So i thought it'd be nice to have a proper thread on this subject... none of this vague, soft, brown stuff, with hours of posts going no where.
I'll cut n paste some conversions i've found. I'm sure HKS7MGT can add his knowledge to this thread, especially with regard to the AE86 steering arm/knuckle. I'm interested in that because of the availability of the T3 parts.
LeeRoy(toymods) wrote:Ok, here is my rack and pinion as it currently stands.
KE70 crossmember, shortened
KE70 rack, equally shortened
KE70 rack ends
TA22 control arms
TA22 steering arms.
The crossmember has had a piece cut out of the very middle of it, then rewelded (tacked) back together. Then the steering rack is totally dismantled for machining.
The external tube can be removed from the gear/worm drive housing and then shortened. Once done it presses back into the housing. The rack shaft once has been shortened on the passenger side, then rethreaded and remachined. On this end the drive gear stops and it's just a solid bar, so there is enough meat to shorten it. The thread needs to be retapped so you can bolt the rack end back in, and the spanner sides machined in so it can be help and tightened.
So, it's basically the same as a KE70 in terms of geometry, only narrower. You can see the relative position of the LCA pivot and rack pivot in the photos. Since ackerman is determined mostly by steering arms it remains basically unchanged. It will however be slightly different (for the better) as a result of the more linear movement of the rack in comparison the the steering box.
Still to be done is some gusseting and reinforcing of the crossmember, then cleaning, painting, and installation of new bushes and ball joints.
....Now, once the rack and front suspension went back in I had some issues with the AE86 power steering arms not having enough offset compared to the stock TA22 ones causing the rotors to hit on the control arms. The 86 ones bring the strut in by around 4 mm, whereas the TA22 ones are a 0 offset - I will revisit this issue later and maybe get some custom arms machined up if I can't find something to suit.
KP61 Engine cross member with rack and pinion into RA29
KP61 engine cross member (with steering rack) appears narrower then the RA29 engine cross member which is why i'm listing it.
TA23 xmember & AE82 rack
Actually now that i see it laid out like this it all makes more sense.
I think it would be nice to attempt to use an TA22 engine cross member to keep things simple. The KE70 engine cross member seems to yield too many challenges. TA23 with AE82 rack looks nice. The KP61 looks good because it comes with the rack already mounted, how hard could it be to take that off and put it on a TA22 engine cross member i wonder.
Gonna have to see if i can get LeeRoy to elaborate on his AE86 steering arm problem...or get a picture of that problem.
MWP would the AE82 steering rack be too wide for TA22?
Handy link here will answer some questions: (lower control arm length database)
HKS7MGT do you recon the AE86 short steering knuckle would work with a steering rack? i can't visualise the full extent of the problem you had with that.
I'll leave it at that for now, i'm just bout having a brain haemorrhage keeping track of all this and getting interrupted every 1-2mins at work