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Extract from May's Octagon Car Club Bulletin

QA Technical Torque

in his article ‘Normally Aspirated’ (No 335), Neil Cairns drew our attention to the need to allow engines to ‘breathe’ properly in order to get the best out of them in terms of performance and economy. I first realised the importance of this when I was introduced to the book ‘Tuning BL’s "A" Series Engines’ by David Vizard (Haynes Publishing Group ISBN 0-85429-732-4) which is based on his extensive experience with these engines and has chapters on many aspects of engine management and ancillaries. What has this to do with MGs? you may ask. Well, the ‘A’ series engine was probably developed from the XPAG and has been fitted to many models including ‘modern’ Midgets and, most recently, the MG Metro. But that is not really the point; the book gives a valuable insight into the general principles of how engines work. It is well worth begging or borrowing and a good read for those who like to know ‘why’ as well as ‘how’ when working under the bonnet.


Unleaded PA

  • Has anyone any advice on fitting inserts into a PA head to allow it to run on unleaded fuel? Are special valves and valve guides needed?
    Simon Mason, Malton, N.Yorks.

    Cost effective wires for TD

  • I’d like to convert my steel wheeled TD to wire wheels. Has anyone researched the most cost effective way of doing this with all new parts?
    Malcolm Poore, Sheringham, Norfolk.

    Modern tyres for TD & TF

  • (please see last Tip & Comment - Bill Scott)

    Rattling TD Box = sore knee?

  • Driving enjoyment is somewhat spoiled by a pronounced rattle from the gear change lever when the engine is pulling. The gearbox seems to be in good order, perhaps a bit noisy in first and reverse but fine in the other gears. Renewing the ant-rattle spring and tightening the engine and gearbox mounting rubbers. I am reluctant to drive with my knee against the gear lever as recommended by some TD owners. Has anyone any other suggestions?
    Ron Houghton, Hardwick, Norfolk.

    ID Seat belts

  • What is the general view of owners on this subject considering the risks involved whilst driving in today’s traffic conditions as opposed to the effect on originality etc? I have seen the method of fitting recommended by Horst Schack. Can anyone advise on an easier solution?
    Ron Houghton, Hardwick, Norfolk.

    White metal bearings

  • (Please see next to last Tip & Comment - Dave Berry)


  • The windscreen wipers on my J2 miss the screen and are useless. In addition, my regular passenger dislikes the presence of the wiper motor on the screen.. Am I legally required to have wipers? I’d like to remove them, but .....! (334)

    Regulation 34(1) Road Vehicles (Construction and Use) Regulations 1986 says:

    "Unless a driver can obtain an adequate view of the road ahead, without looking through the windscreen, the vehicle shall be fitted with wipers capable of clearing an area so that he shall have an adequate view. If the screen is fixed the vehicle shall be fitted with washers, etc, etc."

    None are required on vehicles that cannot do more than 20mph, track laying vehicles, plus a few other oddities. So, if the screen can be opened or removed, to give a clear view ahead, you do NOT need wipers but you would HAVE TO remove or open it during RAIN, or get booked for the above offense!!! If Bob removes his wipers he cannot drive in the rain unless he fits tracks, a governor to limit the speed of his J2 to 20mph and has certificated. Is it worth trying Land Rover blades?

    Neil Cairns, Leighton Buzzard, Beds.

  • Both carb bodies have damaged threads where the banjo fixes the fuel bowl to the bodies. Does anyone have a proven and simple repair suggestion? (No 331)

    I read the following in an Australian workshop manual:
    "Early types of holding-up bolts used for attaching the float chamber to the main body casting employ a sunk cork ring for a seal, and as this is enclosed on three sides by the head of the bolt, it will last almost indefinitely provided no attempt is made to dig it out. The cork ring type was followed by a different bolt using a simple flat seating made onto a solid flat aluminum washer, or its later successor, a rolled bronze washer. These two washers were in turn displaced (but using the same bolt) by a set of three washers, twin fibre ones in the outer positions with a brass one between them."

    The early type of holding bolt with the recess for the cork gasket is fitted to my 46’ TC 0765 and this has 7/16" BSF threads on the banjo. Because of the bad alloy in the carb I would have made a bush with 7/16" BSF to block the petrol; holes). It is preferable not to use a simple drill bit but a reamer or small boring bar.
    Olav Thoresen, Stard, Norway.

