A Body Rack and Pinion Converison

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sydcuda said:
Here's a pic of mine - yeh, right hand drive - but with the rack mounted on arms welded to the K member. The rack is positioned in the same position as the stock drag-link and maintains factory geometry. A Milodon "LoPro" oil pan fits perfectly, with it being notched in the area where the rack passes underneath.

Dont know why you guys over there don't try something like this...there's a lot more room on the left side of the car to fit headers around this kind of rack set-up (it poses a few tight problems on the right side, but doable). Someone over there offers a K member mounted kit for B or E bodies, from memory, so maybe they will eventually offer an A body version.
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Sydcuda, Please post a close up picture of the column attaches to the rack. Looks like an awesome setup.
 
jefflock said:
Sydcuda, Please post a close up picture of the column attaches to the rack. Looks like an awesome setup.
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You mean the arms that extend from the K member, to which the rack is bolted, Jeff? The arms are boxed for strength and were professionally welded using a jig, to ensure correct positioning. This would work on US K frames, and you guys have such an assortment of left hand drive steering racks suited to A bodies to choose from (we dont, basically only a couple of cough..GM (Holden)...cough racks will suit), plus intermediate shafts to suit spline arrangements, it'd be such a cinch.

PS. dont mean to hijack this thread, but may as well put this info here in case anyone is interested.

CIMG1133.JPG


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I really dont see any advantage to a rack in the rear steer setup. A rack is larger than a draglink. Still cant use a truck oil pan. Headers will cook that rack.
 
Anybody tried this system on a car set up for road racing? I'd love to see how it works on something that is meant to handle...
 
RedFish said:
I really dont see any advantage to a rack in the rear steer setup. A rack is larger than a draglink. Still cant use a truck oil pan. Headers will cook that rack.
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You dont see any advantage in maintaining factory steering geometry? Yes the rack is marginally larger than a draglink, but the exhaust is not so close that it would "cook it" at all. I'm using a Milodon high volume pan with it, that's good enough for me. There are pros and cons to forward and rear mounted racks I suppose.
 
i was reading in a mopar action article that some company sells a rear rack setup just like you installed into your car. looks great.
 
Great do it yourself job! I think just getting rid of the steering box is a big advantage. As for headers cooking things,well they do get hot. Shielding and header wrap really help though.

I really feel this rack and pinion conversion will help my big block application. The more room I can get under the hood,the happier I'll be!
 
I was in conversation with Unisteer (.com) over the last couple of years
after seeing their E-body kit. They indicated they were developing an A-body
kit.

I contacted them again at the end of July and found out they have dropped
the A-body project due to costs associated with custom headers.

I suspect it would still be very doable project if an appropriate rear steer
rack was selected.

I'd love to get the existing steering box out of the way as my headers
wrap around it!
 
I'm just going to run block huggers on mine to avoid spending all that coin on custom headers. Or I could get off the shelf tri-ys over here and mod the steering side, but it's more hassle than its worth.

But I'm surprised Firmfeel feel that an A body version of their E body rear rack is not doable....after all you have much more space on the left side of the engine bay to run headers around the rack than you do on the right.
 
I'm still trying to sort out the steering geometry puzzle, akerman angle in particular.
In earlier posts it was stated that this angle is incoperated via the attaching arm on the lower ball joint, and the differences between the left and right hand arms.
I ask you to look at eaby item number 380161464370. Those appear to be mirror image alike. I know the later model arms differ from one another. I guess my question might be when was the akerman angle incorperated and why.
My junior works at a local Quick Lube. I've asked him to look for differences in left and right parts, their lengths, etc., on the many R&P cars he services daily.
He says he is not seeing major differences left to right in these components.
 
RedFish said:
I'm still trying to sort out the steering geometry puzzle, akerman angle in particular.
In earlier posts it was stated that this angle is incoperated via the attaching arm on the lower ball joint, and the differences between the left and right hand arms.
I ask you to look at eaby item number 380161464370. Those appear to be mirror image alike. I know the later model arms differ from one another. I guess my question might be when was the akerman angle incorperated and why.
My junior works at a local Quick Lube. I've asked him to look for differences in left and right parts, their lengths, etc., on the many R&P cars he services daily.
He says he is not seeing major differences left to right in these components.
Click to expand...


If you draw an imaginary line from the balljoint through the outer tie rod centers ,the meeting point from both sides would intersect at the rear axle center point for perfect akerman angle. That is what causes the inside wheel to turn more in a turn. In a front steer application the tie rod needs to be outside of the balljoint so when you would draw an imaginary line from the front tie rod center to the lower ball joint center it would intersect to the rear
Here is link to a good explaination of akerman

http://autorepair.about.com/gi/dyna...le_effect_on_ackerman_steering_principle.html
 
blown71duster said:
If you draw an imaginary line from the balljoint through the outer tie rod centers ,the meeting point from both sides would intersect at the rear axle center point for perfect akerman angle. That is what causes the inside wheel to turn more in a turn. In a front steer application the tie rod needs to be outside of the balljoint so when you would draw an imaginary line from the front tie rod center to the lower ball joint center it would intersect to the rear
Here is link to a good explaination of akerman

http://autorepair.about.com/gi/dyna...le_effect_on_ackerman_steering_principle.html
Click to expand...

i looked at that link and what are the advantages of more or less and all lol. other then tire wear i couldnt tell anything in particular lol
 
click on akerman steering angles on that link. The principle is that the inside tire needs to turn more on a turn.
 
