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  • Adjustable Tie Rods.

    I wondered how Lil Red Roadster got on after fitting his adjustable tie rods and changing the washers around on the top wishbone mounting. It all looked rather promising and is some work I'm contemplating doing in the near future. Just curious how much

    it changed the self centering and the wander for the better ?

  • #2
    Re: Adjustable Tie Rods.

    I would proceed with caution.
    It has been alleged that the geometry of an original Marina Roadster was never perfect, if that can be said about any kit car with non adjustable suspension.
    My gut feel is to set your chassis up straight and level and then check dimensions against the standard Marina chassis dimensions before exploring elsewhere. At least you would start from a known point.
    Then I would check that all the donor parts are in as new condition. Several times we have encountered different torsion bars on each side, or more dramatically twisted suspension uprights from undisclosed accident damage.
    When I converted my Roadster from Marina to Clio brakes (Pitstop) only afterwards did I find excessive play in the Mini suspension arm (Pitstop) there was a remarkable amount of fore and aft play.
    The Roadster suspension is certainly a compromise of several variables.
    My advice, eliminate each variable, whether design, construction, parts or compromises before setting about yet another variable.
    MOC member since 05/97
    1984 Marlin Roadster SWB.
    1800TC, Unleaded ported head, stage 2 cam. Ford Type 9 gearbox, Dolomite Sprint rear axle fitted with MGF disc brakes.
    Three core radiator, Renault Clio vented front discs.
    The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.

    Loads of Marlin Reference can be found documents here or there.

    Comment


    • #3
      Re: Adjustable Tie Rods.

      That of course is sound advice and I think it is a given that all wearing parts should be brought up to new condition. My objective is to be able to experiment with castor angle a little to try to get rid of the vagueness and poor self centering which the car has always had despite polyurethane bushes being fitted.

      I'm interested in the reason for the fore and aft play in the Mini wishbone that you mentioned, was that just wear in the bearings or due to the small width of the mounting on the car?

      Comment


      • #4
        Re: Adjustable Tie Rods.

        Copy of my article here or there from back in 2010
        MOC member since 05/97
        1984 Marlin Roadster SWB.
        1800TC, Unleaded ported head, stage 2 cam. Ford Type 9 gearbox, Dolomite Sprint rear axle fitted with MGF disc brakes.
        Three core radiator, Renault Clio vented front discs.
        The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.

        Loads of Marlin Reference can be found documents here or there.

        Comment


        • #5
          Re: Adjustable Tie Rods.

          An interesting read, Thanks. Looks like there was some fine engineering around in BL at that time. I don't recall there being any problem with upper wishbones when I was playing with Minis and wonder if the extra height of the Marina upright might be responsible in part at least ?

          I was looking at adjustable tie rods for other vehicles and see Minisport do uprated thicker tie rods as a rally modification. These use the standard bushes forward rather than rose joints which would be better for normal road use. I presume they would be too short but something similar should be about right.

          If I'm correct the Marina uprights are actually the old Austin A50 design that would have been penned in about 1945 before the introduction of radial tyres and would have required different geometry with the cross-ply tyres then in normal use. Just a thought !

          Comment


          • #6
            Re: Adjustable Tie Rods.

            I actually bought two sets of shafts and bearings from minispares, guess what, they were different, machining your own, to give a reasonable ‘end play’ that you are happy with, is the way to go especially if you can get an improved caster angle, by changing washer thicknesses.

            I looked at a pair of mini adjustable tie rods. Very heavy engineering, looks like they were built for rally and not road.
            Whichever way I looked at them there was significant amounts of machining to make them usable, to a point where starting from fresh raw materials was more practical and economic.
            MOC member since 05/97
            1984 Marlin Roadster SWB.
            1800TC, Unleaded ported head, stage 2 cam. Ford Type 9 gearbox, Dolomite Sprint rear axle fitted with MGF disc brakes.
            Three core radiator, Renault Clio vented front discs.
            The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.

