I never set one of these up before, need opinions. I bought this whole rack n pinion setup from a guy with a rearended 46 Dodge and transplanted it into my 47. He said he drove his for a long time and it drove straight but I really dont know him that well. If I need to re-do it, I'd rather do it before I have a drivetrain and body installed.
Hard to tell from the perspective in the left photo, but the only improvement to the mount that comes to mind, is to fit a diagonal brace from one side of the front end crossmember/rack mount interface, over to the opposite side, at-the-rack mount, itself. Use tube or a shape-form of stock if you can, as it will be in both tension and compression, depending upon the direction of the load. If the rack was designed for an axle load wt. & geometry similar or greater than your intended load, then it becomes a question of insuring that the geometry is functional. They can be made to work very well. Mounting position is critical, to make it work w/a particular front end.
I'm not a steerring expert by any means, but from what I researched, the pivot points of the rack should be at about the same point as the pivot points of the lower a frames, so you don't get bump steer. A hard thing to do on the early Mopars, as the lower A frames are so long, and the pivots are very close together. I'd look into this further, before continuing!
On the later LH cars, the tie rod ends are connected to the rack in the center. One of those racks might work perfect if you do a little reading up on front end geometry to get the placement right.
I used a mid 90's Cavalier rack in my 47 Plymouth. This has the same configuration as the LH body and Fatman has a kit to mount it. The kit is kinda universal and now that I have a MIG and a few years of confidence that I didnt have at the time I bought it-I would definately make my own brackets for what they charge. The Cavalier rack is plentiful and fairly inexspensive too.
Thanks for the advice, guys. I'm fowarding some pics to Fatman's fabrications, as I have their spindles and brake kit on it. I'd really hate to crash it after all that work.
please post what Fatman Fabrication tells you about this set up. I'm building a 53 Plymouth Cranbrook and was thinking about using thier rack and pinion conversion kit.
Chopolds raises a good point. In order to get a feel for the setup, you might get a pencil and string "comp***" and scribe two arcs...first draw a horizontal ref. line, then scribe the "a" frame length. Second, take a shot at placing the tie rod end to rack-ball joint length, using the same origin point for the new line scribe. Imagine going over a speed bump at 5-10mph, the front end toe-in will be affected if the "rack-ball to tie rod end" length, is different from the a-frame mount to ball joint length. The rack arm length should "compliment" the lower a frame motion arc. There is geometry involved here as well, as to where the ideal axis for the rack to be placed.
Those 50's MOPAR'S steer so nice I'd keep it stock... at least try it stock before you go thru the work and expense to find out that the original set-up was fine...
Fatman's sent me a drawing and showed me it was going to have bumpsteer problems because of the type of rack I was using. I'm going to cut it back out and use one of their kits that was designed for it. No sense taking chances for a few hundred bux.
FV, Check out this thread , it might help you project ! http://www.jalopyjournal.com/forum/showthread.php?t=255971 Good Luck, Sonny
Has anyone got a sample of what our steering arms should look like to illiminate loss of turning radius?
The Jalopy Journal
