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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 - Choke Knob Early TD

Not sure who owns this car as it's one of many pics I've gathered over the past 6 years. The choke knob is identical to mine yet differs from those on other later TD's in my gallery, where the choke & pull starter seem identical. Wondering if others with an original early TD carry the same knob? Obviously the opinion of an owner who has had his car since new car would be highly valued. My choke knob has a recessed C with remnants of white paint in the recess & was fitted to the car when I bought it in 1969. It clearly had seen some prior action. Cheers
Peter TD 5801

P Hehir

My choke and starter knob are identical except the choke has a C in it. They also look like they have been in the car for some time. TD 4139
Bruce Cunha

Here is TD00278 but that left knob looks a little wrong to me. I am pretty sure it's a replacement. The right knob is correct and they should match.



Christopher Couper

Peter - The choke knob on your car looks very much like the one on the TF, pictured below (copied out of the Original T Series by Clausager)

D W DuBois

Both starter and choke knobs on the TD are flat on the top as pictured in the Original MG T Series by Clausager below. I believe that I have seen some choke knobs on a TD with a C on it as Bruce has on his car.

D W DuBois

Finally, the knobs on our TD (pictured below), which are the same as the knobs on the TD that my parents purchased in 1957 (and given to me to drive during my senior year of high school). Cheers - Dave

D W DuBois

Thanks Dave. It seems I have a TF choke knob. As Clausager has been criticised for photographic inaccuracies by Chris & others in the past can anyone provide a pic from a one owner TD showing an original early TD knob? The Driver's Handbook I have shows a late TD (round tail lights) with matching knobs but no evidence of the C. If it turns out that I have a TF knob does anyone care to swap it for an original early TD knob? Mine has just had the knob buffed & the wire cable replaced & is in very good condition. Cheers
Peter TD 5801
P Hehir

Peter: The picture posted above with TD00278 right knob is exactly the same as late knobs that Dave posted for his car.
Christopher Couper

Chris I was wondering about the knob with the C that Dave mentioned he'd seen on some TD's (as Bruce has on his car). Both knobs, starter & choke, it now seems should be matching flat tops but whether the/some early choke knobs had a C is unclear. TD 00278 does have mismatched knobs & the starter knob is certainly correct & I agree that the choke knob is incorrect. I've looked at the knobs in the archived pics & there is quite a variety, hence my request for input from an original early TD owner. George? Joe? Cheers
Peter TD 5801.
P Hehir

Peter. Mine has the same knobs. Neither has a letter stamp. Based on their patina and the amount of time TD 4834 has been in lay up, I would be very tempted to say they are the originals

W. A. Chasser Jr

Have found a TF owner with an original TD knob & I'm swapping it tomorrow. Thanks to all for your input. Cheers
Peter TD 5801
P Hehir

I now have an original TD choke knob, cable, fittings & outer sheath which of course raises a few more questions. I'm digging into the archive to learn how to dismantle the inner & outer elements. I'll replace the wire cable with the bicycle stuff using soft solder. (Dave DuBois has some good gen). I'd like to reuse my outer sheath as I had the dash end re-chromed at great expense. Anybody else who is up to speed on the mysteries of the choke mechanism, (at the knob end), care to offer suggestions on dismantling, reassembly & operation, including identifying the most useful threads in the archive? Cheers
Peter TD 5801
P Hehir

Peter - e-mail me at Donobi.net and I'll send you information on how to touch up the birds mouth and stop for the original choke cable. Cheers - Dave
D W DuBois

Peter - My e-mail address is actually SUfuelpumps@donobi.net Sorry about the omission of the first part of the address. Cheers - Dave
D W DuBois

Thanks Dave. You have mail. Cheers
Peter TD 5801
P Hehir

I've read most of the archive on this topic but still have a few unanswered questions which include:

1. Is the “spring” the cylinder that wraps almost all the way around the shaft adjacent to the knob?
2. How is it removed i.e. is it prised off the housing completely?
3. Where exactly is the 1/2moon & how is it removed & more importantly how is it replaced?
4. I plan to make some as Dave did using a washer unless others have a better suggestion?
5. Should the knob & cable simply pull out of the outer sheath or does the spring & 1/2 moon have to be removed first?
6. I don’t fully understand the action of the original choke i.e. which way is it supposed to be turned CW or CCW & how far?
7. How exactly does the locking mechanism work (I’ve read some explanations but it remains unclear)?
8. What is the diameter of the original choke cable?
9. Will 1mm diameter multi strand bicycle cable suffice for the replacement choke cable?
10. As I’m able to buy 1mm, 1.1mm or 2mm bike cable, what diameter do you recommend bearing in mind I’m an originality nut?
11. Should I try & source solid wire instead if so what diameter?
12. Is silver solder to be avoided?
13. Can I reuse my re-chromed dash housing & sheath? (See pic of my dash on Dash Progress Report)
14. Does anyone have any pics on this topic?

