Restoration of 1952 MG TD 2
|Author: Bob McCluskey|
|First posted: 1 Sept 2000|
|Last amended: Nov 2009|
|Please email Bob McCluskey
|Car No TD/11935|
|Engine No XPAG/TD2/12333|
|Body Type 22381|
|Body No 11301/78948|
There really is only one major caveat in reassembly, and that is that almost all the bolts and studs on the engine itself (but excluding ancillary parts like carburettors, starter motors, dynamos, etc) are metric: mostly 8 x 1 metric fine, but also a few 10 x 1.5. Mostly its not a problem, because things like rocker shaft bolts, for example, are specials, and if you have to replace one you'll probably have to source the correct part from a supplier. But things like sump bolts, and the many brackets, are also metric, but they're machined onto Whitworth/BSF hex stock, so they fit Whitworth/BSF spanners, not metric spanners. This probably accounts for the many stripped threads which have occurred as I've attempted to match 8 x 1 metric with BSF threads.
As you get ready to fit the water pump, don't forget the bracket for the engine steady rod, which bolts onto the front of the engine using two of the bolts for the water pump. Perhaps you can see, in this picture of the engine going in, that I hadn't fitted it yet. Not a major problem, it's not too hard to take the water pump off again, as long as you do it before you fit the fan and radiator. But if you wait till the car is almost assembled, you will find that you become seriously Pissed Off.
And when you fit the engine, this would be a good time to fit the clutch linkage, because if you wait till you've fitted the exhaust system, you'll have to take it off again. The clutch lever is symmetrical, and it doesn't matter which way round it goes; but front lever, which fits onto the side of the sump, is not. It must be fitted with the narrow side closest to the sump, because otherwise there isn't enough room to clear the exhaust system and you'll wear a hole into your expensive new downpipe.
It would also be a good time to fit the speedo cable at the gearbox end, because I found, when I had assembled almost the entire car, that it was very hard to fit it after the floorboards, which meant taking out the seats and floorboards, which in turn meant taking out the steering wheel, and the petrol pump, and diverse other bits. The cable is very flexible, and has a tendency to hang down below the car, which as you can imagine is a trap for bits of debris from the road. I stiffened mine with a bit of heat shrink plastic tube, which, as well as looking good, will, I hope, make it easy to keep bits of crap out of the corrugations in the outer sheath and prevent any further tendency to rust. I also made a little clamp to hold it in place on the firewall.
Fuel System Well I like SU carburretors - nice simple things, with only one huge jet that can never block (contrast this with say Webers, typical of fixed venturi carburretors used on most American and European cars. These have a main jet fitted into an emulsioning tube with an air corrector jet, an idling jet with two holes in an idling jet holder with four holes, an idling mixture adjustment screw and three progression jets, an appropriately named stuffing ball with its stuffing screw, an accelerator pump to cater for sudden demands for acceleration, and about a kilometre of ducts drilled into the body casting, any of which can and do get blocked with the result that the car doesn't work). In contrast this car was driven to its long rest with carburretors that looked like this. I really wouldn't have believed that a carburretor could be so glued up yet still have worked, and I'm sure that it would have worked still, except that the glands were all stiff and dry and the dashpot had no oil. Rebuilding them with new glands, jets and needles was really pretty straightforward, except that all the glands leaked. I had another go with new glands, soaking them in boiling water to soften them first, but the same result. Finally, with yet more new glands, I soaked them in hot oil which I warmed in the microwave, and they worked fine, and it's a good job the glands are so cheap. The big secrets are that the brass gland washers are concave towards the gland washers, top and bottom, and that the langite packing washer especially must be soft enough so that it compresses fully into the bevelled washer, allowing the jet screw to be fully tightened up, so that the copper washers between the jet screw and jet bearing, and between the jet bearing and carburretor body, are fully tightened and can make a good seal.
Before we started the engine, we towed the car around the block to get the oil pump primed and to get oil around the galleries. And having said there is only one caveat, I can now tell you there is at least one more.
The oil pressure bypass port is closed by a metric 10 x 1.5 plug. When I put the engine together I didn't have a 10mm plug, so I covered the hole with masking tape, and when I painted the engine the tape got painted too, and forgotten. So now I am in a position to tell you that a piece of masking tape painted to match the engine colour is not an effective substitute for a 10mm metric plug when it comes to resisting the mighty pressure of an XPAG oil pump.
Having sorted out this minor problem, which dumped a gallon of running-in oil onto the road, finishing in a conspicuous puddle outside our house, we towed the car around the block again to make sure oil was circulating, and then we put the plugs in, turned on the ignition, let in the clutch, and it fired and started on the first compression stroke, and ran for the first time in thirty three years. I drove it back to its garage, and we cracked the champagne.
And although it wasn't registered because it still lacked bumper bars, we hired a trailer and took it to the concours which was celebrating 60 years since TDs were first introduced, where it attracted an appropriate amount of interest.
Oil Pressure Although the car was substantially finished - at least finished enough to drive it in good weather - the oil pressure was disappointingly low. I changed the oil pressure relief valve - no difference. I swapped the oil pressure gauge - no difference. I was puckering myself up for the first serious bit of maintenance - taking the oil pump apart and measuring/reconditioning it, followed by the oil filter bypass valve, and then even taking the sump off and checking the suction filter assembly and associated gasket which are located in the sump itself, which would have meant oil leaks ever after because I hadn't done the lip seal conversion and I don't believe it is possible to assemble the cork rear oil seal correctly without taking the whole engine out - when I thought to trace as far as possible oil pressures throughout the system. Now there is an external pipe supplying the rocker shaft from the lower oil gallery, and the feed to the oil gauge is taken off here. The diagram on Page A2 of the manual (Engine Components) shows the feed being taken off the top of this pipe, but Figure A1 on pA4 suggests that the feed is taken from the bottom of the pipe. All the cars I have seen have the feed coming from the bottom, with a union on the lower banjo, but I thought it made a much neater installation to take the feed from the top, so thats what I did. I inverted the pipe so that the banjo with the union was on the top, and took the feed to the oil pressure gauge from there. So the first step in my diagnostic procedure was easy - simply blank off the feed to the rocker shaft, and run the engine just long enough to check the pressure. Bingo: the gauge registered an acceptable pressure (still a bit lower than I would have wished, but acceptable). Evidently the rockers were taking enough oil flow to lead to a significant pressure drop along the external pipe. Solution: blow through the external pipe, replace it in its correct orientation, and take the oil pressure feed from the bottom. Now an acceptable pressure was registered: still a bit lower than when the rockers were blanked off, indicating a significant pressure drop even along the main gallery, and perhaps also indicating that the oil pump is not capable of supplying demand from the entire engine and therefore requires overhaul but good enough for me to put it off sine die.
more to come...
(Note to self: the new oil filter cartridge is RYCO R2001P (156x773x33)
Good luck, please send me an email