TA22 + rack and pinion

["Z" UTE]

Grega, I have one of those racks waiting in the garage. Simple enough to change the alloy bar out for something to suit the spacing of the lower control arm mounts.

cheers Chuck.

[Grega]

no callum - although they do do something similar.
its a camira rack, with a modified bottom part of the XM steering column

the thread is here : Australian Ford Forums
(i have a 1966 XP guys, hence why i lurk on the ford forums)
i'll ask jason about the bottom of his column.

[Grega]

chuck, it appears thats what jason did also with his on his wagon if you have a read through that link. i've just sent him a message for some info.

[stidnam]

definitely an option I be looking into

Dimensions can be found here

Apparently the Daewoo (ie lanos) racks are the same so would be newer and easier to find

[jb_22]

Hey guys,
Scored an AE71 R&P + crossmember + steering column today & I've got a TA22 crossmember on the way to play with so a R&P conversion is in the pipeline for my sillycar. The AE71 rack is ~3.3 turns to lock, even less with AE86 steering arms I plan to use will be a heck load better than the cement truck steering I got atm. Not keen on that Camira rack because they are ~4.5 turns to lock, which is no quicker than the TA22 steering anyhoo.

For bumpsteer issues I doubt Toyota had it all perfect in 30yo passenger cars, so I'm going to make up some sort of jig to measure bumpsteer of the AE71 steering assembly with a dial indicator & see if that geometry is close to the bumpsteer curve I want. Basically what I'm chasing is a small amount of toe-out on bump from ride height. That should improve turn in under braking & help with mid-corner feedback. I have an inkling that the AE71 geometry will have small toe-in bumpsteer to keep the car stable under brakes (typical passenger car trait).

If this is the case, I may get away with not shortening the rack because the higher rack length:LCA mounts ratio might increase toe-out bumpsteer to somewhere I want it. I can also play with rack location to change the bumpsteer slightly too - having the tie-rods angle backwards from the rack will reduce toe-out bumpsteer - the rack higher than LCA mounts will give more toe-in bumpsteer. I'm hoping to find a compromise where the bumpsteer curve is where I want it but minimal modifications are needed. Guesstimation at the moment I'm thinking I'll need to mount the unmodified rack as close as possible to the crossmember; high as possible without hitting the sump or exhaust headers & possibly space the LCA mounts on the crossmember a little. Using the idler arm & steering box mount points for the rack could be handy, provided the rack position there & bumpsteer is good. That would save dropping the crossmember too

I'll try put some updates on here as I progress cuz I think I'm taking a slightly different approach to what's been said on here before with steering geometry (i.e. make a parallelogram with the LCAs & tie-rods, shortening the *E7* rack, zero bumpsteer etc). Just gotta put a bit of thought into how I can accurately measure bumpsteer curves with some sort of jig & dial indicators. I will even try to check the bumpsteer at various steering angles because the most suspension bump happens during cornering, so really having a moderate amount of toe-out bumpsteer at full lock isn't going to be a bad thing. See how I go anyways!

[Ken_T]

Hey guys,
The AE71 rack is ~3.3 turns to lock, even less with AE86 steering arms I plan to use

I'm not familiar with old celicas but number of turns from lock to lock won't improve by putting on power steering arms. They'll just give you more lock, unless of course your lock is limited by steering stops on LCA's, which they might be since the car has recirculating ball steering in which case it probably has lock stops? I'm not familiar with steering boxes either. lol

Here's a simple way to measure bump steer:

Make that then pull the spring out of the car and move the car through the range of suspension motion (or known suspension travel if you have that information) by jacking the car up and down. You will need a ruler or something to measure the clearance between the rim and bolt and a dial gauge might be easier to use instead like you said.

I'm interested to see what numbers you come up with.

[jb_22]

Hmm... I was thinking of something I can bolt to the steering arms and reference the dimensions to something similar to the above diagram so I can take measurements with the setup off the car. I was planning on measuring the LCA angle of the car at ride height and using a bottle jack on the R&P LCAs to check bumpsteer with the crossmember on a couple besser bricks. Then I'll measure it again when it's in the car to see how well my jig worked Not even going to bother measuring the stock TA22 bumpsteer curve cuz I have a bent draglink.

Yeah, the steering arms have adjustment bolts that hit the LCA on the recirculating ball steering. AE86 arms will give "quicker" steering, which is what I'm interested in. Instead of playing bus driver on roundabouts I will be playing sports car driver

That bit of plywood would be perfect for at home wheel alignments too if it had a base right under the car with the same contraption on the other side...

As for numbers I'm most interested in how much steering angle is going to affect the bumpsteer.

[Ken_T]

As for numbers I'm most interested in how much steering angle is going to affect the bumpsteer.

Are you getting the above "bumpsteer" mixed up with ackerman steering? or are you saying you want to check bumpsteer curves at different steering angles?

