Every figure below is quoted from a published source, and that source is named beside it. Where two reputable sources disagree, both are given and the disagreement is explained. Where no reliable published figure exists, the entry says so instead of offering a plausible number. On a seventy-year-old engine that has almost certainly been rebuilt at least once, your own Workshop Manual and your own measurements outrank any web page — including this one.
How to use these figures
The XPAG changed repeatedly through production, and the changes are keyed to engine numbers rather than model years. The tappet clearance and the spark plug both change part-way through TD production, so the useful question is never “what does a TD take?” but “what does engine number this take?” Read the prefix and number from the block before you set anything, using the chassis and engine number guide.
The XPEG of the TF 1500 is a bored-out XPAG. The published data sheets for the TF do not separate the 1,250 cc and 1,466 cc cars, so treat the ignition and clearance figures below as TF figures generally, and anything dimensional — bore, pistons, gaskets — as strictly XPEG-specific.
Nothing here covers the TA’s MPJG engine. Despite a long search, no transcribed manual data page for the MPJG could be found that would let these figures be quoted honestly, so the TA is deliberately absent rather than guessed at.
Tappet clearances
Set hot, engine at running temperature, with the rocker on the fully closed valve. The change at engine 24116 is a real factory change and matters more than the badge on the car.
| Item | Figure | Applies to | Source |
|---|---|---|---|
| Tappet clearance, inlet and exhaust (hot) | 0.019 in (0.48 mm) | XPAG/TD up to engine 24115 — TC and early TD | Workshop Manual general data; Moss TC and TD sheets |
| Tappet clearance, inlet and exhaust (hot) | 0.012 in (0.30 mm) | From engine 24116 — late TD and TF | Workshop Manual general data; Moss TD and TF sheets |
| Tappet clearance, cold | No factory cold figure found | All | The manual quotes the clearance hot. Set it hot; do not convert a hot figure to a cold one by arithmetic. |
Ignition — timing, points and firing order
| Item | Figure | Applies to | Source |
|---|---|---|---|
| Firing order | 1–3–4–2 | All XPAG and XPEG | Workshop Manual; Moss TC, TD and TF sheets agree |
| Static ignition timing | TDC, distributor at full retard | TC, TD, TF | Workshop Manual general data; Moss sheets agree |
| Total automatic (centrifugal) advance | 32° at the crankshaft | TD | Workshop Manual general data |
| Contact breaker (points) gap | 0.010–0.012 in (first distributor type) | TC and early TD | Workshop Manual; Moss TC and TD sheets |
| Contact breaker (points) gap | 0.014–0.016 in (second distributor type) | Later cars, and TF per Moss | Workshop Manual; Moss TF sheet |
| Spark plug thread | 14 mm | Stated for the early TD plug; the family standard | Workshop Manual general data |
The static setting is TDC with the distributor fully retarded — which is why a worn or swapped distributor throws everything out. If your unit is not the original Lucas one, its advance curve is not the one these figures assume; the ignition timing guide and how a distributor works explain what to do about that.
Spark plugs and gaps
| Item | Figure | Applies to | Source |
|---|---|---|---|
| TD before engine 22735 | Champion L.10S (alternatives KLG E.80, Lodge HN/HNP), gap 0.020–0.022 in | Workshop Manual figures | Workshop Manual general data |
| TD from engine 22735 | Champion NA.8, gap 0.020–0.022 in | Workshop Manual figures | Workshop Manual general data |
| TC | Champion L-85, gap 0.020–0.022 in | Moss specification sheet | Moss TC sheet |
| TD (Moss listing) | Champion L-86 to engine 22734, then N5, gap 0.025 in | Moss specification sheet — conflicts with the manual, see below | Moss TD sheet |
| TF | Champion N5, gap 0.025 in | Moss specification sheet | Moss TF sheet |
The plug disagreement, stated plainly
For the TD, the transcribed Workshop Manual data gives Champion L.10S then NA.8 with a 0.020–0.022 in gap, while Moss’s specification sheet gives Champion L-86 then N5 with a 0.025 in gap. Both are respectable sources and they do not agree. The manual is the original specification; the supplier listing reflects what is available and commonly fitted now, and a wider gap suits a healthy modern coil. Pick the source you are following and stay with it rather than mixing the plug from one and the gap from the other. Our own spark plug guide works to 0.025 in with points ignition for that reason.
Torque figures
These are the XPAG/XPEG figures published by the MG TABC club library, cross-checked against the transcribed manual where it gives a comparable value.
