75 620 SAS.. Help pls!

[Sketchyfromthe541]

Whats going on yall? New to Datsuns 620s and new to the forums.

Hoping someone can answer some basic questions I have without the need for a headache from too much time on google.

(Keep in mimd I'm hoping for pick and pulls and craigslist on all this for now. Funds are tight)

I aqquired a 1975 datsun 620 sas 4x4 conversion that's done fairly haphazardly to say the least. And I know next to nothing about these trucks.

My biggest questions for now are,

 

1. What solid axles seem to go in the easiest and produce the least amount of maintenance down the road? Current front has a significant cracking in it.

 

2.super underpowered with a 1.6L (mostly stock) motor, 4.some-odd differential gears, stock T case gears and 33s on it.

The question there is opinions/experiences with gear ratios on these things to push 33"tires and have some hwy driveability? Is there anything outthere that just seems to be made for swapping into these trucks? If so what?

 

3. Has a dana 20 t case in it with a twin stick set up in it. (No 2nd set of gears)

Has a hell of a whine to it and I'm not much for the dual cases myself.

What's out there that works well for these as far as transfer cases?

 

I know I can Google all of this. But I'd like to hear from someone whos actually done it. Thanks in advance.

[datzenmike]

33's are the problem. Stock are about 23.65" so you're giving up a lot of gear advantage. The 620 has a 4.375 differential but by going to 33" it's the same as putting in a 3.13 ratio diff. You need something like 5.75 to compensate. That front and rear diff and Dana probably has something. Ask   ]2eDeYe  a member on here, what he's running in his 620.

 

The '75 came with a 2 liter engine so yours has been swapped.

 

The 720 4x4 had a divorced T case but to get an integral trans/trans case you would need a D21 Hardbody 4x4 and your engine won't fit it. Or not easily. Look up ]2eDeYe's build thread for ideas.

 

 

Last of all... 4x4ing is an expensive hobby so if funds are tight it might not be for you.... just sayin'.

[Sketchyfromthe541]

I appreciate you taking the time to answer. And I will try and find the user you mentioned..

Idk if I was a little vague or what in my initial post, I am aware that the tires are the issue in my gearing dillema. Tires stay. Gears can be changed. I'm just looking for input on compatable optons for this.

And I gathered that the l16 wasn't designed for even a tiny truck. Let alone one thats bigger and heavier all around. Obviously she'll never be flying down the hwy doing 90 or hauling anything signifigant. But that's not the point of a 620 converted to a wheeler. As it is now the motors cherry. It's my running gear that's the hang up.

So ya, I know there's alot of ways to not make this work. I'm not after those. I just need facts. Whats can be swapped between these and say jeeps or suzuki of toyotas. I'm sure there's multiple options for each component. That's what I'm after.

And ya. All the fun shit in life costs money. Hence why I'm messing with a 40 year old beater spending my time trying to find axles for this thing and not out at the dealer getting a new rig that has "lockers" from the factory. Haha

There's ways around spending a fortune and still getting the job done. Not

'Considering whether or not I'm too poor to go wheelin'

[Sketchyfromthe541]

*side note, had 4.3 gears originally, diffs were swapped to 4.88. Stock in the transfer cas if I'm not mistakin

[datzenmike]

The L16 was used in the '73 620 and will pull it around in 2wd form. This was replaced for '74 with an L18 and in '75 for the L20B.

 

 

As to the running gear these trucks were usually converted by Low Engineering using the stock rear end and Dana 40? and Jeep parts. Contact Steve ]2eDeYe or read his build thread to mine information. I had a Toyota SAS and a 720 trans case in my 620 but never finished the project.

[]2eDeYe]

Stock transfer case gears are likely 2:1 in that dana 20. You can get 2.5:1 or 3:1 gears for it if you keep it. 

The Dana 20 is a stout case. It should only be loud in low range, if you get gear whine in high range you are low on gear oil or have a problem. 

 

Is the T-case divorced or is there an adapter? 

 

If you want to upgrade look into an Atlas transfer case for Advance Adapters.

 

4:88 are pretty good gear wise. I have 35's and 4:88's. Of course I have a KA as well, so that helps. 

 

Toyota or Jeep Wagoneer axles are good candidates for axle swaps do to their width and aftermarket support. 

 

How about some pics of what your working with? Here's mine so you will show me yours. :)

 

 

 

Build thread is in my sig.

[2wheel-lee]

I always think of 620s being similar to Suzuki Samurais - and I have one of each. The Samurai comes with a 1.3 liter 64 horsepower carbed engine. The stock transfer case has 4:1 gears with 3.73 axle gears.

 

Most people who put larger tires on them simply regear the transfer case. It costs less and easier to do.

 

Stock axles  are good up to 31" tires, and 33" with Chromo shafts for serious wheelers. Any larger, and most go with early/mid 80's Toyota front axles and a rear axle from an IFS Toyota truck (for it's width). Nobody wastes their time with those small Jeep axles (anything smaller than a Dana 44). They're mostly considered as junk.

 

The best engine swap into a Samurai is the 96 horsepower 1.6 16V Sidekick/Tracker engine (I did that to mine), so a 1.6 displacement can be great for a wheeler. Some will also swap in a Sidekick/Tracker trans and transfer case as well, which is somewhat common. Lesser common, but still frequently done is swapping in Toyota driveline.  

 

Fortunately, Oregon is not only a hot bed for 620s, but Samurais as well. I'd swear that 80% of the world supply still remains in the PNW, so parts and support are plentiful. 

[Sketchyfromthe541]

Thanks everyone. I'll take more pictures tomorrow.

Real quick tho. Is the 4 speed trans out of a 73 270z the same used on the L16?

 

And how do you identify what year an L16 was made?

[Sketchyfromthe541]

I can't figure how to upload images for the life of me..

[datzenmike]

Thanks everyone. I'll take more pictures tomorrow.

Real quick tho. Is the 4 speed trans out of a 73 270z the same used on the L16?

 

And how do you identify what year an L16 was made?

 

No the Z car 4 speeds were 31.5" while all L16 4 speeds were 26".  Measure the length of the 4 speed, it (the transmission) might be from the '75 truck it was in and only the engine was swapped.

 

Engine ID? No easy way to know, but it can only be from these years....

 

'70-'72.5 PL521 truck

'68-'72 PL510 car

 

If it replaced the original '75 L20B all that's needed is the L20B engine brackets, oil pan and pick up, release bearing collar for an L16. If from a car the carb converted to use a throttle cable. Not much work at all.

[]2eDeYe]

I can't figure how to upload images for the life of me..

 

 

You need to use an image host like flickr or postimage 

[Stoffregen Motorsports]

Depending on what you intend to use the truck for, having dual transfer cases may be a good idea, and not just for the low gears. It adds much needed length to the front driveshaft, decreasing the angles on the u-joints.

 

A few years back, I did some research and found that there are options to be able to run a modern t-case, and possibly a doubler using a D21 trans. A more drastic approach would be to find a bellhousing from a T5 equipped 280ZX turbo and use that as a blank canvas for a trans swap. You could run a Jeep trans behind this bellhousing or some 4x4 T5 variant. 

 

I also found an Aisin trans that came stock in some sort of Nissan that would allow you to mix and match Toyota components to be able to run Toyota everything from the bellhousing on back. I never could find an application for this trans, but I did find a pic while searching the web.

[Stoffregen Motorsports]

My favorite threads never seem to get off the ground. I'd love to hear about this project, so keep us posted.

[]2eDeYe]

Same here, would love an update :)