Re: adjustable strut rods
[Re: krautrock]
#2372841
09/18/17 05:10 PM
09/18/17 05:10 PM
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Joined: Jan 2010
Posts: 1,442 NW Chicago suburban area
Mopar Mitch
pro stock
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pro stock
Joined: Jan 2010
Posts: 1,442
NW Chicago suburban area
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I often wonder about the wear of the LCA bushing -- as it passes through the LCA - and the angular effect of moving the LCA forward with adjustable strut rods (to gain positive caster). With rubber LCA bushings (factory stock design), the rubber material can allow some angular flex of the LCA. However, with less forgiving material, such as POLY or Nylon/Delrin, or so far as steel) that angular motion (in other words, no longer a ~90 degree perpendicular attachment), would be causing excess and premature wear on that non-rubber LCA bushing.
I'm currently installing Firm Feel's Nylon/Delrin LCA bushings... and hope they won't prematurely wear out.
I also wonder about POLY strut bushings (from FF) -- if they will prematurely wear out, say, vs the "forgiving" rubber factory design.
Then... there is the heim-joint designs of struts... would they be "pulling" the strut forward/backward within the range of motion (up/down) of the LCA?... and ultimately wearing out the LCA bushings, especially if they are POLY or nor non-rubber?
(I think these concerns could be adjoined within the original poster's inquiry.)
Mopar Mitch
"Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers!
Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
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Re: adjustable strut rods
[Re: krautrock]
#2372893
09/18/17 06:42 PM
09/18/17 06:42 PM
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Joined: Jan 2003
Posts: 2,094 central texas
krautrock
OP
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OP
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Joined: Jan 2003
Posts: 2,094
central texas
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I talked to Dick at Firm Feel, he said heat, a BFH and a really stout bar to hammer it out.
I think I'm going to use some 1/4" plate I have hanging around here and see if I can weld up a form that will go on the front side of the K-Member mount area and use a 5/8" bolt/washers/breaker bar to pull that area back into shape. Atleast get it close, then use some adjustable strut rods to get everything equal. Sucks to pull it apart again but it should go quick now, everything is clean.
How thick is the K-member at the strut rod mount? It's from 1967. Is it two pieces of 3/32" metal sandwiched together??
Mopar Mitch, I was thinking about the arc that the strut rod makes the LCA follow. It can't be much change at all. How long is a strut rod, like 19" or something? the arc of a 19" radius is pretty flat. Then think about the length of the LCA, the effect on the bushing probably isn't too extreme.
Last edited by krautrock; 09/18/17 07:45 PM.
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Re: adjustable strut rods
[Re: Mopar Mitch]
#2373022
09/18/17 11:03 PM
09/18/17 11:03 PM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
About to go away
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About to go away
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Posts: 14,889
up yours
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Then... there is the heim-joint designs of struts... would they be "pulling" the strut forward/backward within the range of motion (up/down) of the LCA?... and ultimately wearing out the LCA bushings, especially if they are POLY or nor non-rubber?
Heim jointed strut rods that I have seen move the pivot location adding a bind to the setup. Yet another aftermaket pos design that many fall for.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: adjustable strut rods
[Re: Supercuda]
#2373042
09/18/17 11:51 PM
09/18/17 11:51 PM
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Joined: Jan 2003
Posts: 2,094 central texas
krautrock
OP
top fuel
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OP
top fuel
Joined: Jan 2003
Posts: 2,094
central texas
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Then... there is the heim-joint designs of struts... would they be "pulling" the strut forward/backward within the range of motion (up/down) of the LCA?... and ultimately wearing out the LCA bushings, especially if they are POLY or nor non-rubber?
Heim jointed strut rods that I have seen move the pivot location adding a bind to the setup. Yet another aftermaket pos design that many fall for. how much shorter is the radius from the closer pivot point and how much tighter does it make the arc?
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Re: adjustable strut rods
[Re: krautrock]
#2373044
09/18/17 11:57 PM
09/18/17 11:57 PM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
About to go away
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About to go away
Joined: Sep 2007
Posts: 14,889
up yours
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Who knows, I'm not about to start buying poorly thought out items to measure and satisfy someone elses curiosity.
Why induce a problem, however small, into your front suspension when you do not have to.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: adjustable strut rods
[Re: Supercuda]
#2374932
09/22/17 11:14 AM
09/22/17 11:14 AM
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Joined: Feb 2010
Posts: 270 Mountain View, CA
68rrunner
enthusiast
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enthusiast
Joined: Feb 2010
Posts: 270
Mountain View, CA
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Who knows, I'm not about to start buying poorly thought out items to measure and satisfy someone elses curiosity.
Why induce a problem, however small, into your front suspension when you do not have to. What math or real world data do you have to back that up? Generally speaking, the cars that are set up with an adjustable strut rod have tighter suspension with stiffer springs and shocks, using less suspension travel; and requiring less of an ark. Moving the origin point of the arc rearward 1-2 inches over that amount of run probably doesn't make as big of a difference in handling as a properly located lower ball joint, which directly effects KPA and handling while cornering.
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Re: adjustable strut rods
[Re: krautrock]
#2374940
09/22/17 11:24 AM
09/22/17 11:24 AM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
About to go away
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About to go away
Joined: Sep 2007
Posts: 14,889
up yours
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It's called geometry and an understanding of how the suspension is supposed to work.
Both the LCA inner pivot and the strut rod pivot points need to be in a line, said line defined by the LCA pin. When you use a heim jointed (get it right) strut rod you relocate that pivot by several inches. Which moves it out of line and induces a bind.
How much bind is irrelevant, it is there. how much the LCA may move is irrelevant, the bind is there.
Why would you put a part in your suspension that will induce a bind?
If you really wanted a strut rod without the bushing compliance some dislike then fab up one with a ball joint and center that joint in the line we talked about earlier. Then you get a solid, no bind connection. Probably cost less than the heim joint junk too.
Once again, I am talking about a strut rod that uses a heim joint as the front pivot point. It may or may not be adjustable, but that is irrelevant.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: adjustable strut rods
[Re: 68rrunner]
#2375326
09/23/17 02:41 AM
09/23/17 02:41 AM
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Joined: Dec 2003
Posts: 22,696 Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,696
Bitopia
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And you should. The conflicting arcs/bind issue is I guess resolvable be re-configuring the LCA original constraints (1 degree of freedom), but only by making, I suppose the strut a non compliant member. That is quickly approaching and exceeding the scope of most of the suspension mods here in this forum. So what is your LCA pivot solution?
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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Re: adjustable strut rods
[Re: krautrock]
#2383562
10/07/17 08:24 PM
10/07/17 08:24 PM
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Joined: Jan 2003
Posts: 2,094 central texas
krautrock
OP
top fuel
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OP
top fuel
Joined: Jan 2003
Posts: 2,094
central texas
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was able to get some time to pull this crap apart again. this is how much the lower pin pulled out. a simple little plate and bolt with some washers on the other side. not perfect, but should be good enough. the hotchkis strut rods have a nice amount of movement in the heim joint so if it is a little cocked to one side it should be fine. as long as i can get good alignment numbers on this side now i'm happy to move on to the next thing to fix on the car. but zero caster and .25* pos camber wasn't going to cut it.
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