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Re: Rack and pinion for Late model???
Posted by: teddbrown ()
Date: May 22, 2011 06:38PM

Drag link travel from Lock to Lock is 6.75 inches. So its recorded here now.

Ted

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Re: Rack and pinion for Late model???
Posted by: MattNall ()
Date: May 22, 2011 06:41PM

Tierod travel from Lock to Lock is 6.75 inches. So its recorded here now.


Keywords!!





MODERATOR
Somewhere between Sea Mountain and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
.............................PG...................................Turbo

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Re: Rack and pinion for Late model???
Posted by: Tom Z ()
Date: May 22, 2011 06:55PM

..dang,and I just measured it..actually I held the tape in the corner of the subframe and went to the right tierod inner grease fitting--lock-lock I got 6.875" travel,but it was at a bit of an angle..

Tom Z,,Rochester NY


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Re: Rack and pinion for Late model???
Posted by: MattNall ()
Date: May 22, 2011 06:59PM

Verified!!! ggg





MODERATOR
Somewhere between Sea Mountain and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
.............................PG...................................Turbo

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Re: Rack and pinion for Late model???
Posted by: Vairforce1 ()
Date: March 18, 2012 10:19PM

To follow up on what Jonathan and others have to say about rear-steer rack & pinion options (see below and elsewhere in this thread) I found that Unisteer offers aftermarket Dodge Omni racks in a few sizes and can custom build them as well - go to [www.unisteer.com] and search for "Omni" to see their selection.

Dave


Jonathan Knapp Wrote:
-------------------------------------------------------
> Hi Everybody,
>
> Craig, Richard, Eric, and Al have all gotten to
> the correct understanding of bump steer in my
> book. Richard's drawing and Craig's description
> have shed light on both why the problem occurs and
> what produces the solution. I do not agree
> however that obtaining correct Ackerman is simply
> a matter of adjusting the position of the rack
> fore or aft. I talked with you Craig, when you
> were here in Seattle at the Orphaned Car Show two
> years ago, about proper Ackerman for a front
> steering front suspension. Eric, you and I have
> spent time on this subject too. I don't know
> Richard and Al.
>
> My careful graphing of all of the movements of the
> front suspension and steering of my autocross car
> shows that you can never get anything close to
> correct Ackerman on a front-steering Corvair front
> suspension with stock steering arms and the
> problem is way worse with quick arms whether they
> be GM or aftermarket.
>
> The main reason my autocross car is so good at
> turn-in and fast through the slaloms as well as
> neutral all the way up to 1.2 g lateral
> acceleration is because the Ackerman is close to
> optimal. It is not perfect, and could not be made
> perfect with drum brakes. But it is pretty close.
> In the compromise between correct Ackerman and
> correct bump steer I sided as close as I could to
> Ackerman. My resulting bump steer actually helps
> turn-in because as the suspension compresses
> (loaded in a turn) my front wheels toe out
> slightly, giving the inside wheel the extra
> degrees of turn that it lacks from the
> not-quite-perfect Ackerman.
>
> Correct Ackerman for a front-steer front
> suspension would be a straight line through the
> steering arm pivot (outer tie-rod end) through the
> lower ball joint that points directly at the
> center of the differential. That means the end of
> the steering arm has to be quite far outboard of
> the lower ball joint. This is very hard to do on
> a Corvair, especially if you want to minimize bump
> steer (as outlined above) for a street car.
>
> The real solution is the one offered by the
> gentleman who talked about the Omni: a rear-steer
> front suspension.
This way the line through the
> outer tie-rod end and the lower ball joint
> pointing at the center of the differential has the
> outer tie-rod end inboard far enough so that
> controling bump steer is attainable.
> Unfortunately a rear-steer front suspension
> creates big problems for the location of the rack
> itself as well as of the gas tank. There are also
> big challenges for the front suspension front
> strut (torque control) rod and perhaps for rear
> mounted calipers for disk brakes.
>
> Unfortunately Tom, there is no easy near-bolt-on
> product that will work. Each of you will have to
> struggle with imaginative solution for your
> particular car. I will say that if you like to go
> fast in a Corvair around corners on pavement (not
> dirt, Eric!) at high turning angles (that means
> autocross, not road racing) the struggle is well
> worth it.
>
> Jonathan Knapp
> Seattle, WA
> '66 Corsa Autocrosser

Dave Muhlena
Cedar Rapids, Iowa
'65 Corsa 140 project - going nowhere, fast!

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Re: Rack and pinion for Late model???
Posted by: metalman ()
Date: May 24, 2012 03:39AM

Well seems like this thread never really ended, so I'm going to bring up something new.

Hitting a bit on what Vairforce said but saw these:

[www.unisteer.com]

This rack, not the whole kit. Assuming you could get it in manual and front steer.

