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  • 14/45 Scout Seized Engine.

    On my way to the Kop Hill Climb event on 21st September 2019, the engine on my 14/45 Scout seized going up the hill on the A404 half a mile from the M40. I had just changed down to 3rd gear as it was struggling in top and shortly after the engine faded. The engine had seized, I suspect due to overheating.
    I have removed the cylinder head, dynostart, sump, pistons & con-rods and apart from some slight scuffing on the pistons it all looks ok. However, it is quite hard to turn the crankshaft for about one and a half turns, but frees up for about 180 degrees of crankshaft rotation, which tends to indicate something to do with the camshaft. I have removed the fuel lift pump but it makes no difference and the oil pump and distributor gears are free and offer no resistance.

    The cause was blocked water manifold ports opposite cylinders 1 and 6 (see attached photo), which caused overheating. As a result the front camshaft bearing seized, resulting in the camshaft journal picking up material from the crankcase bore (see attached photos). To remove the camshaft I had to grind the high spots on the front journal with a fine grinding wheel in an electric drill after finding the high spots with engineers blue. This was not ideal but I tried using carborundum sticks, which was not working and taking far too long. As it was I spent 13 hours doing this.
    I now have a problem as to how to rectify the resulting damage. I am not aware of any camshafts with oversized bearing journals. Can anyone offer any recommendations please?


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  • #2
    Can't help too much. I know a Blydenstein camshaft was a profile with more overlap that has been used for years in Talbots. I guess the camshaft journals could be metal sprayed and ground back - are the bores in the block worn - if so, guess you'd need to speak to Ian Polson or Foppe to see what could be done?
    Good luck with it Guy

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    • #3
      Blydenstiein was a supplier of tuning patrs for Vauxhalls in the 60s-70s. There was a Brabham Viva and I think that it used a cam profile designed by Blydenstein. More lift and quicker opening.
      My 105 engine had worn cam tunnel bores, which was causing low oil pressure. The solution was to use a camshaft from Ian Polson which had its bearing journals ground at plus 0.010" . The camshaft is made by Kent Cams with the Blydenstein profile ........and get the block honed out to suit. Randall Engineering in Diss have the appropriate hone.
      I should also check the follower bores as these can wear barrel shaped.
      Regards,
      Dick.
      Last edited by dick campbell; 21-01-2020, 10:25 AM.

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      • #4
        Dick,
        Thank you for adding that detail about Blydenstein camshafts and the profile. Great to know the principle and that Kent Cams have the profile. Do you have any comments on the effect on engine performance of the Blydenstein profile over the standard and would you expect it to make any difference to the ignition advanced curve required?
        regards
        Gordon

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        • #5
          Hi Gordon,

          I changed a number of other things so wouldn't know if the improvement in performance was all camshaft related.

          I fitted Arrow conrods and Triumph 2000 pistons, which I made into semi domed by machining the top deck. This raised the compression ratio and probably improved the gas flow.
          I also fitted a contactless pickup in the distributor doing away with the two points sets and the condensor. The auto advance was left as standard......something I might look at later, but it seems ok.

          I changed the rear axle ratio to 4:1 and used AX65 ratios in the preselector gearbox....this works well and for a saloon, albeit a relatively light two door, it has lively acceleration and bags of torque throughout the rev range.

          I changed the cam gear to a steel one. If I did it again I would probably choose fibre which is quieter

          A point on the Blydenstein cam.......if its the same as a 105 then the timing is different and may require a new crankshaft gear. The old gear teeth are machined off the damper and a new gear shrunk on with a light interference fit. When in the right place it is then secured by Allen screws.

          Regards,
          Dick.

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          • #6
            Hi Dick,
            I suspect that your raised compression is a major factor. However if the gas flow was improved by the piston mods this might well compliment the camshaft and help. Certainly Bill Blydensteins work on road cars appeared to major on gas flow and camshaft profile aimed at achieving a flat torque curve to enhance top gear performance.
            Regards
            Gordon

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            • #7
              Having recently bought a new camshaft for my AG 14/45 from Kent cams, I can recommend them. They're not cheap but they made one using the original Roesch drawing for a 75 cam that I supplied them (after confirming with Vinnie that the 75 and 14/45 cams were the same). The chap I spoke to said he'd look at my old cam and the drawing and see if he could make some improvements. Embarassingly, I never followed-up on what he actually made me!

              The point of me mentioning this is that he could quite easily make you a new cam with a slightly larger front journal. It'll be around £1000, though!

              Comment


              • #8
                Thank you all for your response. I am currently talking to Vincent Rawlings about a lower cost solution. I will update when I have more news.

                Comment


                • #9
                  Ron,

                  You could talk to a company that specialises in reclamation of damaged/worn parts. Something on the lines of.....metal spray and regrind the bearing surfaces to provide the correct clearance in honed out bores.

                  Do you know why it siezed....if there is an underlying problem it might fo it again.

                  Dick

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                  • #10
                    Dick,
                    Please accept my apology for not responding to your post. My excuse is that I have to confess that I have only recently been logging on to the new website and I didn't notice the notifications label.
                    Anyway,I will answer your question and update you on the current situation.
                    The reason it seized is believed to be that the thrust face of the front bearing and camshaft gearwheel was starved of oil as well as the front of the bearing. Following a conversation with Ian Polson, it is believed to be caused by the fact that the thrust from the camshaft helical gearwheel prevents oil flowing to the front of the bearing and the thrust face. Apparently, a similar problem has been found with the bigger engines. It seems that this may have been the first on a 14/45. The rectification has been a protracted story, which I won't go into.
                    I have had the camshaft bearing reground on the front journal, the front bearing bored out to take a phosphor bronze bearing. It means that the camshaft can now only be assembled from the rear, which is not a problem. Currently, the cam followers, camshaft, camshaft gearwheel and thrust replacement thrust arm have been assembled. I now want to flush out the oil gallery pipe as a precaution to ensure all the oil-ways are thoroughly clean before resuming the remaining assembly.
                    I have just posted a a request for advice on the removing the aluminium in the rear of the oil gallery.
                    Ron.

                    Comment


                    • #11
                      Hello Ron,

                      I have not had any experience on 14hp engines but if they are similar to 105s then the camshaft bearing journals are pressure lubricated from the main bearings. I would check to make sure that you do not have a blockage.

                      It is interesting how the thrust face got chewed up. Whilst there is always thrust from the helical gear drive, I would have thought it fairly low, given light valve springs and mild cam profile.
                      The thrust will be proportional to the resistance of the camshaft to turn....so was a 'tight' camshaft the original problem and the wear of the thrust face a consequence of this?

                      As stated by others.....the oil gallery plug will be screwed in.......get your lathe out!

                      Good Luck,

                      Dick.

                      Comment

                       
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