  • I have recently purchased a 1939 TA which I believe should have a central lubrication system. Can someone please advise me as to the size of the pipes required and /or necessary fixings. A guide to the correct route of the pipes would be helpful as would any advice on where to purchase all the necessary parts. Is it a worthwhile exercise or is it better to leave well alone? (334)

    I think you can get all the parts for group nippling from Mike Dowley (Sports& Vintage, Shrewsbury). It is probably best to leave well alone; In any case 140 oil, not grease should be used.
    Paddy Willmer, Sandy, Beds.

    MM Cars have well researched lubrication systems, the best diagrams of which are contained in what was Barry Walker’s Pre War MG Parts Centre Catalogue, now available from Naylors in Shipley. Both they and Mike Dowley at Sports and Vintage supply all the parts and are very helpful. Unfortunately the TA/B fitments are substantially different, although they may have been fitted to SA and VA models too. I have no knowledge of them. Terry Bone, who regularly advertises in the Bulletin, recently had quite a few parts (brass bulkhead plates and ‘plumbing’ etc) for a reasonable price and may be worth contacting, although I guess the length of the pipe runs will be different. This could well be significant.

    I too have a 1939 TA (chassis 3202), which I have been sporadically restoring since 1987, and have been trying to determine the details of the system. This is what I have discovered and am finally in the process of installing;

    There are three pipe runs on each side. The piping is 5/32" brass tubing, which is common with the MMM cars and is available from the suppliers mentioned. According to the original MG parts list the length of the runs are ; Bulkhead to front trunnion; 2’10" Bulkhead to brake cables; 5’8", Bulkhead to rear trunnion; 8.9". That’s the easy bit!

    On the bulkhead there are oiling nipples (note oiling, not greasing*). They have a 5/16" BSB or cycle thread of 26TPI. As far as I know the oilers available from the suppliers have a 5/16" BSF thread, but you could check this. It depends on the level of originality you want. If you want BSB threaded ones they would have to be made up from bolts using (probably) 1/8" BSF nipples.

    On the front trunnion boxes the pipe is joined by a double ended male union which has a 5/16" BSF thread to go into the box and a 5/16" BSB/Cycle thread to match the pipe sleeve nut. Identical double ended unions join the pipe to the brake cable oiling points; i.e. you would need 4. At the rear trunnion there is a similarly threaded elbow union, 2 needed. The unions are linked to the pipes by 5/16" BSB/cycle threaded sleeve nuts, retained on the pipes by small compression olives (12 needed unless you go for BSF oilers in which case , in which case you will need 6 BSB and 6 BSF). All of these parts are, as far as I can determine, like the proverbial hen’s teeth. However, despair not. It is possible to make them by rethreading 1/8" BSP unions and elbows which are available from Paul Beck at Vintage Supplies. BSB is a common modelling thread so items may be available from specialist firms. Alternatively, an engineer could make them but this would be relatively pricey.

    The pipe runs are available in 11’ coils (4 needed). To improve malleability of the pipe for tight bends it is worth heating and quenching in cold water. For pipe clips I have modified 5/16" brass pipe clips from vintage Supplies held on by 4BA cheesehead (originally roundhead) bolts from Namricks, Brighton.

    *Apparently systems failed because owners used grease instead of the correct SAE 140 oil.
    Alasdair Enticknap, Harrogate, N.Yorks.

  • Why are the T-types brake drums retained by slim ‘half nuts’ which strip so easily? I have fitted full size nuts to mine with no apparent detriment. (334)

    The only reason I can think of is to keep down the unsprung weight!! I also use full nuts - or, dare I say it, a mixture.
    Paddy Willmer, Sandy, Beds.

  • I have a late TD (Chassis TD24545) which was repatriated from the U.S.A. In the base of the original pedal box is what looks like some kind of stop. The new box has a similar slot in the base but nothing fitted. Should the stop be moved to the new RHD box and what is the adjustment? (334).

    It is a stop for the clutch or brake pedal to prevent too much movement. In my original Service Parts List on page A2 under Chassis frame is listed a part described as "Stop-clutch" and brake pedals Part No 127151 commencing Chassis No TD 0251".
    D.F.Fletcher, Banbury, Oxon.

    From TD chassis 22251 the clutch operation mechanism was changed from a cable type with inbuilt clutch stop to a rod operated type which required a mechanical stop which was placed in the bottom of the pedal box and caught the end of the clutch pedal thereby stopping you turning your clutch inside out. So - yes, the stop button in you LHD box must be transferred across.
    John Bevan, Bartestree, Hereford.

