Au-rite-e! We've talked about torsion, time for leafs

[oldskoolvws]

Okay, so the popular swap to drop is 720 4x4's. Lets see some some oics, have some discussion and see what we come up with.

 

For me, right now I'm leaning towards belltech 720 lowering springs for my 521 as seen here: http://www.stylintrucks.com/parts/rear_-_leaf_spring_-_3-qt-/3346/belltechb265974rear.aspx

 

I know the lengths are correct, but the eyelets are a different size, can anyone elaborate? Any other cool options?...Mr. BT go away, no 4-link.

[Dawa]

i was just looking into this last week.

well first i was looking for 620 specific drop leafs, but could find em.

then i got curious of running leafs from other datsun trucks.

i actually have a set of 720 leafs but havent installed them.

i guess some guys (radim, for one) run hardbody shackles.

so perhaps running hb shackles with these will work?

[oldskoolvws]

Yes that or custom made shackles. One side would be drilled to the 620 (521 for us) diameter and the other to the 720 (or whatever else) diameter leaf spring eyelet, if proven in fact they are different sizes.Then only the other side needs to be dealt with.

 

Here's some really good info below. Based on this info, if a 521 were to be swapped with 720 4x4 springs, it would lower the rear a little over an 1-1/4". 

If a 620 were to run 521 springs, it would lower the rear a little over an 1-1/4". And if a 620 were to run 4x4 720 springs, your looking at a drop of almost 2-3/4".

 

So for me 720 BellTech's make more sense, it's a solid 3" drop vs. 1-1/4". I'd need to do other mods to get what I need. With the BellTechs, I still have minor mods though. But for you, 720 4x4 springs make sense because they'll be a lot cheaper than new Bell's.

 

Allrighty, a few have wondered about using 720 4x4 leaf springs to lower their 521's and 620's. I'd love to see a pic of someone has tried it! So if you have it, post it!

I am curious what kind of drop you would gain. And how the ride would feel!

Datzenmike mentions 720 4x4 has 3.68" spring free arch and is stiffer. Normal for a 521 is 5" (620= 6.34"), so does that mean we'd get an extra aprox. 1.32" of drop for a 521 (and 2.66" for a 620!) by simply using 720 4x4 springs? Or would the softer 2wd spring-flex eat up some of that gain?

(This would also mean you 620 guys could get a free 1.34" of drop from using 521 springs. Again, unless it gets eaten up under load.)




In the mean time I thought I'd organize what info Mike has given us in one thread.

From King Rat Datzenmike:

"The 521, 620 and 720 leaf springs are the same length and width. 720 4X4 springs are stiffer than 2wd and have less arch."

"The 521/620/720 rear springs are all the same length at 1,200mm. 720 4X4 springs are mounted on top of the axle for added height so lots of arch isn't needed with them. All 4X4 spring packs have roughly 1/2 the amount of arch as 2wd springs."

"521, 620 and 720 springs are exactly the same length at 1,200mm.

PL 521

1,200x60x7 Qty two
1,200X60X6 Qty two
1,200X60X12 Qty one

Spring free arch.... 5"

'78 620 rear spring dimensions (in mm) all models.
1,200X60X7 Qty two
1,200X60X13 Qty one
Spring free arch....6.34"
(This is the same spring used on the '84 US 720 2wd)

The '84 Canadian 720 springs were stiffer:
1,200X60X7 Qty one
1,200X60X8 Qty one
1,200X60X12 Qty two
Spring free arch....5.20"

4X4 all '84
1,200X60X7 Qty one
1,200X60X8 Qty one
1,200X60X12 Qty one
Spring free arch....3.68"

I don't think this includes the big flat load carrying helper. "

Some inch conversions:

1,200mm = 47.2" length
60mm = 2.394" width
7mm = 0.275" thickness
6mm = 0.236"
12mm = 0.472"

 

[erichwaslike]

i run stock 521 springswith the second spring(right under the main leaf with the eyes) taken out, flipped over adn put on top of the main leaf. re asssemble and use a 3 inch block. puts the axle 1 inch from the frame with no bump stop. so with no block your axle will be 3 inches from the frame and it rides pretty good. shocks of coarse dictate alot of ride qaulity too. my dad runs the same setup with a 2 inch block and the shortest leaf(very bottom) flipped.

[Lacuchufleta69]

I took the two middle leaf springs off n let her sit. Wasn't a three inch drop but it sure did look better. Needless to say she rode well and it was pretty darn n cheap n easy.

[oldskoolvws]

Mine are dangerous right now. Lets just leave it at that :-)

[oldskoolvws]

Does anyone have an actual picture of a 521 before / after 720 4x4 springs?

