s write up? Most recent and comprehensive ka swap. That is the wrong engine and if you don't have a full equipped shop don't try and start. Can you weld? I have completed a full ka swap in my 82 720 4x4 and yes she is a dream to drive but unless you have another 2k on top of the motor cost and a full shop to do it in go with a rebuild. Also the 2k does not include paid shop time,mine was all do it yourself. I couldn't imagine what it would cost for a shop to do it.

[El_Roy]

Yes way cheaper and easier. You looked at Crytek s write up? Most recent and comprehensive ka swap. That is the wrong engine and if you don't have a full equipped shop don't try and start. Can you weld? I have completed a full ka swap in my 82 720 4x4 and yes she is a dream to drive but unless you have another 2k on top of the motor cost and a full shop to do it in go with a rebuild. Also the 2k does not include paid shop time,mine was all do it yourself. I couldn't imagine what it would cost for a shop to do it.

Yeah definitely looking into rebuilding now!thanks for the info it's really appreciated.

[El_Roy]

Well you are swapping an EFI engine into where a carb engine was. There is no support for the EFI so if keeping it you need to wire the EFI's ECU box and wiring in. This would include the exhaust manifold with the O₂ sensor, the CAS and a EFI high pressure fuel pump. Then there's the incompatible 240sx oil pan that won't fit a truck. The Hardbody KA is much closer to a fit. The 240sx clutch is 225mm while your truck was 240mm... I think the Z series flywheel will fit the KA engine.

https://phoenix.craigslist.org/wvl/pts/d/nissan-hardbody/6225058980.html

 

I was wondering if I could swap my z22 engine for this z24 engine?

[datzenmike]

That is a throttle body EFI engine called a Z24i. Your truck has no support for running it, just like the KA engine.

[84720FourWheel]

It would bolt up though. You'd need the engine harness, ECU, fuel pump and lines. Otherwise you should be able to get a carbed z24 intake and make it work.

[datzenmike]

It would bolt up though. Yo  Otherwise you should be able to get a carbed z24 intake and make it work.

 

You would also need a Z24 distributor as the Z24i uses a crank angle sensor.

 

The basic engine is the same just the intake and distributor are different. If you had a Z24 to begin with this would be a simple swap.

[Charlie69]

I read some where that the timing cover is different to accomodate the Z24I distributor.  Can you verify if this is correct.

 

http://nissannut.com/projects/z24i_fuel_injection/

[datzenmike]

If I remember I can check tonight. I even have one (CAS) at home. Very similar to the KA CAS but 8 plug. I would imagine it's cheaper to keep the distributor base than to make a new timing cover for these years??

[El_Roy]

That is a throttle body EFI engine called a Z24i. Your truck has no support for running it, just like the KA engine.

Oh ok so I just need a carbed z24 if Not I have to change a few things. What years are carb z24?

[El_Roy]

It would bolt up though. You'd need the engine harness, ECU, fuel pump and lines. Otherwise you should be able to get a carbed z24 intake and make it work.

Thanks for the useful info!

[Lockleaf]

83-86 will have z24 engines. Not all though as the z20 was a fuel economy option. Rare, but it does exist.

[El_Roy]

I think I am going to have a friend rebuild my original engine for me since I cant find anything to replace it! I kind of prefer the original engine anyways!anything I can upgrade or change to make it have a bit more power?

[El_Roy]

83-86 will have z24 engines. Not all though as the z20 was a fuel economy option. Rare, but it does exist.

Thank you sir.

[datzenmike]

Time line...

1980.... L20B gas (last year used) SD22 diesel

1981.... Z22 gas (first year) SD22

1982.... Z22 gas and SD22

Nov '82 ('83 model year) Z24 gas, Z20 gas Mileage Option engine and SD25 first year. These three engines used until the end of the 720 in '86.5

April '85 Z24i (EFI gas introduced)

 

The 720 came in 4x4 but not with the Z20 or diesel engines and never with an automatic. All were 4 speed except the Z24 equipped engines, Nov. '83. The '80 only, 4x4 had the differential on the left side, all other years were on the right.

 

The Z20 and Z24 were all 240mm flywheel and clutch. All others, gas and diesel were 225mm. Only 2wd gas engines had a 3 speed automatic option.

[Lockleaf]

I think I am going to have a friend rebuild my original engine for me since I cant find anything to replace it! I kind of prefer the original engine anyways!anything I can upgrade or change to make it have a bit more power?

The only internals that can reasonably be swapped out for more power would be a cam. I think crane makes one, maybe Schneider. But the $400 odd i seem to remember them costing never seemed worth.

 

A Weber 32/36 or 38/38 will add power. 2" or so exhaust, mandrel bent, with good flow muffler will also help some. But otherwise, not much available for this engine.

 

A 3 angle valve job, good porting, extrude honing the exhaust manifold all could help, but who knows how much.

[datzenmike]

Valves will touch with too much lift/duration. Intake and exhaust ports are too low causing a restrictive bend at the valve seat. 

[El_Roy]

Time line...

1980.... L20B gas (last year used) SD22 diesel

1981.... Z22 gas (first year) SD22

1982.... Z22 gas and SD22

Nov '82 ('83 model year) Z24 gas, Z20 gas Mileage Option engine and SD25 first year. These three engines used until the end of the 720 in '86.5

April '85 Z24i (EFI gas introduced)

 

The 720 came in 4x4 but not with the Z20 or diesel engines and never with an automatic. All were 4 speed except the Z24 equipped engines, Nov. '83. The '80 only, 4x4 had the differential on the left side, all other years were on the right.

 

The Z20 and Z24 were all 240mm flywheel and clutch. All others, gas and diesel were 225mm. Only 2wd gas engines had a 3 speed automatic option.

Thank you sir! Very good useful info here,will really come in handy in the future.

[El_Roy]

The only internals that can reasonably be swapped out for more power would be a cam. I think crane makes one, maybe Schneider. But the $400 odd i seem to remember them costing never seemed worth.

 

A Weber 32/36 or 38/38 will add power. 2" or so exhaust, mandrel bent, with good flow muffler will also help some. But otherwise, not much available for this engine.

 

A 3 angle valve job, good porting, extrude honing the exhaust manifold all could help, but who knows how much.

Thanks for the response, but now that I know I dont think I will do anything else to it but rebuild it.