QA Technical Torque

Can anyone out there help me with the fittings for the rear blind of a Y-type? I have the roller but only one of the end stays and no cord or any idea what the end ring of the draw cord (or the cord itself) was made of. Any help or suggestions will be welcome.

Finally after 47 years of faithful service, the front aluminium number plate was broken in two by a careless pheasant (now probably with a large bump on the head). Does anyone know where I can get another one stamped out of the same gauge aluminium so that it matches the rear one?
Paul Barrow, Chandlers Ford, Hampshire.

Answers

I had a similar niggle with my TD so decided to fit new rubber mouldings between the windscreen brackets and the body. It made no difference! So, I made some out of 2mm neoprene rubber as used for electrical worktops.
That's it, fixed!
Obviously there are variations in scuttle top profiles that cannot be absorbed by the thin rubber mouldings and the windscreens don't always fit the resulting gap between the brackets.
Jim Reeve, Wooton Bassett, Wilts.

As a young whippersnapper in the 1960s I remember going to Oulton Park (we used to clamber over the wall near Deers Leap - the entrance fee thus saved could be spent on a packet of Woodbines) to watch, amongst other exotica, the Ford Galaxies being chased by a pack of Mini Coopers and Lotus Cortinas in the saloon car racing. The Galaxies used to give almighty backfires as they changed down for corners, I presume that they were in the peak of tune and I think that Bjarne's explanation in Bulletin 327 is the correct one. Though perhaps the Galaxies felt the only way they could stay in front was by burning the opposition alive, indeed soon these magnificent Dinosaurs had their day - the Cortinas and Minis were always in pole position the next season. On my P-type I have the same phenomenon with backfire on the overrun but only if I'm forcing the revs down seriously quickly when driving with alacrity and dropping down a gear or two for the approaching blind right-hander. (Get flames out of the exhaust too at night. Most entertaining!)
John Buckley, Denbigh, North Wales.

Tips and Comments

Cold Comfort
In the October issue (page 9) I suggested that the use of Trigard based long life antifreeze could help with corrosion. This followed an article which appeared in the Daily Telegraph. Subsequent attempts to obtain the products were unsuccessful prompting me to contact the Telegraph. On their advice I contacted Comma on 01474 564311 and within minutes they told me where I could get the required coolant locally and at what price. For this information ask for the sales dept., for advice on suitability ask for Peter Harbour, Technical Manager.
Neville Mantle, Wetherby, West Yorkshire.

Following this article, the Business Manager of Trigard Coolants has added more information

Playing With Numbers
The standard size of the little M.G. 1250cc XPAG engine is just that 1250cc. As the engine wears it will need attention to restore efficiency and reduce oil consumption. This 'restoration' is called a 'rebore'. The maximum normal rebore is +0.040" which increases the cylinder bore from the standard 66.5mm to 67.5mm. To anyone who did simple maths at school it will be obvious that the engine is now actually bigger that before the rebore. It grows to about 1288cc. That is an increase of about 9.5c.c. a cylinder or 3%. As the 'swept volume of the cylinder is now greater but the cylinder head is unchanged there should be an increase in compression ratio and this could in fact rise from the standard 7.3:1 to 7.53:1. If you missed the point the rebore enlarged the normal cylinder size from 312.63cc to 322.1cc and the piston squashes this into the same combustion chamber size of about 45.5cc all other things being equal.

With 54bhp from the TD and 46bhp from the Y does this 3% show up in an extra power?
Would we notice the extra 1.5bhp? Well it's raining outside and I need something to occupy my mind.....
Neil Cairns, Leighton Buzzard, Bedfordshire.

TA/TB/TC Stub Axle Repairs
After reading the comments of Ernie Smith in the March '97 issue of the Bulletin, I would like to share my experience on this subject. Over the past six years I have performed repairs on about 12 sets of stub axles, mainly TCs. The enclosed photographs were taken during the various stages of the work being done. The complexity and degree of accuracy that must be maintained from start to finish should not be attempted by an inexperienced amateur. This is a task for a professional machinist/toolmaker with precision instruments and machinery. I use a 4142 chrome-moly steel, the same chrome-moly steel I use for axle shafts (see May '85 Bulletin, page8). This steel is far tougher than the original soft forging. The drawings in Mike Sherrill's "TCs Forever" are, in my opinion, almost perfect. The 0.003" interference fir is correct.
I would add a microfinish specification to these two regions on the stub axle that receive the bearings. These diameters need to have a finish no rougher than 16 microinches. This is important. If the finish on these bearing areas is rougher than 16 microinches high spots will flatten after several bearing removals and the bearings will then become a loose fit on the stub axle.
Some owners have used taper roller bearings on the TC front end. I do not recommend the use of these bearings unless the conversion is performed exactly and correctly. In order to have the tapered roller bearings work as designed most owners remove the spacer tube which is fitted between the two original bearings. As a result the entire stub axle becomes weaker. The original ball bearing and spacer tube assembly is a more rigid structure.. If you must use taper roller bearings you must also keep the spacer. This will require a new spacer, with parallel ends, that provides a bearing crush of typically 0.003" - 0.004". This will then maintain the rigidity of the stub axle and calculate the resulting loads before you proceed to alter the original bearing design.
(Members who have access to Bulletin 299 may be interested to read Ray Sales' article on page 27 - MT)

