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MG TD TF 1500 - Right Angled drive for TF speedo cable

Hi all,

Trust that you all had a safe and enjoyable Christmas. It's been mild over most of the UK but two major storms with associated river flooding, and some loss of electric supply - OK in this part of Yorkshire, thank goodness, but my heart goes out to those who've been badly affected elsewhere.

With the floorboards up, a re-sleeved master cylinder fitted, and the gearbox about to be removed for major surgery, my thoughts turn to trying to sort out the very annoying speedo needle wavering. This is probably mainly caused by the tight radius of the cable, close to where it emerges from the gearbox, and I understand from a passing reference in the Archives, that some MGB models had a right hand drive fitted close to the gearbox as an original fitting.

Does anyone have any further info. on this and used the same sort of drive on our TD/TF cars? It strikes me if such a RA drive was used direct into the gearbox outlet, a much smoother running cable run could then be achieved. Any views on this would be much appreciated.

Cheers,

John
J C Mitchell

I don't know if it is original but my cable has a very smooth rout.Straight out of the gearbox between the pedal box and the chassis up to the firewall and into the speedo.Mind you I do have my speedo on the drivers side (driving licence in mind) and this may make a difference.
Ray TF 2884
Ray Lee

Should have said TF2884 is RH drive,
Ray
Ray Lee

John, my RHD '53 TD has the same cable routing as Ray described. There are no real sharp curves in the cable with this routing and my speedo needle is smooth.
BTW, as I remember, there was not much room for the cable to pass through this narrow passageway, but it is the factory routing and took a bit of fiddling.
Jim Merz

Hi Ray and Jim

Thanks for comments - I believe your route is 'original' and the best possible, but it still ends up with a tighter radius than that recommended by the cable manufacturers. My cable took the same route as yours but above 50mph the needle wavers all over the place. I havn't ruled out cable issues as per Archives but with a right angled drive at least the tight curve could be ruled out.

As a matter of interest Ray, does your needle 'wander' - as you know from the Archives it's a very common complaint.

Cheers,

John

J C Mitchell

John,
I'm already working on that problem and have started making such a gearbox using a commercially available small 1:1 bevel stage to come out at 90°. This of course reverses the rotation so I will use two spur gears to correct.
Regards
Declan
Declan Burns

The right angle adapter used on the MGBs would fit on the TF speedometer fitting. Moss Motors carries the adapter under P/N 021-511.
Cheers - Dave
David DuBois

Hi John, my TD's cable follows the same route as Ray's and Jim's. The needle is jerky when travelling up and down the scale as its a chronometric instrument, but at a steady speed it is rock solid, no waver at all. Matt.
Matt Davis

John. Check out my post on the 4.3 conversion thread by Bill Schroeder below. Good article on needle wavering.
Cheers
Peter TD 5801
P Hehir

Dave,
Has the MGB Adapter the right threads?
Does is change the direction of rotation?
That might save me re-inventing the wheel if it works.
Regards
Declan
Declan Burns

Thanks for all the responses,

Dave, Ive entered your Moss Motors part number into both their US and European websites with no success. It may be my fault, but your further comments would be appreciated.

Declan's query about the threads and rotation is also very relevant - do I take it that you have fitted an MGB adaptor to a T type gearbox, or has anyone else?

It would be nice if an adaptor could be bought off the shelf!

Cheers,

John
J C Mitchell

John,
On the Moss Europe Website the part number for the angle drive is 120694 or just type in "angle drive"
The thread on the TD gearbox is 3/4"x26 BSB and M12x1mm on the back of the speedo.. I don't know what the MGB thread is.
Regards
Declan
Declan Burns

Hi John,
present cable has been in for the last 20 years, as long as I grease it every year there are no wild fluctuations. Remember this is an undamped magnetic movement so there will be some waver.
Ray TF 2884
Ray Lee

This is what the connections look like.
Regards
Declan


Declan Burns

Again thanks for all the responses,

Declan, your part no.120694 was successful on both the Moss Europe and the Brown and Gammons MGB websites - thanks. On the B&G site there is a photo of the angle drive, which enlarges quite well on your own computer, but it is hard to tell whether it will fit straight onto a T type gearbox. I'll take the speedo drive out of my gearbox, now it's so accessible, and speak to some people who know more about MGBs than me.

What is really needed is someone who has used/altered an MGB angle drive for use on a T type - anyone out there ? If all else fails it may be that Speedocraft Richfield in Nottingham would be able to make something up - I'll contact them in the New Year.

Cheers,

John

J C Mitchell

John,
If you type in MGB angle drive in Google and click on Images there are quite a few photos. I can't see how it will fit on the TD as the Connections are in my opinion totally different.
Here's a photo of my bevel stage mated to fit the TD gearbox. I have made up a flange on the gearbox to accept this. I still have to shorten the pin that goes into the gearbox.
Regards
Declan


Declan Burns

Hello John I have several M.G.B. right angle drive adapters. Would you like that I post a photo. John
J .R.C Cavey

January.
Input, as shown in the drawing, fit to a 5-Gear FORD Type 9 Gearbox. The Output fit to the original MG TD flexible cable.
The idea behind it is clear: The small correction gear box fits direct to the FORD Gearbox. No additional load for the flexible cable.

The correction gearbox consist of a bevel gear train to come out 90° and in the second train a spur gear can make the reduction you need for your car combination.

For my car with a 5-gear FORD gearbox and a 4.3 rear axle the best fit is a transmission ratio of 21:13 or 1.6154. Remember the bevel gear train has a ratio of 1:1 therefore the spur gear train must do the required transmission ratio. I select spur wheels with 42 tees and 26 tees. All that fit into a small aluminum housing 46mm to 62mm.
Cheers,
Guenter



GK Guenter

Hi to all,

Declan , I didn't realise there were so many images on Google - I agree with you that the connections are different, but perhaps could be altered to fit? If no one comes on who has modified and used an MGB drive on a T type, as I said before, I'll raise the matter with Speedocraft Richfield. I suspect similiar issues have come up before, perhaps with different makes of vehicle.

John Cavey, thanks for offer of photos - have a look at those on Google and if you can add info. through an additional picture it would be appreciated.

I know that smoothing out the cable run will not necessarily solve the needle wavering, but it is generally accepted that the tight curve from the gearbox can cause problems, and really should have had a right angle drive from the onset?

Thanks to all contributors, I'm determined make some progress on this issue and will report back as and when I have some positive info.

Cheers,

John
J C Mitchell

This thread was discussed between 28/12/2013 and 31/12/2013

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.