Author Topic: Four speed gearbox  (Read 5104 times)

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Offline Michael Scott

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Four speed gearbox
« on: 10 Jul 2008 at 15:45 »
Hi
My rebuild of a pile of rusty rubbish is beginning to look like a 1930 S6 - rolling chassis with engine in place.  The current discussion on the clutch is very timely
I am reassembling a four speed gear box
Can any one help me finding the four engagement points (or perhaps the neutral point and the others follow?)so that I can adjust the hand change linkages

Michael

Offline eddie

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Re: Four speed gearbox
« Reply #1 on: 10 Jul 2008 at 17:50 »
Michael,
             You should be able to reassemble the shafts and gears along with the selector barrel in the main gearbox case - then refit the inner cover. The gear that fits on the end of the selector barrel has a keyway and a timing mark. The rack also has a mating mark. Loosely fit the gear and turn the selector barrel until the timing mark points in the direction of the rack - now remove the gear without turning the barrel - slide the rack into place with the timing mark level with the selector barrel and refit the gear with the timing marks aligned. Check that all four gears can be selected without the rack fouling either of it's guide bushes. With the detent plunger fitted, each gear should select positively. When the box is fitted in the frame, the external linkage will need adjusting so that each gear selects when the hand change lever abuts each step in the gate.
          Originally, the 1930 S6 would have been fitted with a 3 speed box. The 4 speed came with the later models and there are at least 3 different types of kickstart mechanism - depending on year. Early 4 speed boxes had a smaller outer case - with this type, the kickstart lever should be set almost horizontal or the quadrant will try to burst through the top of the box on full swing. Also, beware if trying to mix and match the internal pinions as early boxes had stub tooth gears whereas later boxes had involute teeth.
                     Good luck with the rebuild,
                                                             Eddie.

Offline Michael Scott

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Re: Four speed gearbox
« Reply #2 on: 12 Jul 2008 at 19:43 »
Eddie
Many thanks
I will check it out on monday and let you know my findings
Regards
Michael

Offline Michael Scott

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Re: Four speed gearbox
« Reply #3 on: 18 Jul 2008 at 14:11 »
eddie
Went together beautifully.  thanks
now onto tidying up the kick start area.  I have all the bits but not necessarilly correct. However I can see a way through the thickets

Michael

 

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