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DS engine with 'Hydraulically' operated Gearbox

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C6Dave   
Wed Aug 29 2012, 03:39pm

Joined: Oct 01 2009
Member No: #1
Location: Northumberland
I've been looking at Tractions recently and came across one that had a DS engine and 4 speed gearbox combo fitted along with the hydraulic pump, accumulator etc. and the gear change is done via hydraulics with a valve behind the dash and actuators on the gearbox instead of the usual levers.

Starter is activated by the gear lever and is top right of the gate (bottom is reverse)

Now I know some of you have other classic Citroen's and wonder if anyone can shed any light onto this set up?

What are the pro's and cons of it?
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Tjensen   
Wed Aug 29 2012, 04:02pm
Joined: Jul 17 2012
Member No: #954
Location: Bergen
Sounds like the original "DS" setup from 1955 and onwards. The cheaper "ID" had manual, and gradually manual gearshift became more common on the DS. But this semi-automatic hydraulic gearshift is regarded as the true DS version. Never tried it, but the advantages is the smooth operation that shifts when engine revs and load makes it sensible, to the preselected gear, as well as no need for clutching.

In my DS years, my garage always said I should be glad to have 5-speed manual, too much adjustment and complication with the semi-automat. Frequent clutch adjustments is one of the stories.

But it is close to the hyper-modern preselect steering wheel shifting system in function....... And the "true" DS system. (But I would be scepitcal to this in a TA)
C6Dave   
Wed Aug 29 2012, 06:11pm

Joined: Oct 01 2009
Member No: #1
Location: Northumberland
Hmm, the car had a clutch which I presumed the owner was using when changing gear so I'm more confused now.
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pclark   
Thu Aug 30 2012, 08:10am
Joined: Oct 08 2009
Member No: #3
Location: North Yorkshire
Hello Dave. The DS system had a hydraulically actuated clutch that was operated entirely automatically when the driver changed gear or started and stopped. There was no clutch pedal. Maybe the Traction conversion you saw had the hydraulic gear change part but retained the manual clutch pedal.

The DS BVH system is very similar in principle to the modern EGS system found on the C4 etc. in that it's a conventional gearbox and clutch operated semi-automatically. The difference of course is that the DS system is entirely hydraulic rather than with electronic control as on EGS.

The elecronics on the EGS also of course allow a fully automatic mode, unlike the DS. (there was also latterly a fully automatic DS but that had a torque converter Borg Warner gearbox) - Click Here -
C6Dave   
Thu Aug 30 2012, 09:08am

Joined: Oct 01 2009
Member No: #1
Location: Northumberland
Thanks Philip, I had just found that page via Google before I read your post!

Makes for an 'interesting' Traction as apparently it's the only one like that in the UK.
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drummond   
Thu Aug 30 2012, 05:41pm
Joined: Sep 20 2010
Member No: #238
Location: Aldeburgh
I can't quite see how it's got a clutch pedal, but I shall look forward to a revisit!

Tim
C6Dave   
Thu Aug 30 2012, 05:46pm

Joined: Oct 01 2009
Member No: #1
Location: Northumberland
OK armed with your replies I have asked a few more questions and it's not the 'semi auto' box.

It's a manual gearbox that is operated hydraulically instead of using the levers a traction would normally have. This leaves more room in the engine bay but adds the hydraulic pump belt driven off a double fan pulley, the other side of which turns the alternator.

It has a standard clutch that has to be depressed to change gear so ruling out one of the weak points of the system.
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Hawkie   
Fri Aug 31 2012, 09:12am
Joined: Feb 01 2010
Member No: #45
Location: Stockholm
I think it is a very odd solution on a TA. I would not like to have a TA myself with that "option", but the choice is free.

I do not have any problems with adjustments of the clutch and can't see that it should be a weak point. It is a standard clutch that is depressed and released hydraulically by itself instead of using the foot.

If the clutch need adjustments it is exactly the same procedure as in a manual car, but you also have other adjustment for at what revs it shall disengage and engage and how fast it is going to happen. On a newer DS the time for the clutch to engage is also sensitive for the accelerator. As more you push accelerator down, as quicker it will engage the clutch.

/HÃ¥kan
drummond   
Fri Aug 31 2012, 07:13pm
Joined: Sep 20 2010
Member No: #238
Location: Aldeburgh
My garage in the Manche restored my DS (which has the BVH), and despite the guy knowing and working on DS's, made a complete balls of the semi auto. Ah!, I thought, I've got the English workshop manual, and it covers the BVH....yes, it does, and I improved it by about 75%, but it was still no good.

I took it back to England, and Darrin who runs Citroen Classics in Staines did his own method- which works. And no, it does not require any adjustment, at least not in 12000km.

My project for the winter is to hoick the engine out of the DS and rebuild it properly, and whilst it's out repipe the car, new brakes, and a new steering rack. Well, why not?!!!

Tim
 

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