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Mar 22, 2018 4:36 pm
Mar 22, 2018 4:36 pm
Subject: Re: V12 timing gears
Hi Charles,
I've now found those engine photos I mentioned earlier, so will email these to you later today or tomorrow.
Amazingly, I've also found part of the instruction notes I gave to the engineer machining the idler gear spigot for me in 1977. Quoting from that, "Copper plated retainer is removed by holding it and undoing nut. The stud in main housing has a LEFT hand thread, but should not need to be removed. When reassembling, note that the retainer has a vertical line which is in line with the stud hole which does not have a small hole drilled near it. The retainer is a tight fit, and should be rotated backwards and forwards as it is pushed in, to ensure that it is fully home."
So, it looks like Lagonda dealt with the anticlockwise rotation of the gear by making the stud left-hand threaded where it screws into the spigot itself. So, as opined previously, it seems that self-unscrewing of the nut on this stud would be dealt with by using a castellated nut and split pin. Unfortunately I don't think I've got any photos showing this detail. If your stud is undrilled, Loctite with an ordinary nut should do the job just as well.
Incidentally, the firm that made the new gear for me back then was Schofield & Samson Ltd, in north London. Unfortunately it seems they no longer exist. Their invoice does detail the gear specs so if that might be helpful, let me know.
Laurence
Hi Charles,
I've now found those engine photos I mentioned earlier, so will email these to you later today or tomorrow.
Amazingly, I've also found part of the instruction notes I gave to the engineer machining the idler gear spigot for me in 1977. Quoting from that, "Copper plated retainer is removed by holding it and undoing nut. The stud in main housing has a LEFT hand thread, but should not need to be removed. When reassembling, note that the retainer has a vertical line which is in line with the stud hole which does not have a small hole drilled near it. The retainer is a tight fit, and should be rotated backwards and forwards as it is pushed in, to ensure that it is fully home."
So, it looks like Lagonda dealt with the anticlockwise rotation of the gear by making the stud left-hand threaded where it screws into the spigot itself. So, as opined previously, it seems that self-unscrewing of the nut on this stud would be dealt with by using a castellated nut and split pin. Unfortunately I don't think I've got any photos showing this detail. If your stud is undrilled, Loctite with an ordinary nut should do the job just as well.
Incidentally, the firm that made the new gear for me back then was Schofield & Samson Ltd, in north London. Unfortunately it seems they no longer exist. Their invoice does detail the gear specs so if that might be helpful, let me know.
Laurence