Rack and Pinion Conversion

[FiatMac]

OK, this may be a klutzy way of doing this but I am attempting to set this up as a separate thread by copying info from Rob's V6 Engine swaps thread.

I have looked at ways to convert to rack and pinion steering in the past, and this subject is of interest to me and I suspect many others. Therefore, it deserves it's own thread.

Fiatmac wrote,

Daniel,
Not clear from your post, but are you attempting to put rack and pinion steering into a standard configuration 124? If so, the Pinto rack will not work. The Fiat configuration is rear steer (steering arms located behind the axle/spindle). The Pinto rack is for a front steer configuration(steering arms in front of the axle/spindle). It worked for Rob because he modified to front steer to clear the V6 engine. A Pinto rack installed with rear steer spindles will result in a right turn when you steer left and vice versa!

Daniel wrote,

thats ok ill just adjust my driving style! lol gez thank God you told me about this hmmm now i need to rethink my
ideal what if i did the front position with the rack that would solve this issue? I'm re doing my oil pump and pan
so i can make it any way i want at this point. I was planning on moving the pickup to the middle of the pan plus
modify that as well.

V6 Spider wrote,

Hi Daniel,

If you are just trying to convert to rack and pinion then I highly recommend looking at the 1985 Pinifarina spider. It is setup for rack and pinion stock. On my setup I used the pinto rack because i needed to convert to front steer for my v6. i your case if you are sticking with the rear steer and using a twin cam engine than i would totally recommend go with the rack setup from the 85 spider. its plug and play. Otherwise you'll be fabricating steering arms and rack mounts and a bunch of fiddly stuff... let me know if you are and I can provide you with details on how I did everything...One option if you don't want to spend the dollars for a new pinifarina rack is to find another rear steer rack from a junk yard that mounts similar to the Pinifarina spider. But like fiatmac stated needs to be rear steer IE behind axle center...best thing would be to find a wrecked pinifarina spider and take all the pieces from it..

As for making the tie rods fit the pinto rack arms all i did was re-thread the tie rods so they would fit .. simple easy fix...

Daniel wrote.

Finding an 85 1/2 would b next to impossible, from my understanding the 131 rack was the same or close so I was ok with doing the fab work to make this fit. Im open to other options but would like them to be on the simple and cheaper side.

V6Spider wrote,

Hmm... I'll do some research and get back to you...
Rob

V6Spider wrote,

Hi Daniel,

The dodge omni has a manual rack and pinion and it is rear steer...probably a lot of them at the wrecking yards...also the pinninfarina tie rods may bolt right up as it is metric.. also it has similar mounts as the pinninfarina unit...

Rob

Daniel wrote,

Thanks Rob

I checked out the pricing for an Omni rack seems to be all over the place 120 to 500 but the 120 was on ebay and
it's listed as new. That's what i was looking at for a new pinto rack, I was even considering a X1/9 rack since they
are a good deal and still available. You may of hit the nail square on the head with the Omni RP though all the rubber
bushing mounts are easy to find 42inch wide etc. I'll do a little more digging before purchasing a unit who knows
maybe someone else will come up with a better solution? before that happens...

Spiderrey wrote,

This is something that I am very interested in. I dont think the x rack would work though, or I think it would have been done by now. I have one sittin in the garage. What are the dimensions of the rack on an 85.5 spider? What are the dimensions on the omni rack, those things are pretty scarce at the local yards, even more scarce on the road.

V6Spider wrote,

I'll see if I can't come up with some specs to compare...

Rob

Fiatmac wrote,

VW Rabbit is also rear steer, but I have not been able to find dimensions or information on turns lock to lock and stroke. Also, I believe that the Toyota Echo and Scion are rear steer.

V6Spider wrote,

I figured there were others but I chose the omni rack because it is popular with hotrod building...and I know it's dimensions...need to know the dimensions of the pinninfarina rack.....Hopefully we'll find info soon...

Thanks
Rob

Daniel wrote,

I could measure the 131 power steering rack maybe that would be a good starting point?

