Technical Advice to get more steering

Well flaming rivers quick ratio box is 4.5 turns lock to lock.
I'd say you need to check out this 2-3/4 turns lock to lock.


And by looking at pics in post 7, there's not much a longer or shorter drag link will do to solve the tire to drag link interference in a left turn.

I'd say there could be a bunch of issues and everything I said earlier was without the key piece of only 2-3/4 turns. Everything maybe fine or it may be all fucked up, but the main actor isn't functioning

 

I understand the point of what you he said and what you added but even with it done like that the stop bolts and tires will not reach the stop or wishbones. I'm thinking I have an issue with steering box that I need to tackle first. 2 3/4 turns lock to lock doesn't seem like enough

 

I will attempt to explain it better, Ray. I understand your parallelogram theory somewhat, but disagree.
It is very difficult to explain with words, as opposed to creating a model( which I have done). Maybe someone with better computer skills can create or post a 3D model for us?
Just try to imagine the axle traveling upward on the arc that is created where the wishbone attaches to the frame. As the axle travels up, it also moves slightly rearward because it is traveling on an arc. As it travels rearward, it pushes the pitman arm back an equal amount, therefore steering the car ( bumpsteer).
People tend to think that the geometry used in a parallel four bar carries over to the wishbone/ drag link relationship, but they are two different things.
If you look at Ford's original design, you will see that it matches my description in my original post. It doesn't matter whether the wishbone is split or not.

 

Charles, I would agree you need to look into the 2 3/4 turn thing first. That is curious.

 

Thanks for all the help guys, I haven't had this much input on a thread and appreciate it lots. I think I will start with the box issue and go from there. I will keep this updated once I get to that point

 

Wish I could post a video, it's such an odd thing, I'm not sure how I missed that when I was in the fabrication stage

 

metal man, thank you for the reply. I thought about making a scale model with paper/cardboard
and may do that. I do understand the arc of the front axle. However, it seems to me the drag link
moves in an arc for the same reasons. If the radius rod and drag link are the same length they should
move in the same arc. Does that not negate any steering input from axle movement?

Ray

 

It's not enough. My Corvair reversed box is 4.5 turns lock to lock. There is something wrong with your box.
As far as the left tire hitting the drag link, sprint cars use a bent drag link that hooks around the tire, so they can turn farther left. Works just fine.

The rear of the drag link looks like it need to be mounted where the center of the steering shaft is for best geometry, parallel with the bones.

 

Stock Corvair box is about 4.5 turns Lto L . Run into that issue one time with lack of travel, my friends did not assemble the box correctly. Took it back apart and reoriented the ball nut and sector and that fixed it.

 

No, it does not. Think of a triangle, drawn from the wishbone attachment at the frame, to the front attachment of the drag link, and back to the drag link attachment at the pitman arm.
If you can visualize that triangle, now imagine it pivoting at the wishbone mounting point as it does when the suspension travels. What happens to the point where the drag link meets the pitman arm? It moves back, steering the car to the right.- Jim.

Edit:'this particular post is based on a situation where the wishbone and drag link are parallel or near parallel . If it is set up the way I described in my first post ( the way Ford did it) it does not push the pitman arm back, and therefore does not bumpsteer .

 

To get full wheel turning movement, it doesn't matter if the steering box is two turns, or ten turns, lock to lock. It is a matter of geometry....lever length.... The difference between a small number of turns in the steering box, or a larger number, is the effort it will take to turn the steering wheel.

I think 31 Vickie pretty well covered the issues. Assuming you have the steering box centered with the
wheels in straight ahead position, shortening the steering arms at the spindles would provide a cure.
That is a simplified answer as there may be other issues that arise from clearances, etc. But as for the
geometry outcome, it is correct. It is true that lengthening the pitman arm would do the same thing,
but it seems plenty long to me.

The issue of drag link angle is being debated here, as you have read. But, in general, I agree with those that advocate re-reversing the steering box, lowering it's mount, and facing the pitman arm upward.
Now, if analytical geometry proves one or the other drag link angle theory (more) correct, then maybe that suggestion would be withdrawn.

EDIT: I just read the post that the lock to lock should be 4.5 turns and that the box may be assembled incorrectly. THAT, by all means, should be corrected, if that is true.

Ray

 

How about convert to Vega type cross steering.

 

I believe this steering problem can be fixed pretty easily by fixing the steering box itself, and possibly shortening the upper left steering arm. I believe now that the box has a problem and that is all it really needs. Changing over to cross steer would be a lot more fabrication.

 

All I have to add at this point is, if the box doesn't have 4 1/2 turns lock to lock, if should be looked into. And, side steer, or traditional steer if you will, rules, not cross steer...

 

UPDATE: Tore the steering box apart, I bought it originally as a reversed box off of the classifieds section here. It must not have been assembled right. I now do have the 4 1/2 turns now that it is assembled correctly. As far as my left turn issue with the tire hitting the drag link as well as the bump steer/death wobble I will worry about that at a later date when I can actually drive the car more on the streets without it being Wisconsin temp.

 

Very good.