            Loads of Marlin Reference can be found documents here or there.

            Comment


            • #7
              Re: Adjustable Tie Rods.

              I'm a little disappointed that Minispares sold parts off specification like that considering most machining nowadays would be CNC. Actually I arrived at looking at the top wishbone as a way of altering the castor angle by (You'll love this !) using eccentric bronze bushes to

              alter both castor and camber. It might sound a little unusual but racing karts have used these on kingpins for quite a long time to achieve a wide range of front wheel settings. I also wondered if bronze full length bushes instead of roller bearings might wear better than

              the Mini roller bearings.

              Probably what I'll do with the tie rods is modify some Morris Minor ones and get my friendly machine shop to make the outer sleeves.

              Comment


              • #8
                Re: Adjustable Tie Rods.

                Originally posted by velovol View Post
                Probably what I'll do with the tie rods is modify some Morris Minor ones and get my friendly machine shop to make the outer sleeves.
                Ha...exactly what I did..! Except I bought the outers from McGill Motorsports...along with the Rose joints.

                Can't give much feedback in terms of improvements as the car has been grounded pretty much since I fitted them.
                Now re-wired, re-engined and hoping for an MoT this week...followed by some new tyres & maybe then I might be able to work out if they make any difference.
                Marlin Roadster, LWB...1860 B Series + Ford Type 9
                Renault Espace 54mm front calipers, vented discs, cycle wings and adjustable tie-bars.

                Comment


                • #9
                  Re: Adjustable Tie Rods.

                  If only my friendly machine shop just outside Henfield was still in business. He did a lot of prototyping for me. now fewer and further between.

                  Minispares, I doubt that they do a thorough in house inspection. I doubt that any reseller does these days.

                  Eccentric bushes would be nice, my CPO might have given me a smile for thinking of it, whilst we were dead in the water, and then given me a b********g for being smart, whilst remembering that it might be a solution for the future.
                  MOC member since 05/97
                  1984 Marlin Roadster SWB.
                  1800TC, Unleaded ported head, stage 2 cam. Ford Type 9 gearbox, Dolomite Sprint rear axle fitted with MGF disc brakes.
                  Three core radiator, Renault Clio vented front discs.
                  The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.

                  Loads of Marlin Reference can be found documents here or there.

                  Comment


                  • #10
                    Re: Adjustable Tie Rods.

                    I'd love to hear about the road test when "lil red roadster" gets on the road again. Interestingly Powerflex do some very professional looking adjustable bushes of around our sizes.

                    I'm lucky in that I have a brilliant small company in Bognor that are so busy they don't advertise or have a website that do some very interesting stuff for BRISCA racers, but as you say few and far between now.

                    I'll get in touch with McGill and see what they can do as well.

                    Comment


                    • #11
                      Re: Adjustable Tie Rods.

                      My tuppence worth on this
                      As my car is going to be certified as a "Scratch built" I have to show my certifier that my suspension is fit for purpose (New Zealand)

                      Which is NOT that difficult! - basically I need
                      to measure the various angles -
                      move the suspension up and down and show the amount of angle change in bump, squat and roll
                      Show that I don't have any bump steer

                      All of which can be done by making some simple plywood measuring bits
                      Which I have lying around for when I did my roadster (6 years ago) - if I can find them

                      That is about a year away at my current rate of progress but I will document it and share it here when I do

                      Comment


                      • #12
                        Re: Adjustable Tie Rods.

                        A plywood triangle, initially made at 5 degrees with the base on the floor and sighted from the side is what I was thinking of as well. There is a magnetic Inclinometer on eBay for about £ 30.00 which I may buy. The Chinese magnetic camber gauges for just under £ 10 are a load of rubbish and will simply waste your time, I binned one very quickly last year.

                        I've ordered a Mini upgraded adjustable rally tie bar pair, the length appears right and the thickness is around 3mm more than the Marina. At £ 28.00 that may save having them made.Part Number is 21A1091.

                        I'll let you know when I've fitted them.

                        Comment

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