Rikrock@aol.com wrote:
>
> Listers,
>
> I spent Friday afternoon visiting The Roadster Factory, and Classic Motors
> (Gene Bird).
>
> Here's what I learned about Vixen uprights and a few other parts......
>
> While the source for the uprights has been previously identified as Herald
> drum brake cars,
Specifically, the 12/50 Herald, drum brake variant.
the uprights on Spitfires up to Commission #15,575 are
> identical to the ones I removed from my Vixen.
They could be. Over the years many people have used non-standard front
suspension parts to allow the use of more common and stronger uprights
and remove the requirement for Standard 8 steering arms.
>
> Dave at TRF was very helpful. I took my old upright with me, he brought some
> uprights to the front counter, and we compared. He didn't have a Herald
> upright, but he had an early Spit, and a GT6 part. We measured EVERY
> dimension with a vernier caliper. The early Spit upright checks out perfect.
> The GT6 upright dimensions match up except for the hole for the stub axle.
> The stub axle on a GT6 is larger diameter, by about 1/16". Looks like using
> the GT6 upright is possible, but it means going with GT6 bearings/seals.
Correct. The GT6 stub axle cannot be used with the TR4-6 front hubs
as far as I know. The GT6 one is fatter and shorter.
>
> Spit and GT6 steering arms are considerably shorter than the ones on my
> Vixen. Dave didn't recognize my arms,
'cos they are Standard 8 which is probably a bit rare in the US.
and didn't have a Herald arm for us to
> look at, but we looked at a TR4-6 steering arm and it is completely
> different. It will not bolt up to the Vixen/Herald/Early Spit upright--the
> hole spacing is wrong.
Correct.
>
> The caliper mounting plate on the Vixen is from a TR4-6, but is modified to
> fit the Vixen/Herald/EarlySpit upright---four new holes are drilled in it to
> make it fit!
As far as I know the TR2-6 caliper mounting plate (133499, UK, n/s)
(133500, UK, o/s)
go straight onto the normal uprights (209222, 209223 : sides swapped)
without
any modification.
>
> So I bought the early Spit upright from TRF and headed to Johnstown, PA to
> see Gene Bird. Gene had told me he had a set of uprights in stock, I wanted
> to compare them to what I had just bought. The uprights Gene has are
> slightly different. Not in any of the machined dimensions, or hole size for
> stub axles, ball joint, trunnion , etc. but they are just a LITTLE beefier in
> the dimension of the stiffening rib that runs vertically, and a LITTLE wider
> in the area just above the threaded portion of the upright. Gene would only
> sell the pair, I decided to go with what I had.....I didn't think that the
> extra material in his parts would make much difference. The way I see it,
> the weak point is at the top of the threads,
uprights normally fail just above the thread due to inappropriate
lubrication
and putting on too much lock. The amount of steering lock that the
Rack allows put too much lateral loading on the upright. Most failures
are low speed parking ones. Same goes for rear pivot bar failures.
so the only way to improve the
> part is to make the threaded portion thicker, along with reinforcing the area
> where the threaded portion meets the rest of the upright. If anyone thinks
> I've missed, or got something wrong, please speak up!
>
> I'll keep you all posted on how it goes. Got to get the car back together
> for Giants Despair Hillclimb next weekend!
Good Luck. I've just acuqired another Vixen S3 for £1,000 as it had
a heated glass screen and DG £700 for a second-hand one (£1200 for
new!).
>
> Rich Rock
> Pottstown, PA
Regards,
Dr John Upham, TVRCC Helpline person
--
Dr John Upham, The UKMotorSport Index,
http://www.ukmotorsport.com/, webmaster@ukmotorsport.com,
Voice: +44 (0) 976 634 053 (W), Voice: +44 (0) 125 287 2551 (H),
Voice: +44 (0) 976 634 053 (M)
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