V6spider wrote,

Here are the specs for the Pininfarina rack:

40.5" overall length (outer tie-rod ends removed).
63mm input shaft length.
3.5 turns lock-to-lock.
M12x1.5 threads on inner tie rod end

The Dodge/Chrysler Omni Manual Rack can be purchased in these lengths:
R1507-1 Omni Manual - 39.7" OAL Rear steer
FR1507-3 Omni Manual - 41.7" OAL Rear steer
FR1507-2 Omni Manual - 45.0" OAL Rear steer

Stock Dodge/Chrysler Omni Rack Dimensions:
41.7" in length with a 9/16" - 18 thread

Rob,
A critical dimension for minimizing bump steer is the dimension from ball end to ball end on the inboard side of the tie rods (where the tie rods mount to the rack). This should be roughly equivalent to the dimension between the passenger and driver side lower control arm pivot points. Or to match up with the stock steering system, this would be the length of the drag link between the steering box and the steering idler arm. (Eyeballing this shows the location to be about 1.5-2 inches per side inboard of the lower A-arm pivot.) I measured the drag link and it is 19.5". I also measured the stock tie rods and found them to be approximately 12" which gives an overall length with tie rod ends of 43.5". If one were to use the distance between the A-arm pivot points then the rack ball ends would be about 22.5" apart and the tie rods would be shortened to about 10.5".

Does anyone have the ball end to ball end dimension on the rack for the 85.5 rack? How about for the other racks mentioned.

The other critical information would be the the number of turns and rack travel from lock to lock. I believe the Omni rack is 4 turns with a travel of 5". Rough measurement of the stock steering on my Spider is approximately 2.75 turns and 5.5" tie rod travel. The 5" travel on the Omni rack would result in a slightly larger minimum turn radius, and the steering wheel would have to be turned further to get the same response as the stock steering. Steering effort would be somewhat less. If a 1.5:1 ratio steering quickener (used by racing teams)were used, the Omni 4 turns would become 2.67 which would be close to the stock value in turns and steering effort.

Flaming River and Unisteer will make custom racks. Unisteer looks to be cheaper at $499. However, if a rack from another car can get close to the right dimensions it would be worth a try.

I may have to buy junk yard Omni rack to get some measurements if no one has the information.

[Daniel]

Thanks Stan

I did a little looking around as well seems some honda cars might be a good options as well when i get some time
ill post some photos and measurements of the 131 power steering rack i have looks to be the same width wise as
the manual counter part. in 2005 i replaced every part on the front end of my 131, the brand new rank was sitting
around for a while so i took a good look at it, about a year before Hal had told me about his 124 V8 build and he was
using a 131 rack that is when i became interested in this but as serious like i am now. I think we can come up with a
simple cross over unit with the right research.

[divace73]

Don't know if you got the Alfa Alfetta models in the US but here in Oz they are a common candidate for Rack and pinion conversion for the 124's..

[Daniel]

Don't know if you got the Alfa Alfetta models in the US but here in Oz they are a common candidate for Rack and pinion conversion for the 124's..

If the price is reasonable and shipping isnt to bad ill do it but with all the options between honda and some Omni RPs
that i found so far sellers here in the US its more appealing to look into. Distance cost wise is another factor but if
ordering some thing overseas making the fab work and setting up easier sure why not. So far I've seen 2 or 3 people
go the 131 route which seemed to make sense at the time. When i purchased A rack in 2005 my my 75 131 it cost me
about a buck 20 and I drove to Norwalk picked it up from Herman. Now finding a 131 rack is very hard so in time finding
rebuild parts or another one will be very very hard later on. Finding something from a popular car that is newer and
plentiful makes sense.

The Power Steering 131 rank i have was listed as a 131 rack on ebay that i purchased almost 2 years ago for my 124
project, i feel these guys either didn't know what they had or just pawned it off on me.

[Daniel]

This is where i'm at so far on my project but hope to be in the thick of things soon once time and monies come into
place the photo below is of my bare engine bay which shall be filled with a nice shiny new rack soon or lets just
say sometime in 2014...



