71roadster

Well, here is the steering mod the rest of us have been waiting for, tho once I think you all learn the details you might think twice about this.


So far it has been a LOT of friggen knuckle busting work. This box is HEAVY. and requires a lot of grinding to get everything dialed in. I may still pull it out and try a different mounting scheme for the front bracket. I used the stock rag joint with some modifications and I think a ptiman arm off a early '70s monte carlo (and probably a lot of other cars too) pitman arm will work.

There is NO WAY I could have done this with the engine in the car and am still not positive that it will clear my headeres, tho I suspect it will, just barely. With the box installed, my steering is about 2.25 turns lock to lock...very quick. So it remains to be seen if this will be drivable. Fortunately nothing I have done cannot be undone to put the old steering back in. I'll let you all know how it goes.

Chris

Racer16k

Interesting...... Is the gearbox threaded for the bolts holding the adapter plates? What is your opinion of adding new holes in the frame of a modded car?

PROSOUTH

Chris, hope you're feeling better. I know you've had a rough two weeks and with the problems you have encountered on the engine and fooling with this project didn't help I'm sure.

Was it the struggle to obtain the right positioning of the box that was so difficult? If a template was made from your mounting plate wouldn't this eliminate most of the frustration of putting it in? I know trail and error is nerve wracking but in the end I hope we have needed improvement.

I don't understand how the box is rated at 3:1 ratio and is showing 2.25:1 in your car? Maybe Jim Shea can enlighten us on that.

On my wife's new Grand Cherokee this box is great! It has a good steeriing ratio with a good ammount of steering resistance to level it out.

lets wait until you can give it a test drive and final analysis before we give up. JIM :yesnod:

redvetracr

Chris,
Is that the "605" box?? There is a way to adapt the mount from a Vette to a 605 box but you need to fab a mount from the 605 box to the top of the frame and you need to use a Corvette pittman shaft. ...redvetracr

71roadster

racer16k, yes, the tabs on the box are threaded. 12mm metric which explains why the bolt heads are so big. That is something I might try to change before I put my motor in. Drilling holes in the frame is always possible but requires anti-squish tubes be welded in. More complicated than I wanted to get. Plus, you need to know exactly where to put the holes.

Jim, getting everything lined up involved a lot of grind to fit with install and removal in between. When I have a setup I am happy with I will try to develop a template to make it easier for the next guy. The steering hits lock due to the steering arms hitting the stops on the a-arms, not the box going lock to lock.

redvetracr, this is not the 605 box. It is a box out of a 2000 Jeep Grand Cherokee. Among other things, the shaft is supported by roller bearings rather than bushings. I'm sure Jim Shea can comment on the benefits of this box over the 605 box.

Chris

Chuck Harmon

Chris,

You beat me to it. Looks like you've done a nice job! I am looking forward to hearing how well it works. When I measured my original compared to the replacement, I should have the same clearance from my headers. Hopefully this will be the case for you too.

Looks like I will probably need to be coming up to Fremont to sit at your feet and hear how it should be done!

Chuck

71roadster

Chuck, I'm just a guy with a grinder and a mission. Nobody should be sitting at my feet! Probably a little smelly down there anyways!

I still have a few issues to work out and would be curious to see how your install goes to see how it addresses the issues I am having. Is there anything in the directions of your kit that say anything about moving or adjusting the angle of the idler arm at all? That is something I am considering and it may correct some of the bumb steer as well.

I'm not saying to anyone that this can't be done, but unless you have a bolt in kit, it would be very very difficult to do this with the motor in the car. I think once I get all the issues and angles worked out this will be one of the sweetest mods ever. One thing I have noticed about my car while canyon running or autocrossing is that my hands are very very busy with the steering wheel and it can be hard to find time to free up the right hand for a shift. Hopefully this mod will address that.

Chris

Jim Shea

Excellent picture of your installation. Your picture points out the problem that I was aware of concerning the overlapping bolt connections.

Just scaling your picture, I calculate that you had to rotate the gear about 5 degrees clockwise from the stock position of the manual gear in order to keep the bolts from crashing into each other. Is it possible to rotate the idler arm a like amount? You should try to keep the pitman shaft and the idler arm pivot right in line with each other.

What flexible coupling are you using? Your Jeep Grand Cherokee gear has a special input shaft that is 15.4mm across flats. It does not have any serrations. I don't think that there are any GM flexible couplings that will directly attach between that gear input shaft and the flange on the Corvette steering column. I know that the Jeep had a Torrington intermediate steering shaft assembly. The one end of the shaft is a flexible coupling with the special 15.4mm flange. I would guess that the other side of the flexible coupling connects to a tube. Be very careful with these connections, you are steering your car through them.

Good luck,
Jim Shea

71roadster

Hi Jim
Let me first say Thanks to You and PROSOUTH. I would not have attempted this without your help. You answered every question I had and every answer helped. Thank You.

Actually, the box is rotated counterclockwise a bit, so that the pitman shaft is more verticle. I had to grind into the upper forward ear of the jeep box to make clearance for the stock bolt coming through the frame. As you can see, it is about as close as I can get it to the large bolts that mount the brackets to the box. In this position there is about 3/8" clearance between the most forward/lower point of the box and the frame. I am considering grinding the two forward ears of the box further so that the pitman shaft is closer to the original box's angle than it is now, but that may be too much material to remove from the ears of the jeep box. My concern is that the tie rod comes pretty close to the A-arm at full lock, but so does the stock arrangement. My other option is to move the upper idler arm hole back a bit to get the idler arm at the same angle as the steering box. I think this will help reduce toe steer as well, since the inner end of the tie rods will remain on a horizontal plane, much like rack and pinion, rather then getting closer to the ground as they move from the straight ahead position. I might try a shorter pitman arm to get the tie rod away from the a-arm as well, but then I would want to find a matching idler arm and it may get too complicated.

I used the stock coupler. All I had to do was grind off the serations of the side of the steering box and it fit over the shaft and uses the flat section to locate it. I then drilled through the whole assembly and inserted a press-fit pin. safety first, always!

Thanks again
Chris

PROSOUTH

Chris, This is going to work out and it will be sweet when it does!

Your Manual Steering Relay Rod went out UPS today so it should be there early next week. I think that it will clean up the Tie Rod Asm. and improve the looks of the system.

I would also like to thank Jim Shea for answering all of my questions and providing the blueprints of both boxes back when we first started this Think Project.

Chris and I have been swapping ideas on this for about 6 or 8 months. I had hoped to get to mine first, but a short interuption of a '78 El Camino came up and I have it about finished. As soon as weather breaks my Vette is coming apart and this mountain of parts I have are going in it.

Hey Chris, mind saving me a copy of that Template? :yesnod: Thanks JIM