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'82 720/Z22 - Needs Some PEP - What To Do?


Bamadawg

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I have had this lil '82 720 several years now... Like most... I had dreams of tweaking it with a engine swap, or head swap, but jus haven't got around to it.

 

My main gripe with the lil truck is its non-ability to pull hills with any gusto - a VW Bug comes to mind compared to mine. Maybe this is not normal to begin with for the Z22 eqipped with 111,000 miles? I know the exhaust is worn, so maybe a clogged CAT?

 

I am wondering, besides a new exhaust, what other lil tid-bits can be done to the stock Z22 to give it a lil zing. I think I have read about a distributor swap which deletes the exhaust plugs with only 5 wires. Any other tips would be great... Seems I have read a few posts online about pepping the lil stocker, but that was a few years back, and those brain cells are surely gone by now, so any links to mods are greatly accepted also.

 

I do have a L20 head and some aftermarket SS valves I bought back when I had great ambition to do the head-swap, but that involves a tranny swap and lots more than I have time for now... I have a 16 y/o that will be going to college next year, so free time isn't that plentiful right now, but could do some weekend-warrior tweaks to it before it gets cold weather.

 

ALSO: What flavor tires go good with this year 720? I have found the Goodyear Wrangler AT's I think they are, but man... $175/ea. for those LT tires!!! I think I read the OEM was a Dunlop tire... jus wondering what has worked on yalls 720s... Seems any LT I find (few and far between) in 195/75R/14; 205/75R/14 is so over priced.

 

Thanks...

Nate

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Yea, I was def gonna try to de-emission it, since we dont have tests in Alabama. Yea, the MSD box is one of the things I had read about... did you switch out the distributor to a 5-wire? If so, what models can swap - I know where 2 L20B trucks are in a JY. What intake manifold did you use for the Webber? I was planning on that swap also. I know it will not be a tire-burner - I jus want a lil more umph out of the lil stocker... The exhaust is on my list as I stated... 2.25" was my thinking also...

 

Thanks for the reply.

 

Nate

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well desmoging the engine will no improve hp but makes for a lot cleaner engine and weber install. I used the stock intake welded up all the holes also. with the weber adapter plates (which keep in mind are the same as any L motor so they can be found easy used) I kept the stock distribitor just added a msd to the intake side of it (it takes 2 msd boxes to operate both intake and exhaust ignition coils) i was going to put a header on my truck but figured it was probabbly a waste and would not fit right anyways. The best thing to do if you want to make bigger hp is to ditch the napz head and use a l20b head. with the right head & headwork you can make some pretty good power that way. the napz engine itself with the stock head is not really worth putting a bunch of money into their pretty much only good for either turbo charging (with the stock head) or just the short block itself.

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Leave the two plug per cylinder. It shortens the burn time thus you need less advance than a single plug. The stock ignition with good wires plugs, rotor and cap is way more than enough for a stock motor. The only way a MSD will make your truck faster is because your wallet is lighter.

 

Save your money and get a nice new Weber with an idle cut solenoid and electric choke heater. This will give the most bang for the buck. Next, I don't know what the Z22 exhaust down pipe size is, but the Z24 uses 2" so maybe a Z24 system if yours is in bad shape or a custom 2 1/4 exhaust system without the cat. Going from a 2" to a 2 1/4" pipe increases the flow by almost 30%!!! Do not go bigger or torque will suffer. To prevent the EGR working just pull the vacuum hose off, and plug the end going back to the carb.

 

If I was doing this I would get a Z24 head and intake for it. The chambers are the same volume as the Z22 but the intake ports and runners are bigger. Also the Z24 intake has a larger bolt pattern than the Z22 and I think the Weber will bolt on without an adapter plate.

 

http://i138.photobucket.com/albums/q251/datzenmike/00770026.jpg[/img]"]00770026.jpg

 

The bottom head is a Z22, top is a Z24.

