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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - TD Clock Restoration

I've checked the threads in the archive on the TD clock & gained some useful info. The location of the feed, colour & gauge of wire, the push method to trigger the clock plus also confirmed that there is no mention of the clock in the original wiring diagrams. However the method of earthing the clock was not mentioned anywhere, which leads me to ask the question. There may have been a black wire attached to one of the screws at the rear of the clock or the earth may have been via the tacho drive cable. Obviously there has to be a path to earth as the instrument sits in the wooden dash & as such is electrically isolated, except of course for the tacho cable which is earthed at the genny via the block.

Also as a confirmed DIY type can anybody provide details, hints, tips on maintenance & also of a simple & reversible mod to improve performance of the original clock? Diodes & transistors were mentioned in the archive but no detail on 'how to'. I'm unwilling to send my clock anywhere overseas as I've lost items this way in the past & original TD clocks are almost impossible to replace. Besides I'd much rather do it myself. Cheers
Peter TD 5801
P Hehir

See clocks4classics.com and buy the kit.
Dave H
Dave Hill

There is a replacement battery run clock and replacement dials available and it looks pretty good-not cheap though.
Regards
Declan


Declan Burns

Peter

The Clocks 4 Classics kit seems your best bet for a close-to-original solution. The major advantage is that it eliminates the whisker contact which remains a potential flaw in the transistor modification.

I built a transistor mod some years ago so I can help with circuit details if you do opt for that solution.

The natural route for an earth wire would be from one of the mounting screws to an earthing point provided by the dash harness.

Tim
TD1580
Tim Wilkinson

Peter, see http://www.ttalk.info/TDWiringDiagrams.htm and note that the tachometer has its own black ground wire. That provides the ground for the clock. The path is from terminal E of the regulator to the instrument panel to the tachometer.
Hal Kramer wrote an article in the June, 1991 TSO giving detailed directions for transistorizing the clock. I had him do mine and it's still going fine. Bud
Bud Krueger

One may ask what is "to improve performance of the clock" ?
A minute will always be a minute.

No electronic in mine (this is my job yet). I managed to clean the contact, bend it. Cleaned every gear with the help of a magnifier.
The coil was open. I reeled off the wire until the open circuit was visible, solder and reeled it on. Took a week but it is now a great pleasure to hear it ticking whith the original mechanism.

About reliability ? I've got a battery cut-off switch. My clock is off most of the time and it is on when I drive. It will probably last for years.


Laurent.



LC Laurent31

Actually it is about reliability. Not everyone uses a cut-off switch, and some people do use their T types quite a lot. The clocks4classics conversion retain almost all of the original mechanism and still ticks
Dave H
Dave Hill

A watchmaker told me that idle clocks will run in problems that running watches will not have.
W_Mueller

That's probably correct for dust, grit. But the main problem with our clock is the little spark that gnaw the contact each second. You can see that spark in darkness. I can't make up my mind for running or idling the clock...
To cope with the spark, I added a free wheel diode in parallel with the coil.

Laurent.


LC Laurent31

My hard drive rolled over & died not long after posting this thread & I've only just now got my computer back. I'll need time to digest the info above & I'll then respond. The clock is now sitting on the bench & when connected to a 12 V battery it runs for a few seconds & then seems to jam on the whisker. I'd love to try & clean the whisker but it appears to be incredibly delicate. Be really great to see some pics & sketches of the clock & a brief rundown on how it works. I figure I'll need a 10 power eyeglass to even see what the issue is. The fact that it does tick is reassuring & suggests that a good clean may solve the problem. Thanks for responding. Gotter love the T Type fraternity, especially those who use this site! Cheers
Peter TD 5801
P Hehir

Peter,

Copy paste from the archives.

John



Posted 16 February 2016 at 19:56:38 UK time
J Scragg, France
Bela,

I used this document to repair my clock, it is the best that I could find at the time. It contains a diagram of the complete electric circuit.

http://www.sa.hillman.org.au/TT_SmithsClock.htm

There may be others, if you want to search for them, try using the key words: "smiths pin car clock repair".

John

52 TD
J Scragg

Laurent as Dave says it's about reliability. By this I mean to simply attempt to ensure a reasonable degree of reliability & functionality. Not interested in 'altering time' (except to adjust the clock once I get it running so that it is reasonably accurate).

Declan I can't change the clock for one that doesn't look correct, so I'm keen to get mine up & running.

Bud I see the earth on both the tacho & speedo on Dave's diagrams. Neither instrument was earthed on mine so I'll add both to the earth circuit.

