Adjustable strut rods... adjustment?

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67dartgtgo

67dartgtgo

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Ok...I plan on rebuilding my 67 Dart front end and have new PST adjustable strut rods. My question to the suspension gurus is how do you know where to adjust them too after installation? I've rebuilt a spare set of LCA's with support plates and new bushings. Have a set of firm feel tubular UCA's from a previous purchase I plan on using along with new 1.03 PST Torsion Bars. I don't have anything apart yet as I'm still debating additional parts purchases and the car's still very drivable as is.
How can I know how far forward or back to locate the LCA with the strut rod adjustment? Thanks guys.
 
So when I set up my adjustable strut rods I install the LCA's completely with the torsion bars. I use poly or Delrin LCA bushings, so the LCA pivots get torqued. I install the spindles, the UCA's, and all the bump stops. That way you should have the LCA's and the suspension where it's going to be, and you know the range of travel. Then I set the length of the strut rods so that there's no binding when I cycle the suspension through it's range of travel, bump stop to bump stop. That's done with the torsion bar adjusters removed from the LCA's and without the shocks, so you're just working against the weight of the suspension. The idea there is to replicate how the suspension will act when it's on the road. In the past I've also done a rough adjustment with just the LCA's because they're easier to move around than the whole suspension, but I found that bolting up the rest of the suspension changes enough things to make setting it with just the LCA not worthwhile. Plus it can be hard to gauge what the actual range of travel is with just the LCA.

I set my strut rods as short as they'll go without causing any binding at the LCA. That keeps the LCA forward on the LCA pivots (because the poly bushings let the LCA's slide on the pivots), and also may get you some additional positive caster. Free movement of the LCA is the most important thing, but with that set up a little extra positive camber usually comes with.
 
Perfect blu....that's exactly what I was looking for. I wasn't sure just how short to go but figured that was the way I would start it out and see if I had any bind then back it off from there. Thank you.
 
72bluNblu said:
So when I set up my adjustable strut rods I install the LCA's completely with the torsion bars. I use poly or Delrin LCA bushings, so the LCA pivots get torqued. I install the spindles, the UCA's, and all the bump stops. That way you should have the LCA's and the suspension where it's going to be, and you know the range of travel. Then I set the length of the strut rods so that there's no binding when I cycle the suspension through it's range of travel, bump stop to bump stop. That's done with the torsion bar adjusters removed from the LCA's and without the shocks, so you're just working against the weight of the suspension. The idea there is to replicate how the suspension will act when it's on the road. In the past I've also done a rough adjustment with just the LCA's because they're easier to move around than the whole suspension, but I found that bolting up the rest of the suspension changes enough things to make setting it with just the LCA not worthwhile. Plus it can be hard to gauge what the actual range of travel is with just the LCA.

I set my strut rods as short as they'll go without causing any binding at the LCA. That keeps the LCA forward on the LCA pivots (because the poly bushings let the LCA's slide on the pivots), and also may get you some additional positive caster. Free movement of the LCA is the most important thing, but with that set up a little extra positive camber usually comes with.
Click to expand...
@72bluNblu
Do you set them to have a little forward pull to support the lca ??
I built a mickey mouse set to help beef up my magnum force setup, I was kinda worried about the back bolt shearing off the lower arm.
Didn`t put much pull on them, and have no binding. ?????
 
I followed what Blu said when I did mine, which were QA1 but the PST are similar in design. Given the pivot point of the spherical rod end, there will be a point through out the arc of the from bump stop to bump stop that you will get a small amount of resistance. This is because the center line pivot of the special end is not inline with the center line pivot of the lower control arm. Also, make sure you clock the bracket to clear the rod as it moves up and down. Its a rial and error deal, just mock it up and play with it. It like rocker arm geometry, sometime you can only get so close to perfect and live with it. Once ride height is set, front end aligned you may need to go back to adjust them some. I also installed grease-able lower control arm pivots at the same time.
 
famous bob said:
@72bluNblu
Do you set them to have a little forward pull to support the lca ??
I built a mickey mouse set to help beef up my magnum force setup, I was kinda worried about the back bolt shearing off the lower arm.
Didn`t put much pull on them, and have no binding. ?????
Click to expand...

I set them so there's no binding in the range of travel, that's the priority. I try to set them up so they're at the forward end of that "no binding" range though, so usually there is a little bit of forward tension on the LCA. With the poly or Delrin LCA bushings that helps keep the LCA located better.

dano said:
I followed what Blu said when I did mine, which were QA1 but the PST are similar in design. Given the pivot point of the spherical rod end, there will be a point through out the arc of the from bump stop to bump stop that you will get a small amount of resistance. This is because the center line pivot of the special end is not inline with the center line pivot of the lower control arm. Also, make sure you clock the bracket to clear the rod as it moves up and down. Its a rial and error deal, just mock it up and play with it. It like rocker arm geometry, sometime you can only get so close to perfect and live with it. Once ride height is set, front end aligned you may need to go back to adjust them some. I also installed grease-able lower control arm pivots at the same time.
Click to expand...

