521 Options - sorta' newbie Q's

[nukeday]

Alright, after a lot of consideration, I think I'm going to get work on the '70 521. It seems there are several options for modern 'usability', and I've searched here, but not found a comprehensive list of upgrades for the 521. Did I miss it?

 

The objective is to make the truck drivable for today's conditions. I know that several engines will drop in place of the 1300, and a 5 speed can be installed as well.

 

The less fab work the better, as a matter of fact if it will bolt in, THAT is what I'd like to do. So what are the options for the following?

 

-Engine/Trans transplants

-Front Disk brakes

 

I need a bit more education in the L, J series engines also. I'm not looking for a fuel injected NAPZ engine, a carb'd engine would suit my needs.

 

The lack of self adjusting drums, and no discs really has me looking over my shoulder at my old Luv...

 

I'd just as soon keep the 1300 if I can put in a 5 speed and a later rearend. If there are factory bits that would allow this, I'm all ears. The front brakes seem to be the 'gotcha'. Is a custom driveshaft mandatory with the 5 speed, or is there a way to use one from another model?

 

Thanks guys, really trying to sort this out before I start plunking out coins.

[420n620]

heres a 520 w/ front disc. maybe this thread will help you. I'm not 100% if 521's or 520 have the same set up.

 

http://forum.ratsun.net/showthread.php?t=7592

Edited December 28, 2008 by 420n620
521/520

[nukeday]

Thanks for the link, but ummm...there is no bolt in work being done in that thread.

 

Thanks for getting me addicted to the build though...hahaha...

[moparvwfreak]

your front suspension SHOULD be similar to my 73 620. and if that's the case then maybe the upper control arms that are custom made by Beebani here on the site, might be what your looking for. that would allow you to use late model 620 disk brakes on your truck. i WILL be doing this swap as soon as i can afford the control arms. at that point it would be sort of a "bolt on" deal.

[datzenmike]

Besides the J13 a J15 variant was used in various countries through '80 also there was a J20 used through the '73 Nissan Cedric. I can't find reference to any 5spd that will fit the J engine. This would mean keeping the 4spd or an expensive adaptor to use a 5spd from another motor or switching to another motor. Just as an example, the running gear from a '77-'79 620 would give you an L20B motor, 5spd tranny, shortened driveshaft and 4.375 rear end ratio.

 

 

The L series engines won't drop in if you have a 1300 in there now. The motor mounts are differently placed so some fab work will be needed for that but once done, any 4cyl L series or Z block will 'drop in'.

 

Once converted to L series a '77-'79 200sx dogleg 5spd. will fit in the short tranny space. The problem is that besides being somewhat rare and by now, well used and passed around, this tranny is meant for 1.4- 1.5 liter motors like the B-210 and will work with the L16 and the L20B but there are better and stronger boxes out there. One advantage is that it has a short tail and fits the 521/510and early 620 4spd location without mods to the driveshaft. If you are changing to an L motor set up then a little more change isn't a big deal. The later, and stronger 620 and 280z 5spds can be fitted, but they are longer and will require a shorter front drive shaft. I believe that the shorter front driveshaft from a '74-'79 620 should work as these used the longer 4 and 5 spd tranny.

 

Because of the extremely low 4.875 rear gears in the 521 you really should get a 5 spd with over drive. If you plan on keeping the 4.875 then the best tranny would be one from an '80-'83 280zx (non turbo) with 0.745 overdrive to reduce highway cruise RPMs.

 

If you plan to reduce the rear gears to a more manageable number you might consider a 4.375 if using it as a truck and carrying loads. You could go lower if you plan on having a larger L20B engine and/or use it for a DD and require fairly good mileage. A 4.11 would work, or you could go even lower to a 3.889 but combined with the high over drive ratio of the previously mentioned tranny this combination would lower cruise RPMs too much for a 4cyl motor. A lower ratio rear gear would allow the use of the more common '77-'80 280 z and 620 5spds with a lesser over drive ratio.

Edited December 29, 2008 by datzenmike

[Cuts metal like mad]

just to recap what mike said, there is no bolt in upgrade for tranny, and bolt in motor upgrades are more expensive and harder to find than doing an L series...

 

You don't need to swap the whole axle to get better gearing, just the third member, disc brake options are just a search away...

[nukeday]

So, from what I'm seeing here, swapping the rear gears may be all I need to accomplish safe highway speeds. I'll do some more research on this.

 

So I'm wondering if I could use a dual master, proportioning valve and upgraded brake hardware and keep the drums. Seems like there should be a way to use a self adjusting setup from a later model drum setup.

 

This truck is really rotten in the floors and the inner fenders. All I need it for is to pull my pop up, and haul stuff to the dump and Home Depot. I don't plan to make a daily out of it. If we use it for camping, I'll do something with the cab floors, probably road signs and rivets.

 

In order to move all my people and the pop up trailer, I'm going to need some sort of canopy as well (additional weight). The pop-up is very light, I'd guess about 800# fully loaded. Most of our camping trips would require some mountain climbing (Oregon Coast range, Willamette Pass, etc.), I don't mind going slow uphill. The real concern is stopping the whole mess on the way down.

 

Thanks for your comments, I definitely need to do some more research here.