GTD Shift Mechanism

[Brian Wilson]

I have recently acquired a 1984 build GTD, which I'm generally very happy with. Found that headroom was a major problem - particularly with helmet - so making up new seats which will be bolted directly to the floor. At present the most comfortable driving position is seated on the floor!

My only other gripe is the gearshift, which is something like a knife through treacle! It uses what I assume is the original cable setup, which I understand from others normally works reasonably well. It has a recently rebuilt and upgraded Renault UN5 transaxle, which appears to have replaced a UN1. My question is - Does the GTD cable shift setup work ok (assuming it's in good condition and properly adjusted)? If so, then I'll dive in and do some work on it, rather than replacing it. I'm used to rod shifters in open wheel race cars which are extremely positive and quick to operate when designed properly. I'm not expecting this level of performance, but it would be nice to know I can get any particular gear when I want it.

Brian

 

[Frank Catt]

Call Bernie Mylon in AUS, ( you will find him on the FORUM ) HE CAN ADVISE YOU, Frank

 

[Paul fortin]

My gtd has cable shifter too I find it lose but works . I had some play where it mounts to the transmission but we fixed that and it's better but not tight like linkage.

 

[Malcolm]

If you rose joint the ends, insulate around the gearbox end and set it up then yes they can be made to work quite well. They lack feel and as a result directness but if loooked after can last a long time.

 

[Brian Wilson]

Thanks for the advice guys - very helpful. Think I'll persevere with the cable setup for a bit. Will look at ways of getting some of the slack out of it with rod ends etc.

If I still don't like the result, will go to a rod setup.

I wonder how engine/transaxle movement might affect a rod system. Will look at the mounts to see if this is a potential problem. In race cars the engine is solid mounted so rods work perfectly once set up.

Anybody know a rod setup I can get off the shelf which will fit a GTD? It has a 302 Windsor and Renault UN5 transaxle.

Brian

 

[Malcolm]

Mick Sollis at Southern GT do a system that looks right and works well. You are right about engine and box movement maybe causing issues but with thought and done well it can be overcome.

 

[Graham T]

Brian,

retro fitting a rod linkage is going to be possible, BUT awkward and very time consuming, especially if your chassis is all panelled out and well upholstered in the cockpit gear lever sill area.

Do use proper rose joints front and rear, insulate the cables near any exhaust heat and generally make sure there are no sloppy joints, and you will have a very long lasting and trouble free gear changing mechanism.

I changed my adapted cable system to a rod linkage four years ago, and to be honest I preferred the old system and did have a good "feel" with it. I used my 40 hard for racing so talk from experience.

 

[Brian Wilson]

Thanks Graham and Malcolm - very helpful. Think I'll hold off on the rod conversion and get the cable linkage working better for now. It works pretty well in my Porsche 2.7 race car, so why not here. With the Porsche, the main problem was the length of throw at the lever - easily cured by a short shifter which also seemed to improve feel. It uses good quality rod ends at the gearbox, so no slack.

Will let you know how I get on.

Brian

 

[Brian Wilson]

Well, when I got the car back from having its new seats made (so I can fit in it) I found it has a rod mechanism! Looks fine. The rubbery feel was coming mainly from the fact that someone thought greasing the ball joints was a good idea. Needless to say they had picked up quite a bit of rubbish. A good spray with WD40 dislodged most of it and - lo and behold - the feel is back.

Now I'll move on to the "sticky" throttle cable.

Brian

 

[Paul fortin]

Send pic of seats .

 

[Eric Johnson]

Brian,
I am also interested in seeing your seats. Who made them for you?
Looking to get some made as well possibly. A little tight in there...


Eric

 

[Brian Wilson]

Eric and Paul - the seats were custom built by the same guy who re-upholstered the GTD40 seats (with runners) which the car came with. The new ones are bolted through the floor in the same holes as the old runners. The seat and backrest cushions are removable to fit thin foam pads for more headroom for helmet etc. I'm a bit over 6'1" in old money and fit easily without a helmet now. With helmet, it's better using the foam pads. The seats are covered in black leather and look quite like the originals. Backrest is lower to allow proper alignment of harness shoulder straps.

I guess we're in the wrong forum thread now!

Will get some pics for you tomorrow and post. These were done by an upholstery specialist here - Sydney Motor Trimming and Upholstery - who specialise in Cobras etc. Not cheap, but top quality job and completed from scratch in only five days.

Cheers

Brian

 

[Brian Wilson]

Now, my next question is...does anyone know how to get a "straight" H pattern shift with a rod linkage and a Renault (UN5) transaxle? I'm used to Hewland gearboxes and having terrible trouble with the "slanting" shift pattern of the UN5 box. The actual change is ok.

Brian

 

[John]

Brian what do you mean by "Slanting" shift pattern.

cheers John

 

[Brian Wilson]

John

I mean that the movement from 2nd to 3rd (say) is not parallel to the centre line of the car (same for reverse to 1st, and 4th to 5th). The movement - with right hand shift - is away from your body as you pull the lever back. Not by a lot, but enough to be confusing. Very easy to go from 2nd to 1st by mistake, when trying to change up to 3rd!

Hope this makes sense!

Brian

 

[Brian Wilson]

Paul & Eric - I have taken some pics of the new lowered seats as you requested. Will post them now in this Tech section as a new thread in Exterior, Interior etc

Cheers Brian

 

[Malcolm]

......and having terrible trouble with the "slanting" shift pattern of the UN5 box. The actual change is ok.

Brian

To me this sounds like the rod running down the side of the car is not parrallel to the centre line.