TYIA for your suggestions & advice. Cheers
Peter TD 5801
P Hehir

Just a few comments. The spring or sheath just slips off.

In doing that you will probably drop the half moon piece which is just a tiny piece of metal. I think there was a thread a few weeks ago titled "hardest thing to do" or something where somebody mentioned how they tried to make one with a bandsaw blade.

The knob can only go in one way and turns 1/4 if I remember. Pull it out, turn 1/4 and it locks. To release just turn back. It basically engages the half moon on the shafts indents.

The size cable is the one that fits. If its too big it won't go in the hole. You will need to heat the knob shaft up with a torch and get all the old solder out plus use some flux and get it hot while insert the new cable.

Tin the loose end after you figure out where you are going to cut it. Tin first and then cut it after where you tinned it.

There should be no reason you cannot use your existing body. I would doubt it is worn out. Biggest problem is the cable and half moon piece.

TTALK has a great set of pictures

http://www.ttalk.info/Choke/
Christopher Couper

Thanks Chris. I'll check it out. I've read almost all of the threads on the subject & saw the bit about the hacksaw blade, tinning etc. Dave is sending me detailed instructions which will arrive in the next couple of days. Cheers
Peter TD 5801
P Hehir

Also thanks to Patrick Earles for the pics! Cheers
Peter TD 5801
P Hehir

This might help you Peter.

http://www.mgexp.com/phorum/read.php?1,2071172

Rod
Rod782

Rod - That link deals with a MGB choke cable assembly, which works slightly different from the one for the T series cable. The MGB cable uses a raised area on a half round rod, providing an infinite number of settings. The TD uses a rod with 5 'birds mouths' cut into it, giving just 5 discrete settings. The half moon for the MGB is also at least twice as thick as for the T series cable. Cheers - Dave
D W DuBois

Rod: Looking at your MGB examples shows how the world has cheapened out over time. When you compare the MGB version of the choke cable mechanism to TD you can really spot the quality differences.

In the old days engineering was about solving problems. The next generation of engineers spent all their time trying to make things cheaper, hopefully to a point that nobody would notice.
Christopher Couper

Rod that was definitely a help. Although as Dave said it was a B choke that was described, I now have a pretty good idea how to take the TD version apart, how it should operate & how to use the choke to ensure the longevity of the repair I'm about to undertake. I particularly liked the suggestion to create the half moon out of an appropriately sized bolt & will look at that option as well as the washer idea. Wear it seems is the enemy so the choice of material, steel, brass, key stock, hardened steel etc is obviously important. As the half moon can work its way out through the split in the sleeve I wondered, space permitting, if a small jubilee clip might secure it & solve that problem? I'll wait until Dave's instructions arrive before I begin. (I agree Chris & with China causing manufacturing all over the world to fold, it's getting even "cheaper"!) Cheers
Peter TD 5801
P Hehir

Peter,
Yes sorry about that - did not note it was for a B.

A while back I posted some pics of a modern choke cable for a TD to explain how it worked and that a cloths peg was not really required if it functioned correctly.

I don't think a jubilee clip will help much as it has to have spring tension on the pawl to hold the shaft in place but also allow it to be free so it can return easily.

Difficult to show if you don't have one in your hand but this may help.

I will add that the original MGTD choke cable was different and worked in the opposit way to the modern replacments, as it had retchet teeth on the shaft and would hold when pulled strait out. It was twisted only to push it back in. The twist releived the pawl from the teeth and it slid back in smoothly.

