Jump to content

Z'd LCA's for 2" drop on kingpin trucks, mklotz70


Recommended Posts

I did a set of these for my NL...nice to have suspension travel back! smile.gif These have been in the works with pl521sss for quite awhile now. I know Canby's coming. I should be knee deep in my own projects, but I've got a couple of these kinds of projects hanging over my head....I'd like to get them done. It's a good thing I took so many pics of my NL's LCA's when I did them!!!! I keep having to refer back to them to figure out what I did!

Disclaimer!!! This is how I did it. I used a set done by a shop in town many years ago as a guide. I think mine are actually stronger. I know they have better ground clearance. Anyway....I don't know that they are stronger. Mine have held up for the last year or so, but I don't drive the NL much. I just don't want to see someone cobble some scrap together, then try to blame my design when there crap breaks! Got it?! Anyone even hints at holding me responsible for their F'ups, I'll quit posting pics of this king of thing all together!!


We start off with two stock 521 lower control arms. these are pretty much the same as the 320/520/620 arms, with some minor differences. The 320 shock mount is different, but that won't matter any way.

I took my templates from the NL's brackets and drew them up in CAD. I printed them in actual size so I could glue them to tag board. It's easier to cut them out with the tin snips. The tag board makes them a lot more durable and gives a tall enough edge to drag a scribe around when marking the metal.

100_4209.jpg

100_4211.jpg

100_4212.jpg

100_4215.jpg

100_4216.jpg




The gussets will "build" a pocket into the arm so that the shock will mount between them, not on top of the arm. It gains about 1.5" of shock travel. I had to do it to the 320 since the shock towers are shorter and the shock would bottom out if mounted on top. Not sure on the 521's if this is needed. It would be a ton easier if it wasn't needed!!!! But...pl521sss wanted the pocket anyway. On the NL...I could drop it another 3" and still have shock travel.....but I'd be metal on metal before then. I make a new tension control rod mount while I'm at it.....so the one hanging underneath isn't needed either. Adds some needed ground clearance!!!

100_4267.jpg

100_4268.jpg

100_4269.jpg

100_4270.jpg




Time to do some marking and cutting. The shaft is from a front strut I cut up. Fits really nicely...not much play. Makes it easier for me to get an accurate measurement. I'm not going to go into explicit detail since this is just for your viewing pleasure smile.gif

100_4280.jpg

100_4283.jpg

100_4285.jpg

100_4294.jpg

100_4296.jpg

100_4297.jpg

100_4298.jpg

100_4299.jpg

100_4300.jpg




You certainly don't find this in any of today's cars!!! Slag!! These were made before MIG was common. The needle scaler made quick work of it, then back in the blast cabinet smile.gif

100_4304.jpg

100_4307.jpg

100_4308.jpg




Started mocking things up to see if the artwork I did was close enough. It needs a few tweaks, but it's pretty close.

100_4312.jpg

100_4313.jpg

100_4314.jpg

100_4321.jpg

Link to comment
  • Replies 220
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

....dang 30 pic limit!! :)

 

The stock 521 shock mount is 1.25" wide. The square tubing is a couple thou wider....should make for a slip fit when done. I put an extra plate on each side for added strength. The shock bolt goes through 3/16", 1/4", the shock, 1/4", 3/16"......I'm pretty sure it's at least as strong as the original design. :) These 1/4" pieces are simply for a thickness reference....not the actual pieces.

 

100_4329.jpg

 

100_4330.jpg

 

 

 

 

Traced the gusset onto the 3/16" plate. The vid is a bit of the bandsaw work. Here's the pieces, waiting to be tacked together.....maybe tomorrow.

 

100_4323.jpg

 

th_100_4331.jpg

 

100_4350.jpg

Link to comment

If my kids wanted to learn/do this stuff......maybe you guys would be spared a bit :)

 

....hhhmmm....Professor sounds a lot better than short, fat guy!! :) Although.....I only have the qualifications for the short, fat guy part!! :(

Link to comment

LOL....that's funny. :)

 

I've been cutting the second set inbetween dipping the new brake brackets in the acid. Madmax sent me some beautiful pieces!! Pics of them will go up in Mend. More pics of the arms should go up tonight :)

 

You didn't say matte or gloss..... ???

