Re: Did a Front Steer Rack Conversion on my Road Runner
[Re: STEFF]
#1541279
11/29/13 01:18 PM
11/29/13 01:18 PM
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Joined: Jun 2004
Posts: 2,360 Mobile Alabama
SB412DUSTER
top fuel
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top fuel
Joined: Jun 2004
Posts: 2,360
Mobile Alabama
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Quote:
Critical comments......Fire away.....I'm cool with it.
I would add a few pieces of tubing to help support the part that the LCA goes in, It will certainly move around when it's stressed like wheel stands or hard braking.
Something like this will help
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Re: Did a Front Steer Rack Conversion on my Road Runner
[Re: Blown61]
#1541281
11/30/13 12:12 PM
11/30/13 12:12 PM
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Joined: Jan 2009
Posts: 813 Ontario,Canada
brads70
super stock
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super stock
Joined: Jan 2009
Posts: 813
Ontario,Canada
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Dude I don't mean to be rude but that's just flat out dangerous and should never be on the road( or track) Your going to kill yourself and/or someone else. I understand your intent and desire and I applaud that but for starters that "steering arm" WILL fail and with catastrophic consequences. The "k-frame will flex and bend and break in short order too. Not to mention how it will steer even if it didn't break. PLEASE PLEASE PLEASE find someone with a lot of experience to help you with this before something very horrific happens. Again your best interests are at heart here, not trying to rain on your parade or insult you in any way.
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Re: Did a Front Steer Rack Conversion on my Road Runner
[Re: Blown61]
#1541283
11/30/13 02:25 PM
11/30/13 02:25 PM
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Joined: Jan 2003
Posts: 3,874 Smyrna, South Carolina
STEFF
OP
master
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OP
master
Joined: Jan 2003
Posts: 3,874
Smyrna, South Carolina
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Quote:
No torsion bars? what holds the back of the lcr in?
thanks
Torsion Bars will be used. They just aren't in, in the pic. I will go to coilovers once I get some front struts in from the cage.
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Re: Did a Front Steer Rack Conversion on my Road Runner
[Re: brads70]
#1541284
11/30/13 02:40 PM
11/30/13 02:40 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Dude I don't mean to be rude but that's just flat out dangerous and should never be on the road( or track) Your going to kill yourself and/or someone else. I understand your intent and desire and I applaud that but for starters that "steering arm" WILL fail and with catastrophic consequences. The "k-frame will flex and bend and break in short order too. Not to mention how it will steer even if it didn't break. PLEASE PLEASE PLEASE find someone with a lot of experience to help you with this before something very horrific happens. Again your best interests are at heart here, not trying to rain on your parade or insult you in any way.
DAMN... some of you thing you have to have a 2" square piece of cast to get the tires to turn... you sure wouldnt like mine
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Re: Did a Front Steer Rack Conversion on my Road Runner
[Re: brads70]
#1541285
11/30/13 03:12 PM
11/30/13 03:12 PM
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Joined: Jan 2003
Posts: 3,874 Smyrna, South Carolina
STEFF
OP
master
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OP
master
Joined: Jan 2003
Posts: 3,874
Smyrna, South Carolina
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Quote:
Dude I don't mean to be rude but that's just fmmlat out dangerous and should never be on the road( or track) Your going to kill yourself and/or someone else. I understand your intent and desire and I applaud that but for starters that "steering arm" WILL fail and with catastrophic consequences. The "k-frame will flex and bend and break in short order too. Not to mention how it will steer even if it didn't break. PLEASE PLEASE PLEASE find someone with a lot of experience to help you with this before something very horrific happens. Again your best interests are at heart here, not trying to rain on your parade or insult you in any way.
Those steering arms are for mock-up and getting bumpsteer and ackerman figured out. Once finalized. A more robust arm will be made.
The k-frame does NOT support the motor. I have a motor plate. I'm going to add an additional rib like SB412duster posted. But, other than that, it'll be plenty strong. It's really no different than someone cutting the center out for oil pan access.
I did plenty of research looking at many different frames, for mopars and many other makes as well. There isn't as much steel in them as you'd think.
Thanx for the input and crtiques.
I appreciate the input and crtiques.
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Re: Did a Front Steer Rack Conversion on my Road Runner
[Re: STEFF]
#1541288
11/30/13 10:39 PM
11/30/13 10:39 PM
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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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I believe when using TB's, the K sees the weight from the motor, whether is on mounts or plate, but when going to coil overs, the k only sees the motor when on mounts, although on coilovers it does see a small %, depending motion ratio stuff.