 

This is how I see setting up drag link angles.
As the axle moves up and down in the Y axis rotating about the bones mounting point, it moves back and forth in the X axis a certain amount. If the drag link is the same length as the bones and is mounted parallel to the bones, the front of the drag link will swing in the same arc and move the same amount in the Y and X axis as the axle and will induce no bump steer. Any variation with the length of the drag link or out of parallel will induce bumpsteer because the arcs do not match. The more variation, the more bumpsteer.
The OP's setup will have wicked bumpsteer.

 

Steering drag links have been mounted like the OP's since, well since split bones. Intersecting points, or parallel work fine, the longer the better. Yes they/we get away with less than perfect geometry since the travel of the front axle is around 2 inches most of the time. As long as they are within a couple inches or so in length, there will be no ill effects.

 

I understand where you guys are coming from, but I still disagree . I wish you would make a model or a simple drawing with the aforementioned triangle.
By the logic above , all '28-'34 fords would have wicked bumpsteer . It doesn't work that way.
I will say this, the problem gets worse the shorter the wishbone or with more travel.

 

The triangle you talk about is not a constant. It is changing shape.

 

No problem with the OP's set up, this is how it has been done and will continue to be done. My previous post explains it.

 

Hey, charlesincharge09, I really hate to rain on your parade, BUT that Corvair steering box is super lightweight and used very seldom in a ride with engine in front. Most all builders today use cross-steering because it works so good and eliminates bump-steer, which you have because your tierod is different length than your split wishbones, therefore each travels in a different plane. And, don't let anyone tell you that cross-steering is not "traditional". Model T Fords and '35-'48 Fords had it. Please think hard about that weak steering box. Vegas or GM 525 boxes are small yet work great. FYI, the GM 525 comes in Novas and other body styles in that weight class.

 

Listen to metal man, 09. The wishbone and draglink need to be not only parallel, but the same total length, including tierod ends or heim ends, whatever you are using.

 

Not true.

If you were running a parallel 4-bar setup this would be true.

With radius arms, or split bones, the drag link needs to be on a trajectory that intersects the pivot of the arm/bone, the longer the better, but not past.

Ideally, the rear TRE on the drag link would be aligned with the arm/bone pivot.

 

I don't want this to turn into a urination contest, but...
Let's define bump steer, shall we? When you're driving straight down the road without turning the steering wheel, and the suspension travels up or down resulting in a steering of the wheels left or right, you have bump steer. Ideally, the suspension should travel from full bump to full droop without steering the wheels. Virtually impossible to achieve, all cars whether they have solid axles or independent suspension, have some amount of bump steer. With all due respect, Metal Man, in posts 33 and 40 you talk about various things pushing the pitman arm back, thus steering the car. The only way the pitman arm moves is if the driver turns the steering wheel. That's not bumpsteer. The point where the drag link joins the pitman arm is a fixed point around which the drag link rotates, when you're driving straight down the road.
In a car with a straight axle, wishbones and side steering: the least amount of bumpsteer will be achieved when the wishbones and drag link are parallel and horizontal at ride height, and they are the same length. If for whatever reason (shorter length, different angle off horizontal) suspension travel causes the front end of the drag link to exhibit more fore and aft movement than the king pin, (which travels with the axle and wishbone), the drag link will push or pull on the steering arm of the spindle, thus rotating the wheel around the king pin. It then becomes a question of how much bump steer is tolerable to the driver.
There are many good books on chassis and suspension theory and design readily available. Sophisticated race cars and buggy sprung hot rods are all subject to the same laws of physics and geometry. The factory engineers and designers didn't understand bumpsteer till the 1950's.

 

I have to guess that bumpsteer was minimized in "28thru '34s because the draglink had a greased spring and socket off the sector which apparently "adjusted" the obvious bumpsteer created by the difference between a wishbone measuring about 45" versus the draglink measuring about 30". What do you think, metal man ? Am I full of shit like my "buddies" claim ?

 

The aforementioned "parallelogram hypothesis" does hot hold up under examination.

In order for a parallelogram to exist, all for corners of the rectangle must be unconstrained. In other words, the must all be capable of moving.

In the case of a radius arm or split wishbone suspension setup, only three of the four corners are unconstrained.

The corner of the "would be parallelogram" which is where the arm/bone meets the axle is constrained. It is fixed. It cannot move.

It is therefore not a parallelogram, and the hypothesis is void.

 

Take a good look at 117harv's pictures.

That is the correct way of doing this, from and engineering standpoint.

 

I am not referring to Model A's or the early V-8 Fords. They obviously had short draglinks which weren't close to being parallel to the unsplit wishbone. I DON'T understand how those draglink cars didn't have horrible B.S. My only guess is the spring-socket on the rear of the draglink. Please enlighten me. Have you been to Pier 39 lately ?

 

Pier 39 is for the tourists. Locals steer clear.

Early Fords had terrible bump steer. I learned to drive in a 1930 Model A pickup, all stock.

It was unpleasant, by the standards of today day.

The only thing that made it survivable was the short suspension travel at speed.

The spring loaded joint helped, but I still remember the pain of having the steering wheel spokes hit mu thumbs.