Early 911 Alum. Control Arms/Adj. Plates

kstar · 10-03-2001, 04:50 PM

Greetings:

Just researched the archives on the Early 911 adjustable spring plate, aluminum control arms conversion . . . now I need to make sure I have my facts right.

1) Use '74 aluminum control arms.
-No need to drop engine for install
-Keep present rotors/brakes/e-brake
-Keep present Weltmeister sway bars
-mount is ok for the alum. control arms

2) Use any '89 or earlier adj. spring plate
-Factory plates work
-Aftermarket work, provide more flexibility

So, short some bushings, I just need one of the above adj. spring plate choices and some bare '74 alum. control arms, right?

And if I am correct in my assumptions, does anyone have any of the parts above for sale?

Thanks again for any help!

Best Regards,

Kurt Starnes

kstar · 10-03-2001, 04:51 PM

BTW, the car in question is a '72 911T . . .

kstar · 10-03-2001, 05:16 PM

Noah:

If someone can confirm your '77 aluminum control arms will work on my '72, I would be very interested in talking to you about buying the whole spring plate/control arm package from you.

Best to you,

Kurt
kurt@starnes.com

Jack Olsen · 10-03-2001, 05:32 PM

I'm going to throw some misinformation into the ring, probably. But I believe you want the 74 trailing arms, not later. And, as I recall, there's some advantage to the factory semi-adjustable spring plates over the aftermarket ones. Maybe it has to do with available bushings, but I can't remember right now. Clearly too much lead in the paint of my crib.

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Jack Olsen
My Rennlist page • My Pelican Gallery page • My Porsche Owners Gallery page

[This message has been edited by JackOlsen (edited 10-03-2001).]

kstar · 10-03-2001, 07:06 PM

Jack:

I think I read that you put the '74 alum. trailing arms in your '73 beast - is this correct? I think the '72 and '73 are identical stock with the same steel trailing arms?

My question is: Did you have any problem with the conversion? Was it simply bolt-on and did you do this with the engine mounted?

Also, did you need to make any other brake/e-brake/bearing changes to accept the alum. control arms?

And, finally, did you use the factory adj. spring plates and if so, from what year?

One more ?: What sway bars/size are you running in the rear - and you did add the s-bars before or after your control arm switch?

Thanks in advance for your assistance!

Best Regards,

Kurt

Early_S_Man · 10-03-2001, 07:18 PM

The reason '74 arms are peferable is the CV-joints and axles are the same as '72-'73, and you really run into a hassle trying to match output flanges, stub-axles if you use the '75 and later arms, but the arms would fit, and sway-bar links are all compatible, '69 thru '77.

The reason for going with factory adjustable spring plates is that you can use the Neatrix bushings, which are the highly-rated replacements for the factory vulcanized bushings. Sway-A-Way spring plate bushings are polyurethane, and odd-sized, only available from Sway-A-Way!

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Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

89911 · 10-03-2001, 08:03 PM

I don't think you can use 87 to 89 spring plates on earlier car. They changed the teeth number on the T bars for these and earlier T bars may not fit.

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8 9 9 1 1, The last of the line.

Jack Olsen · 10-03-2001, 09:28 PM

Kurt -

I, er, had the trailing arms put in by my mechanic, didn't do it myself. Embarrassing, but true.

I also had it done at the same time as new torsion bars and brakes, so I'm not sure how much of a hassle it was. The engine was not dropped for this.

Warren confirms what I had forgotten. The Neatrix bushings can be used with the factory plates. I think mine were from a 77. The factory bushings were originally vulcanized, but the ones the factory sells now (I'm told) aren't, and they squeak a lot.

I use a Weltmeister adjustable 22mm swaybar in back, using the Weltmeister mounts, since my factory mounts are broken.

------------------
Jack Olsen
My Rennlist page • My Pelican Gallery page • My Porsche Owners Gallery page

kstar · 10-03-2001, 09:48 PM

Jack:

I think I read that you put the '74 alum. trailing arms in your '73 beast - is this correct? I think the '72 and '73 are identical stock with the same steel trailing arms?

