weird problem with trailing arm swap

[adomakin]

my friend has a 67 911 that had a 2 litre / 901 box fitted and he's fitted a 3.2 carrera/915 box. the car is an rs replica and has been converted to long wheelbase. or at least we think it has. the rear fibreglass rs bumper fits fine, carrera rear quarter panels have been fitted and as far as we can see the distance from the hole in the rear quarter to the start of the wheel arch is of the larger size rather than the smaller size that the short wheelbase cars have. imagine his suprise then when he went to bolt sc trailing arms on only to find that, when fitted, they have moved the wheels back in the arch by about 2.75 inches! he don't get it and nor do i. are we both being divs and missing something here or wot?

[MT912RS]

The arm mounts are the torsion tube is different the easiest fix is to cut the center of a late car torsion tube out and weld it in to your car with some pieces of tubing for sleeves on the outside. The just don't teach you that fact in school. Here is what I did.

[CamB]

Showoff!! That is cool!

[adomakin]

jesus christ! i think we'll persist with the porsche bits thanks! that rear end is well cool and far too clever for my mate and me. got any more pics?

[surflvr911sc]

Well... aren't you going to show us the rest of the car???

[jluetjen]

THAT is the most fascinating non-sequiter that I have ever seen!

I like it but will never have an application for something like that. I havev to admit that what you have done would definitely be the envy of the RGruppe crowd. It could also get you an article in any number of 911 magazines.

[Embs]

Originally posted by MT912RS
The arm mounts are the torsion tube is different the easiest fix is to cut the center of a late car torsion tube out and weld it in to your car with some pieces of tubing for sleeves on the outside. The just don't teach you that fact in school. Here is what I did

AWESOME, More pics please!!!!!!!!!!1

[MT912RS]

[CamB]

OK, that is my new favouritest thing ever (because it is orange too). Look at how long those rear wishbones are!

I wanna learn to weld.

[Allenk]

I weld, but I wanna learn to do that! I want one,I want one,I want one! Come on man give us an article one how to build that system. I just moved to Wisconsin and I hear winters are long and I have a TV in the garage.

[HawgRyder]

What uprights are you using?
The rest of the install looks straight forward...only mild steel tubes I asume.
What are the coil-overs from?
Bob

[cowtown]

That is great! Please contact Excellence magazine and tell them about what you're doing. I'm sure they will put a writer on the next flight to Montana.

[scca_ita]

While your at it, why not just cut the torsion tube out completely? Save some weight. Do you have clearence problems with the rear?

[scca_ita]

I have 66 tub with LWB. To accomplish this you need to weld in the new LWB torsion tubes.

[adomakin]

ok, so the orange porky has got the trickest rear end ive seen ever, but can we get back to my problem!! scca-ita, are you saying that my mate has got to replace the torsion tubes with the later long wheelbase ones? i thought it was just a trailing arm swap and rear quarter panel mods?

[scca_ita]

You will need to have later spring plates and torsion tubes and arms. The bushings on the spring plates will have to be replaced with smaller ones because the holes are smaller on the pre 72 911's tubs.

The spring plate is the gating issue. The rear quarters will have to be moved back to the LWB pisition if not already done.

[adomakin]

ok, back to the drawing board then!
thanks blokes

[ValveFloat]

Is it possible that the previous owner of adomakin's friend's car modified the trailing arm mounts to move the SWB arms back enough to make the car LWB? And maybe used LWB spring plates? Maybe you could compare the spring plates on the car with some on a known LWB car, or just measure from torsion tube center to wheel hub center and compare the measurement to a LWB car.
Just a thought.

[adomakin]

cheers vf, worth a measure

[MT912RS]

The key is that the mounts on the torsion tube are different on the later cars. The longer wheelbase arms are longer by more than the difference in wheelbase (aside from the angle bit of the equation).