911 E to S front suspension conversion

[Rick B]

I am working on the planning for converting my 1970 911E to 911 S suspension. The parts manual indicates that the A arms for the e and s are the same part number (911 341 901 00 for the left hand arm for spring and shock from the 1973 parts manual, part drawing number 12), but the wording indicates one is for spring struts and one is for shock struts. Is there a difference in the A arms?

I understand that the E did not have a torsion bar. I will be using torsion bars and shocks in the new setup.

Also, is there a major difference in the auxiliary support? These are parts numbers 901 341 013 04 (spring), 901 341 013 03 (shock), and 911 341 013 05 (shock, 1972 onward)? The 2.7 Carrera support looks to be the strongest in the various pictures that I have seen.

I am planning on using the ER polybronze bushings and Bilsteins as well as adding a sway bar.

Thanks in advance. Rick

[88-diamondblue]

Can't help much on the suspension but recommend calling Chuck at Elephant Racing or Steve at Welcome to Rennsport Systems, Porsche Performance Products for the 21st Century to get advice on what you want to accomplish with the suspension. They would be able to make a recommendation and of course both sell Elephant products as does PP.

[equality72521]

I've got a pair of late model A-arms and a set of Bilstein struts if you're looking.

[djpateman]

The E may or may not have splined A-arms to take the torsion bars. It also helps to know if the struts are the original hydropneumatic version still. If they are, then you already have the S calipers, and the struts can be converted to use shocks. Also, you might be able to just add torsion bars. To find if the A-arms have splines, you may have to remove the end cap at the front to find the splines since rust might prevent a torsion bar from engaging them.

[Grady Clay]

djpateman is right on with this little known fact.
In late ’70 and 1971, Porsche ‘left off’ some of the parts that make up the A-arm and front cross member. There isn’t any spline provision for a torsion bar. The forward end of the A-arm tube is open.

Also, the bottom of the arm is open; it is just a ‘channel’ out to the ball joint rather than a ‘box’.

Some are tempted to use a 914 A-arm but the torsion bar splines are different from the 911.

Another part that was ‘left off’ is the receiver on the front cross member for the torsion bar lever and adjusting bolt. Here the 914 part is interchangeable.

Refitting the Hydropneumatic struts with shocks is possible but isn’t a good idea. These struts used the ‘pinch-bolt’ method of attachment between the strut and the ball joint. IMHO this was defective and should have been recalled in ’72. New (or later) struts use the ‘wedge-pin’ method of attachment and are very safe. The ball joints are different between the two methods; a ‘half-moon’ in the pin for the early ‘pinch-bolt’ version and a ‘V-notch’ for the later ‘wedge-pin’ type. You must replace the ball joint with the strut.

All 911s with Hydropneumatic struts used the 3.5” spacing 911S aluminum calipers. These were standard on the 911E and also came with the “Comfort Group” on the 911T. Standard were the 5½x14 Fuchs with 185/78x14 tires.

If you search Pelican, I posted images of all these parts.

Best,
Grady

[Rick B]

thanks to all for the information. Yes, the caliper is aluminum. I will look for the pictures. Rick

[Shaun @ Tru6]

Rick, please let me know if you will be selling your hydro struts.