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SWB 912 or perhaps not?
Posted: Wed May 11, 2016 2:21 pm
by Bathtub57
Am I right in thinking my torsion plate hole on my sill is in the LWB position - i.e. in the wrong place?

Re: SWB 912 or perhaps not?
Posted: Wed May 11, 2016 2:48 pm
by Nick Moss
Yes, it looks as if you have LWB rear quarters fitted.
Re: SWB 912 or perhaps not?
Posted: Wed May 11, 2016 4:36 pm
by fetuhoe
If you have LWB rear quarters then there are other significant mods that must have been made.
As the wheelbase change is around 57mm you must also have LWB Trailing Arms fitted and this will mean that either the torsion bar tube has been changed or the trailing arm brackets have been cut off the SWB tube and the LWB Trailing arm brackets fitted.
Re: SWB 912 or perhaps not?
Posted: Wed May 11, 2016 5:53 pm
by jury
I could be wrong, but from the photo it looks like there is a lot of space between the tyre and leading edge of the rear bumper...
Could it be that LWB rear quarters and rear bumper are fitted, but the car is still SWB ?
Re: SWB 912 or perhaps not?
Posted: Wed May 11, 2016 5:53 pm
by Nick Moss
Looking at the position of the wheel in the arch it's still fitted with SWB banana arms
Re: SWB 912 or perhaps not?
Posted: Wed May 11, 2016 5:55 pm
by Bathtub57
Thanks for the quick replies guys.
I knew that the rear arches had been replaced and it would make sense to use a larger panel but the part about moving bar tubes etc sounds worrying. The torsion bar hole does match up with the torsion bar cover, or at least it looks like it does which it shouldn't if the panel is wrong?
I'll jack it up now and take some pics with the wheels off.
Re: SWB 912 or perhaps not?
Posted: Wed May 11, 2016 6:55 pm
by Bathtub57
Not sure if this picture makes anything clearer?

The torsion bar lines up with the hole

Re: SWB 912 or perhaps not?
Posted: Wed May 11, 2016 7:02 pm
by fetuhoe
The torsion bar tube never moves it is in the same position on any car from 1965 until 1989.
The 57mm increase in wheelbase is created by changing the length of the trailing arm and the spring plate.
When the SWB cars was changed to LWB for the B Programme the position of the brackets on the tube moved and the trailing arm length increased.
You cannot fit long trailing arms to SWB Tube brackets as this would also seriously change the rear track and cause several other problems.
You either need to change the brackets or the complete tube.
The SWB Arch is located in a different position so the hole in the wing for the Torsion Bar in the SWB wing is much closer to the edge of the wing.
The trailing arms do appear to be SWB but the position of the arch still looks wrong.
The photograph below shows both a 1967 SWB Car and a 1969 LWB we have in our shop.
Both cars have 185 x 70 x 15 Wheel/tyres and the white box is where the LWB arch would sit in a SWB Trailing arm was fitted.
I guess if you have small diameter wheels an low profile tyres it could work but gearing may be odd.

Re: SWB 912 or perhaps not?
Posted: Wed May 11, 2016 7:26 pm
by Bathtub57
fetuhoe wrote:The torsion bar tube never moves it is in the same position on any car from 1965 until 1989.
The 57mm increase in wheelbase is created by changing the length of the trailing arm and the spring plate.
When the SWB cars was changed to LWB for the B Programme the position of the brackets on the tube moved and the trailing arm length increased.
You cannot fit long trailing arms to SWB Tube brackets as this would also seriously change the rear track and cause several other problems.
You either need to change the brackets or the complete tube.
The SWB Arch is located in a different position so the hole in the wing for the Torsion Bar in the SWB wing is much closer to the edge of the wing.
The trailing arms do appear to be SWB but the position of the arch still looks wrong.
The photograph below shows both a 1967 SWB Car and a 1969 LWB we have in our shop.
Both cars have 185 x 70 x 15 Wheel/tyres and the white box is where the LWB arch would sit in a SWB Trailing arm was fitted.
I guess if you have small diameter wheels an low profile tyres it could work but gearing may be odd.

Wow, great summary. I think I get it now. It would appear that the rear wing and arch are from a lwb car but they have been modified somehow to fit the wheel better. As Jury says looking at it now looks like the wheel sits too far forward in the arch, which would make sense.
Re: SWB 912 or perhaps not?
Posted: Wed May 11, 2016 7:56 pm
by Bathtub57
The approximate measurement from the centre of the torsion bar hole to the centre of the wheel cap is approx 460mm. If anyone with a SWB car could verify the distance on theirs I assume that would let me know if anything else is out of kilter.