Link to comment

My buddy Dave called yesterday and made a comment about how I was giving this info away. Was wondering if I was worried about somebody taking it and making them to sell. My hope is that someone will take this info and take it to the next level, or tackle the project for themselves and save a ton of coin. Z'd control arms used to be a pretty common mod back when kingpins ruled the world :) The set that I used as a model cost $500/set from Charlie's Drop Shop in PDX according to the original owner. They're not near as involved as these. These are done this way to get the rig really low. If you run the torsion bars in the stock location, with stock shocks, these would be much simpler arms. I came up with this design to "tuck" the shock since I reindexed the torsion bars (which ended up back in stock location anyway :( ) I can tell you that if I do any more of these...they'll be much closer to $400 for the set. pl521sss is getting a killer deal :)

 

What I don't want to see is somebody doing a hack job and someone getting hurt. So...do it right or don't do it at all!!! Keep in mind...I'm not an engineer....so if someone sees a flaw in my design....please let me know! I'm running a set of these myself and I'd prefer not to wrap the NL around a pole! :) Anyway........

 

 

....in the ongoing saga.... :)

 

 

I'll start with the vids...get them out of the way. Nothing fancy, just an example for those guys with limited tools. The bandsaw is nice, but @ $500-700...I seriously doubt too many guys have access to one. So....this is just to show that a $20 harbor freight 4.5" grinder and some cut off wheels can get you the same results. At least close enough!! :) It actually took about the same amount of time this way as on the bandsaw. The third vid got cutoff by the camera for some reason....oh well. This is pretty basic stuff and probably pretty boring. I'll probably save doing vids for some of the more entertaining stuff :)

 

th_100_4376.jpg

 

th_100_4378.jpg

 

th_100_4380.jpg

 

 

 

 

These will give you an idea how I set it up to get it lined up. The torsion bar end of the arm is two different thicknesses....plus, using the block/rod, I get it leveled to the holes, not the arm. Everything pivots on the holes. The arm could be off from manufacturing or damage. On the fulcrum pin end, I did check it against the holes, got my reference, compared it to the top of the arms....then shimmed it so the pin will have about 1 deg of caster lean in it. Anyone that has messed around with the front end on these rigs knows that getting caster with the dogbone just isn't going to happen. The LCA holds it where it wants it and just squishes the heck out of the UCA bushings(hence the delrin versions). So, by putting 1 deg in the bottom, the top can lean back at least a little and not kill the stock rubber bushing. Anyway......

 

100_4382.jpg

 

100_4383.jpg

 

100_4385.jpg

 

100_4389.jpg

 

100_4392.jpg

 

 

 

 

 

Sorry there's no pics of it being tacked up. The camera battery died and I was already to this point when I realized my phone would do the trick. The gussets are just resting in place to check fit. I'll give the artwork one or two tweaks and call it good. They're closer than I thought they'd be. Some of the tack welds were not ground yet, so they hold the gussets further away then they should. Both are tacked up and ready for welding. I've been spraying everything down with anti-spatter spray. I'm really starting to like that stuff. It's not that it stops it from spattering, it stops the spatter from sticking!!! Which will save a ton of time on final cleanup and grinding. I'll just have to clean them well with brake clean before I PC them.

 

0527091816-00.jpg

 

0527091817-00.jpg

 

0527091817-01.jpg

 

0527091817-03.jpg

 

0527091817-04.jpg

 

0527091936-00.jpg

 

0527091936-01.jpg

Link to comment

Woah Mike. Crazy awesome goodness here!

 

You know, you have all these photos. You've done alot of write-up allready. Perhapse a how-book is in your future?

Link to comment

One of these days, I'll learn how to do web pages and I'll put these all on olddatsuns.com ....that will be as close as it gets to a book :)

 

Weekend's over...time to head to work :( .......in the NL :)

Link to comment

Thanks Steve. I'm trying to decide if I want to have more gussets cut(water jet) and Z some more of the arms I have around here. I can only think of one other guy that has said he wants a set, but I haven't seen him around in awhile. I think they'd have to sell for around $250/set before I'd get excited about doing any more! That's half of what they used to go for and I doubt anyone is doing them any more...no clue...haven't checked.

Link to comment

Yup, that guy is getting a killer deal on this alright.

