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patrick lovering
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Hi all, just notice there is a Sunbeam Rapier gearbox with a laycock overdrive on ebay uk at the momment, I realise this might be not much use to you in the States, but just thought I'd mention that I have made this conversion to my Mk2 and it works well, the extra gears really relax the engine on motorways and effect quite a saving in fuel.
The gearknob mounted overdrive switch from a Triumph Stag works a treat and looks pretty cool too.
Patrick

Frank Schwartz
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Too bad such things never appear here in the US....

patrick lovering
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they're pretty rare over here too, I think the Laycock overdrive units were also fitted to Jaguar, Austin Healy, Alpine, Hillman, Triumph, MG.

Greg Fletcher
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Ages ago, Richard Appleyard in the UK did an article for our club newsletter on how to do this conversion. I'll have to dig that out. Sounds worthwhile, but I remember it being expensive back then and some of the parts where already hard to get. It did require a fair amount of fiddly work and fabrication.

patrick lovering
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The overdrive is just a bolt on affair and electrically activated via the stag gearknob switch, the cables running up a supplementary metal pipe I braised onto the gear stick. you are also supposed to drill and tap a cut out switch that stops you selecting reverse whilst in overdrive. I did'nt do this out of laziness and as a result made the gearbox make some horrible noises a few times! 

Spaceman
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So do you still have that article, I just bought a Sunbeam Rapier OD, and wonder what parts I need to get with it? Do I need the long shaft sticking out of the Rapier 4 speed?

noomg
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Unless your J/H is a 4sp I'm not sure why you'd want to try to adapt what sounds like a very rare gearbox which is going to require a lot of engineering and fabrication to make it work. The Getrag 5sp is a very nice gearbox and works really well in the J/H. If you do have a 4sp I think it would be much easier to find a Getrag and do a swap, I think you'd be pleased with the results.

subwoofer
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Joined: 04-01-2008
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The Getrag has a taller rear end, so effectively it already has an overdrive compared to the 4-speed. Top is 1:1 for both boxes.

--
Joachim



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