So remembering from my 4X4 days, the longer the tie rod, the less bump steer you would have as long as it's in line with your lower arm correct? Though issues I see with this rack is how difficult it would be to mount the rack and still get the tie rods to line up with the steering arms (i.e. the tie rods actually pointing back a little)

But then with them so long, would it really matter?

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Re: Rack and pinion for Late model???
Posted by: cnicol ()
Date: May 24, 2012 05:18AM

Metalman wrote: "
So remembering from my 4X4 days, the longer the tie rod, the less bump steer you would have as long as it's in line with your lower arm correct? Though issues I see with this rack is how difficult it would be to mount the rack and still get the tie rods to line up with the steering arms (i.e. the tie rods actually pointing back a little)

But then with them so long, would it really matter?"

Craig replies:
Long or really long isn't quite the right answer.

In addition to being parallel to the lower arm, the inner tie rod pivot must fall on an imaginary line drawn between the inner pivot of the upper arm and the inner pivot of the lower arm.

This placement ensures that as the suspension moves up and down and the knuckle gets closer to the centerline of the car, the tie rod gets shorter by exactly the right amount (radius of tie rod end movement matches knuckle's radius)

This means the rack must be exactly the right length between tie rod inner pivots so it falls on the imaginary line when the tie rod is parallel to the lower arm. Any other length (as in a random rack from another car) will exhibit bump steer.

Also, the fore-aft position must be correct in order to get the Ackerman angles right.

In a nutshell, there's only one correct position (in space) for each of the inner tie-rod pivots. Any other pivot position will either exhibit bump steer, Ackerman problems, or both.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
66 Red Monza 2dr 140/4 EFI 60k
61 Seamist Jade Rampside 140 PG
65 Cypress Green Monza 140/4 4dr
65 White 4-dr 110/AC/PG (parts)



19 Tons of parts in boxes

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Re: Rack and pinion for Late model???
Posted by: lgoodwin ()
Date: May 24, 2012 08:22AM

metalman, that kit has a power-assist, which leads me to think it requires one. Not a good choice for a Corvair (engine not in front, so no belt to drive the power steering pump). Seems like Mustang II was supposed to be "the" R&P to use in a Corvair? Don't remember where I read that. They have been used in a lot of HotRods...

1962 Corvair 900 sedan1967 Corvair Monza 140/4-speed1968 Corvair 500 coupe1983 Mexican Mustang 5.0
1962 900 sedan needs a home1967 Monza 140/4-spd1968 500 coupe (now my son's)1983 Mexican Mustang 5.0

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Re: Rack and pinion for Late model???
Posted by: Tom Z ()
Date: July 20, 2012 02:01PM

..I actually talked with Arch Evans on this,a couple weeks ago..He noted the Mustang ll and Corvair designs being "very similar"..swapping the COMPLETE Mustang setup into the Corvair is the ONLY way to 'get it right',so I'm looking at making fixtures off the Mustang subframe I have, to locate ALL of the Mustang parts-rack mount,U/LCA's spindles w/9 1/4" disc brakes and rotors with the 5x4 3/4" Chevy pattern..** IF ANYONE ** here can check the frame width (between the rails,above the 'axle' C/L) on a STOCK 32-early 50's Ford or Chevy car or truck I'd appreciate a PM or email,,looking for one that's close to the Corvair 25" ID...Speedway lists new,weld-in subframes in their street rod catalog for $300 and I'd rather work with 'new steel'..

Tom Z,,Rochester NY


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Re: Rack and pinion for Late model???
Posted by: cnicol ()
Date: July 20, 2012 02:51PM

The other way to go is to measure the attachment area:

Outside to outside
Frame height
Front to rear angle of the attachment area relative to horizontal
And the distance from the bottom of the "frame" to the ground

Then call Heidts, TCI, or Fatman Fabricaitons. They know these dimensions for all of their subframes and will set you up with one that'll work. I've done this several times for vehicles that aren't in the catalog. Be sure they know it's a unibody structure not a thick steel frame.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
66 Red Monza 2dr 140/4 EFI 60k
61 Seamist Jade Rampside 140 PG
65 Cypress Green Monza 140/4 4dr
65 White 4-dr 110/AC/PG (parts)



19 Tons of parts in boxes

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Re: Rack and pinion for Late model???
Posted by: Tom Z ()
Date: July 23, 2012 01:30PM

..measured the "Mustang II" (if it actually is..) with the mid 4.3 Corvair since the trunk is gone..29" between the 'Mustang' UCA bolt centers (note the shafts are bolted 'down' vs the Corvair's bolted from the side),,29" puts them even with the vertical lip on the outside 'wall' of the Corvair unibody 'frame'..it's possible to locate the lower Mustang section using the Corvair mounting pieces,adding the UCA points to the lower may be possible if the subframe is raised up where the idler arm and steering box are and slid back into position..the upper spring/shock pieces *could be* bolted in place,but I'll probably weld them together onto the unibody frame on this car..