| Item | Figure | Applies to | Source |
|---|---|---|---|
| Cylinder head nuts | 50 lb ft | XPAG and XPEG | MG TABC torque page; Workshop Manual (600 lb in) agrees |
| Connecting rod (big-end) bolts | 25 lb ft | XPAG and XPEG | MG TABC torque page; the manual's 320 lb in (≈26.7 lb ft, to the next split-pin hole) is consistent |
| Main bearing cap nuts | 63 lb ft | XPAG and XPEG | MG TABC torque page. The transcribed manual figure here is plainly corrupt — do not use it. See the caveat below. |
| Flywheel to crankshaft bolts | 19 lb ft | XPAG and XPEG | MG TABC torque page |
| Rocker tower bolts, 8 mm | 16 lb ft | XPAG and XPEG | MG TABC torque page |
| Rocker tower bolts, 10 mm | 43 lb ft | XPAG and XPEG | MG TABC torque page |
| Gudgeon pin clamp bolt | 25 lb ft | XPAG and XPEG | MG TABC torque page. The printed manual figure of 400 lb in is a known factory error — the clamp bolt shares the 8 mm thread of the big-end bolt. |
| Manifold nuts | No figure published in either source | — | Not verifiable — tighten evenly and progressively, or use your own manual |
Two figures you should not take from a transcription
The transcribed manual page carries an obviously corrupt main-bearing figure — a value in the region of six pound-feet, which would be dangerous on a main cap — and a gudgeon pin clamp bolt figure of 400 lb in that the reference sites themselves flag as a factory error for an 8 mm thread. Both are the sort of number that a reprint or an OCR pass mangles. For anything holding the bottom end together, work from a clean paper or PDF copy of the Workshop Manual and, if the figures still look odd, ask the club before you pull the wrench.
Fluid capacities
Capacities are a guide to what to buy, never a substitute for the dipstick and the level plug. Note that the TF column is quoted in US measure because that is how the source sheet gives it — do not read those numbers as imperial.
| Item | TC | TD | TF (US measure) |
|---|---|---|---|
| Sump (engine oil) | 1⅛ imp gal (9 imp pints) | 9 imp pints (5.1 l) to engine 14948, then 10½ imp pints (5.96 l) | 12.6 US pints |
| Gearbox (non-overdrive) | 1½ imp pints | 1¼ imp pints | 1.5 US pints |
| Rear axle | Not listed | 2¼ imp pints | Not listed |
| Cooling system | 14 imp pints (1¾ imp gal) | 12 imp pints | 12.25 US pints |
| Fuel tank | 13½ imp gal | 12½ imp gal | 14.4 US gal |
One conflict worth knowing: the Workshop Manual records a sump change from 9 to 10½ imperial pints at engine 14948, while the supplier sheet lists only the earlier 9-pint figure. Fill to the dipstick and the argument goes away. Grades and the practical routine are in the oil and filter, gearbox oil and rear axle oil guides.
Tyre sizes and pressures
| Item | Figure | Applies to | Source |
|---|---|---|---|
| TC — tyre size and pressures | 4.50-19; front 24 psi, rear 26 psi (cold) | TC | Moss TC sheet |
| TD — tyre size and pressure | 5.50-15 (165×15 modern equivalent); 18 psi (1.27 kg/cm²) | TD — the manual gives a single figure, not a front/rear split | Workshop Manual general data; size also on the Moss TD sheet |
| TF — tyre size | 5.50-15 (165×15 modern equivalent); pressures not published on the sheet | TF | Moss TF sheet |
Pressures are the weakest published area of the lot. The manual gives the TD a single 18 psi figure with no front/rear split, and the supplier sheets leave the TD and TF pressure fields blank altogether. If you are running modern radials in place of the original crossplies, the original figure is not transferable anyway — ask your tyre supplier for a recommendation against the actual tyre and the car’s weight.
Oil pressure and thermostat
| Item | Figure | Applies to | Source |
|---|---|---|---|
| Oil pressure, normal running | 40–45 psi (2.8–3.2 kg/cm²) | XPAG per the Workshop Manual | Workshop Manual general data |
| Oil pressure relief valve setting | 50–70 psi (3.5–5.0 kg/cm²) | XPAG | Workshop Manual general data. Moss's sheets give 50–70 psi as 'normal' — that is the relief-valve figure, not running pressure. |
| Oil pressure at idle | No published figure | — | Not verifiable — the supplier sheets leave the field blank |
| Thermostat opening temperature | No published figure found | — | Not verifiable from the sources above. Modern replacements are commonly sold at fixed ratings; ask the club registrar what your car should have. |
The 50–70 psi that circulates as the XPAG’s “normal” oil pressure is the relief valve setting. The manual’s running figure is 40–45 psi, and a warm engine sitting there is doing what it should. Falling pressure on a hot engine is a bearing and pump question, not a gauge question — start with the symptom-led diagnostics.
What this page does not give you
Naming the gaps is more use than filling them. As of this revision, no reliable published figure could be confirmed for: cold tappet clearances; manifold nut torque; idle oil pressure; thermostat opening temperature; and any of the above for the TA’s MPJG engine. Nor is there a separate XPEG clearance or plug specification distinct from the TF generally.
If you hold a Workshop Manual page or a club technical bulletin that settles any of these — particularly the MPJG data and the main-bearing torque — please write in. I will add it with the source named, and credit it.
Sources
M.G. TD/TF Workshop Manual, General Data (transcribed, MG Car Club pages)
Factory manual, transcribed
MG TABC — XPAG/XPEG torque figures library page
Club reference
Moss Motors — MG TC specifications
Supplier specification sheet
Moss Motors — MG TD specifications
Supplier specification sheet
Moss Motors — MG TF specifications
Supplier specification sheet
Transcriptions and supplier sheets are convenient, not authoritative. The paper Workshop Manual for your model, and the technical registrar of the MG Car Club T Register or the New England MG T Register, are the last word.