Last edited by jcc; 11/30/13 10:41 PM.
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: Did a Front Steer Rack Conversion on my Road Runner
[Re: STEFF]
#1541290
12/01/13 11:10 AM
12/01/13 11:10 AM
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Joined: Jan 2005
Posts: 3,635 Oakland, MI
dizuster
master
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Joined: Jan 2005
Posts: 3,635
Oakland, MI
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Ok I'm not trying to stir the pot, but here is my two cents. Tried to explain it in the simplest way possible.
First, remember the old saying. "Every action has an equal and opposite reaction".
When the car brakes, nose dives, comes of a wheelie, etc... here is part of what happens.
First look at Figure "A" in the top left corner.
This is a section through the frame rail and rear attachment point of the K-member. Force #1 represents the weight of the car pushing down in the frame rail. Force #2 represents the force from the lower control arm holding the car up. In principal, this is what keeps the car "Up". You can see that these forces are not in line. What this means is that there will be a "twisting" of the frame rail.
Now look at Figure "B" at the bottom.
You can see the same Force #1 and Force #2. This results in the "twisting" that I was trying to simply explain in Figure A. The twisting is shown as Force #3.
So what counter acts the twisting of Force #3? It's safe to assume that most of Force #1 is also distributed through the front portion of the untouched K-frame. It is much larger/stronger then the rear square tube that was added.
As Force #3 twists up, it creates a Force #4 on the square tube. Force #4 and Force #1 (on the front of the K-Frame) are now "fighting" eachother to keep the car up. This is what normally happens with a stock K-frame.
But what you can envision, is that there is a huge mismatch of strength between the old front box section of the K-frame, and the new 1" square tube that has been added. The new square tube is clearly not as strong as the old boxed K-frame section.
To make things worse, the holes that are drilled for rack attachment bolts, is right through the worst part of the load path in the small square tube.
If Force #1 is hard enough, it will try to bend/break the new square tube because of the translated Force #4. This will most likely occur right at the rear hole that was drilled for fastener access to the rack attachment.
If it were mine, I would cut the square tubes off, replace with adequate size round tube, and weld tabs off the round tube to attach the rack. That way the tube is not compromised because of the rack attachment hole.
Just my opinion....but something to think about.
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Re: Did a Front Steer Rack Conversion on my Road Runner
[Re: dizuster]
#1541292
12/01/13 01:06 PM
12/01/13 01:06 PM
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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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I agree the added square tubing is imo also a problem area, the stress concentration on the mid angle welded joint is going to be rather high, and competing with the thru bolts for weakest area. I think it can be reinforced, or upgraded with a replacement, without starting over. I would not automatically suggest round tubing, as it's greatest strength attribute compared to equally sized square? tubing is torsional strength, and not sure that is a big concern on this support piece.
However the Op's point on the many over the years rather cut-up/butchered drag race k's for oil pan clearance makes for a rather compelling argument, although street/road vs drag are two different animals.
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: Did a Front Steer Rack Conversion on my Road Runner
[Re: STEFF]
#1541293
12/01/13 02:37 PM
12/01/13 02:37 PM
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Joined: Feb 2011
Posts: 1,454 Glendora Ca.
Just-a-dart
pro stock
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pro stock
Joined: Feb 2011
Posts: 1,454
Glendora Ca.
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Steff I have been watching this thread and can relate, I'm in the middle of a K-member project myself for me and a couple of buddies a-body cars.
I would suggest you buy a caster camber gauge (if you don't have one) and set the caster/camber before you spend too much time on the bump steer and shape of the steering arms. It will make a difference, when you move the top of the spindle back it will raise the steering arm and vice versa.
Last edited by Just-a-dart; 12/01/13 02:50 PM.
"Just a Bracket car dressed up like a streetcar"
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Re: Did a Front Steer Rack Conversion on my Road Runner
[Re: redmist]
#1541295
12/01/13 10:51 PM
12/01/13 10:51 PM
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Joined: Jan 2003
Posts: 10,039 MN
JERICOGTX
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,039
MN
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I also built a K member with a rack for my Roadrunner.
69 GTX
68 Road Runner
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Re: Did a Front Steer Rack Conversion on my Road Runner
[Re: STEFF]
#1541297
12/02/13 04:11 PM
12/02/13 04:11 PM
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Joined: Jan 2003
Posts: 2,877 SE Nunya
Bubba
master
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master
Joined: Jan 2003
Posts: 2,877
SE Nunya
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