It really is a trail and error kind of thing between adjusting the length of the strut rod and adjusting the clocking on the K frame mount. That's also why I set the length with all the suspension except for the shocks and torsion bar adjusters attached. Different lengths have different areas of resistance, and you want to match everything up so that you get the least resistance in the actual range of suspension travel that your car uses.
 
72bluNblu said:
It really is a trail and error kind of thing between adjusting the length of the strut rod and adjusting the clocking on the K frame mount. That's also why I set the length with all the suspension except for the shocks and torsion bar adjusters attached. Different lengths have different areas of resistance, and you want to match everything up so that you get the least resistance in the actual range of suspension travel that your car uses.
Click to expand...

As I recall this is what I did, biasing any resistance to the bottom side of travel. It took me several days of playing with it to get it figured out.
 
Thanks dano...I've been researching and at this point I'm not worried at all. I figure I can't be worried about how long it takes or maybe getting it right on the first time...as I get older I realize I'm just not as on my "A" game as I used to be. Slow and steady, one thing at a time, in order seems to be working more for me these days.
 
67dartgtgo said:
Thanks dano...I've been researching and at this point I'm not worried at all. I figure I can't be worried about how long it takes or maybe getting it right on the first time...as I get older I realize I'm just not as on my "A" game as I used to be. Slow and steady, one thing at a time, in order seems to be working more for me these days.
Click to expand...

It’s not that bad to do. It takes some playing around with it, but once you’ve gone from binding to free a couple times you get the hang of it. The first one you do will take 2 or 3 times as long as the second one.
 
I just got some RMS adjustable struts. They look exactly like the PST ones.
The only thing I find thats a pain with installing these is that you have to leave the LCA side of the new strut loose to make adjustments at the heim side. The problem with leaving the LCA loose is that when you adjust the strut length, the LCA side wants to thread or un-thread itself, moving that side of the strut either closer or further away from the LCA. Then, when you do tighten that side up, it changes the overall length of the strut.
But...I totally appreciate the tips here on how to get it right. It makes sense to keep most of the front suspension together and then test for binding through the range.
Its funny because the directions to install these say to just cut out your old struts and adjust the new struts so you have 3/4 of an inch of thread showing and install. Done, simple, easy...lol
 
"the directions to install these say to just cut out your old struts and adjust the new struts so you have 3/4 of an inch of thread showing and install. Done, simple, easy...lol"


Yeah, I got a kick out of the level of detail given too.
 
ChuckDock said:
I just got some RMS adjustable struts. They look exactly like the PST ones.
The only thing I find thats a pain with installing these is that you have to leave the LCA side of the new strut loose to make adjustments at the heim side. The problem with leaving the LCA loose is that when you adjust the strut length, the LCA side wants to thread or un-thread itself, moving that side of the strut either closer or further away from the LCA. Then, when you do tighten that side up, it changes the overall length of the strut.
But...I totally appreciate the tips here on how to get it right. It makes sense to keep most of the front suspension together and then test for binding through the range.
Its funny because the directions to install these say to just cut out your old struts and adjust the new struts so you have 3/4 of an inch of thread showing and install. Done, simple, easy...lol
Click to expand...
Update:
Well, after removing the shock, and the bolt on the strut at the LCA end, it was super easy to see the horizontal travel the LCA has with no strut attached. So it was just a matter of moving the LCA slightly towards the front of the car, then adjust the strut to just fit in. Then put the bolt back in at the LCA side. Then test travel to make sure no binding.
 
ChuckDock said:
Update:
Well, after removing the shock, and the bolt on the strut at the LCA end, it was super easy to see the horizontal travel the LCA has with no strut attached. So it was just a matter of moving the LCA slightly towards the front of the car, then adjust the strut to just fit in. Then put the bolt back in at the LCA side. Then test travel to make sure no binding.
Click to expand...
Update #2:
For you guys considering adding these to your car, plan on buying a 5/8 inch drill bit, and a 1/2 allen wrench if they are not in your current tool collection. I had to open the LCA holes a little to fit the massive allen bolt through the LCA and the allen bolt requires a 1/2 allen tool.
 
@67dartgtgo, not that I mind looking at the Dart and the Vette (they're both amazing) but jeez, that's got to be the biggest signature picture ever. :D

 
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