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    Correct oil pump spring?

    I put this at the end of an old thread but didn't get anyone looking at it, so I'll post a new thread!

    I have just stripped the two oil pumps I bought at Stoneleigh. One has a cracked casting and very pocked rotor, the other is pretty good and will make a good 'un.

    My question, though, is about springs. The two springs, both from Hobourn Eaton bodies, are different in length. One is 1.75" (44.45mm) long, the other is 1.60" (40.64mm) long. They are otherwise identical.

    Does anyone know the original free length of the correct spring?

    Richard
    Mabel is a white 1972 Mk1Ĺ, TV8, ZF 4HP-22 auto,
    2016 RBRR finisher. 400 mile C2C 21/22 April 2018!

    #2
    I don't know the correct length however they are not difficult to change insitu on the car so if you are not happy with the idle or maximum pressure you can quickly change the spring over and try the other. Craig

    Comment


      #3
      Try here:

      https://socforum.com/forum/forum/sta...-pump-pressure

      and posts 401 onwards in this thread: https://socforum.com/forum/forum/sta...an-stag/page11

      Drew
      If you can't say something nice, don't say it !

      Comment


        #4
        Be a bit careful as the Houborn Eaton spring is shorter than the County spring. It sounds like you have one of each because someone has fitted a new County Saab pump and swopped out the springs so that they have retained the correct original spring. If you use the longer spring from the County pump you will cause problems.

        Comment


          #5
          This might interest too: https://socforum.com/forum/forum/sta...ourn-oil-pumps

          Drew
          If you can't say something nice, don't say it !

          Comment


            #6
            Will measure the spring I have when I get back from the pub

            43.35mm
            Last edited by MandM; 10th March 2018, 18:51.
            (The Sun Rise Colour) "The UK,s Most Easterly Stag" Quad Exhaust- Header Tank - HIDS

            Comment


              #7
              Thanks Andrew, I'm still not finding the new search function easy to use!

              I am particularly interested to quantify the differences between pumps and springs, there are many comments in the threads you mention of the "I tried this and then this" approach. I would like to nail down the variables in pumps - there seems to be too many differences in the reported springs and pressures and a tabulated approach would make me happier!

              I will review the threads you've highlighted and see if I can find some commonality.

              Richard
              Mabel is a white 1972 Mk1Ĺ, TV8, ZF 4HP-22 auto,
              2016 RBRR finisher. 400 mile C2C 21/22 April 2018!

              Comment


                #8
                Originally posted by MandM View Post
                Will measure the spring I have when I get back from the pub

                43.35mm
                Thanks! That's close to the 1.75" one that I have although about 1mm shorter. I'll have to ask for the wire diameter as well, I can see that this might be a critical factor!
                Mabel is a white 1972 Mk1Ĺ, TV8, ZF 4HP-22 auto,
                2016 RBRR finisher. 400 mile C2C 21/22 April 2018!

                Comment


                  #9
                  Will add when back from shopping

                  Hi Richard the close coil bit is 21mm long and the wire thickness/gauge is 1.3mm

                  Hope that helps
                  Last edited by MandM; 11th March 2018, 13:00.
                  (The Sun Rise Colour) "The UK,s Most Easterly Stag" Quad Exhaust- Header Tank - HIDS

                  Comment


                    #10
                    At work we use a lot of springs , some come from Lee springs link below, I would have thought they would reproduce the correct spring for SOCTFL, expect there would be a minimum order, will find the other companies details that we deal with if anybody requires it?

                    http://www.leespring.com/uk_index.asp
                    (The Sun Rise Colour) "The UK,s Most Easterly Stag" Quad Exhaust- Header Tank - HIDS

                    Comment


                      #11
                      Iím pretty sure that the design of this spring is partly a cost saving exercise, the coil-bound part saves a separate spacer.

                      I will measure the actual valve and find out if there are differences in the dimensions which might account for the different springs.

                      Meanwhile itís back to spring design school to remember how to unravel the springs we have and perhaps work out what we need!
                      Mabel is a white 1972 Mk1Ĺ, TV8, ZF 4HP-22 auto,
                      2016 RBRR finisher. 400 mile C2C 21/22 April 2018!

                      Comment


                        #12
                        Originally posted by mole42 View Post
                        Iím pretty sure that the design of this spring is partly a cost saving exercise, the coil-bound part saves a separate spacer.

                        I will measure the actual valve and find out if there are differences in the dimensions which might account for the different springs.

                        Meanwhile itís back to spring design school to remember how to unravel the springs we have and perhaps work out what we need!
                        Hi Richard,

                        I'm sure Glen aka Seaking had some made that were the correct specifications. Drop him a pm to find out.

                        Cheers...Al
                        1975 Mk2 3.0 V8 MOD, new strommies, tubulars & quad exhaust = 166.8 bhp

                        Comment


                          #13
                          Originally posted by Arbman Al View Post

                          Hi Richard,

                          I'm sure Glen aka Seaking had some made that were the correct specifications. Drop him a pm to find out.

                          Cheers...Al
                          These were to the 'Frith' specification. I have one fitted and it is fine.
                          Dave
                          1974 Mk2, ZF Auto, 3.45 Diff, Datsun Driveshafts. Stag owner/maintainer since 1989.

                          Comment


                            #14
                            Robsport have had them manufactured ..

                            https://www.ebay.co.uk/itm/Triumph-S...-/291922404704

                            So many cars, so little time!

                            Comment


                              #15
                              I am the originator of the 'Frith' spring.
                              Look for my previous posts on this subject for a full explanation. The standard spring design is rubbish. Completely the opposite of what a relief valve should be, and it allows bypass at very low pressures.
                              As mentioned, I had a 'proper' spring designed in the late 1980's, and up to the mid-1990's, I used to get batches made for sale. A few hundred were sold. It is a much longer spring, thinner wire (so 'softer'), and no closed coils.
                              If you are interested, I have had this spring in my engine (which I built from new in 1984) for about 80,000 miles now, and still have excellent oil pressure, and no discernible wear anywhere in the engine. Many of those miles were clocked up towing a caravan around Europe each summer, so the engine was made to work for its living!

                              In the mid 1990's, I changed profession, and lost contact with the manufacturer who had made them for me.

                              A similar thread was on the forum a couple of years ago, and I passed my specification to Seaking, who had a batch made.

                              However, the design office who drew up the spring specification were working with an original Oil pump. I suspect there are dimensional differences in the County pump relief valve, so the 'Frith' spring might not give the right pressures in one of these.
                              '72 Manual O/d Saffron Yellow

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