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720 Life is an addiction lol


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Hello again all, I have just recently scored three more 720 pickups. A one ton dually, a std cab short bed, and an absolutely trashed (body wise) sd22 diesel pickup. I plan to eventually get the dually on the road and later the std short bed pickup also. This will make 12 trucks total (7 are for parts). I also picked up a set of O.G. 6x5.5 dually wheels and a steel bed for the one ton.


My question is, what tire will be recommended to run on the one ton? The factory recommended tires are like $200 a pop and listed as trailer tires. They convert over to a 195/14. What I'm wondering is, if I could get it up to a 215 tire size. I know that will drop the gearing a bit and that I don't mind (wont be used other like hauling wood). 


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You can likely use as big as a tire as you can get on the rims, what counts is that the tires do not touch each other when mounted and under load.

What are your plans for the SD22 engine?

At this time I have LT195/75R14 tires on my dually, I have had no issues with hauling firewood loads.



I did this load with regular P195/75R14, 4 tires rated at 1500lbs each equal way more weigh than you likely ever going to carry.


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That's awesome! What do you max out on the highway at? That's my worry. As far as the sd22 I haven't decided yet. I have a good running sd22 with rebuilt injectors sitting on a stand, one in a wrecked truck and a parts motor. I also have a low mileage sd25 (58k miles). I think the one ton will get my z22e as it needs a motor was planning to put it in my 4x4 but its turned into a daily driver.

Edited by SLO720
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Cab/Chassis models (engine tag starts with an E) use an E 78 14 tire on a 5" wide rim or 5.5" aluminum mag. E78s are 7.65" wide and 26" tall.


195 /75R14 are 7.68" wide and 25.5" tall....  just over 2MPH at 50MPH

195/80R14 is 7.28" and 25.65" tall............... same

205/75R14 are 8" wide and 25.3" tall.......... almost 2.5 MPH fast at 50MPH


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I was just making sure you were not going to put a SD series engine in front of that dually axle as it is not geared properly for a SD22/25 diesel engine, I suppose if one had the 4.1 gears  which are the best gears to be had from Nissan for the C200 in a 4wd with really big tires one might be able to figure it out using tire size, that dually axle is a C200, it likely has 4.3 or 4.6 gears, the tag in the engine compartment will tell you.

My 1982 Datsun 720 SD22 diesel I used to have would barely do 70mph in 5th gear, I was turning 3000rpms with 3.89 gears in the rear axle, down hill it would easily go faster but anything above 3000rpms starts sounding over revved except in 5th gear, but one is only going to go so fast with 61hp in 5th gear and when a hill comes up I had to start down shifting to try and keep going at least 50mph, I got really crumby mileage with that truck on the freeway, about 27mpg, but in the city I got 25mpg, once I got 35mpg going 55mph, it drove me crazy going that slow on the freeway.

I have two custom Datsun diesel trucks, both have SD25 engines in them, they are both turbocharged, I turn 3.3 gears in both of them, my 720 dually truck is a cheat, it has a H190 axle with adapters I had made for the H190 to except dually rims, the adapters were very expensive, and I would never haul much weight with them adapters, but I don't have any issues towing with that truck, they both have the torque to get the truck moving with them gears even towing another diesel truck behind my diesel truck.

That dually truck in the photos I posted has an LZ23 in it, even with that load in the second photo I can go way faster than I should, you can see them car tires were squatting a little, keep in mind that truck has vented rotor power disc brakes, they will stop that truck.

If the Z24 engine in that dually axle truck is good I would stick with that engine, it has a shit load of torque and is a good engine for that truck, the Z22e is a good engine, I used that block to make my LZ23 in my flatbed work truck, but the Z24 has more torque for hauling weight unless you were to make it into an LZ24, that likely would be the best engine of all.

This is my 720 dually.



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The one ton has a z24 the guy had rebuilt and an "rv" cam installed. Unfortunately he drove it for 800 miles and the same rod on the crank started knocking so he parked it. I think the efi z22e will do just fine in that truck. I'd love to turbo it using a cast kae manifold and it may happen eventually. I've been looking for a set of 3.33 from an early 90s d21 trying to get a limited slip third member. I've only ever seen one z20 720 with the 3.33 economy gearing in a pick n pull. The guy really loved that dually and had new floor pans installed and the seats reupholstered. "L" series powered vehicles are ridiculously hard to find around here. I know where a, what looks like an '80 720 is. It looks like it has the bed spikes of a 620 almost like a mexican or international bed. I looked at the truck 5 years ago. It was left on a farm and the guy has no title for it so I never bought it. I need a 5 speed for the LD28 I picked up so I may talk to the guy again. The only thing I really remember is it had a set of vent visors mounted to the doors and I wanted those badly. There are a ton of these trucks around me and i try to keep as many from getting crushed as possible.

Edited by SLO720
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So he didn't blow it up/throw a rod, I would first make sure the issue was a rod knocking and then pull it out and remove the crank without removing the pistons and see if it can be fixed, but again I would first make sure it was not something else knocking, maybe he blew a head gasket and it was trying to hydro lock.

It took me years to find two 3.3 gearsets for my diesel powered trucks, I was using 3.5 gears in my 521 diesel before finding that set of 3.3 gears, the 3.5 gears were alright, better than 3.89 gears.

The H190 LSD is a very rare option, I found one in a 1993 Hardbody with 3.5 gears, after driving around for a few years with it I determined it was not really all that great as I had the back end try to come around more than once when making a left turn in traffic when wet outside, and when dry the truck would shake/vibrate when making a sharp turn under power.

When I mentioned LZ23/LZ24 I was talking about making a hybrid engine, putting an L head onto a Z22 or Z24 block and mounting it in the vehicle like it is just an L20b, but it takes more than just building an engine as you need everything off an L20b including the transmission to do that.

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Yeah I'm pretty sure it had the vents but it didnt have a single straight body panel on it. The z24 probably can be fixed and I have a couple z24s sitting around also. And right, by getting the transmission also, I was meaning that I could get two birds with one stone. The gentleman that has that truck has a canary yellow 85 720 (z24), and a blue shortbed sd22 truck as well. He wont come off the other two, I've tried.


I thought that building an lz you had to modify the timing covers length? It's been awhile since looking at the stuff. Also a slightly modified hg too if I'm thinking right. I remember reading that people take the cranks out of a z22 to stroke out an l20b which I'd assume would be of Similar results?


I'm looking forward to messing around with the z22e efi system finally. Also I have been thinking more about utilizing kae pistons in a z24 block and a 240sx head/intake for a better breathing efi system. 

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You would need to modify the front cover if using the Z24 block or just use the Z24 front cover and modify it so it don't leak oil, the Z22 and L20b have the same block height, and I believe they use the same crank stroke, so one uses the L20b front cover.

The LZ23 head gaskets are a pain to make, but I believe that they can be bought on ebay now.

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