[mrbigtanker]

Okay, so the popular swap to drop is 720 4x4's. Lets see some some oics, have some discussion and see what we come up with.

 

For me, right now I'm leaning towards belltech 720 lowering springs for my 521 as seen here: http://www.stylintrucks.com/parts/rear_-_leaf_spring_-_3-qt-/3346/belltechb265974rear.aspx

 

I know the lengths are correct, but the eyelets are a different size, can anyone elaborate? Any other cool options?...Mr. BT go away, no 4-link.

I like this idea.

[ol'skoolrob]

I took the leaf out under the main leaf and then skipped one and took another out

also have 3 inch blocks and no bump stops

only an inch or two of travel but its definately a lot lower

you could also de-arch your leafs instead of buying new ones with less arch

[oldskoolvws]

Well, I just ordered D21 leafs from Belltech. We'll see what's up when they get here.

 

Anyone offhand have the shaft diameters of the front and rear shackle bolts for the 521?

[mrbigtanker]

Do they come raw or painted black,this looks like a cheaper idea then i was going and better for that matter.I am happy with my drop just want to bring the back down 1 more inch.

[mrbigtanker]

Also whats your thoughts on addco front sway bars.According to the guys at the SEMAN show last year they said they have the year for our trucks but i am thinking for the 620 which came out the same year in 1972.

[oldskoolvws]

The ones for my Colorado came painted black so I'm assuming this will be the same. I'm hoping to only need a 1" block after this.

 

Front: http://www.ebay.com/itm/Addco-887-Front-Performance-Anti-Sway-Bar-Stabilizer-Kit-/120951833685

Rear: http://www.ebay.com/itm/Addco-228-Rear-Performance-Anti-Sway-Bar-Stabilizer-Kit-/120951695627?pt=Motors_Car_Truck_Parts_Accessories&hash=item1c2948690b&vxp=mtr

 

This in my plan. If I had to choose one first before the other, I would take the rear. Front already has the factory one. Find universal poly for everything if you want firmness, except for the tension rods. Run rubber for those.

[oldskoolvws]

reference:

 

[oldskoolvws]

Plan is to try to find poly bushings for 57, 58, 2 (11 or whatever). Also for the shocks, 73 and 74.

[skyblue]

Does anyone have an actual picture of a 521 before / after 720 4x4 springs?

I think jrock has a pic. i know he put some on his.

[uberkevin]

I think jrock has a pic. i know he put some on his.

And I know I've seen one.

[datson4life]

hey oldschool are your fenders rolled?

on that trip to san leandro i noticed my back tire hits the fender on freeway bumps, i didnt wanna roll the fenders but i might have to :( or stiffen shocks...........or put bump stops back

[Laecaon]

Im not a fan of Poly with Leafs...

[oldskoolvws]

hey oldschool are your fenders rolled?

on that trip to san leandro i noticed my back tire hits the fender on freeway bumps, i didnt wanna roll the fenders but i might have to :( or stiffen shocks...........or put bump stops back

Nope, not yet anyway. Shocks will help but it will still likely rub on hard cornering or big bumps. My offset is -2 so I'm right there with the 8" wheel and the smalls stretch of the 195's. What size are your tires?

 

I have a fender roller but one does not let that one go without a replaceable deposit.

 

Im not a fan of Poly with Leafs...

 

Funny, this morning I was contemplating that again and then decided on the rubber bushings. Only thing that will change that is if I cannot find a good way to mount the Belltech's and I have to swap the bushings. What are my chances it will bolt right up? Not likely.

 

 

Anyone have the bolt diameters of the front and rear of the leaf springs?

[oldskoolvws]

One bad thing for me about these Belltechs is that they are linear, or same spring rate through the load. I might add in my factory overload to give it more of the 2-stage effect. Firm handling is on top of the suspension list. Mounting is step one for these leafs though.

[datson4life]

my tires are 195s too, but my wheels sticks out a bit more than yours

[Phixius]

Before: stock 521 leafs and 3" blocks

 

 

After: 720 4x4 leafs and 3" blocks

 

 

 

521 next to 720 4x4

 

 

[oldskoolvws]

Nice! According to the stuff I posted earlier, it's supposed to be a little more than 1-1/4"'s worth. Judging the pics, that looks about right.

 

What the hell are the deals with the small springs under the overload? Looks like the one on the left is an overload for the overload, the right vibration damper????

[oldskoolvws]

Oh yeah, the Belltech's 720's showed up today. Wife sent me these, I'll post more pics and details soon.