620 suspension quesions

[JNHEscher]

14mm 1.5 is the thread.

[JNHEscher]

The 620 frame accepts the 720 upper control arm easily. It will bolt right on, but I highly recommend drilling out the nuts enough so that you can rethreading them for the larger 720 bolts. If you don't, you'll have too much slop and will be putting tension on the small bolts that could snap them.

The 720 arms are shorter, so your camber will go way negative. If you're into the stance thing, you're good to go, lol. I notched out my upper arm towers and bent them over so that i could straighten up my camber. Best thing to do is get a set of adjustable arms, unless you're set on cheap and want to do some fab work.

[JNHEscher]

Rear shot to show how the 620 and 720 torsion bars bolt up the same way. I replaced my splined bolts with some 18mm and nylock nuts.

 

 

[orangie]

Rear shot to show how the 620 and 720 torsion bars bolt up the same way. I replaced my splined bolts with some 18mm and nylock nuts.

 

 

Take care using different bolts.  The stock bolts are shouldered and can only tighten down so far.  Without the shoulder, it's possible to overtighten the bolts so the control arm does not move up and down freely.

[JNHEscher]

That's why I used nylock nuts. The arms move well and no slop. So far it drives good and tight. Once I have it legal I'll take it on a faster open road.

[davis62]

The 620 frame accepts the 720 upper control arm easily. It will bolt right on, but I highly recommend drilling out the nuts enough so that you can rethreading them for the larger 720 bolts. If you don't, you'll have too much slop and will be putting tension on the small bolts that could snap them.

The 720 arms are shorter, so your camber will go way negative. If you're into the stance thing, you're good to go, lol. I notched out my upper arm towers and bent them over so that i could straighten up my camber. Best thing to do is get a set of adjustable arms, unless you're set on cheap and want to do some fab work.

[davis62]

what process did u use to run the thread down the caster rod further, what size die it looks like it got pretty hot? and what di u mean by notching in relation to camber? how does one notch.

[ggzilla]

The 620 frame accepts the 720 upper control arm easily.

 

Do you mean the 1978-1979 Datsun 620? Because 1972-1977 frame won't accept a late 620 uca.

[JNHEscher]

Do you mean the 1978-1979 Datsun 620? Because 1972-1977 frame won't accept a late 620 uca.

If there's a way to check the date of my frame, I can answer that for sure. My truck is a 74 and none of the mounts look to have ever been broken loose. The 720 uca's bolted right onto my king pin uca towers. The arms are too short, of course, and the mount nuts had to be resized, but they worked. Not trying to debunk any info, especially since I'm decades behind several members here. Just laying out how everything worked on mine. I'll see if I can find a thread that points out the reason 720 uca's don't fit early 620 frames.

[ggzilla]

I didn't say 720 uca's don't fit early 620 frames.

 

I was wondering if all 620s worked with your mod, or only certain years.

[JNHEscher]

what process did u use to run the thread down the caster rod further, what size die it looks like it got pretty hot? and what di u mean by notching in relation to camber? how does one notch.

The heat stain is from me using a grinder to shave down twith ods so that a threading die would fit on. The rods have a shoulder beyond the OE threads that is too large to thread at 14mm. Once I had it shaved down, I just spun the die down the existing threads and continued threading until there was enough to work with the 620 bracket position.

 

I pie-cut the bottoms of my uca towers so that I could lean the down and outwards in order to provide more surface to mount an upper bag plate to and to compensate for the uca being too short. I was able to bend the towers out enough to straighten out the camber angle. Getting the uca's from beebani or anyone else that makes them is the way to go. What I did was cheap and by no means a great way to do it, but it did the job.

[JNHEscher]

I didn't say 720 uca's don't fit early 620 frames.

I was wondering if all 620s worked with your mod, or only certain years.

Ah, gotcha. Reading too much at once. I wish I knew exactly, but this being the only one I've had the pleasure of tinkering with, I don't know. Everything just happened to work out. I did some reading on here, ran across the 720 in the weeds, looked it over and said, "Hey this will swap".

[davis62]

The heat stain is from me using a grinder to shave down twith ods so that a threading die would fit on. The rods have a shoulder beyond the OE threads that is too large to thread at 14mm. Once I had it shaved down, I just spun the die down the existing threads and continued threading until there was enough to work with the 620 bracket position.

 

I pie-cut the bottoms of my uca towers so that I could lean the down and outwards in order to provide more surface to mount an upper bag plate to and to compensate for the uca being too short. I was able to bend the towers out enough to straighten out the camber angle. Getting the uca's from beebani or anyone else that makes them is the way to go. What I did was cheap and by no means a great way to do it, but it did the job.

[davis62]

ok. cool ive got the upper controll arms fitted with the lower ones just ripped the whole lot out of a 83 720 king cab and whacked it under the 74 gn620. first problem was the steering wheel doing the oppisite of returning to centre. car was angry. had to drive it home. then i read somwhere swap uca 's from side to side. so much better. at least i could drive it. id straight up buy custem uca's from sombody but i thaught here in australia it could be a problem. meeting design regs have to be certified?

[JNHEscher]

Ya I've read that everything in Aus has to pass a certified inspection. That sucks, man, but its a good idea. Some of the hack things you find on the roads here get scary.

My steering did the same thing. Go around a corner and it wanted to dive further into the turn. I swapped my uca's and got some improvement. Its drive able, but still trouble. No driving with your knees.

[davis62]

Ya I've read that everything in Aus has to pass a certified inspection. That sucks, man, but its a good idea. Some of the hack things you find on the roads here get scary.

My steering did the same thing. Go around a corner and it wanted to dive further into the turn. I swapped my uca's and got some improvement. Its drive able, but still trouble. No driving with your knees.

mynes pretty good now. i mean im i. the ballpark, id upload this alignment sheet i have but i havnt fivured out how to yet. its fruztrating.

so ial quote y alignent report. currently i have camber -1°57 ps and 1°28 ds, caster should get better but currently i have +2°52 ps and +00°37 ds. so instead of grinding down the caster rod and running the 14mm thread down further im lookin at buying a 13/16 die and running it down past the step. using 2 nuts on each rod so i can adjust the caster and lock the furthest foward nut. hopfully ghat wittl sol e the caster problem and hopefully some of the camber problem. iam more leaning to folding my towers out as u did by notching my towers. im looking at dropping an l20b in with 5 speed so i.want to sort steering issues out first. i see you made your tie rods adjustable. do u or any body know if the 720 tie rods and ends will fit the 620 drag link. this info would be greatly use full. and hay thank you all so much for all the info im new to posting to forums and i highly appriciate everybodys knowlage and patientice

[JNHEscher]

The 720 tie rods should fit with no issue. They have adjuster sleeves which will allow you to rotate the end accordingly. I avoided the 720 rods because they're so much thicker than 620. I had to have the clearance for air bags. Just keep in mind the bending the tower down will take away the upper shock mount. I'll get a pic of how I mounted my shocks.