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Need help with my first Datsun


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Hello everyone.


Need some help and/or direction. I am new to Datsuns but have extensive experience with Toyota Land Cruisers. 


My 17 year old son was given a super clean 1982 720 regular cab 4x4. The truck spent it's active life in Riverside California and Yuma Arizona. The previous owner brought it up to Canada in 2008 and it has been parked inside a clean workshop since then. He started talking parts off the engine - carb, manifolds etc. and then gave up on it. The PO has since passed away and his son had no interest in it - but he knew he wanted to give it to someone who would appreciate it. He knows about my crazy love affairs with my Land Cruisers (I've got seven of them plus a whole bunch or parts) so he knew that it's the right family. 


The engine (I believe it's the Z22 - it has the eight spark plugs) is seized. Penetrating oil has been used to see if it will free up. Hope the rings are just a little tight after 12 years of sitting. 


My questions are: 

1) if the engine is pooched - should I rebuild? Replace? If replace, with what?

2) it currently has a 4 speed. Is that okay or should I also swap it out for a 5 speed? This change is quite favourable in the Cruiser crowd. 


I haven't figured out how to attach pictures yet. I'll send some once I do. 




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Welcome to Ratsun Dan. The '82 did indeed have a gas 2.2 liter, Z series NAPS (Nissan anti pollution system) engine. If it was running and then parked in a dry garage it should run now. Find out why he would start removing things off of a good running engine. Maybe it wasn't running well.


Check the oil. If it ran dry and spun a bearing I doubt he would fill it up. If low oil be suspicious.


Drain the oil and pull the oil filter and check the oil inside. If a spun bearing it will contain fine metal flakes in it. A sure sign a bearing is spun and seized.



If you can free it up and the bearings are ok you'll have to drive it and see. It may run just fine but if not and just worn out, you have a good starting point for a rebuild.


If the engine has spun a bearing it's almost impossible to find another crank. I think replacing it with a KA24E or KA24DE from a D21 Hardbody truck or #12/13 240sx is a nice up grade and it will fit your 4 speed. ]2eDeYe on the forum (Steve) sells engine mounts for KA conversion for trucks so that will make this easier. The KAs are EFI so you will need a high pressure fuel pump and be able to wire it up into the 720's wire harness.


Another option is if you use a truck KA you can make a simple adapter plate and mount a carburetor. Doesn't get much simpler than this.


If you travel a lot or commute on the highway a 5 speed is nice. If mostly in town a 5 speed isn't worth the bother. A 5 speed doesn't make you go faster it only lowers the cruising RPMs slightly for better mileage. But to answer your question.... YES it's certainly OK.



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Thanks Mike!!


My son & I might delve into the Z22 this weekend however the weather is so nice. . . . . I might save it for next weekend. I looked into the KA specs and it certainly seems to be a big increase. I'd for sure want to put a 5 speed in it then. Then looked at the SR20DET specs . . . . is that the 12/13 240 specs? Don't think that's good for Junior. LOL.


Still can't figure how to post a picture. . . . no paperclips or attachments button. Typical noob. . . . . 



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The RWD SR wasn't available here but only as an import engine. My take on it is for use in a heavy truck you want bottom end torque from a large(r) displacement engine. True the SR has extreme power but only when revved up. I think of it as a thoroughbred race horse pulling a wagon.

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Ahhh yes - torque. Never thought about that. . . . 


All but one of my on the road Cruisers are diesel, with most having a turbo & an intercooler. My gasser has a 454 in it. 


Thinking about 4 cylinder gas engines is totally new to me. Really looking forward getting to know it. 



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Your engine is locked up because ot probably had a headgasket failure. Every one of these engines had a headgasket failure by 100k miles. Cheapest option is fix it. I am running a KAe 8n my 82 4x4 and love it. Although it "Amost" drops in olan for at least 3k for the swap. Well documented on here.

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Hello sir, you can use a host imaging site like postimage. Once you up load the photo there, you click and copy the link it offers, come here click "insert other media", paste the link it gives you and you photo will be available for everyone to see :). 

Edited by SLO720
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1 hour ago, bottomwatcher said:

Your engine is locked up because ot probably had a headgasket failure. Every one of these engines had a headgasket failure by 100k miles. Cheapest option is fix it. I am running a KAe 8n my 82 4x4 and love it. Although it "Amost" drops in olan for at least 3k for the swap. Well documented on here.


While it may have a head gasket failure it's predominantly the taller Z24 block that is prone to gasket failure every 100k. The Z22 block is basically a bored out version of the tried and true L20B block. The Heads on the Z series are the same and so are the bolts do this leaves the block. I've heard it's the metallurgy and the bolts don't go sufficiently deep enough, but my opinion is the threads don't come up high enough in the holes.The upshot is the gasket delaminates and slowly compresses and the bolts loose their clamping pressure over many tens of thousands of heat cycles. The preventative measure is to loosen and retorque the bolts once a year. 


If this was a Z24 I would definitely entertain the thought that the head gasket had failed in the past, coolant got into a cylinder and rusted it in place.

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A repetitive blown gasket can also be from a warped head. My first L20B was from a car and put into my 521. The previous owner had replaced it. In 3 months it blew so I replaced it. It blew again within weeks so someone suggested the head was warped. I had  the head surfaced and replaced it for the last time. This was in the late '70 when I knew nothing.

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