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  • Distributor springs

    dizzy springs.docx

    please see the doc attached - I reckon we all need these!!

  • #2
    These springs will presumably be for the 18 and 21 hp cars. The Delco part numbers are in the Technical Manual under Ignition on pages 21 & 22 I think. They show variations for all the models. Whether the differences for the different models of 18, 21 and 23hp are significant I don't know. Which spring numbers do the Arthur Archer drawings correspond to? I think that they are unlikely to be suitable for the 14/45 which had a very different advance curve. Whether your distributor is original after 90 years is worth checking out. The plate that has the slot defining the max advance may have 2 different slots with different amounts of max advance. The 14/45 had amax advance of 63 degrees and I have seen plates with this limit and another one with 55 degrees !
    Are there plans to produce springs for the 14/45?
    This of course opens up the question of what is the correct advance curve for the 14/45 with modern fuels and possibly a change of camshaft. There are 14/45 cars with Blydenstein profiles and BA75 to my knowledge and there may be others as well!!
    Last edited by gordon higginbotham; 16-05-2020, 09:32 AM.

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    • #3
      Martin Bryant's research:

      Mr Archer's drawings are not referenced back to the Delco part numbers. That is why I validated the drawings by comparing them to the springs Foppe supplied, which he would normally fit to 18/21/23 hp cars. They corresponded within a few thou and are identical on wire gauge. All our experts believe they are a universal fit across the Delco 650 KA and KB range and that the ignition advance curves for the three engine sizes are the same.

      I also cross correlated with contemporary evidence as shown in the attachments :-

      !. The letter from Delco makes it quite clear that the 14hp distributor is the 656Z. This has a completely different advance curve and quite differently numbered advance spring (seemingly 2 identical springs fitted on this model). Hence the new springs are advertised as for the 650 range only and will not be suitable for 14hp cars.
      2.The attached Delco factory advance curve is for the 650 KA and KB and referenced for the 75 and 90 models. I have plotted on this chart in red the advance curve measured by Norman Sharp on his 105. This vindicates our expert's view that the advance curves across the cars using these distributors are the same.
      3. I have looked again at the contemporary Delco parts list. It shows spring numbers 1835699 and DRH 495 as fitting the 650 KA and KB. The Talbot models listed for these dizzys are ,75, and 105 (I think my catalogue pre dates the launch of the 110).

      We plan to use Alberta Springs for the bigger cars - 01473 311783. They are incredibly helpful. If we could find some new ones to copy - ? ask Vinnie

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      • #4
        Guy,
        Thanks for that information which clarifies the position. I will talk to Vinnmie and see if he has a suitable sample of a 14/45 that could be used to get new ones made. If Vinnie has a suitable sample would TOC spares stock them?

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        • #5
          From John Dodd - a14 owner can also use the springs that Martin B has ordered, they would work OK. They would work better than a shagged out pair of original springs.
          I'm sure we would order some for the club Gordon

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          • #6
            Gordon - according to Foppe, the springs Martin has ordered should be fine for a 14hp - it's just the slots in the base plate that differ apparently

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            • #7
              Guy,
              Thanks for your 2 posts. I have a problem with the information because :
              1. The advance weight Delco part numbers for the 14/45 (656Z), 1930 AM70 (656ZA), 1930 -1937 AM sports, AW75, 65, 90,105 (650KA or 650KB), 1931 - 1936 AM,Std, AY75, AY95and AV95 (656ZB) all had the same advance weight part numbers so I assume they are all the same weight. But the spring part numbers for the 14/45 are quite different and unique.
              2. I attach an extract of 1954 Delco letter that gives details of the advance curves for for the 14/45 656Z and the 650KB.
              3. Since the only way of controlling the movement of the weights below the limit imposed by the slot is the strength of the springs and the weights are the same then using the recommendations can only result in a very different rate off advance.
              4. Attached is a plot of the advance curve for the 650 KA and KB ant this shows the advance scarcely reaching the limit imposed by the slot so I suggest that the 105 springs fitted to the 14/45 656z may not allow full advance got be achieved.

              I am sure the engine will run but will its performance be optimum?
              Yours puzzled,
              Gordon





              Last edited by gordon higginbotham; 18-05-2020, 05:54 PM.

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              • #8
                Gordon
                I guess it comes down to trying to get some original 14hp springs if they can be found and getting Alberta Springs to make them. Have you tried Vinnie?
                Guy

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                • #9
                  Guy,
                  Faced with the problem of not knowing what advance curve would best suit the build of my engine which includes a Blydenstein profile cam and a worn advance mechanism I decided that as phase one I would invest in a concealed programmable computer based advance mechanism. This I could then use to develop an advance curve for my engine. This I have done and the rolling road shows considerable improvement. Roughly +8% bhp and torque ac ross the rev range but with a massive 22% torque increase below ~1750 rpm. I could now get the distributor rebuilt by the Distributor Doctor to reproduce the advance curve I am using but at a significant cost! So at the moment I am saving my pennies!
                  Gordon.

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