Question ,is there a way to make a k frame with r&p steering without using an expensive aftermarket one ?
home made k frame
- Thread starter squidbob
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If you can weld- go for it!
junkyardhero
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sure, if you can fabricate.
the biggest problem is that the t-bars and lower control arms pick up off of the K as do the strut rods, so your engineering and measurements have to spot on. the steering portion isn't as critical in that you can correct a bunch of that with rack placement and some bumpsteer blocks.
but you're likely going to go coil over, so that solves some problems and creates a whole 'nother set of 'em.
the biggest problem is that the t-bars and lower control arms pick up off of the K as do the strut rods, so your engineering and measurements have to spot on. the steering portion isn't as critical in that you can correct a bunch of that with rack placement and some bumpsteer blocks.
but you're likely going to go coil over, so that solves some problems and creates a whole 'nother set of 'em.
Super-Cuda
MOPAR .. Move Over, Plymouth Approaching Rapidly!
A few of questions you need to ask yourself.
1. Do you know enough about suspension and steering geometry and the body structure engineering to attempt this?
2. Are you an experienced welder?
3. Are you willing to bet your life on the results?
Cheap is relative.
1. Do you know enough about suspension and steering geometry and the body structure engineering to attempt this?
2. Are you an experienced welder?
3. Are you willing to bet your life on the results?
Cheap is relative.
Read post number 4 very carefully and reread it many times. Especially item #3.
67Dart273
Well-Known Member
Engineering. Engineer. Math. Maff is hard.
Also realize this:
Just because someone manufactured one and markets the thing does not mean it is strong enough. Or that it has even been engineered mostly "at all." It also does not mean that a given product can put up with street use, jouncing, impact, cornering / side/ front/ rear braking, the bouncing of the tremendous force of an engine mass against it.
Also realize this:
Just because someone manufactured one and markets the thing does not mean it is strong enough. Or that it has even been engineered mostly "at all." It also does not mean that a given product can put up with street use, jouncing, impact, cornering / side/ front/ rear braking, the bouncing of the tremendous force of an engine mass against it.
Super-Cuda
MOPAR .. Move Over, Plymouth Approaching Rapidly!
Absolutely correct!
I saw first hand, the results of poorly engineered and shoddy workmanship in manufacturing K members from a company that is now defunct.
It was taken over and revamped by QA-1 .
I can't speak on the quality of their re-released products but it seems by the number of vehicles built with their components I have seen on here, they have improved.
67Dart273
Well-Known Member
I realize that the T bars, etc, can be a challenge to would be swaps etc. But the long lived almost nearly design unchanged front suspension, which, really, exists not only from the first A bodies but the larger cars as well, and in the case of A bodies, even just the 67-76 series nearly unchanged design. and still survives today!!
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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There may be a good reason to consider a Rack-N-Pinion steering, but for the street, I don't know of it.
I have a revamped QA1 k-member and although it is a nice piece, the mounting brackets for the strut rods are a few degrees off and not spot on. Otherwise, they are nice.
I've built a rat rod air ride suspension before.
Burn those welds in.
Don't be afraid to change it.
Go slow on test rides, widening your distance from home slowly.
Be methodical.
its just life. Nothing permanent.
I'm building a pushrod suspension for the '34 and will probably hack in some A body stuff for T bars to have that F1 look.
Burn those welds in.
Don't be afraid to change it.
Go slow on test rides, widening your distance from home slowly.
Be methodical.
its just life. Nothing permanent.
I'm building a pushrod suspension for the '34 and will probably hack in some A body stuff for T bars to have that F1 look.
Is there a way? Of course there is.
But if you want it to be something that actually drives and handles well and will last on the street by the time you've done everything you'll need to do to be successful you'll almost certainly be behind the "time is money" curve compared to the products already out there. There's a reason they cost what they do.
The R&P basically has to be front steer to fit, which means Ackerman has to be accounted for. You can use MII stuff like everyone else does, but there's still steering angles, roll center, camber curves etc to consider because using MII stuff with different suspension points changes all of it. And that's before you even get into where the chassis was designed to carry the suspension loads.
Exactly.
Exactly. There are products out there that won't hold up on the street, and even the widely used and established coil over conversions don't really address all of the chassis loading changes that occur with the conversion. How much chassis reinforcement is needed is a matter of opinion, clearly the major players have had their conversions on the market for a long time. But some of those cars are reinforced above and beyond the conversions, and many aren't driven all that much or competitively. So what should be done and what you can "get away with" are different things.
Very good points^^^^
R&D could take a couple tries.
If you could get your hands on one of the aftermarket and copy a bunch of the pickup points, that would narrow down some mistakes.
But why??
Header clearance?
Rack?
R&D could take a couple tries.
If you could get your hands on one of the aftermarket and copy a bunch of the pickup points, that would narrow down some mistakes.
But why??
Header clearance?
Rack?
weedburner
Well-Known Member
I've designed a few K-members, here's one that I used to produce that allowed putting SBC/LS engines where a rotary used to be in the '93-up Mazda RX-7. Made mostly from 14ga sheet, lighter than the factory unit but plenty durable for autocross and road racing. Pretty easy to make a jig for as the stock subframe had great suspension geometry, just needed a redesign to make room for a rear sump pan and lower V8 crankshaft location...
There's a lot to be considered when fab'ing up a K-member from scratch. If you want to install a rack where one didn't exist, you need to find a rack with an effective width that works with your existing control arm geometry.