[jb_22]

Not getting mixed up, I understand what ackerman angle is. Yes to check the bumpsteer at different steering angles. The tierods change angle relative to the LCAs through steering angles, which will slightly influence bumpsteer.

[stidnam]

If you are putting the ae71 rack in unshortened then ok but if you plan on reducing the front wheel track of the ae71 crossmember back to the ta22 specs then you'll have issues with the rack uni joint wanting to share the same space as the block (well on a 3s it does).

Camira rack is good to keep the stock wheel track and not have issues with the uni joints as it will be closer to the rails. Apparently you can or could get a quick rack from the UK so some hunting is in order.

What is the stock TA22 turns lock to lock figure?

[Ken_T]

Ok, cool. I didn't expect anyone to go to that much effort for steering geometry on what I'm guessing is a street car that does occasional sprint stuff? Even more excited to see what numbers you measure.

Gotta start paying attention to this thread, it seems I gotta do a rack and pinion swap on a MX22 Mk. 2.

[Grega]

Hello All,

I got a message back from Jason from the Ford Forums ;

Grega,
I used some WOODWARDS steering gear from the USA, have a look on google and they have lots of usefull info about whats what and adapters. For mine I got one of their weld in stub adapters welded it into the lower shaft section and then got a suitable uni to go from stub to 9/16" 36 spline to mate to the rack. As far as the bottom of the column I used the support bearing from the bottom of a commodore column and welded it into mine, but if you have access to a lathe machine up a bearing housing and mate it up to your column. As for bearings find out what diameter your steering shaft is and go visit a bearing supplier abd get a bearing with an I.D. to suit and the smallest O.D. to make it eaiser to fit the housing. Read back through my posts and I think I describe it in there a bit more.

Cheers
Jason

For the context it would be worthwhile reading the thread on the Ford Forums folks.

Also, the website for Woowards is here Equipment for Racing Professionals--Woodward Precision Power Steering!

Hope this helps.

[jb_22]

Stidnam, the track on my TA22 is already 50mm wider than stock, so I'll won't be trying to keep the stock sillycar geometry. You reckon I'll still have issues with the rack uni & block? I was planning on using a spare TA22 crossmember with rack mounts from the AE71 welded onto it along with T3 adjustable LCAs & possibly AE86 steering arms. I'll have a look at using the idler arm mounts too, but it'll be easier to get the geometry right with a whole crossmember/steering assembly. The adjustable LCAs will let me play with bumpsteer a little too. TA22 recirculating ball steering is over 4 turns LTL (I run out of lock cuz of my wheels hitting the firewall so I don't know exactly).

Ken T, I figure that if I'm going to make up a jig to measure bumpsteer through suspension travel, then I might as well go one better and get measurements through steering angle as well. That extra 3 or so hours I spend in the shed figuring out bumpsteer curves through different steering angles will be worth it even if it improves the steering feel by just a smidgen. The car hasn't even hit the track... yet... I just enjoyed playing mechano as a kid

[stidnam]

I assume that you have widened your front track by different rims? If so this will have no effect on the steering geometry for bumpsteer as the lower control arm pivot points are in the same spot. If you are using the stock TA22 crossmember then you will need to shorten the AE71 (same as ke70) rack to suit the TA22 crossmember lower control arm pivot points as the AE71/KE70 crossmember is wider and has the lower control arm pivot points wider than the TA22 crossmember. If not shortened then the bumpsteer will be hideous.

I took the approach of shortening the AE71/KE70 crossmember so that the lower control arm pivot points are in the same spot as the TA22 crossmember. I could have put rack mounts on the TA22 crossmember but this seemed easier. I also shortened the rack the same amount which gave a short rack housing that was inboard from the rails a fair bit which then fouled on the block when I tried a 3s in the bay. I only positioned the motor in the bay and roughly measured the position to make sure it was central but it was very close to (1mm) or was hitting the block. This was with a stationary car and non running motor so I'd expect that there would be fouling during normal operation if you could get it to clear. Would certainly not pass engineering as you need 10 or 20mm clearance minimum and steering is kind of important.

The 2t block may be narrower than the 3s block so you may be ok but it would be close. You mention that you intend to run adjustable lower control arms. That will not really help as it is the lower control arm pivot points that are important to match to the rack. If you adjust the lower control arm out you will need to adjust the tie rod tube the same amount to keep the same wheel alignment. Adjustable lower control arms would only be useful to give you more camber and track.

If you use the AE71/KE70 crossmember as is then you will have increased wheel track over the stock TA22 and not need to shorten the rack. If you are running wider rims with offsets that are 0 or + as well as using the unshortened AE71/KE70 crossmember then you will get even more front track which will likely give clearance issues on guards and firewall when turning.

[xa-mont]

i'm planning on making an S13 silvia rack fit my TA22, so thought i would just chime in to ghetto subscribe.