My question is: Did you have any problem with the conversion? Was it simply bolt-on and did you do this with the engine mounted?

Also, did you need to make any other brake/e-brake/bearing changes to accept the alum. control arms?

And, finally, did you use the factory adj. spring plates and if so, from what year?

One more ?: What sway bars/size are you running in the rear - and you did add the s-bars before or after your control arm switch?

Thanks in advance for your assistance!

Best Regards,

Kurt

****Don't know why this post showed up twice - at two different times?! I promise I am not losing my mind . . . I think.

[This message has been edited by kurtstarnes (edited 10-03-2001).]

911pcars · 10-03-2001, 10:07 PM

As Warren points out, matching the stub axles to the hub flange will be the determining factor in whether you can use the later alloy arms. This is easier done with the matching 915 axles/drive flanges

The only difference between pre and post '77 alloy arms is the method of attaching the factory sway bar drop link; there's a ball stud on the early alloy arms and a bolt-on with the later arms. The aftermarket rear sway bar you use may help you decide. Weltmeisters use the spring plate to mount the drop link, so if you're using WM's, you can use any alloy arm. Charlie Bars and some others (?) use the bolt-on mount on the control arm.

Although the factory adjustable arms have the advantage of an additional bushing choice, the SAW spring plates have more adjustment range and adjustment is easier. If you're not close enough with the factory adj. spring plates, you have to go back in and reset the torsion bars anyway; about the same hassle as having the stock spring plate. However, the factory spring plates are more affordable.

Sherwood Lee
http://members.rennlist.org/911pcars
http://www.seinesystems.com

kstar · 10-03-2001, 10:31 PM

First, thanks for all of your responses and knowledge!

My rear swaybar is Weltmeister - so the plate attachment keeps my options open regarding the control arms - excepting the axle/cv/flange problem.

Noah - drop me an email on what you would want for the 'package' - kurt@starnes.com

FWIW, I find this BBS more valuable than the Rennlist on these technical matters; I post here first. I don't want to take anything away from the Rennlist, just a personal preference of mine.

Maybe Wayne should create a Pelican membership . . .

Thanks and Best to all of you folks,

Kurt

joefrantz · 10-04-2001, 09:02 PM

Hello folks,
I wonder if someone can elaborate on the stub axle compatibility issue.
I've got a set of 76 aluminum arms and stock '73 stub axles.
The car is a 73 with stock 915 gearbox, axles and cv's.
Although I haven't installed in the car yet, I have test fit the stub axles to the arms and don't see a problem.
Am I missing something?
What are the mis-match symptoms?
Thanks for your help.
Joe Frantz

911pcars · 10-04-2001, 09:45 PM

The earlier stub axles-to-CV joints were joined by 4 bolts. The later CV's use 6. Can't quote the size but the 6 are smaller diameter. You have the six?

Sherwood Lee
http://members.rennlist.org/911pcars

joefrantz · 10-08-2001, 10:08 AM

Sherwood -
Thanks for your response. I've done some additional checking and test fitting.
I'm using 4 bolt CV's with stock '73 stub axles. The Cv's measure approximately 110 mm in diameter.

I did test fits of the CV's/stub axles and arms in both the aluminum arms and the stock steel arms.

Everything appears to go together identically in both cases.

The aluminum arms are part nos: 911331513OR and 911331514OR. The casting date is 8/29/75. The hubs in the aluminum arms are those that came with the aluminum arms.

Thanks again for the explanation - hope the part numbers help others.
Joe Frantz

Early_S_Man · 10-08-2001, 01:34 PM

I believe the engine/transaxle package will need to be detached from the shift coupler and dropped down about 5" to 6" in order to change the arms ... no need to disconnect electrics or fuel & oil lines. You just want to get the nosecone out of the way for access to the bolts and to put a dimple where the inboard nuts can be loosened like the later cars. All you have to loosen is the 12 mm bolts thru the engine/trans mounts.
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Warren Hall
1973 911S Targa
1992 Dodge Dakota 5.2 4X4 parts hauler

[This message has been edited by Early_S_Man (edited 10-08-2001).]