Rack and Pinion conversion. Pros and Cons.

[ROB]

Ok, looking at the pros and cons to do a rack and pinion conversion. I was thinking I could use Mustang II/Pinto spindles. With an inexpensive bracket adapter, I could use 70-78 F-body rotors, with Pinto bearings, and metric calipers. This will still allow the use of the Chevy bolt pattern.

A: S-10 or Pinto, either way you got to get a set of spindles, cost about the same.
B: If I got to rework the control arms for ball joints, what’s the difference?

So, if I go with the 82-88 Cavalier rack like this:

Cavalier rack 82-88.jpg

Then this will allow a custom made plate to attach and then I could possibly achieve zero bumpsteer (pro). A gear box has got to weigh about 50lbs or more than a rack (pro). Don’t need to obtain the ever expensive drag link (pro). With the gear box out of the way, I can run an F-body serpentine belt system and not have to relocate the power steering pump (pro). What will suck is I would have to run a custom made steering link (con). BUT, since this would have to be moved over to the side anyway, MAYBE this would allow use of “normal” SBC headers, therefore bigger tube size and cheaper (pro)? Possible the rack will hang lower and cause clearance issues (con)?

What do guys think? Any more pros/cons? So for, I think this is worth pulling the trigger on.

Rob

[ROB]

Got a couple more:
As someone suggested to me, While custom making a K-member for the rack, I could include provisions for motor mounts, freeing up even more room for "other" headers (pro). Possibly, with the shorter steering arms, this will allow adequate room for an 8" wheel up front (pro).

So far this idea is just getting better and better.

[spencerforhire]

Sorry to burst your bubble on the Cavalier rack idea, but like 99% of FWD cars, the Cavalier is rear-steer(rack mounts behind the front spindles). When you turn the steering wheel to the left the car will go right. Not sure what geometry issues you would run into with Pinto spindles on H-body control arms; I suspect there would be problems with it. S-10 is probably the simplest.

[ROB]

Good point on the rear steer, didn't even think about that. I'm not loosing hope on a rack idea, back to the drawing board.

[Fastmax32168]

I think a Chevette rack would steer in the right direction.
Roy

[waybad]

I think a Chevette rack would steer in the right direction.
Roy

here is my Chevette power rack

[spencerforhire]

My drag car has actual Pinto spindles with aftermarket "Pinto-style" control arms and it steers quite well considering the 25x4.5 Goodyear Frontrunners. I have a power Chevette rack I intent to put under my 77 Wagon along with S-10 spindles(if I ever get around to working on it). The freshly rebuilt rack which only has about 100 miles on it, came off of a 34 Plymouth street rod that had a whole S-10 front frame section under it. The guy said "it steered funny" so he took off his self engineered Chevette rack and coughed up nearly $800 for a "bolt-in" custom setup. The car still steers funny; as it turns out, it has so much "rake" built in that there is no way to get enough caster dialed it to make it not wander.
I am slightly concerned that with Chevette rack the Vega will steer slower than if I kept the GM power box that's in there now.

[ROB]

I am slightly concerned that with Chevette rack the Vega will steer slower than if I kept the GM power box that's in there now.

This shouldn't be an issue with the Pinto spindles having the shorter steering arms. Looks like I just might have my answer. Can anyone address if there is any bump steer? And do they make a 2.5-3 turns rack for the Chevette?

[cacmanjr]

I had a chevette power rack with s10 spindles on my 77 Skyhawk for a few months. I couldn't keep it in the mounts using 205/60/15 tires. It would pull out on sharper turns because of the effort required to turn the wide tire. It also steered so slow that I had to back up to make a tight turn in some instances. I wound up biting the bullet and installing a Flaming River power rack......problem solved.

[spencerforhire]

I think Carl has experienced exactly what I fear; I will end up with slow steering if I put the Chevette rack in my street car. Great at 140+ mph with 4.5" wide tires but not so much fun on the street with big rubber. On my drag car the Flaming river narrowed 5" manual Pinto rack with Pinto spindles(and control arms) is not all that slow with 3.25 turns lock to lock.
I doubt if the Pinto spindles with their short steering arms will have even close to the right geometry to be able to use them on H-body control arms.
Bump steer? Entirely depends on where you mount the rack; if you get it mounted where the tie rods are parallel to the lower control arms it should be liveable. Some bump steer is caused by the difference in the distance between the pivot points of the lower control arms and the inner tie rods; this is why the rack should be from a donor car with a fairly narrow track. I have heard(but no personal knowledge) that an early Datsun 240Z rack is a better solution than the Chevette one.
I intend to carefully examine the possibility of shortening the steering arms on the S-10 spindles; it has been discussed in another thread on this board.

[cosvega76]

Rob,

While it will tend to hit some of your "cons", I have a 12:1 conventional power steering box in my Vega. As well as it steers now I don't even consider a rack conversion anymore. Maybe Clyde can comment on how his gearbox swap went, as well.


Chuck

[ROB]

I know where you're coming from Chuck. I remember the steering in my 86 Trans Am, and that box would bolt right in. This was/is going to be my choice, depending how this rack idea pans out. There were a lot of cool pros that I want.

[cacmanjr]

I intend to carefully examine the possibility of shortening the steering arms on the S-10 spindles; it has been discussed in another thread on this board.

I bought the Brunton steering quickeners to shorten the effective length of the S10 spindle steering arms but never installed them. When I bought mine, they were available for $90.00 which is a cheaper option than the Flaming River rack.

[Monza Harry]

Carl will those (Brunton quickeners) help with the "Ackerman", (also an issue with the swap) with the S10 spindles? Can you post a link for them Please? Harry

[ROB]

Ok, I might be on to something. When you look up a rack for MII on Speedway's website, it states that they use a T-Bird rack. Well, according to Rock Auto, they have a 2.5 turns lock-to-lock for under $60. And if you can shorten a MII rack, you should be able to shorten the T-Bird rack, (this has to be a cheaper option to a Flaming River rack). This is also the same on the Fox body Stangs. And another forum I saw recommended upgrading to the SN95 rack and use the Fox inner tie rods to work. (more options). SOOO, if the T-Bird/Fox Mustang has a steering arm length of 4.9" or more, I'm in business. I got the 4.9" length from Willwood's MII spindles. They are supposed to be the same specs an a MII/Pinto spindle except taller.

Anyone know the steering arm length of T-bird/Fox spindles?