Tom Z,,Rochester NY


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Re: Rack and pinion for Late model???
Posted by: metalman ()
Date: July 28, 2012 08:25AM

Another idea I've been thinking about is :

Flip the steering arms for rear steer and put in a rear steer R&P mounted to crossmember. Use a Miter gear to redirect. Issues: Sway bar and/or strut bar interferance. Also gas tank modification to clear miter gear.

Quicken steering, helps correct Ackerman. Possibly more work than it's worth but you never know.

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Re: Rack and pinion for Late model???
Posted by: Tom Z ()
Date: July 28, 2012 02:39PM

..I think it's been tried,tho just 'reversing' the bolt on arms probably hasn't worked..using 1st-gen Camaro (rear-steer) has also been tried too,IIRC as the B-J distance (height) and centerline is different..

Tom Z,,Rochester NY


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Re: Rack and pinion for Late model???
Posted by: Tom Z ()
Date: July 28, 2012 03:17PM

--OMG-!!! I ordered the 3-pc Mustang II subframe from Speedway Thursday,just checked FedEx tracking and it said DELIVERED!!,,found it on the front steps!!!--opened it,and took the measurement I felt was first-critical,the INside Corvair 25" width,,and the 35-40 Ford is 'angled',going from 24.625" (front) to 25.625" rear..yeeehaaaaaa,time to make some "fudge"!!!

Tom Z,,Rochester NY


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Re: Rack and pinion for Late model???
Posted by: Tom Z ()
Date: July 29, 2012 12:34PM

here's the pic,so it DID happen!!..no 'instructions',but it's obvious which upper is right/left besides the stamped "l" on the left upper piece..undecided as to continuing on this thread,or starting a new one-may take a week or 2 to get the car back into the work area..

Tom Z,,Rochester NY


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Re: Rack and pinion for Late model???
Posted by: cnicol ()
Date: July 29, 2012 02:54PM

No instructions???

How about this: Click here


Two tips: When it's all said an done and the car is on its tires @ final ride height, the lower surface of the crossmember MUST be parallel to the ground (front to rear) and 2) the position of the top hats, front to rear, determines your range of caster adjustment. Getting their position right is remarkably difficult - a magnetic caster gauge is one tool you can use to help get that right.

The car shown below had a 4-degree frame rake so it took maximum swing on the upper arms to get the caster to the minimum. (Grrr!) I ended up cutting the upper plates off and moving them back. The next one I did I just tacked in place and checked the caster before final so I could get the adjusters closer to the center of their slots.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
66 Red Monza 2dr 140/4 EFI 60k
61 Seamist Jade Rampside 140 PG
65 Cypress Green Monza 140/4 4dr
65 White 4-dr 110/AC/PG (parts)



19 Tons of parts in boxes

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Re: Rack and pinion for Late model???
Posted by: Tom Z ()
Date: August 08, 2012 02:14PM

..got the 'mid4.3' rolling shell back out behind the garage again,front is blocked up and have started gathering all the parts at that end inside..need to get reference points established,then drop the Corvair subframe out and fit the Speedway center in..locating the upper spring/shock pieces will be tough..thinking of replacing the (common)caster/brake reaction rods with "tie-rods",with heim ends--the anchor point is a ?,as it moves in an arc,affecting caster as it follows the LCA movement up/down..

Tom Z,,Rochester NY


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Re: Rack and pinion for Late model???
Posted by: jimmyo ()
Date: August 08, 2012 02:34PM

Pretty interesting stuff. Honestly allot of it is over my headeye rolling smiley, I'm excited to see how it works out. Thanks for sharing your brain!

Jim O'Connor
45 miles north of The Bronx, N.Y.
1962 Greenbrier 110 4spd
1964 Monza Convertible 110 PG
"Wherever you go....There you are"


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Re: Rack and pinion for Late model???
Posted by: Tom Z ()
Date: August 09, 2012 02:50PM

..went to www.heidts.com/instruction_manual and found all but one measurement to locate the parts..one missing was the '40 Ford frame 'height',but gave the rail width as 2.625"..the rack mounts to brackets that tilt the rack so the steering column shaft angle is different than the stock Mustang member I have,so I'll need shorter bolts..

Tom Z,,Rochester NY


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Re: Rack and pinion for Late model???
Posted by: Tom Z ()
Date: August 12, 2012 10:57AM

..compared a spare Corvair subframe with the new Mustang II, and will start a new 'topic' here..re-measured and found that the Speedway 35-40 Ford subframe 'matches' the Corvair unibody frame inside-dimension IF the lower 'lip' is removed..should have the Corvair assy out today..

Tom Z,,Rochester NY


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