Ok I understand the general pricipals involved. What I dont quite picture is how in the world would you get the tie rod end outside the balljoint center ( front steer ) without getting into the wheel or tire. Also,, The center line of the ball joints reletive to the center line of the rack. What would result from moving the rack further forward of the ball joints, other than more angle in the tierods ?
I sure wish I had something else to drive. The spool mount small block K for this project is in use :(
I do appreciate the responces and that link guys.
 
RedFish said:
Ok I understand the general pricipals involved. What I dont quite picture is how in the world would you get the tie rod end outside the balljoint center ( front steer ) without getting into the wheel or tire. Also,, The center line of the ball joints reletive to the center line of the rack. What would result from moving the rack further forward of the ball joints, other than more angle in the tierods ?
.
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I believe it may be possible to acheive some akerman by moving the rack towards the centerline , at least that is the way I understand it. Notice in this link how they show the wheels on a left turn and angles of them below

http://books.google.com/books?id=5a...esult&ct=result&resnum=6#v=onepage&q=&f=false

I would think you would have to have the tie rod position changed as close to the rotor as possible and move the rack also. And check the wheels on a turning plate with degrees marked to check the angles as the wheel moves.
If you just switched arms from side to side the angles would be way out of wack for sure.
Interesting thread I would like to go to a rack myself.
 
You fellows ever hear of anything called bump steer, or Akermann compensation angles? There are rigid laws of suspension geometrics. Ignore them at your peril.
I watched a guy at the track last year who had a setup just like the one I'm looking at in these pictures, who only escaped shiny side down by a miracle. He hit a dip in the track just past the timing lights at over 120. He said it felt like a giant had grabbed the steering wheel and whipped it from side to side. Scared the crap out of him. Very lucky that's all it did. I can tell just by looking at these tie rod angles that this setup is a out by a mile. I'm sure the owner won't appreciate these comments but if it saves his life I suppose it will have been worthwile.
 
Marshalearp said:
You fellows ever hear of anything called bump steer, or Akermann compensation angles? There are rigid laws of suspension geometrics. Ignore them at your peril.
I watched a guy at the track last year who had a setup just like the one I'm looking at in these pictures, who only escaped shiny side down by a miracle. He hit a dip in the track just past the timing lights at over 120. He said it felt like a giant had grabbed the steering wheel and whipped it from side to side. Scared the crap out of him. Very lucky that's all it did. I can tell just by looking at these tie rod angles that this setup is a out by a mile. I'm sure the owner won't appreciate these comments but if it saves his life I suppose it will have been worthwile.
Click to expand...

i have been running my setup at the track for a couple years now. runs 112 mph all day long. track is rough. drive it on the street alittle. have never had this bump steering issue. i am not saying it won't happen. but i myself have no issues with my setup other than loss of some turning radius. i am not telling people to do this setup. was just sharing my work from a few years back. sure is nice to work on the car without all that damn rear steer and steering box out of the way...
 
One OEM example of front steering that I have here to study is a 92 Mustang.
That tierod end does sit about 1.5 inches outside the lower ball joint center.
Infact they had to cut a hole in the backing plate where about .25 segment of the tierod knuckle peeks through it. That knuckle is very close to the brake rotor. Anyway.. I guess the challenge will be to achieve something similar using the OEM mopar parts.
A better plan for me might be just put this Dakota p/s rack back on ebay where it came from LOL
 
blown71duster said:
If you draw an imaginary line from the balljoint through the outer tie rod centers ,the meeting point from both sides would intersect at the rear axle center point for perfect akerman angle. That is what causes the inside wheel to turn more in a turn. In a front steer application the tie rod needs to be outside of the balljoint so when you would draw an imaginary line from the front tie rod center to the lower ball joint center it would intersect to the rear
Here is link to a good explaination of akerman

http://autorepair.about.com/gi/dyna...le_effect_on_ackerman_steering_principle.html
Click to expand...

Good article. I had heard the term "akerman" but really never understood the physics behind it. Now I understand the pit falls and will wait until I can afford an Alterkation set up that is properly engineered.

Also, I recently checked with Flaming River to check on the possibility of them offering a rack and pinion conversion for A bodys. The answer was no. Probably due to the tie rod center having to be located outboard of the ball joint centerline to achieve proper steering geometry. Probable not feasible with the stock setup.
 
another example to add to my confusion is a 90 something Lincoln Town car.
Front steer r&p yet the tierod ends appear to be about 1/2" inboard of the ball joint center. Maybe width and length of the wheel base has a bearing. Dunno
 
RedFish said:
another example to add to my confusion is a 90 something Lincoln Town car.
Front steer r&p yet the tierod ends appear to be about 1/2" inboard of the ball joint center. Maybe width and length of the wheel base has a bearing. Dunno
Click to expand...

You are right. That doesn't make any sense after what I have read on the subject. ????
 
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