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Thanks Mike... thats some great advice... I will look for a Z24 head and intake... have it worked over a bit and install new parts for it. I remember reading that the stock ignition isnt bad... most recommend jus getting new OEM coils for it, and updating the parts... I already use the NGK Iridium (sp) plugs. Was def gonna redo the exhaust and delete the cat - replace it with a resonator and decent SS muffler. Will try and find a Weber for it - that will get me where I want to be I think. Yea... I dont want to jus throw money at the lil engine - jus want a bit more pep out of it.

 

I will prob replace the cam when I find a used head... should I jus get a factory Z24 truck cam, or will a mild performance upgrade cam be better?

 

Thanks for all the info guys...

Nate

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Step 1 taken today... Replaced the 2 ignition coils with some HQ OEM type Borg-Warner coils. One of the coils I took off had some oil inside where the dist wire plugs in, so it obviously had a leak - they were both orig factory coils, so the new ones should help in the spark area. I have some quality 7mm wires from NAPA on there already, and replaced the cap/rotor same time i did the last spark-plug change.

 

Now to track down a Z24 head/intake... I think the guy that had the 2 L20 datsun trucks also had some hard-bodies in his inventory - hope so cause the few wrecker yards around here crush their vehicles, so few parts from them.

 

Nate

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The Z24 cam is the same as the Z20/Z22. Hardbody head is OK, but they use TBI throttle body injection and the bolt pattern on the intake is... very weird. You would have to modify it to fit a weber. Try for a very late '83 and up 720. If you look on the inner passenger fender below the hood hinge there is an aluminum tag. The bottom two rows list the engine series and size... and the tranny/rear end ratio.

 

Look for Z24(S).... 2389 cc. A Z24 head will not have a block off plate covering the old fuel pump hole. Refer to the picture I posted above.

 

The only draw back to the 8 plug system is the distributor cap and rotor. On a 4 wire there is lots of room between wires and terminals, but the Naps has 8 of them jammed tightly together plus the rotor has two connections for the coils. If the average owner doesn't look after or replace every tune up they can cross fire under load. Use good quality parts for this if nothing else, and you'll be fine.

 

Did I mention a good new (if possible) Weber???? Make sure it has an idle cut solenoid and an electric choke. You will need an adjustable fuel pressure regulator as Webers can be overpowered by the 720's electric fuel pump and flood.

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I have read that the z heads respond well to porting. The only other thing to do is shave it for higher compression. There really isnt a better cam since added lift and duration will make the valves hit each other due to them being on opposite sides at an angle.

If you need better hill climbing and instant get up get a different rear diff. You should have a 5 speed already.

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Thanks... wasn't sure if I can jus use the same diff and change the gears, or a complete swap would be most beneficial - I am not that technical on the drivetrain side.

 

The Weber is def at the top of my list as soon as I track down a Z24 head - or may jus be stuck with porting the Z22 without having to go 60+ miles or so to find a head.

 

Nate

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Found this reply from Mike about differentials - this may be the thing to look for... If i can find a '84-up 720 with the Z24 head and this diff - I would smile big :)

 

"The '84 and up 720 2wd standard transmission had 3.70 H-190-A differentials in them."

 

My info tag is at the office, I took it off so I could have it handy, so I am not sure what the '82 has in it.

 

Nate

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your wasting time energy and money with any napz head the port design sucks and valve geometry is goofy. I mean ya can if ya want but do a search on lz hybrid motors or ask someone that has one (I did in the 90's) they are very strong running with the right porting and headwork ask anyone thats into datsuns or raced them they will tell you the same thing i am. if your searching for anything 2.4 a nice shortblock with the L head is a good setup takes a bit of work and a 2.4 napz with no cracks but a good torquey engine. do a search for "fineline" on here and check his 620 with a lz turbo engine:)

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Thanks Mike... Doesn't the 720 have a mechanical fuel-pump? So I would need to block-off where the mech pump was and use a regulated electric pump? What brand pump is ideal/reasonable?

 

Datsunfish: What differential should I look for if I wanted to swap it?

 

Thanks...

Nate

 

Sorry if I wasn't clear....

