Greetings, - this is the much awaited Steering update for the SPC Daytona Coupes – From what I can gather -as of 01-10-12
My section of the shop (The New Mustang Ranch) has had a few Daytona’s in and out; however, primarily our experiences are with the 0054 chassis that I am rebuilding, as well as a customer’s car ; 0139’ – and somewhat on 0102, and occasional calls to our friends.
The purpose is to relay the information gained so that you can make your own determination on the RACK-ATTACK you would like to pursue on your own individual SPF Daytona. / Shelby Cobra Coupe - etc.
I do not have daily access to a CSX 9000 car at this time, so I am purposefully framing this commentary and discussion as the Gen 1 Coupe / AKA Brock Coupe / AKA SPF Coupe.
I will refer to them as SPCs as this is the first portion of the chassis serial number, and thus not representative of any political affiliation or team.
I personally like to call them (expurgated) Coupe or the (redacted) Daytona and occasionally I call them (censored) .
Note: Was thinking of the CA personal plate “Brocksh” for the coupe. – but that is another story.
Pursuant to the natural forces at work in Hurricane Katrina; - my steering rack was corroded inside and out.
We removed it from the car, beginning the process of reverse engineering the rack and obtaining a replacement.
The goal with my SPC rebuild was to build a car with the ethos ;
“what if we made every little bit, a little bit better” , where could we go>?
Personally, -- when the car is completed, I want to not have to wince when asked : “does it have this>? ”, or does it do that >? ,
- - I wanted to construct a no apologies GT coupe of the highest order.
- the High Tech Factory did a fine job assembling the coupe the first time, however, as with any manufactured product there are tradeoffs, constraints and compromises.
Now to the Meat and Potatoes;
The steering in the SPC is a power assisted rack and pinion Ford unit from the 1980s as found in specific lightweight cars of the period.
Its overall design as it sits in the SPC chassis is known in industry speak as a “Rear-Steer” rack, as the rack is BEHIND the spindle centerline, as opposed to a SPF cobra where the rack is in front of the spindle centerline. In a rear-steer steering rack car , when you turn the steering wheel clock-wise (to make a right hand turn,) the rack interior rail/rod moves from right to left linearly down the long axis tube, pulling the rear trailing arm of the right spindle inward. t - Illustration below:
The Ford cars that this rack was found on was power steering optioned front wheel drive cars such as the 83-85 Escort, Escort GT, EXP, Tempo, Topaz, Mercury LN7 from about 1982 to 1986 ( I actually had one of those , {the 1983 LN7} not by choice mind you.
Ford EXP - Wikipedia, the free encyclopedia
Where did they come from >? ;
The core rack is from an
Escort GT ( I used a 1984 Ford EXP with Power steering as your reference car , if you feel better- they had a EXP
turbo {120hp} in 1984. ) is modified from the *as produced* ford version in a few areas to fit and work in an SPC.
Background;–
The OEM Rack was produced by TRW Corporation at that time (1980s). Then seemingly somewhat spontaneously - In late 1986, Ford went to a different manufacturer and the design
substantially changed from the previous generation and cannot be retrofitted to an SPC without significant rework to the mounts. ( Thicker core tube, that completely eclipses the mounts on the right hand side.
My personal success was with the following part number;
E6FZ-3504-A and E5FZ-3504-A.
From what my Ford parts guys tell me they are 100% obsolete from Ford. However, we found that Ford still has rebuild kits for these on the shelf, including pinions and such..
You may want to search the NOS parts guys for these – you might get lucky.
Keep in mind TRW was the OEM provider of many steering racks and other components to various people in the 1980s Including Chrysler, GM, and even Ferrari.
---My way of thinking on this is that our core rack design probably was subject to engineering changes and resold many times by TRW to many people at various times , - so it is possible that the core design as found in our SPCs exists with a slightly different casting in another car of the period.
-- one rather poetic and ironic possible example being the Dodge Daytona 
== didnt they have a Shelby Dodge Daytona in the 80s;>?
Although, - with my particular problem solved I and my parts found,- I have not moved further in that line of research.
The NOS TRW/OEM/FORD Escort/EXP rack as provided is of somewhat a small diameter main tube compared to a Mustang II piece, or a more modern Corvette or Viper piece ( not to mention the conflict with the rear steer dynamic )
– and the German racks I found were all for Front steer rack applications which would behave in the opposite manner of installed in the SPC location.