Hope this make it a little clearer.
Rod



Rod782

Rod I now think I'm sorted. Just got the info & pics from Dave who has answered all my queries above. Cutting the half moon from a bolt does seem to be the way to go. I initially thought I may use a HT bolt. However the original designer would have considered a number of materials for the pawl, brass, MS etc & would obviously have wanted the pawl to wear rather than the indented brass knob shaft. So I'll stick with the MS bolt. Still unclear about lubrication. Perhaps a little Vaseline over the restored indents? Ideally the choke when twisted 1/4 turn CW should release easily & return to its stop under the tension exerted by the carby choke springs, with just a little pressure applied by the operator. Once I remove the old original cable from inside the sheath I'll measure the diameter & source that size cable from the bike shop. I'll also experiment with the jubilee clip over the spring steel ensuring it only applies enough pressure to secure the spring yet still allows the knob shaft to turn easily. Cheers
Peter TD 5801
P Hehir

I would not think the jubilee clip would work, maybe a ht rubber cover - spark plug end?
mog

I'm sorry. I got my chokes mixed up. The one in the 67 B has the C. on it. The TD are both the same and like Dave's.

Bruce Cunha

Thanks Mog. Some sort of rubber sleeve is probably the way to go. Bruce in the pic you just posted, the knobs seem longer than the short knob in the first pic in this thread? Chris, just rereading the earlier posts & comparing them with Dave's instructions. Earlier you said "The knob can only go in one way and turns 1/4 if I remember. Pull it out, turn 1/4 and it locks. To release just turn back. It basically engages the half moon on the shafts indents". Dave instructions suggest that on the original when you pull it out against the choke spring tension it locks at whichever of the 5 indents that you stop at & it is only to release it that you then have to turn it a 1/4 turn CW. I was wondering if maybe you have the later choke cable which may operate the way you described? Cheers
Peter TD 5801
P Hehir

Just had a look at my spare cables, 1 thing to note is ( cannot be sure ) starter and choke the same? why would they be, and if so why would the starter have a pawl?

mine are different in material it looks from a quick look, 1 brassy 1 silvery

knobs are the same late and early, I think the early cars & Tc etc maybe had single strand, later multi cables?

I think the soldered part is also a clamp, so before soldering the wire in, clamp the end of the wire in the rod part, to remove the cable: drill or cut the wire end out of the rod to allow the clamp joint to be heated and wire twisted out, hope this bit makes sense.

might be mistaken on a couple of bits.

mog

clamp

mog

same for starter & choke?

mog

Peter: Dave and I are describing the same behavior. He is probably more grammatically correct than I.
Christopher Couper

After reading Dave's information Mog I can confirm the following: Your first pic shows two choke cables. The one on the left illustrates the slot/housing for the half moon pawl. The one on the right shows the pair of indents that act as a stop when the knob is rotated. You're correct there is no pawl on the starter. The recommendation from Chris, Dave & others to heat then remove the old cable is the way to go. Drilling is not necessary. TD's had multi strand cable however don't know about TC's. I'm pulling my original apart today & once revealed I'll measure the diameter of the cable & count the number of strands then. Not sure what I'm looking at in the second pic. Third pic, both starter & choke knobs are correct and they are the same. Thanks Chris. I'm confident I now understand TD choke cable refurb & operation. I'll take some pics of the process & post them once I've finished. TYA for your help. Cheers
Peter TD 5801
P Hehir

I've measured the 3 choke cables in my possession using a digital vernier. The TF is 18 strand x 1.1mm & both of the original TD's are 12 strand x 1.3mm. Whoever described the pawl as about the size of an ant wasn't kidding. Some of the solidified bits of grease that fell out were bigger! Cheers
Peter TD 5801
P Hehir

The replacement cable for the original TD choke can be had from your bicycle shop as suggested in the archive. A multistrand stainless steel inner gear cable from a Sram pushbike is 2m in length with a diameter of 1.1mm. This is enough to repair 2 original TD chokes with just a little left over. Cost per choke is just $3:50. The recutting of the birdsmouths with Geneva files was simple & straightforward as was the buffing of the knob. The only difficulty encountered thus far is with the flux. Bakers Soldering Fluid is ineffective, as is the rosin in the 60/40 rosin core solder. Apparently the only suitable flux for stainless is 965. I'll pick some up tomorrow & hopefully the replacement of the cable will then proceed without difficulty. I have taken a series of pics which I'll post in a day or two. Cheers
Peter TD 5801
P Hehir

Peter

The best way I have soldered stainless is to use acid core solder.

"Blackwoods" and "Masters" are listing it on the web. If you use it make sure you neutralize the acid residue.

Graeme
G Evans

The choke cable is refurbished, looks great & works just as it did 64 years ago. I used the 965 Graeme without any issues. I've taken about a dozen pics of the process & am drafting a "how to" which I'll post on a new thread in due course. Many thanks to Dave DuBois for your valuable assistance. Cheers
Peter TD 5801
P Hehir

This thread was discussed between 14/01/2015 and 27/01/2015

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