Early steel trailing arm to 911 aluminum upgrade

[ppetion]

How easy is it to upgrada from steel arms to aluminum with 911 part number?

Any modifications or cutting required?

I remember reading that on the later turbo ones I would need to modify the schlock bolt hole or something like that.

Thanks

[Flieger]

It's a PITA if you have an early car. How much do you want them?

[ppetion]

It's not that I want them but I am in a situation and trying to figure out what to do .
I am doing a resto , the car is a 70 and I habe 3.2 motor with the matching transaxle .
I am using the cvs / axles and hubs from a 930 with the older steel arms . After assembling everything with new Bearings , ( motor and trainy is still out) I installed the axles and notices that there is a play on the wheels holding them at 6 and 12 o'clock . I am beginning to think that I have to use the arms as well . ( I have another thread in that )
Any input will be appreciated .

[Flieger]

A play in the wheel like that sounds like the 930 spindle isn't fully seated in the 911 bearing. I did not think you could mix those because the 930 uses the beefy double tapered roller bearings (if I understand correctly) and the 911 has the sealed ball bearing.

[ppetion]

You are correct . It looks like I will have to use the other trailing arm.

[Flieger]

I'm pretty sure you can get a combination of axles and CV joints that will allow you to use your steel arms. Turbo aluminum arms will not fit at all. You will need to add new pickup points on the torsion tube.

[kent olsen]

Curious, as I replied to ppetion's private message. 20 years ago I had to replace the left rear wheel bearing on my 72T 3 times. A Porsche friend recommended the 74 or later aluminum, somewhat lighter and with a larger wheel bearing. They've been on the car ever since with no issues.

[tholyoak]

Only a PITA on 69-71. 72-73 it is a simple bolt on solution

http://members.rennlist.org/911pcars/911AlloySuspAll-a.pdf

[kent olsen]

tholyoak that's a great article.

When I purchased my 72T I wasn't aware of the difference between the "T" and "S". Once I was I quickly found the price to go to an "S" was pretty steep. So being an old hot rodder I started the easy way by removing weight. The car originally weighed 2350lbs. Over the years I was able to remove 150lbs. Of course then comes power, I went from the 2.4L to the2.7L, which stayed in the car for about 15 years. Now it is powered by a 245hp twin plug 3.0L and makes 9:1 power/weight.

[Evans, Marv]

I did this for my '69 a long time ago. Used '74 aluminum arms and had the bosses for the shock bolts milled down an inch. I had to use rubber bellow dust covers since I still couldn't use the steel ones, because there still wasn't enough clearance. They are lighter and the bearings are more robust but if I had the choice now, I'd just use the stock arms. Mine is a street car so other than being an interesting exercise in modification, There really isn't an advantage performance wise.

[78-911SC]

Did this exact exchange and milled down about a inch than used washers to make it line up exactly. Still in the process of restoring the car so I haven't had it on the road yet. Will be using turbo brakes so I used 83 trailing arms.

[targa44]

Also, for easier work in removing/replacing the banana arms on your early car some time down the road, consider WEVO's "E-Z" pins to replace the orig. pivot pins.

[ppetion]

My aluminum arms are the 911 type, not the 930's I took them to a machinist , trimmed them an inch , new bearing and had them installed. All went well , no more play . Thanks all for all the info provided.