Checked out both articles John & it seems the likely culprit is carbonisation of the offset & contact pins. (Glad I took the precaution of wiring up the battery with + earth to the case else I would have fried the 'rectifier bridge and other items rendering the clock inoperative'.) Nothing though on cleaning the balance wheel assembly, including the 'whisker'. I'll examine these components tomorrow using the best magnification I can find. I'll also try & take some close up pics & post them here. Cheers
Peter TD 5801
P Hehir

Peter, the tachometer and speedometer cables will also provide a path to ground. Adequate for the lamps, but questionable for the clock's well-being. Bud
Bud Krueger

Peter,

Copy paste from the archives (again)



John Scragg, Antibes France, john dot scragg at wanadoo dot fr

This may or may not help, but just thought Ill let you know how I got my clock to work.

I cleaned the contact tip, cleaned and oiled the movement, tested it on the bench, powered by the battery charger, ran fine for days. Put in the car, Nothing! back on the bench ran fine.

I supposed that it was a voltage drop problem, I changed the feed wire to a larger diameter and placed star washers under the two clock fixing screws and the speedometer earth wire.

It has been running now for 4 years.


John

52 TD
J Scragg

Both Greg Howell and I have the Clocks4clasics electronic fix in our TD clocks and so far No problems encountered. Clock looks the same as original and works just fine. They have good videos and instructions on what to do to clean and install the required PCB and decal. Only use clock oil and not too much at that. Been several months now and running like a champ.
Rod
Rod Jones

A couple of emails offline suggested a mechanical clean. While still assembled I carefully scraped away at the balance wheel pin & retested. Last evening she ran for 3 hours before stopping. I'll have another go at cleaning off the carbon today. Yet to take any pics. Cheers
Peter TD 5801
P Hehir

It seems a combination of the clean & the addition of some surgical spirit to the top bearing on the balance wheel shaft has done the trick. I have the still assembled mechanism supported face down so that I could easily apply a drop of the surgical spirit to the shaft bearing & she's been running non stop for 16 hours now & counting!

On the first couple of attempts after cleaning the contacts, the balance wheel would bind in exactly the same position suggesting that one or both of the bearings needed cleaning. I'll leave it run for another 8 hours or so then with the clock inverted I'll also treat the more difficult to reach bottom bearing. The idea being that gravity will assist the surgical spirit in cleaning out the bearing while the mechanism is operating. The spirit contains a small percentage of castor oil. I've also applied a drop to each end of the worm drive. I intend to repeat the procedure with the clock in both of the horizontal positions - the normal orientation as well as upside down with 6 o'clock at the top - applying a tiny drop to any bearings I can easily reach. Not sure whether to apply clock oil as well or just rely on the castor oil in the surgical spirit? Looks promising though. Thanks to John S & John CF. Cheers
Peter TD 5801
P Hehir

Not too much oil. Only on the balance wheel bearing.
Just dip a needle eye in very thin oil and touch the bearing with the needle eye.

I bout this especially to fix my clock.
http://www.ebay.fr/itm/Lunettes-loupes-dhorloger-a-leds-eclairantes-bijoutier-bijouterie-de-precision-/142109395156?hash=item21166148d4:g:GNAAAOSwzgRWzKY9
Really worth it.

Laurent.

LC Laurent31

Interesting test results. The clock functioned perfectly running for over 24 hours in the vertical position, both with the face up & face down. However when placed horizontally it would only run for a matter of seconds. After studying this for some time I became aware that the transverse escape assembly appeared to have a considerable degree of end play which I estimated at about .060". This appeared to cause the mechanism to jam almost immediately. One of the posts seemed to be bent slightly which I carefully straightened, reducing the end play of the transverse shaft to about .015". I again tried the clock in the horizontal position & she now appears to be operating normally. (Obviously when vertical, gravity ensured that the transverse escape assembly remained engaged with its escape gear). I also applied methylated spirits to the bearings I could reach to remove any traces of the castor oil from the surgical spirit, thinking that may have added to the problem.

Couple of odd things though. Although the hands move & keep reasonable time there is no audible ticking. Also there is a whisker mounted on the side of the mechanism dangling down towards the balance wheel but not making contact with anything. This seems to have no purpose whatsoever. This whisker is visible on the left of the pic, which shows the clock in operation, hence the blur below the balance wheel. Cheers
Peter TD 5801



P Hehir

Peter,
That whisker is the tension applied to the transfer shaft.

