Mad4classics Posted August 7, 2019 Report Share Posted August 7, 2019 Interesting throttle return spring arrangement you've got; is that to enable the peddle feel to be set the way that you like it? David Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 7, 2019 Report Share Posted August 7, 2019 less springs equates to less, spindle wear the double set up does apply a lot of load where you dont want or need it Pete Link to comment Share on other sites More sharing options...
johny Posted August 7, 2019 Report Share Posted August 7, 2019 yes I prefer the Stromberg concentric springs set up as I think these on their own should be easier on the spindles.... Link to comment Share on other sites More sharing options...
Clive Posted August 7, 2019 Report Share Posted August 7, 2019 4 minutes ago, johny said: yes I prefer the Stromberg concentric springs set up as I think these on their own should be easier on the spindles.... Also used on later su's. The bodies are usually very good too, unlike many of the earlier variants. Link to comment Share on other sites More sharing options...
eddyinfreehold Posted August 8, 2019 Author Report Share Posted August 8, 2019 The current arrangement is exactly how I bought the car. It struck me as clumsy that the springs fouled the retaining plate in front. My OEM manual seems to show completely independent spring mountings cast into the inlet manifold (pp 1-309). On my vehicle I seem to have 'angels wings' behind the plate that you show in your photo to which the springs are attached. I'll try and dig out some better, weaker springs to fit the plate as shown in your image. I totally get the imbalanced pressure these springs give, as if the inside point of each spindle is being pulled towards the nearside, using the outside point as the fulcrum. That's the best way I can explain it. Thank you all again. Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 8, 2019 Report Share Posted August 8, 2019 whilst oil wont last long in the spindle zone any lubication of moving parts helps extend life .......along with weeny springs Pete Link to comment Share on other sites More sharing options...
Mad4classics Posted August 8, 2019 Report Share Posted August 8, 2019 I think we've got the same manual. The pictures in the manual on 1-309 depicts the Spitfire 4 arrangement, when it was updated they obviously didn't think it worthwhile to show the differences between this and MK2 and MK3. On the MK3 there should be a couple of small holes in the rectangular plate bolted to the manifold where the springs attach. As Pete says, weeny springs; the correct springs have only a small extension when the butterfly is closed. Mine are something like 65mm free length 70mm fitted approx. David Link to comment Share on other sites More sharing options...
eddyinfreehold Posted August 8, 2019 Author Report Share Posted August 8, 2019 Thanks Pete & Mad4Classics. I have that plate as you can see with its two corner holes, and also the 'angels wings' behind with two larger holes. The original plate looks standard but I will have to locate much shorter springs & of less strength to accommodate this setup. Any advice for sources? Any idea where those 'angels wings' behind have come from? Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 8, 2019 Report Share Posted August 8, 2019 I would say the angle wing shaped retainer is quite standard.for the twin spring awfull set up. Im sure the guy who designed it had shares in throttle spindles sales !!!! Pete Link to comment Share on other sites More sharing options...
Mad4classics Posted August 9, 2019 Report Share Posted August 9, 2019 The springs for MK3 are Triumph 145197, available from all the usual suspects. Burlen lists lots of return springs but you'd need to phone / email quoting the carburetter spec (should be AUD257 for UK MK3) to pin down the right one. I've never seen the angel wings on any SU installation. I think they're some kind of patent remedy. David Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 9, 2019 Report Share Posted August 9, 2019 https://www.canleyclassics.com/triumph-spitfire-mkiv/1500-acceleration-control-twin-carb-engine This shows the wing shaped spring plate the lower spring retuns the trottle loads the 2 short onto the plate return the free play required to make the choke fast idle free play throttle easier they are much too strong and these wear the spindles If these springs or spring are removed then the throttle will not settle back to idle and you get very high uncontrolled idle speeds You need 2 spring thats got extention with less load and theres two as each carb has the idle choke free play mechanism. Pete Link to comment Share on other sites More sharing options...
eddyinfreehold Posted August 9, 2019 Author Report Share Posted August 9, 2019 Thanks again both. I'll spend some time on a spring hunt. I'm wondering firstly if this set up relates to a one-size-fits-all solution to vehicles being sold to both home and overseas markets with alternative carburettor arrangements. There are holes on the flat plate and two on the 'angels wings' after all. Secondly I am thinking that at some point in the last 50 years the brackets have been removed and replaced backwards and no-one has noticed! They would be perfectly sound the other way round. They do look 'factory made' and not a piece of home-shop work. Link to comment Share on other sites More sharing options...
eddyinfreehold Posted August 9, 2019 Author Report Share Posted August 9, 2019 Pete. Our messages have cross posted. I don't think that diagram relates to my setup. That's a sort of bellcrank arrangement from what I can see. Mine are just fixed anchor plates bolted to the manifold. The choke is a solid unsprung wire in a sheath. It's not even a cable. It just pushes back and fore and is connected directly to the jet mechanism through the twin linkage. Link to comment Share on other sites More sharing options...
Mad4classics Posted August 9, 2019 Report Share Posted August 9, 2019 The later 1500 arrangement is totally different to that found on the MK3. David Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 9, 2019 Report Share Posted August 9, 2019 i was just showing the' wing' shaped arrangement , spoken about im not into the right or wrongs of evolution and stick to the basics of how these things are supposed to operate the mix and match problems of lots of bright ideas through the years gives room for lots of who's got what fitted by previous owners all choke are solid cable as its pull push operation , there is generally a 'mechanism ' to allow easy fast idle this needs a spring to return to idle........ but not anything aggressive. or you get ' the wear factor' Pete Link to comment Share on other sites More sharing options...
eddyinfreehold Posted August 9, 2019 Author Report Share Posted August 9, 2019 Pete. Totally get where you're coming from here. No worries. Latest update is I went back to my machine shed at work on the cricket ground and went through my spares. Two decent Briggs&Stratton 13hp throttle springs are now doing a decent job even if they look a little ugly. There is virtually no tension on either spring here yet they return the butterfly very well. Also Pete, I was wrong. I removed the 'angel wings' from behind what I assume is an OEM rectangular spring retaining plate. They appear to be home-made from perhaps Dexion shelving or something like big meccano with chipped paint and different dimensions. Did someone once have the wrong size springs? Photo attached. As fitted and working with old springs shown lhs and old 'angels wings' rhs. Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 10, 2019 Report Share Posted August 10, 2019 Thats looking pretty sensible ,, long live the spindles Pete 1 Link to comment Share on other sites More sharing options...
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