One thing though, the NOS OEM TRW rack had a very nice precise movement that was
as nice as about any German rack I have ever felt up.
( sorry I had to say that, want to make sure you are paying attention )
Steering column / shaft geometry; I looked at changing out the rack , but it bumps into so many inter-dependencies, that I went back and pursued the NOS ford piece, I am very glad I did.
Mounts:
The Rack as installed in our SPC coupes is a solidly mounted affair via a pair of milled aluminum blocks , that look much like a smaller aluminum stockade. These cross bolted through the frame tabs to steel threaded bars that act as lock nuts of a sort.
TURNS ; Lock-to-Lock , etc – linear travel. –
You will notice that on your SPC coupe, turning radius is accomplished in 2.8/2.9 turns lock-to-lock of the steering wheel, where an escort / EXP rack accomplishes this in 3.1/3.2 turns on the bench.
The linear travel in inches of rack shaft per pinion rotation is identical. We have verified this with the following racks;
1. Original SPF provided in SPC 0054,
2. Original SPF provided in SPC 0102
3. Original SPF provided in SPC 0139
4. A1-Cardone (rebuilt) rack as purchased for a 1984 EXP with power steering.
5. NOS ford rack E6FZ-3504-A
6. NOS ford rack E5FZ-3504-A
When you get your hands on your subjects rack , - You will notice that the EXP/Escort rack as it ships is about 44” long end-to-end measuring from the threaded end of the inner tie-rod end. ( outer tie rod ends removed ) – and the SPC is about 46” , - no problem. = this is simply accomplished with a pair of rack extenders that are screwed down to the ends of the core of the rack, underneath each inner tie rod end.
Spacer Removal ;
You will need to press/hammer/tap out the retaining roll pins, and wrench these off of your rack, and reuse them.
Spacers; note they are different lengths right and left side. They screw down over the inner tie rod threads and down on the shafts, thereby providing the limiting or narrowing of the travel of the rack inner shaft. - you can see this in the above jpg(s).
Now when you look at the FORD piece you will notice that it has 3 small hard formed metal tubes as attached to the rack. – the first two are the hydraulic pressure tubes, propelling fluid to and from the piston assembly providing the fluid forces to help you wedge into your parking space. The third tube is an air crossover /bleed tube between the left and right rubber bellows allowing air to funnel from one rubber bellows to the other during turning / linear rack movement.
How did we find one >? -- I called our friends at Sunnyvale Ford who broke out the microfiche and the
PRINTED Ford parts crossover guide from the Regan era. - We scoured the Ford inventory, pulled microfiche and went over the illustrations in agonizing detail -- and found the last 2 NEW racks in the USA, one is in my car, one is in a customer’s car.
In our quest to make things a little bit better and add functionality, we cross-drilled the SPC mount blocks to allow the SPF omitted crossover air-tube to be used, preserving our air-tight-seal on the bellows, hopefully enhancing durability and smoothness of operation. I don’t know if this tube was intentionally or unintentionally omitted from the SPC, but I can see a reason for it being there.
Note: the rubber bellows as found on the NOS ford rack were nicer rubber than ANY other bellows as supplied by any rebuilder or on the SPCs.
A note on rebuilt racks – I so far have not been happy with *anything* but an NOS ford rack in this application. Early on, -I had I pulled in a A1-Cardone rack from a local auto parts house, and I was unimpressed with its quality and in-fact , I think it was BENT. – unacceptable.
However now that we had the NOS pieces , we went to work cleaning them and making them fit the application.
The inner and outer tie rod ends were from the same application and are available from Moog if you need them.
I used NOS ford inners, and Moog outers. – and painted them black.
The rack lines up with everything and was a direct fit – keep in mind there is also an portion of the aluminum mounts that act as a bellows remount as well. –
If you are having difficulty with vague steering on your coupe or free play, there can be many issues at work, only you and your mechanic can know for sure what to do – if you need help feel free to call / post email – or come over .
All I can say is that a NEW rack has made a world of difference and is a dramatic improvement.
The precision gained with the OE TRW and Borgeson U Joints has really improved steering precision to a new level.
My next update will be the
Radiator /Cooling and AC Improvement we are now offering to SPC Coupe owners, they seem to work
REALLLY well !!!!
34F AC at the vents, full cold AC available on a 100F+ degree day in LA traffic with no issues with a Aluminum ROUSH 427W. –
Till Next time , Steve –
Linear Mode