 

All North American 720s use an electric fuel pump, so don't worry about that. The Z22 head has a block off plate to cover where it WOULD HAVE BEEN. The Z24 isn't open, so no plate. I only mention this as a way to quickly identify a Z24 head.

 

As we all know, power is made by the head. It's the combined cam, port and valve angle, port shape and size, combustion chamber shape, valve size and weight, and spring pressure that produces RPMs and power. Good power is made at higher RPMs... more in... more out.

 

The NAPS engines were designed for low pollution and low RPM power and torque to pull the increasingly heavier 720 4X4. Good breathing wasn't important and is adequate below 5,000RPMs. Weak valve springs prevent high revs due to valve float... again not needed in a low pollution low RPM engine. The heads don't breathe well because of small intake ports with very sharp turn radius.. again, not needed in a low RPM.pollution engine. Valves are slightly longer so heavier... not a concern in a low RPM engine.

 

On the plus side... Combustion chamber is close to the ideal HEMI shape. Dual spark plugs for increased efficiency and a decreased burn time allowing less ignition advance. Cross flow design allows more room on exhaust side for a turbo.

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Easier and probably about the same cost but the turbo would far out power the KA.

 

A turbo is a great equalizer. The motor does not have to work at all to breathe... the turbo pounds the air in. Small valves or ports? no biggie just turn it up. Turns mice into lions. (may cause feelings of superiority, use only as directed)

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Yes... I know all about the LZ engines - that was my original intentions, but at the moment I jus want some bolt-on - weekend warrior type mods that will make the truck act more like a truck - if that makes sense. Like I explained before - the power really falls off bad if/when I drive it up hilly highways, which we have around here.

 

I would jus buy a port/polish kit and do some mild work to the head - nothing HP, jus to improve it - so that dosen't seem to me to be throwing money at it. It has the OEM exhaust on it, so that gotta be replaced anyways... will splurge a lil and get a resonator and decent SS muffler. Spent bout $70 for those 2 B/W coils - so I am not going crazy with the expenses. Figured I should be able to get a head and diff if I can find them for round $200ish. My friend owns a NAPA store, so I get parts from him at jobber prices - that helps alot. Gonna do some shocks and new tires and brake refresh all around, cause shes losing BF now and again.

 

I have a L20 head in the wings, and I am keeping my eyes open for a Z20S block so that I can eventually do that LZ motor when I get my 16 y/o off to college in the next cple years.

 

Nate

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Sorry if I wasn't clear....

 

All North American 720s use an electric fuel pump, so don't worry about that. The Z22 head has a block off plate to cover where it WOULD HAVE BEEN. The Z24 isn't open, so no plate. I only mention this as a way to quickly identify a Z24 head.

 

 

Thats the reason I asked Mike... cause my '82 def has a mechanical fuel pump - not electric?

 

Nate

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Nate, could you post a picture of your motor showing the fuel pump? As I said all NAPS motors used electric pumps but if the original failed someone could have put an L series pump on it. I put one on once just to see if it would fit.

 

Can't recall if you said you had a manual or auto. Look on the aluminum tag on the passenger side inner fender below the hood hinge, the rear end ratio is listed just after the tranny and would look something like :

 

HF 41 the 41 would means it had a factory 4.11 installed.

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From Alabama... War Eagle tho :)

 

No smog testing done here - tho I wish there was, like in Georgia - get some of these horrible clonkers off the roads.

 

Mike... itsa raining today from the tropical storm, so I will snap a pic ASAP. Thats what I was thinking... maybe someone added the pump at some point and time, but the factory fuel lines look like they were setup to run to the mechanical - not sure where the elect pump woulda been mounted at tho. It is a manual 5-spd.

 

My lil tag is in my desk at the office - I will swing by there later and take a look at it - I took it off the truck so I could have it handy for ordering parts, etc.

 

Thanks

Nate

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720 electric fuel pump is mounted on the outside of the passenger side frame just ahead of the rear wheel. There will be a couple of bolts there for holding the cover over it.

 

Nothing wrong with a mechanical pump on a 720. Someone was smart enough to think of it.

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