In addition, never hammer the knock-off hub nut whilst the tyre is off the ground. Hammering whilst the tyre is elevated will transmit shocks and jolts throughout the front end of the car and possibly damage the king pins etc. The front end assembly is relatively weak and should not be subjected to such blows. It has sufficient fatigue problems without adding more by pounding with a heavy hammer.

Assembly of the parts is as follows: the new stub axle is packed in a tray with ice and acetone for about 1 hour (if you have access to liquid nitrogen that is even better). The yoke is heated with a large acetylene torch making certain that it is heated evenly until the colour is that dark straw yellow on the newly machined surfaces. This will be about 600 to 700°F. To verify the temperature you may purchase 'temp-sticks'. They are available from welding supply stores or heat treatment companies. When the yoke is hot and the new stub axle is cold it is ready for assembly. This assembly process must be done at lightning speed. All the tooling must be on hand and ready (this is not a good time to be looking for it.) A 3 ton arbor press is a must. Place the hot yoke over a heavy walled steel tube under the arbour press. The ends of the tube must be flat and parallel with each other. the tube must also be long enough to clear the stub axle as it is pressed in place. Quickly lift the new stub axle out of the ice tray and press it into the hot yoke by pushing it home with a 1" diameter steel plug about 3" long. This plug must also have flat parallel ends. Maintain the pressure on the stub axle for a few seconds as the assembly temperature equalises. The job is now complete.

Be very careful when pressing the parts together. If the stub axle enters the bore crooked it will seize in place when partially pressed into bore. You will then be unable to either push or pull it out and will be forced to machine out the new stub axle as you did with the old one - Beware. Even a 20 ton hydraulic press will not move the axle once it seizes - I know this from experience!

None of the stub axles I have prepared in this manner have failed. If you have any questions you may call or write to me.
Phil Marino, Riverside, California. (909) 352-4419

Editor's Note - I could not reproduce all of Phil's photographs due to colour space constraints but you will find two shots on the centre pages.

4-speed M-type
When an earlier Bulletin arrived I had to do a 'double take' when reading the article "M-type upgrade". I had just been down the same road and fitted a 12/12 M-type gear box to our Jarvis M-type. It was 1" longer than the 3 speed box and so I too had to shorten a propshaft to fit. Also the front floorboard bearers had to be moved back to clear the prop shaft spider at the front, since it was 1" further back. The handbrake mounting bolts were now in a vertical line as opposed to the original horizontal, so I had to make up a triangular adaptor plate to bolt to the different gearbox. The hand brake was also nearer to the brake cross-shaft so that the rod linkage between the two end forks had to be shortened and the thread on the rod extended towards the centre of the rod to get the adjustment.
If you are working around the M-type hand brake be careful that the rod does not project too far into the rear yoke as, when the foot brake is applied, the cross-shaft lever comes forward in the yoke (which has slots to allow this to happen) and pushes this connecting rod forward applying the handbrake and engaging the ratchet which then holds on the handbrake when the footbrake is released. This happened to me a number of times during a driving test at Beaulieu and slowed progress somewhat as the handbrake had to be released each time!
Another tip with the handbrake and its curved ratchet is to reprofile its teeth by filing with a half round file. This tends to remove some of the material from the tops of the teeth and so the pawl does not engage very well. The trick here is to tap the underside of the ratchet which slightly straightens the curve and thus pushes the teeth upwards for a better engagement with the pawl.

The final alteration of the 4-speed box was that the cover to the gearbox/propshaft had to be completely built up form scratch, as the profile was very different to the 3-speed cover. However, now that all this work has been done the extra gear is a great improvement allowing me to change down to third when going around roundabouts, tight bends or hills whereas previously one had to hang onto to top gear to the last minute before changing down to the low second gear. It allows one to keep up the revs for those with a 12/12 camshaft which enables the engine to rev more freely.
Philip Bayne-Powell, Normandy, Sussex.

TD Seating - Aches and Pains and Warren's* Lament

*(Warren Wendt is president of the Classic MG's of Southern California Club and wrote, in the September issue of their Clattre Chattre magazine, of the severe pain and numbness he experienced the day after returning from a 12 day long trip in his TD. His doctor attributed this to possible damage from the pressure of prolonged sitting in exactly the same position.)

