Help! More Locost Committee Engineering requested.

[sony1492]

Problem: Steering rack in only supported in the center, we need a 3rd mount on the RH side to mitigate movement. Ive got some ideas about mounting it to the frame triangulation just forward, 5-8mm away but my imagination is lacking on how that mount should really be designed.

Considerations: The RH mounting area has rubber underneath that cannot be removed, welding to the on the rack should be avoided if possible.

My ideas involved welding a half moon C shape onto the chassis then bolting the other Half of the C over the rack to clamp it in place. Seems okay as an idea but deciding how to actually build it given the 15° angle of the forward frame has seemed beyond me.

Thanks for the help everyone from the previous installment of Committee engineering. Above is the idea in practice, not perfectly triangulated because the panhard needs to be able to swing down, but its better then my imagination could do.

[OPPOsaurus WRX]

isn;t the default answer zip ties?

[sony1492]

@opposaurus-wrx

[EngineerWithTools]

@sony1492

Nice work on the rear end!

For your clamp, a suggestion: make the clamp a little undersize, so that without fasteners there is a little gap between the pieces - they don’t quite come together. If you make it exactly the correct size, you won’t get any squeeze and things will rattle. Either use the deflection in your clamp, or tension in your clamping fasteners as the clamp’s “spring”. (Also, apologies for not being in a position to send a finger-CAD sketch of this suggestion.)

[sony1492]

@engineerwithtools My problem with figuring this is how do I mount my C to the frame along with the dowels for captive nuts in a way that isnt ridiculous. As it sits ive got some tube cut in half about 2" long that fits around the rack, but it needs support to mount properly to anything. I guess make tabs at a ridiculous angle that fit sideways behind the C and weld to the frame.

Or a different mounting scheme all together.

[3point8isgreat]

How was that steering rack originally mounted in the donor car? Just the two center bolt locations you're using now? If thats the only original mounting, it seems like it can maybe use a stiffer bushing to mount the rack to control motion.

Or if you really want to pick up that RH side, maybe mounting a P-clamp? Can just make whatever spacer you need to get it into location. The P-clamp would also have a nice consistent clamp load compared to making a handmade C.

[sony1492]

@3point8isgreat the rack was originally about twice as wide, the two mounts were on the far Left(now center) with a clamp over the passenger side. It does have solid bushings but being in the center they have little authority over up down movement at the rod ends (though they do located it side to side)

original rack width and setup

[just-a-scratch]

@engineerwithtools @sony1492 the idea to keep a gap between the sides of the clamp is a good one.

Consider making the circular part of the clamp with bolt holes, then cut it into halves with a band saw. The saw kerf should be pretty close to what you would need for a gap. On the frame side of the clamp, leave it a bit long so you can cut and grind a bit at a time until it fits. Then tack it in place. After it's tacked, remove the rack finish weeks and reinstall. The clamp should be in the right place. Does that make sense?

[Jb boin]

Something involving an exhaust clamp or coupler of some sort?

[MM54]

I suspect a u-bolt (exhaust saddle clamp-esque) could go around the rack and forward through the vertical brace on the front - the roundness if the U-bolt will make the kinda-weird angle not an issue, and you can use some stuff rubber or hard urethane between the rack and that upright to make up the difference (or use an actual exhaust saddle clamp and grind the stamped part to fit for a completely solid mount). Just don't crank on it too hard or it'll damage the tube of the rack.

Did you shorten that rack or have someone do it? I have an "eventually" project in mind that the ability to modify the width of a steering rack would be very handy for.