With those side gussets on LCA, I can still do 5 feet hydrulic hops that they do on trucks, right?

 

 

 

 

These will give you an idea how I set it up to get it lined up. The torsion bar end of the arm is two different thicknesses....plus, using the block/rod, I get it leveled to the holes, not the arm. Everything pivots on the holes. The arm could be off from manufacturing or damage. On the fulcrum pin end, I did check it against the holes, got my reference, compared it to the top of the arms....then shimmed it so the pin will have about 1 deg of caster lean in it. Anyone that has messed around with the front end on these rigs knows that getting caster with the dogbone just isn't going to happen. The LCA holds it where it wants it and just squishes the heck out of the UCA bushings(hence the delrin versions). So, by putting 1 deg in the bottom, the top can lean back at least a little and not kill the stock rubber bushing. Anyway......

0527091936-00.jpg

 

0527091936-01.jpg

 

Delrin Version, when are we gonna see that?

Link to comment

Go for it! .......as long as your paying full price for the second set!! :)

 

Certainly would be interesting to find out......just not curious to donate a set for the tests! LOL

 

Delrin version of what???

Link to comment
  • 4 weeks later...

Don't have much time for the posting, but I have made some progress on the arms. Geez!!! I forgot just how involved these dang these were!!! I won't be doing any more for less than $300 a pair!!! Anyway......here's some pics :)

 

 

 

Needed to grind down some of the welds to get the gussets to sit flat onto the arms.

 

100_4963.jpg

 

100_4964.jpg

 

100_4965.jpg

 

100_4966.jpg

 

 

 

 

Did a bit of clean up grinding, then a whole lotta welding!!! Some welds are certainly prettier than others, but the metal melted together...so it's stuck!! :)

 

100_4968.jpg

 

100_4970.jpg

 

100_4971.jpg

 

100_4972.jpg

 

100_4974.jpg

 

100_4975.jpg

 

100_4977.jpg

 

100_4978.jpg

 

100_4979.jpg

 

 

 

 

Time to figure out the shock mount. My CAD drawings located the hole pretty close, but I think I'll tweak the drawings....not that I'm doing another set anytime soon!! The shock hits the back of the arm hole when down, the front of the arm hole when up, the bump stop mount when down....basically, it just doesn't want to be there!!! So...had to do some clearancing. Did part of it with the die grinder....some with the mill. Cut the bump stop mount area back a bit with the cut off wheel.

 

100_4985.jpg

 

100_4986.jpg

 

100_4988.jpg

 

100_4989.jpg

 

100_4990.jpg

 

 

 

A few more of the clearancing. The shot of the shock hole is to make sure that the shock will go into the whole further than just lining up....the rubber isolator is going to give a bit in use, this gives it a bit of room to move. The last shot of this set is with it lifted all the way up. With the bump stops in, it won't be this close since it will stop sooner.

 

100_5000.jpg

 

100_5005.jpg

 

100_5010.jpg

 

100_5011.jpg

 

100_5013.jpg

Link to comment

Clamped the arm to the mill to drill and bore the holes. A bit more time to set up, but so much nicer to actually drill them with! Plus...I could zero the DRO and move away from the arm to change the drill bit, then go right back to where I was. The large holes are to clear the sockets needed for the torsion arm bolts. :)

 

100_4992.jpg

 

100_4995.jpg

 

100_4996.jpg

 

100_4997.jpg

 

 

 

Now that the shock mounting is squared away....time to move onto the TC rod mount. For that, I need to hold the arm at ride height....or guessed ride height. I need to fab the tabs first.....so Abraham....if you want more angle to the arm...let me know. :)

 

100_5015.jpg

 

100_5016.jpg

Link to comment

This set certainly reminded me of how much work I put into mine!! And mine were the first.....so they took longer to figure out!!!! :)

 

Hopefully, the next shots will be of them cleaned up and PC'd :)

Link to comment
  • 2 weeks later...

I'm sure glad I'm not waiting for ME!!!! I take forever on some of this stuff!!! :(

 

So I got the arms cleaned up and blasted....set up the PCing stuff.......almost forgot to drill drain holes in the bottom of the shock pocket!

 

100_5140.jpg

 

100_5141.jpg

 

100_5144.jpg

 

100_5146.jpg

 

100_5148.jpg

 

100_5149.jpg

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.