It rests on the shaft very lightly and I guess stops it from reversing and causing a jam.

This is the one on My TD Clock [with the PCB Mod]

I has to be a light touch to not stop the movement.

Rod


Rod Jones

Peter, '
When I cleaned my clock and removed the moving parts I did not remove this spring.
It is held to the base with a screw. On my clock it is almost parallel to the escapement wheel and function
OK.
It may be the camera angle but in your pic it looks to be almost vertical?? I can't explain that unless it is on the wrong side.

Just a thought.
Rod
Rod Jones

A slightly better shot of the spring. Showing the small plinth it is mounted too on the base plate


Rod Jones

Thanks Rod. I also sought clarification from Mark at Clocks4Classiscs, who has been very helpful. He concurs with the info you've provided & he advises that;

'The "whisker" you refer to is actually a damping spring which is used to reduce oscillations in the gear train. It should rest very lightly against the polished end of the shaft on the transverse gear but be careful as it will stop the movement if it bears too heavily on the shaft. To be honest most clocks will run quite happily without the damper so if it is working I wouldn't worry too much. Regarding the tick - this is vary variable from clock to clock; some are very loud and some very quiet. You will probably find that it is quite a lot louder when it is installed in the dash.'

I have bent the damping spring so that it now bears lightly on the shaft & am now retesting the operation. I may have to back the tension off slightly if the clock stops. Thanks to all for your input. As I now have a working clock I'm not going to bother with the mod at this stage. Cheers
Peter TD 5801
P Hehir

I've spent some time trying to locate clock oil here in Oz with no success. Seems the good oil is that the best product is synthetic Nye oil @ $12/oz however retailers in the States are charging 5 times that to supply & ship, if they ship at all. As I only need a drop or two there has to be a better solution. No pun intended. Interesting research available here: http://www.kensclockclinic.com/wp-content/uploads/2015/02/Clock-Oils.pdf Suggestions welcomed. Cheers
Peter TD 5801

P Hehir

That's easy to find. I've done some restoration work on old clocks with wooden works. The preferred lubricant is porpoise jaw oil. The last person with whom I shared a discussion about that was Carl Cederstrand, he of the differential gearing. Bud
Bud Krueger

Not so in Oz Bud. I may be able to locate some Horolube 9 - C though, which along with Nye oil, Ken from Ken's Clock Clinic also recommends. This is made from whale oil but has not been available for at least 35 years. I've inquired about a small bottle that was made prior to 1963 and was part of a retired watchmaker's stock. I intend to buy it as long as the shipping is reasonable. Cheers
Peter TD 5801
P Hehir

Peter,
Go to the next Swiss watch representative (Omega, Rolex, IWC, Longines, Tudor, etc...). All these brands have mechanical movements (not quartz). They will probably give you the few drops of oïl that you need.
C.M. groucho

Peter,
Sending down in overnight bag today some Swiss made "Moebius" clock oil plus an oiler.
Watch oil is to fine to be used in clocks it will work but not for long.
Retired Horologist - Watch & Clock maker. Old school.
Cheers John
J.K. Chester-Freeman

Thanks John. Apparently the old school Moebius clock oil is really good stuff. The link above from Ken's Clocks is a great read & he suggests that the recent Moebius oil is not a patch on what it used to be. If you can find the time when you're next in Sydney I'll pull a bottle of red from the cellar. Cheers
Peter TD 5801
P Hehir

Close but no cigar.. The clock runs beautifully when vertical & seems to want to run forever but still refuses to run for more than a few seconds when horizontal. I can even hear a very feint ticking now after the clean & light oil. I've yet to completely strip it but because it's fine when vertical I believe that excessive end play somewhere, rather than a cleaning/oiling issue, is the problem. Driving me crazy though. I may have to admit defeat. Cheers
Peter TD 5801
P Hehir

Peter,

You could check the coil is moving the escapement wheel far enough.
The teeth on one cross shaft are quite thick and the other cross shaft with the scroll gear needs to move it enough so as not to impact a tooth on the way back.
The position of the coil is critical. The arms bend up or down easily but must be inline with the shaped weights on the escapement wheel and be as close but not touching them. My camera is crap but you can see the motion and how far the wheel has to swing to not allow the cross shaft to impact on a tooth. Also how long it will run after power is removed. A test on tightness of the movement. Check also the coil resistance. It wont be many Ohms but there should be some. Reinforce the wires with a dab of glue where they out of the coil as well. I found a small brass dishes washer under the first big gear that going to the hands. It matters which way round this goes on my clock. Dished towards the movement seemed to work and the other way round it stopped the movement. Go figure.