Back in the mid '80's when I designed my first Dirt Latemodel chassis, I basically designed the front frame around the steering rack that I planned to use. I chose a Ford Fairmont power rack, as it was cheap and easy to find in junkyards at the time. I started by drawing a front view mock-up of the components on poster board, which allowed me to work out control arm locations/lengths that worked with the Fairmont rack width and spindles I planned to use. The goal was to minimize bump steer and give me a front roll center that worked. The downside to using a Fairmont rack was 3 turns lock/lock, but I fixed that by making a home-made quick steer box out of a T-350 planetary. Effectively converted that 3 turn rack into a 1 turn rack. I had more time than money, using the junkyard rack just made sense.
With all the front suspension mounting locations worked out, I made a simple jig that located the steering rack in relation to the upper/lower control arm locations. Then built the rest of the car around that jig.
There's also spindles to consider. If you are converting from rear steer to front steer, simply swapping the spindles side/side will have a huge effect on your Ackerman geometry. Ackerman geometry is designed mostly into the spindle arm and controls how much the toe changes as the steering angle changes. Swapping the spindles side/side will have the effect of converting a rear steer car's stock Ackerman geometry to anti-Ackerman geometry....
...Textbook Ackerman generally keeps all 4 tires aligned 90* to a common radius center as the front tires are steered. Basically the inside front tire needs to turn a tighter arc than the outside front tire. For a daily driver on the street, textbook Ackerman will minimize tire wear. It will also make the car easiest to push by hand regardless of steering angle.
...Zero Ackerman is where both front tires steer in the same direction without regard to how tight the steering arc might be. I've seen lots of tube frame drag cars with no Ackerman.
...Anti-Ackerman is something we use with the dirt cars as it helps keep the car from spinning out under power. With the tail hung out thru the turns, anti-Ackerman keeps both front tires pointed in the direction that the car is traveling. Generally makes a car handle better when it gets out of shape under power, but hard to push by hand around corners in the pits.
With driving Outlaw Dirt Latemodels in my background, I don't mind some anti-Ackerman in my street/strip rides
Grant
There's a lot to be considered when fab'ing up a K-member from scratch. If you want to install a rack where one didn't exist, you need to find a rack with an effective width that works with your existing control arm geometry.
Back in the mid '80's when I designed my first Dirt Latemodel chassis, I basically designed the front frame around the steering rack that I planned to use. I chose a Ford Fairmont power rack, as it was cheap and easy to find in junkyards at the time. I started by drawing a front view mock-up of the components on poster board, which allowed me to work out control arm locations/lengths that worked with the Fairmont rack width and spindles I planned to use. The goal was to minimize bump steer and give me a front roll center that worked. The downside to using a Fairmont rack was 3 turns lock/lock, but I fixed that by making a home-made quick steer box out of a T-350 planetary. Effectively converted that 3 turn rack into a 1 turn rack. I had more time than money, using the junkyard rack just made sense.
With all the front suspension mounting locations worked out, I made a simple jig that located the steering rack in relation to the upper/lower control arm locations. Then built the rest of the car around that jig.
There's also spindles to consider. If you are converting from rear steer to front steer, simply swapping the spindles side/side will have a huge effect on your Ackerman geometry. Ackerman geometry is designed mostly into the spindle arm and controls how much the toe changes as the steering angle changes. Swapping the spindles side/side will have the effect of converting a rear steer car's stock Ackerman geometry to anti-Ackerman geometry....
...Textbook Ackerman generally keeps all 4 tires aligned 90* to a common radius center as the front tires are steered. Basically the inside front tire needs to turn a tighter arc than the outside front tire. For a daily driver on the street, textbook Ackerman will minimize tire wear. It will also make the car easiest to push by hand regardless of steering angle.
...Zero Ackerman is where both front tires steer in the same direction without regard to how tight the steering arc might be. I've seen lots of tube frame drag cars with no Ackerman.
...Anti-Ackerman is something we use with the dirt cars as it helps keep the car from spinning out under power. With the tail hung out thru the turns, anti-Ackerman keeps both front tires pointed in the direction that the car is traveling. Generally makes a car handle better when it gets out of shape under power, but hard to push by hand around corners in the pits.
With driving Outlaw Dirt Latemodels in my background, I don't mind some anti-Ackerman in my street/strip rides
Grant
Dave999
Well-Known Member
here is how Elko performance in Australia do it
variable rate rack off a holden, you can have power or manual
this is what the advert said
$1295 -AP6 & VC slant 6 Valiant Rack & Pinion setup- 1 only- Includes
Modified k frame,
power rack
tie rod ends
intermediate shaft
steering knuckles
Modified steering shaft
Can be converted into V8 setup with our V8 conversion mounts
if you want one "Left hand drive" and later style K you would have to call them, they don't keep them on the shelf and their website is rubbish at illustrating any of the parts they may have to sell
The rack is off a holden (australia) /chevy caprice police car 2011-17 (USA)
can't comment on bump steer or sump problems. never had one
Elko Performance
variable rate rack off a holden, you can have power or manual
this is what the advert said
$1295 -AP6 & VC slant 6 Valiant Rack & Pinion setup- 1 only- Includes
Modified k frame,
power rack
tie rod ends
intermediate shaft
steering knuckles
Modified steering shaft
Can be converted into V8 setup with our V8 conversion mounts
if you want one "Left hand drive" and later style K you would have to call them, they don't keep them on the shelf and their website is rubbish at illustrating any of the parts they may have to sell
The rack is off a holden (australia) /chevy caprice police car 2011-17 (USA)
can't comment on bump steer or sump problems. never had one
Elko Performance
thanks for all the great reply's Jegs sells a good conversion
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