Speedster with SC Running Gear

[Edwin Ek]

Circa 30 years ago, a hot set up was to put SC running gear in a Speedster body: disc brakes, SC motor, 741 transmission, later steering box and suspension. Anybody here do that, still have a car like that? Anybody undo that? Recollections and impressions?

[David Jones]

Friend of mine has a speedster with that configuration and I was impressed with the handling. Very tight and way better than my normal cabrio of the same age and of course way faster.
He may chime in, Robert?

[Ron LaDow]

Edwin,
The 5th image on the home page has a white Speedster with discs; dunno about the engine or steering gear.

[Al Zim]

We have a ca like that in our shop now. In my opi8nion the value of speedsters is higher if they are original. While these parts interchange sometimes they do not fit properly and most shops do not have the experience or the parts to make things look factory. al zim

[George Hussey]

my 61 roadster has a 912 engine, C disc brakes, Bilstein shocks, 12 volt conversion, Carrera wood wheel, Fuchs alloy wheels and low profile tires, yet still looks fairly stock

[Albert Tiedemann]

Circa 30 years ago, a hot set up was to put SC running gear in a Speedster body: disc brakes, SC motor, 741 transmission, later steering box and suspension. Anybody here do that, still have a car like that? Anybody undo that? Recollections and impressions?

Yes, I did this in 2000 to Speedster 82984. I did not use the Solex carburetors as Zeniths are nearly trouble free once you get them right. I did apply the reinforcement piece to the to the forward member that carries the front suspension, otherwise the entire floor, diagonal member and battery box are original as is all the external skin. All original impressions in the floor for rigidity were retooled by hand [I provided the buck back up as the craftsman worked below/top as necessary.] This resulted in a preservation of the dihedral angle of the floor as original. I also had doubler plates welded to the door sill area as this is a weak link when the car is lifted at either end especially when lifting from one side at the strongest lifting point in the front [directly below the sway bar mounting to the chassis] Regarding the sway bar, I used the one off the 1964 donor car--a 16mm diameter and a 1 mm "upgrade". When in the lift mode, the doors still open and close effortlessly. I also added a removable roll bar that was fabricated and installed from a Factory drawing that I obtained while doing consultation work throughout Europe in the time frame of restoration. Material analysis and wall thickness were upgraded [4130 seamless tubing with .120" wall] The Factory disavowals all knowledge of this archaic drawing--of course- and has cut the drawing identification from the print of the drawing. The latter is likely the consequence of safety issues arising therefrom traceable back to the Factory. This addition adds appearance of the era and would not pass safety tech in SCCA racing [no diagonal member] if such still exists. Since it is a bolted in bar, it adds some torsional resistance--but not one necessitating a penning home to Mom, due to the flexibility of the bolted joint. I did use the correct size tires 155mm x 15 inches but mounted them on the rare 1967 911S Fuchs alloy rims. When coupled with adjustable Koni Shocks all around including the steering damper, the steering feels very light and quite responsive. Not sure if really needed, but the brakes are dual circuit and the custom fill reservoir mounts two "cans" [the Factory plastic ones coupling the Factory bent entrance lines as used on the 911 master cylinder furnished with the conversion kit. The transmission has Carerra gearing [BBAA], 7/31 ring gear and crown wheel [12 bolts] and mounted on a ZF, jelly bean, LSD. To preserve the interior look of the car I retained the monkey motion shifting mechanism which required changing the nose piece on the transmission to use a 716 type that I had on hand. I think a 644 nose piece will work as well. I was going to use the cast iron intermediate plate, but was cautioned against its use by Vic Skirmats This nose piece was modified to include a seal for the shift rod as suggested by Mike Robbins. You cannot change this seal unless you remove the nose piece; so, get it right the first time. The 155mm tire on the Fuchs wheel fits well into the battery box and does not need deflating to close the trunk lid. I forgot to mention that the car is 12V and all relevant elements were transplanted from the donor car, a 1964 356C with a Factory installed 12 V electrical system. In the treasure trove of parts accumulated prior to the restoration I found a NOS 12V, 356A windshield wiper motor for a Carerra which permitted a transformation to electrical upgrades without the use of compensatory elements like voltage reducing devices. I used the 12V Optima battery with the red top mounted on its side and oriented such that the positive terminal favored the position of the relevant connection to the electrical system in the opening for the original battery. I did not fit a cover for the battery although I think one could be custom fashioned since there appears to be ample clearance for same at the spare tire interface. Spare clears well and there is no interference with the original jack or its mounting. I also installed an electrical fuel pump for carburetor fuel bowl priming only-- although it could be used for engine supply in an emergency. It is located on one of the center vertical walls of the chassis below the passenger's floor board and is recruited by one of the original, bullet connector, dash mounted Carerra ignition switches [NC; off in, on out] in original setting flanking the GT Carerra mechanical tachometer of the era. The car originally had Coupe seats but I supplanted these with a pair of Speedster ones obtained from one of Bruce Jennings' race cars. The latter are mounted on GT frames, which when coupled with a small diameter Factory steering wheel, allows far easier entrance and exit from the driver's perspective, especially if the top is up, as I often drive the car with the top up because it has a more sinister appearance.