I have no affiliation to Classice4Cocks but their fix worked just fine for me and also Greg Howell here in Port Charlotte
Rod Jones

Sorry This is the link
https://www.youtube.com/watch?v=dSg5p6kqvZw
Rod Jones

Peter, what do you mean by 'vertical' vs. ?? Why would you be testing the clock in a horizontal position? Bud
Bud Krueger

Just checked the link Rod & it seems yours may have a slightly more positive & robust motion however mine still runs for about 15 seconds when started manually without power i.e. by moving the balance wheel. I had removed the hands & the two gears during my tests so the dished washer isn't the issue. The fact that it runs perfectly when vertical is the bit that I don't get. All this suggests that the coil is fine. It measures 60 on the x 10 ohms scale.

I wonder how long it takes for the clock to run down a car battery? I've been using this 2nd hand battery to perform the tests for a while now so maybe that's the issue? I'll replace it with freshly charged unit today & see if that solves the running on the horizontal problem. Cheers
Peter TD 5801
P Hehir

Bud vertical means the hands & face are pointing to the sky. Horizontal means the way the clock is fitted to the dash with the hands facing the driver, albeit with a slightly tilted up orientation. Testing it in this manner as this is how it's fitted to the car. When watches with a movement are being calibrated they are tested with the face up, down, left & right so this is just a habit from my instrument fitting days. The stand that I have the clock mounted in is capable of presenting the clock every which way. This helps with cleaning & oiling. Maybe you can answer the 'how long does it take to run down a car battery question'? Cheers
Peter TD 5801
P Hehir

The test battery I'm using is down to about 5.5 Volts. I'm hoping this is the problem. I'll let you know how I get on when it's fully charged. Cheers
Peter TD 5801
P Hehir

Peter, I think you're missing a significant parameter in your testing. You are not emulating the clock's habitat. In use, it is subject to the vibrations of the drivetrain of the vehicle, as well as the motions of the tachometer.
I can see no validity in your 'vertical' testing. That would be fine if this were a ship's chronometer.

As far as running the battery down -- Lazarus' kept running from early January until mid-March in 2015. Lost about 15 minutes, but the car started. Bud

Bud Krueger

Peter, I think 5.5 volts is much too low. I suspect there is a bit more friction in the gear train in one position than another and the low voltage is insufficient to give the clock the necessary "kick".

Bud, your clock was working after sitting through a winter without (I suspect) any sort of vibration to keep the clock working. Also, if your car started after the winter hibernation then the battery voltage must have been much more than the 5.5 volts that Peter is using for his test.
Hugh Pite
H.D. Pite

Thanks Hugh. That's pretty much what I thought. Finding out that I only had 5.5 volts made sense of the symptoms. I was really encouraged that she'd run for about 15 seconds without any power. This indicated that the cleaning & oiling was successful with minimal friction in the gear train. Battery still on charge with the electrician across the road so yet to test. Cheers
Peter TD 5801
P Hehir

I'm sure it was much more than 5.5. I'm guessing that Peter is using a rechargeable 12 volt battery. Bud
Bud Krueger

Bud the 12 volt car battery registered 5.5 volts on my multimeter. Cheers
Peter TD 5801
P Hehir

Peter, I'm amazed that it was still functioning at that low a source. Though mine has been transistorized that wouldn't affect the power rain. Bud
Bud Krueger

The good news is that the clean & oil must have been really effective. Keen to feed it 12 volts. Cheers
Peter TD 5801
P Hehir

The clock is now running perfectly in the horizontal orientation. Borrowed a car battery showing 12.6 volts on the multimeter. Thanks to all who've offered advice. This experience suggests that the TD pin clock is a very robust & well designed apparatus & that once the pin & the electrical pivot are cleaned, most clocks will run & will then only need a clean with the application of a suitable light clock oil. The problems I experienced after the de-carbonisation, clean & oil were due to a battery registering just 5.5 volts. Worth noting however that these clocks will run, after a fashion, even at such a low voltage. Over & out. Cheers
Peter TD 5801
P Hehir

Peter,

Good news, if your clock worked as you described at 5.5 volts, at 12 volts it should be in orbit. I had problems with my clock with about a 2 volt drop.

John


J Scragg

This thread was discussed between 14/09/2017 and 14/10/2017

MG TD TF 1500 index

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