In the meantime if anyone needs a power steering rack for a 131 It's going for a reasonable price!

[SoFlaFiat]

Please educate me guys, the power rack Daniel has for the 131 is hydraulic? Correct? Is that true of all power steering racks? Is a power assist just another name for a hydraulic power steering rack? Or is it a gear driven rack with hydraulic assist? And how does that work?
Thanks!!

[vandor]

Just a few comments. I converted my Spider to the 85.5 steering rack setup many years ago. The stock rack is 3.5 turns lock to lock as opposed to the 2.7 of the steering box, however, for some reason with the rack the car's turning radius is smaller (ie. the wheels can be turned further).
I would not consider a rack that turns the wheels less (max angle) than stock, as IMO the stock Spider has too big a turning radius for a car this small.
Steering effort is much less with the rack, not only because of the slightly slower ratio, but racks in general need less effort than steering boxes. So the advantages of a rack are less steering effort and reduced on-center play. I would not consider power steering unless there is a specific reason to do so (disabled driver, heavy V8 engine, etc), and even then I would go for an electric unit that mounts on the steering column. I actually bought a universal unit to experiment with, but it's just been sitting around for years. if anybody wants to take it off my hands it's available.

[SoFlaFiat]

Csaba,
An electric unit would be the same in all aspects, to belt driven power steering, except what powers the pump correct? I wasn't really interested in power steering but I might be interested in experimenting for the right price. Is it a readily available unit that other members could purchase if the results turn out well? Let me know what you are looking to get for it.
Thanks!

[Daniel]

Just to clear things up a little bit the only reason i have a power steering rack from a 131 to begin with when
searching for a Manuel 131 rack on ebay came across a unit listed as such! So after it arrived I was a little
surprised when opening the box. I traded some emails with the seller and somehow time elapsed now 2 years
later I'm still sitting on it. Not going to suggest power steering for a spider since I've never seen it done but
if the factory fiat 131 had it I'm sure it can be install on a spider as well.

In 2005 after replacing every bushing and new rack on my 131 the feel was so comfortable 0 play, smooth
on the road and the steering felt easy to use have wanted to do my next spider that would be a keeper
since.

[spiderrey]

I took a 77 alfetta apart a few years ago. Dont recall what I did with the rack. It sounds odd but when I had my 3 liter Milano guys on the forum talked about getting rid of the power assist by just ditching the pump and plugging the hoses. They still used the stock rack, but now it was manuel with no issues. thats what I read a while back anyways.

[FiatMac]

I have seen info on the web suggesting use of a disconnected power rack in place of a manual rack. The suggestion has been to remove the piping, install grease fittings and pump in grease. If grease is not used the rack will go dry if the seals are bad or if they fail. The grease keeps it lubricated.

Power racks usually have lower ratios (quicker - fewer turns per inch of travel). They also are usually a bit more bulky, but could be a good choice if they will fit the space.

[vandor]

Daniel,

FWIW you don't have to have PS to run a PS rack. You can just connect the two hydraulic fittings together and use it as a manual rack (make sure there is fluid in it). We used to do that on racecars.
The only possible problem might be if the PS rack is a quicker ratio than the manual one, because that would increase steering effort.
Just as a FYI, the 131 PS racks used different tie rod ends than the manual racks.

[SoFlaFiat]

Thanks Stan, Csaba and Daniel, my questions have been answered. I have a friend who is driving a 96 honda who will let me lift his car and measure what he has for a rack. It's a start at least on my end for finding a compatible transplant. I'll post what I find.

[Daniel]

Hmmm these are some interesting things to consider thanks for the suggestions

[Daniel]

I have seen info on the web suggesting use of a disconnected power rack in place of a manual rack. The suggestion has been to remove the piping, install grease fittings and pump in grease. If grease is not used the rack will go dry if the seals are bad or if they fail. The grease keeps it lubricated.

Power racks usually have lower ratios (quicker - fewer turns per inch of travel). They also are usually a bit more bulky, but could be a good choice if they will fit the space.

The grease seems like an option but wouldn't that also make the movement slower or have more resistance?