Regarding going back and forth between "original" and making the cars safe to drive and to keep up with and/or pass interstate traffic, I have used all the mechanical upgrades offered by the Factory--taking the "old" Factory part off and putting the "upgraded" one on; so, in my case, it does not present a problem. Structural upgrades could present a problem, but who would go back to a weaker arrangement/design. My car remains in full trim but is painted a non-Factory color and although it has Porsche upholstery [Alcantera; obtained from the Supplier to Porsche], it is not material of the era. The burlap, square weave carpet material is the same used but may not be the exact color. The top and side curtains are fabricated from the correct materials, but the color is not one likely available of the era. In addition, custom machined/formed from thicker wall copper alloy tube and lavishly chromium plated, were obtained from Jeffery Felman in FL and embedded in the door garnish moldings and serve as the anchor points for the side curtains. These moldings, door panels, instrument bow, dash covering and seats sport the Alcantera fabric which I furnished to Autos International to use their patterns and expertise in producing, offsite, the items needed for installation at the residence assembly site. Yes, the entire car was mechanically built/rebuilt and the entire assembly was carried out in one bay of a two bay attached garage. I include a picture of the painted "shell" with some metal restoration [never hit--anywhere] as delivered to the Hillside site via flatbed with every nut, bolt and washer removed. Nerf bars for handling, fresh engine hiding under cover in the stand.

About to install adjustable spring plates to permit external adjustments to 1 minute within a Factory 50 minute tolerance.

I have not taken the car out too much lately, but when I do, it always attracts a crowd of "lookers"

Here is a picture of my car.. That is me in the striped shirt and the taller gentleman is the legendary 4 cam mechanic, Heinz Bade who passed a little more than a year ago.

[Edwin Ek]

Albert, thanks! That is brilliant. The Speedster in your picture must be the one you converted? How is it to drive? You didn't want to use 165 tires?

[Albert Tiedemann]

Albert, thanks! That is brilliant. The Speedster in your picture must be the one you converted? How is it to drive? You didn't want to use 165 tires?

Yes, that is the one.

I have driven it to many ECHs. The longest was to Michigan [from Maryland]. Eight hours at 4300 rpm with occasional bursts to 5500 for passing and no problems encountered in either direction. Temperature indicated max about a whisker past the "L" on the gauge, but I had fit the best, Aftermarket oil cooler available and the middle motor plate was not missing [63% of cars on the road do not have this piece as I always make a survey when I go to an event]

155mm was the delivered size tire. At the time I did not think that I was going to have to put on a lot of interstate miles to get to some of the ECHs. I recently replaced the 155 size with 165s. The rolling/loaded radius for these tires is tabulated at 826 and 800 rev/mile. So, at the speeds traveled on the interstates, rpm should drop by the factor, 800/826, or about 3%. Not much. I was hoping for more. Guess I should have left the transmission BBAB with ZF LSD as it was special ordered with these ratios from the Factory by my friend when he went there on Holiday and picked it up [donor car was a 1964 Coupe' that I purchased from him].

Here is a closer picture of the rear of the car which the avatar does not show.

[Edwin Ek]

Thanks again. And are you using 155 tires, or is that a typo?

[Fred Otjen]

There's been one in my garage since '86. It's got SC engine, 741 trans, C disc brakes, decambered. Also came with a roll bar and Fuchs because it was set up for vintage racing at Summit Point, WV in the '70s. More fun and performance than any A,B,C or 912 I've had.

[tracy pellett]

Just finished a 3 day , 1600 mile run from SC to Maine , out foxing the weather system that’s been attacking the eastern US .We left on August 1 and arrived at our cabin on August 3 . Top down the whole trip, 10 minutes of hard rain and a few areas of mist in 30 hours of driving . SC+ engine , C gear box with speedster gears , upgraded steering box , original drum brakes with Tecno Mag wheels and new for this year an 123 distributor with a Winterburn CD . All this on a 1956 Speedster. A great car for back roads but can hold its own on the interstate. I also have a smaller steering wheel to help getting in and out . It’s changed a lot since the first Maine trip in 98. No regrets and all reversible . I did keep the original monkey linkage on the shifter . Will head back in two weeks and hope the weather isn’t as challenging.

[Alex Finigan]

Yes, my '57 has been that way for over 30 years. SC engine, trans, discs, and ZF steering box. MUCH nicer to drive than my stock '57.
Driven from Ma. to Ca. in '04 for the Speedster Reunion with no problems, around 700 miles a day @ 75 - 80mph.

[Edwin Ek]

De gustibus non disputandum est. That is Latin for "concerning taste, there must be no dispute". Alex, I think your car looks fantastic! The only thing I would change is to use Speedster headlight grilles instead of the later fry baskets. For some reason, your C wheels look especially good to me. Fuchs alloys look a sminch too modern, me thinks- but still very cool. Obviously they are quite a bit better technically.

[Robert Thiemrodt]

Yes, David is correct. My 58 Speedster runs with a Super 90, 741 Tranny, and disc brakes. It is very fast (For what it is) brakes on a time, and shifts like a dream. A recent low profile (charity car show) had some experts pointing out these inaccuracies, I believe saying it is incorrect. My response, "My Car, my money, so it's 100% correct"

I will never win a huge trophy and have my picture go down in the record books with my car. However, my 100 h.p. is a hell of a lot more entertaining than 60 h.p. At the 5500rpm redline in third gear my Super 90 will take me to 90 m.p.h. And my brakes stop excellent, with no sign of fade, ever!!


Purchased custom made baby moons which hide the disc brake calipers from a Registry member. So I have best of both worlds, in my opinion.

[Brett Johnson]

Hi Robert,

I was apparently one of those expert people at the low profile "charity show" that commented -- I don't recall your stated response, though it is okay with me, just not really accurate. Regrettably, I am into the authenticity thing and I'm updating my book at this time.

My 95 hp 55 coupe is pretty swell, as well.