Warren's story of his accumulated aches and pains, after his trip to the Park City GoF, struck a sympathetic response in me. My TD initially had a similar effect on me when I was in my twenties. For someone 6'6" the seating in a stock TD is somewhat uncomfortable. For journeys of any distance it is very uncomfortable! I purchased my TD in the early 50's, rebuilt the engine, and then immediately drove from the University of Illinois to Washington D.C., slapping the outside of the door and singing songs all the way.

While Joan and I got out if the car, 700 miles later, I felt like someone had been beating me with a baseball bat. I had aches and pains and numb appendages that continued into the next day. Joan's only complaint was that she was distressingly cold during our drive through the night. It was July, I was wearing a cotton T shirt and a pair of short pants. I thought that the cool night air felt wonderful after our roasting during the day. I had fitted a pair of Brooklands Aero Screens - what else could one possibly want? This was before I understood that most ladies lack body temperature control (thermostats).

After our return to Illinois, I initiated a series of seating modifications. These modifications continued for several years and have been quite successful. Even now, as a septuagenarian, I can comfortably drive all day. This is what I did to make the seating tolerable:

1. Inclined Seat Ramp First and foremost was to cut two seats of inclined (triangular) seat ramps. As supplied by Abingdon, the seat slide asemblies are bolted directly to the floor boards. As a result when I sat in the stock seat, my weight was supported on a small area on my bottom. After hours of driving, my posterior felt like it had been given an injection of Novocaine. I became so stiff that I could hardly walk. my right leg threatened to atrophy from remaining in the same stressed position for hours. After raising the front of the seat by two inches, the seat contacted the back of my legs. As a result, my weight was now supported by my bottom and the back of my legs. This provided a tremendous improvement in my seating comfort. I no longer had to endure a novocained rump and I could relax my right leg. These triangular ramps are 2" high at the front and taper down to 1/8" at the rear.

2. Smaller Steering Wheel With the front of the seat raised two inches, the stock steering wheel rubbed against my legs. I fitted a smaller steering wheel which clears my legs by 3/4".

3. Remove Pedal Extensions The factory fitted pedal extensions to the brake and clutch pedals. An additional 1 1/4" in leg room can be obtained by removing these extensions. I also removed the accelerator 'roller and rod assembly' and shortened it so that the roller moved forward into the same plane as the repositioned pedals.

4. Seat Back Packaging The back of the seat was modified to provide support for the small of my back. This was accomplished by adding an appropriate block of foam to, and in between, the existing coil springs. Foam blocks were added to both driver and navigator positions.

5. Seat Back Bracket Originally, the back of the seat was fitted with a slotted bracket that allowed the back of the seat to follow the seat forward and so vary the inclination of the back seat. I replaced this adjustable bracket with a fixed bracket that firmly anchored the back of the seat in its rearward position. This provided a secure seat back that never moves.

6. Alternative Drivers What do I do when someone considerably less that 6'6" needs to drive the TD? No problem - it takes five minutes to remove the 6'6" long leg configuration. The original pedal extensions are always carried in the car along with the original slotted seat back brackets. Since the seat slide assembly now rests on the triangular ramps, the seat rises as it moves forward. Rising is exactly what is required for shorter drivers. The seating has been improved for both shorts and talls!

7. Supporting Modifications With the seats taken care of, there are several other modifications I would make to produce a cross country TD. Change the ring and pinion from 5,125/1 to the 4.3/1. Forget about the original Dunlop 5.50-15 crossply tyres. Bog stock - bah! Fit Michelin XZX 165 x 15 radials. Fit a stabilizer bar (anti-roll bar) to the front end. Add heavy thermal insulation under the floor mats and cover the fire wall. Recore the radiator with a 93 tube core instead of the original 63 tube core. The 93 tube core would be the Craig CI-SF-1818 with metric serpentine fins. Finally, either change the fan to a modern multiblade unit (many Japanese fans have the identical bolt patters) or add an additional stock blade to the existing two blades. With all of these changes in place, you can motor across country in comfortable equanimity, The TD, rides smoothly, steers beautifully, and no longer revs the engine to death. When the ambient air temperature rises above 100°F, both occupants and engine remain at an acceptable operating temperature.

May I nominate Warren to receive the 'iron man' award from his Park City journey? If i'd made this trip on stock TD seats, I would have been hauled off on a stretcher to an orthopedic hospital somewhere in the middle of Utah. That's my story, you take it from here.
Carl N Cederstand, Brea, California, USA.

(It is difficult for those of us who have driven our M.Gs. Only in the UK to really appreciate the distances and temperatures experienced by USA M.G. enthusiasts. Carl also sent me a photograph of Gene Wescott wiping his hands after checking the distributor cap of his TC with Carl looking on. The photograph was taken outside a gambling casino in the middle of the Nevada desert where they had stopped for lunch during Gene's return drive to Fairbanks, Alaska having attended the GoF in Utah. That's a distance of around 3000 miles one way (!!) with air temperatures sometimes exceeding 100°F! - MT)

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