  • We use our TF most days. Recently someone tried to steal it. Fortunately they failed. Does anyone have any advice on how to thief-proof such a car? (334)

    I also use my TD regularly for shopping etc. I have three theft deterrents to help stop the car being stolen. However, nothing will stop a really determined thief. Likewise I do not know how to prevent a would be thief venting his anger if he cannnot take the vehicle. However, at least you keep you car.

    (i) Put an on/off switch into the back of the glove box and run one wire from it to earth. Run the other wire to the coil so that when the switch is ON the coil is earthed and the ignition will not work. Conceal the wires as much as possible. My glove box locks.

    (ii) I have two separate switches, one amongst the normal visible ones and one concealed. Both should be reached from the cockpit. They are wired so that to make the electric fuel pump work they both need to be in the ON position. If this is not done the car will start but will run only about 30 yards. I never leave the car without using them.

    (iii) Another method is a "Bullock" deterrent. This clamps together the clutch and brake pedals and can only be removed with a key or hacksaw. This is more difficult to fit and I only use this when leaving the car for a long time. Steering wheel clamps may deter a joy-rider but can be overcome by bending/breaking the wheel.
    D.F.Fletcher, Banbury, Oxon.

  • I’ve often thought of fitting wire wheels to my TD. Are they as easy to fit as the suppliers of the conversion kits say? What are the pitfalls? Several spares I have bought have been faulty or needed additional work. (333)

    This is a very straightforward but expensive job. One part - modifying the spare wheel carrier - is a once only conversion for which conversion parts are probably not available.

    The ‘shopping list" is:-

    4 Wire wheel brake drums
    2 front and 2 rear splined hubs
    4 knockhoffs
    2 small (6304) and 2 large bearings
    2 lip seals
    24 3/8 BSF half nuts
    12 lock tabs
    5 wire wheels, tyres, tubes and rim tapes
    1 scrap TA/TC splined hub with knock off (preferably rear)

    Tips on fitting:

    Take off hub caps, put car in gear with handbrake on. Remove split pins from front stub axle nuts and rear axle retention hub nuts. Release these nuts one turn. Remember that front nuts are LH and RH whilst rear are both RH thread. The car can now be jacked up to remove all the road wheels and the brake shoes slackened to allow removal of the drum/hub assemblies. a hub puller will be necessary for the front hubs and may be needed for the rears.

    Starting with the rear axle note the position of the split pin hole in the end of the half shaft and line this up with the hole in the new to allow a new split pin to be fitted when the nut is put back on the shaft. It is expedient to put a small amount of copperslip grease on the half shaft splines prior to fitting the new hubs. After fitting the hubs fir the washer and tighten the nut to pull the hub up on the shaft splines. Fit new brake drums with 1/2 nuts and lock tabs.

    On the front hubs fit new small bearing, use bearing spacer from existing removed hub/drum assembly, fit large bearing, new lip seal and seal spacer to stub axle with washer and nut. Tighten and fit split pin. Fit new brake drums as above. Adjust all brakes and fit new wire wheels with knockoffs. Lower car to ground. Remove rear knockoffs, one at a time, and finally lock up half shaft nut to 75lbs / ft torque or next castlation. Jack up, remove wheel and fit split pin (through hole in splined hub) into nut half shaft. Refit wheel with knock off. Remove jack!!

    The spare wheel carrier will require removal from the car so that it can be modified to accept the spare wheel. Take the scrap TA/TC rear splined hub and have the flange reduced to 3.75" to fit inside the large tube after removal of the three stud flange and one inch of tube. Set modified hub into the tube, weld and paint. Refit to the car, fit spare wheel with knock off. You may also wish to fit a radiator badge into this knock off as a final touch. Job done - happy motoring!

    Note: Hubs, drums, knock offs, and wheel can be purchased from Orson Equipment, Wythall, Birmingham. Bearings and lip seals are available from your local bearing supplier. Nuts and lock tabs from any ‘T-type’ specialist supplier. Conversion Kits from ‘T’ suppliers do not contain wheels, only mechanical parts. I have found that B&G wore wheel kit contains spare wheel carrier conversion parts but I don’t know of these are available separately.

    You will need to have the wheels balanced by a firm who can do this properly - your general local tyre firm cannot usually do this as a specially modified balancing machine is needed (i’m lucky as the Morgan Car company is not too far away).