Freeskier7791

This came up in another thread and thought I would start this for everyone. Has anyone looked at fitting a domestic aftermarket steering box in an SA/FB? I have a power steering car and it looks like the box is similar to a chevy steering box. I havent looked into it much but maybe someone has. Always a good option instead of doing a Rack swap

WANKfactor

iTrader: (1)

I'm all ears. Its tragic to have a perfect sports car with an inch an a half of steering slop.

hcaulfield57

iTrader: (1)

I'd be very interested if anyone has ever done anything like this. However, it's my impression that new steering boxes can still be bought from Mazda?

That being said, there's a reason why information is sparse on steering box swaps. Likely swapping to a different steering box would require: modification of steering column, mounting points on frame rail and modification of pitman arm to retain stock steering geometry. At that point, I'd imagine most people would just swap to rack and pinion if they're already going to such considerable effort. It would be more interesting in my opinion to see if Flaming River (or someone else) could reproduce worm gears, sector shafts, etc. Although do these items really wear if the steering box has been lubricated and free from water, rust, etc? I wonder if a sloppy steering box was rebuilt with new bearings and seals if it would improve anything.

Rack and pinion steering is definitely superior to recirculating ball steering boxes in most ways. However, assuming everything is working properly, there's really nothing wrong with steering boxes. I actually like the stock steering on the RX-7, it has a good weighting and a nice chunky feel. It is somewhat vague on center, but that's just the way it is. I have noticed that if ANYTHING is screwed up on the front suspension, it seems to amplify it and make the steering feel awful. It's taken me a very long time to dial everything in on the front suspension, but it's worth the effort.

Honestly I wouldn't accept a sports car with sloppy steering, I would have sold the car if I couldn't get the steering sorted.

peejay

The Mazda steering box looks remarkably similar to Ford steering boxes from the 1960s.

KYPREO

^^ Pretty much what hcaulefield57 said. As far as steering boxes go, the RX-7 is actually a decent implementation of the design when the steering and suspension is properly maintained and in order working order. The sloppiness is just an inherent flaw in the type of steering. For the trouble of using a box from a different car, I doubt you'd ever actually improve what's there.

Either sort the front end out like hcaulfield57 documented in his thread, or convert to FC rack and pinion (which I maintain is really the best solution out there).

rk970

iTrader: (1)

There is a big difference between pre/post 83 steering boxes.. All the FSM use the adjustment procedures for the early box and never updated them to the newer type

https://www.rx7club.com/1st-generati...ments-1055752/

JIMMY54

iTrader: (2)

I've taken some rough measurements of my extra box, and would like to compare. Obviously our steering shaft would need to be cut and welded a union, but seems like it might be possible to set up a performance box with easier modification than complete rack and pinion. I just don't have the time to design a kit anymore and feel like this would be best way forward.
Some boxes are available with quick ratio and offer different sizes of pitman arms etc which would be easy to get sized.

The body total length is about 11" and the input shaft and output shaft are about 8" at a near perpendicular to one another.

Bolting holes really don't matter because a plate could be welded in place to bolt to frame or some other such method.

I feel the the most important factors are general size of box and the angle of the input and output shafts.

Freeskier7791

That is a good point on seeing if the internals fit. I honestly have no issues with my power steering box yet but wanted to get the discussion going. With a power steering rack it is already 2 pieces so its probably easier to modify for a new box or rack

peejay

I did my FC suspension swap in part because it was so easy since I was starting with a power steering column in the car.

I don't see how the FB steering is "sloppy". I don't drive with precision steering inputs, I drive with steering pressure against the tires, and the main thing I don't like about the manual steering is that it is sooo slow that you never get very much pressure build up. Even with my depowered FC rack setup, steering never takes more than a couple fingers. My Volvo's power steering has heavier steering.

