Another attempt at improved gearchange.
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PhilTheGeek
GTM delivered
Joined: Wed Aug 17, 2016 8:34 pm Posts: 37
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Another attempt at improved gearchange.
Although the MGF gearchange is better than the original rattle rods it's still to sloppy left to right. After some careful searching I've found this: Attachment:
IMG_20170218_165818.jpg [ 63.1 KiB | Viewed 7711 times ]
At this point I've disconnected the cables and removed it from its original housing but it has no discernible slop in it whatsoever and spare bushings are available should it develop any. The whole unit with its cables was only £25 on ebay so its worth a go. Next step will be to cut off the ends of the cables and thread them M6 so they'll connect to the MGF cables with an M6 joiner. Then I'll make up a plate to hold it with a bracket hung below to hold the 2 cables.
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Sat Feb 18, 2017 6:49 pm |
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librakv6
Part built GTM
Joined: Sat Feb 11, 2012 2:51 pm Posts: 134 Location: NE GTM: Libra
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Re: Another attempt at improved gearchange.
There is actually nothing wrong with the 'rattle rods' that people call them, for people that didn't originally build the car I can explain, you basically transferred the bushes from your donor metro, when I was doing this I noticed that there was a lot of wear on the original plastic and metal through bushes. This play would not really be apparent in the front engined metro with short gear linkages, to alleviate any unwanted play which can cause the vibration, I made my own bushes from brass bar and also spent a lot of time shaping the gear rods so they did not interfere in any plane. It also didn't really help the fact if you reused the old bearings, the bush fork in the end of the gear change rods instead of having say an 8 or 8.2mm hole for the bolt is more like 9.2mm which with a worn bush assembly can create vibration, you could actually move the rod back one forth with it all tightened up. With this set up I don't get any rattles and with an extended gear lever ,mine is 13 inches (oo er misses), the change feels nicely weighted, centred and precise, it is also nearer to the steering wheel and you don't have to feel down on the floor for it as with a shorter stick and you can do quite a fast gearchange. I think cables are a good idea but I think you can lose weight and feeling between you and the box if not set up correctly and having to use springs to centre everything, I think people have thrown idea of gear change rods away as a bad design without looking into the cause of the problem.
Jamie
_________________ V6 GTM Libra '10 years in the making!!!'
Libra V6 Hawk AC Ace TVR 3000M MG ZTT 180 Skoda Fabia VRS TVR Griffith 400 (coming soon)
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Sun Feb 19, 2017 1:22 pm |
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sanzomat
GTM Nirvana
Joined: Sun Oct 19, 2014 10:10 pm Posts: 1136 Location: Bristol GTM: Spyder
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Re: Another attempt at improved gearchange.
Out of interest Jamie, are you using rods with a PG1 or is your V6 going through an R65?
I didn't build my car but it came to me with rods and an R65. Not sure if it was the rod set up, which certainly had lots of wear/slop in the various joints, or the gearbox itself but it was very difficult to get reverse and changing down from 3rd to 2nd I sometimes found myself in 4th. To be fair they didn't ever rattle noticeably though. One day whilst giving it a bit of a shove to get reverse the lever snapped off - not sure if its an original metro part but the gear stick was a hollow tube and it had snapped where the thread starts. My set up had another hollow tube over an an extender about 60mm long to the knob (ooh matron). As I was doing my PG1/VVC conversion soon I bodged it up for a month or so then did the MGF cable change at the same time as the engine/gearbox swap (did the passat rad at the same time so had the cooling pipes out of the way anyway).
For me the new set up has been great with a nice feel and reasonably precise. I didn't add any springs as I find it centres well enough without.
I know others still don't get on with the MGF and have tried Mike Satur/MGF or Elise shifters but I'm happy with MGF.
I get it that the rod set up isn't a bad design and as long as the various joints are all okay it'll work but it does seem there are a lot of joints and as such even a small amount of play in each adds up to a lot in total.
