please explain Manual Quick Radius Steering to me

[SFRT]

turns out this is what I have.

pros?

Cons?

[Ghoste]

I think you mean quick "ratio".  The pitman arm is shorter which moves the center link a little quicker.

[SFRT]

ok..ratio...this gives you better response?

[Ghoste]

Yeah, but with a little more turning effort.  Think of it as the lever between the steering gear andthe steering linkage.  A longer lever moves a load easier but slower and a short one is the opposite.

[Mike DC]

Factory manual boxes ran 24:1 gearbox ratios in stock form. 
There was a 20:1 ratio gearbox made for the NASCAR teams.


The PS boxes were all made as 16:1 ratios. 
The AAR/TA Cudas and Challengers got the longer pitman arm.  It made a 16:1 PS box work as a 12:1 ratio.

   

[Ghoste]

Is the quick one the longer one or the shorter?

[SFRT]

will the gearbox have a stamping on it so I can determine what  XX:X  it actually is? or do i simply have a power steering box with no PS? or is it some 'special' set up ?

because I want to put PS back on it, so can I use this gear box or will i need a different one?

[Mike DC]

The manual and PS gearboxes are two totally different animals.  They look different, the manual one uses a longer steering column because it's a smaller item, etc.

The faster-ratio manual gearboxes (20:1 ratio) are not very common at all.  I'm not 100% on this, but I don't believe there was really any "normal" assembly line usage for them other than the NASCAR teams wanting them. 




The PS gearboxes were large cast-iron deals that had hose fittings for the PS fluid pump.   The shorter pitrman arm (MUCH more common) was the slower ratio.  The longer arm was the fast-ratio thing.  It was a rare item that showed up on those few E-bodies.  Somebody (Firm Feel inc?) reproduces the longer arms now in a couple of different spline sizes & stuff.     

I think there was such a thing as a "Fast ratio PS gearbox" but this was not actually a different PS gearbox ratio.  It's just the normal 16:1 ratio PS gearbox, but it has some internal stops added at the extremities of the gear travel so that the wheels don't get over-steered with the longer pitman arm.  (It's not any big deal if you just swap a longer pitman arm onto an original 16:1 PS box though.  You can fabricate some other little stopper on the LCAs or maybe just let the tires scuff the subframe rails.) 

[Ghoste]

Didn't the 70 Trans Am cars also have a different ratio steering gear in addition to the different pitman arm?

[375instroke]

All PS boxes are 16:1.  The T/As and AARs had a longer pitman available.  I don't know if it was optional or standard, though.  The box on them was still 16:1, but with different internal stops.  The idler arm was the same length so the car turned one way quicker than the other.  I think C-body pitmans and idlers could work, but I haven't tried, and I think the master spline is in a different location, but that is easy to fix.  The 20:1 manual box was a NASCAR type item, I think.  The 16:1 manual was optional, and I found one at a junk yard in a Formula S.  It has about 3.5 turns lock to lock, and is an easy way of checking it out.  The regular 24:1 manual box has about 4-3/4 to 5 turns lock to lock.

[Ghoste]

What is the advantage of the different stops in the TA box?

[Mike DC]

No advantage other than it stops the wheels at the extremes of their side-to-side travel.  Without it, the wheels just turn until the inner side of the tires hit the framerails.  That's all the stops do.

(The "stops" are not any kind of complicated valving setup or anything. They are literally just pieces stopping the mechanical parts from moving past a certain point.  You can weld a little chunk of metal or something onto the control arms to do the same job.)

[Ghoste]

So why would the TA box need unique stops from the other E-bodies?

[Mike DC]

Because with the longer pitman arm (quick ratio setup), it's gonna be able to push the wheels farther than the stock setup does already.  The added internal stops were there to fix a side-effect problem with the basic pitman arm change. 

[Ghoste]

Oh okay, that makes sense.  Would I be correct in assuming that the reason for not using a Pitman arm between the TA and stock one would have something to do with having to supply a completely different steering ratio gearbox?

[Mike DC]

Not sure what you meant by that last question. 

I'm guessing here, but they probably developed the pitman arm change so they could avoid having to redo the internal gearing ratio in the stock PS steering boxes.  It was a ghetto-rigged setup with the longer pitman arm not even matching the length of the stock idler arm on the passenger side.  (You can get repro longer idler arms to fix this now.) 

The whole E-body AAR/TA program back then had shades of the wing car operation.  It was largely another slammed-together homologation project that they did to legitimize those improvements on the race cars.

 

[Ghoste]

Sorry about that.  I'm trying to envision the different systems in my mind and all the why's and how's.  You answered my question though even if I didn't explain it properly.
Thanks for your patience btw Mike.

[Mike DC]

No prob.

The fast-ratio steering setup was a cool option.  Helps make cars fun again.  I'm kinda surprised we don't see more of it on people's restored cruisers these days.

[SFRT]

Hopefully I can leave it in, as its 1 less system to buy ...I used to drive my manual steering '53 Dodge M37 weapons carrier all over town and park it no problem...but I have a sinking feeling that my gal is going to want power steering.