I'm probably going to devert my car to FB front suspension. It looks like there's a way to use FC struts with 1st-gen TCAs with a certain late model ball joint, and the 1st-gen suspension has much better geometry than the FC does.

mhr650

I am in the process of converting my car to power steering, 2hr stints on a hot day really takes a toll on the drivers. The other big thing for me is that I had to cut out the trans tunnel and move the seat over a couple of inches to get the wings on the full containment seat to fit inside the window opening. That means that I need to move the steering wheel over, I plan to use a circle track style steering column mounted with a spherical bearing coming from the cage and at the firewall, then a couple of u-joints to jog over to connect to the steering box. The stock SE steering box has a shaft that sticks out about 6 inches or so, I plan to cut it off as short as I can and machine it for a Double-D to fit to the u-joints. I have a power steering box from an SE, and have some connections to get a NASCAR style racing pump, the pump is setup so you can run various size restrictors in the fittings to dial in the amount of steering effort.

Freeskier7791

Mazda 626 balljoint

hcaulfield57

iTrader: (1)

You're switching back to the FB front suspension and FB steering or the front suspension with FC steering?

TimWilbers

iTrader: (1)

Atkins Rotay has rebuilt 79-85 manual gear box and column.
750+150 core charge.

Has anyone had experience with this rebuilt?

Opinions on a rebuilt?

Seems pricey, but I have 1.5" free play at the wheel and everything past the box has been replaced.

hcaulfield57

iTrader: (1)

At that price I'd just buy a new one from Mazda for 1k.

How are you measuring the freeplay? For instance, in my car, if I'm sitting in the car at a stop, I can move the wheel about 1/4" in each direction for 1/2" total play. Have you tried adjusting the box?

I recently helped my father rebuilding a 50+ year old Alfa Romeo steering box, it's not hard if the parts are available.

TimWilbers

iTrader: (1)

Yes, car is parked.
Turn wheel to stop, mark it with my finger then turn it in the opposite direction.

I've only tried to adjust the using the adjusting screw in the 14mm nut, but it is 1/4 turn from fully tight.

I did find other refurbished units for a little of $461, with a $350 core charge.
Mazdatrix lists the 84-85 unit as NLA so I assumed Mazda did not have them anymore.

And I also found this from Mazspeed.com:
http://www.mazspeed.com/steeringgear.htm

I'll give that a try.

peejay

I'm debating it. FC struts/uprights, FB everything else.

The FC steering arms are shorter so the steering ratio should be faster with the same box.

Mainly I want the better geometry, but engine mounting with the FC subframe is problematic. The driver's side mount breaks so easily I just gave up and chain the engine down over a broken mount, and there is no easy way to mount on the passenger side unless you have an FC engine *and* you relocated the subframe mount bolts to keep the axle centerline the same. I didn't.

peejay

That's the absolute last thing to adjust, and making that tighter than spec will make the steering bind and then it WILL feel like crap since the car won't keep a straight line. There's an ancient link that I'll look for

Ah, you found it

There's actually a spec for what he describes, but yes, adjust the main gland nut first and foremost.

hcaulfield57

iTrader: (1)

Wait, so you're planning on using the FC steering arms with the FB steering box? Isn't the FC front steer, how will that work, or am I missing something?

I've actually wondered why no one has made quicker ratio steering arms for our cars. I actually don't mind the slow steering ratio, but I'd imagine if you were into rallying or something you'd want quicker steering.

peejay

Mazda used to make a 2.5 turn box, good luck finding one nowadays. The 3 turn power box is a useful approximation. I ran a depowered box for years. It will bolt right in as long as you also grab the power column.

The FC uprights work just fine flipped around backwards. Andrew Havas's rally car used this setup and tubular A arms with the original steering setup, with a quickener grafted in to the column. Look for havspeed videos on YouTube.

j9fd3s

iTrader: (3)

just a thought, but instead of cutting up an FB steering column, you might want to just get a miata column. its similar to the FB, because thats what they used to make the miata.

peejay

I want to find one and see for myself. I worry that it is closer to FC than FB... FC is a no go, way too short above the mount.

Jeezus

iTrader: (4)

I have a NB miata if you would like pictures.

peejay

I don't need pictures, I need a tape measure

Freeskier7791

PJ,

Have you added a steering quickener in as well? I have debated it since they are pretty cheap and I already have power steering, I have also debated doing the FC knuckles but may just shorten the FB steering arm instead