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Sun Feb 19, 2017 4:52 pm |
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librakv6
Part built GTM
Joined: Sat Feb 11, 2012 2:51 pm Posts: 134 Location: NE GTM: Libra
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Re: Another attempt at improved gearchange.
The box is a PG1 from the MG ZT, I don't have any problem going from 3rd to 2nd the only niggle I get sometimes is selecting reverse but a back to neutral and a pump of the clutch sees it successfully engaged. I remember having to do this when I had a Rover 45 and a MGF for that matter probably down to the fact it's at the extremities of the lay shaft and being at rest nothing's twirling. I used an extender which was the Metro gear-lever cut down to which I welded an old control lever from an offshore Sealion crane, I love recycling parts and it hasn't snapped YET!! Jamie
_________________ V6 GTM Libra '10 years in the making!!!'
Libra V6 Hawk AC Ace TVR 3000M MG ZTT 180 Skoda Fabia VRS TVR Griffith 400 (coming soon)
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Sun Feb 19, 2017 11:15 pm |
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PhilTheGeek
GTM delivered
Joined: Wed Aug 17, 2016 8:34 pm Posts: 37
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Re: Another attempt at improved gearchange.
Change of plan. I've gone for M6 rod ends rather than cut the ends off the existing cables. I'm about to submit a 3D printing order to elevate the housing and then I'll be manufacturing an assembly from aluminium to hold the gearstick and existing MGF/MG TF cables.
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Wed Mar 01, 2017 7:32 pm |
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PhilTheGeek
GTM delivered
Joined: Wed Aug 17, 2016 8:34 pm Posts: 37
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Re: Another attempt at improved gearchange.
The housing extension has arrived and I've started getting it mounted to a plate. Next job is to fabricate a bracket to hold the cables and then TIG it to the main plate. Attachment:
IMG_20170312_121823.jpg [ 183.17 KiB | Viewed 7505 times ]
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Sun Mar 12, 2017 5:09 pm |
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PhilTheGeek
GTM delivered
Joined: Wed Aug 17, 2016 8:34 pm Posts: 37
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Re: Another attempt at improved gearchange.
Finally got it test fitted. Feels great and I now need to get it properly bolted in.
Attachments:
IMG_20170511_184302.jpg [ 182.16 KiB | Viewed 7251 times ]
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Thu May 11, 2017 8:01 pm |
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yazza54
On the Road
Joined: Sun Feb 15, 2009 9:00 am Posts: 595
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Re: Another attempt at improved gearchange.
Nice work
_________________ I'm unhappy cos I eat and I eat cos I'm unhappy
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Thu May 11, 2017 8:06 pm |
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stewb
Part built GTM
Joined: Thu Jan 23, 2014 10:26 pm Posts: 73 GTM: Libra
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Re: Another attempt at improved gearchange.
Didn't think the ZT used the PG1? Thought it was Getrag. Always thought the Libra V6 setup was ZS?
There are a few shifters off the shelf which can be adapted. MR2 has potential as does older prelude (metal so can be cut'n shut). Some of the VAG ones have potential too but would need jiggery pokery at the gearbox end to get the correct travel / direction.
Just fitted a BMW Mini remote to a K20 engined Libra too which is perfect! Can't take the credit for that as the PO worked out the setup & I just executed it.
Cheers, Stew.
_________________ ___________________________
StewB
'09 Libra K20 '69 TVR Vixen V8 '86 Capri 2.8i S ‘78 TVR 6200M-TT
Ex Libra V6
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Mon Sep 04, 2017 5:18 pm |
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librakv6
Part built GTM
Joined: Sat Feb 11, 2012 2:51 pm Posts: 134 Location: NE GTM: Libra
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Re: Another attempt at improved gearchange.
sorry meant ZS Jamie
_________________ V6 GTM Libra '10 years in the making!!!'
Libra V6 Hawk AC Ace TVR 3000M MG ZTT 180 Skoda Fabia VRS TVR Griffith 400 (coming soon)
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Mon Sep 04, 2017 11:04 pm |
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