Steering Rack Depower Questions
 

Hey guys,

I got a powered rack from a friend that I depowered yesterday so I can just swap it out when I get the Miata in the air next time. The depowering part was easy with FM's instructions but I also read that people who welded the pinions shafts together got rid of the slop in the steering. Is this step necessary or is it just a nice benefit? Does anyone know how bad the slop is without welding it? My welding isn't competent enough to not warp the pinion shaft.

Another question is does anyone know the thread pitch and sizes for plugging up the holes? I know Miataroadster has a 6 plug set for $50 (seen here: http://miataroadster.com/miataroadst...s/g-63109.aspx) but I feel like if I knew the sizes of the plugs needed I could purchase them at a much reduced cost.

And the last question is what are your thoughts on the MiataRoadster Delrin solid steering rack mounts? Seen here: http://miataroadster.com/miataroadst.../i-407777.aspx Worth it or just keep the rubber OEM mounts that are in there now?

I don't have mine welded and I don't notice any significant slop. But I've never driven a welded rack. No idea on the plugs, I just welded mine and the bushings are nice if yours are worn out. Anything to help keep the rack in place I guess..

I just use silver epoxy putty to seal the casting ports flush. And a dab of black silicone to seal the steel tube ports which I like to cut off at the main tube. Looks clean.

On feel…note that when powered, the pinion shaft twists very little most of the time since as it twists, more assist is added, which cuts how much further it needs to twist.

When you de-power, the skinny rod twists as far as the spline allows all the time. You can see how far it twists is in this video:

http://vimeo.com/15245486

If I get a spare moment I'll make a little in-car viddie. Showing the lack of slop and that when fully depowered, welded, etc...the effort is just fine above a few MPH. You don't need biceps like Hustler, those are just to get the girls.

Yeah that's why I wanted to get other people's opinions on in-car experience to see if it was really a big deal or not. I saw that vid in the writeup at Motoiq.com. It doesn't look like it twists all that much but I guess it could be different when driving.

Sweet on the in-car viddie, would be cool to see.

If you drove my car you'd weld your pinion without further discussion. My pinion spline was worn pretty bad too from hour and hours of track time.

Do yourself a favor and do it right, the first time.

That twist in the viddie is at the shaft…watch it again from the perspective of the grips on the wrench. See how far it travels? It will be comparable or worse at the steering wheel.

A Miata I'm working on has a rack that I de-powered. And it also has a bad front wheel bearing. Which whines or is quiet depending upon steering direction. This may provide a cool audio indication at to the lack of play. Very little initial steering leads to a left or right turn initiation along with the bearing sound. With the old slop-rack, the steering wheel needed to be turned further. It just feels better at turn in, and provides the attentive driver with more information at the cornering limit.

On Coleman's site with the de-power article. I think he is overemphasizing the importance of the strength of the weld. Like you're gonna die or something or the evil lawyers are waiting in the wings ready to jump his bones if someone reads his article and **** happens. Using special high ductility wire, 360º, etc. You don't need mad skillz, TIG, or special wire. There is always the spline and torsion rod backing you up. I'd have to play with it a bit, but I am 95% sure you don't even need to weld. I bet you could glue or loctite the thing solid. Something like LocTite 640 bearing retainer might do the trick, or certain epoxies. Or basic welds.

Right, we are talking about a 5-10 minute welding effort. With the bits apart you just "gotta do it while you're in there".

Well that's good to know then. I guess I can weld a couple of beads around there to set it; I'm just hoping the heat doesn't warp the shaft out of alignment.

There was a guy on rx7club that had his nice tig welds break in the pinion. No damage and he could still drive the car but it does happen. I'll try to dig up the thread. That's basically the only reason I decided to skip that step.

This guy?