MGB Special Tuning p.455 - Suspension Tuning, Road Spring Rates & Competition Parts
MGB Special Tuning data: lightened flywheel part CAHT 86 (16.5 lb), steel timing sprockets, oversteer/understeer factors, fly-off handbrake parts and a competition ignition coil table.
This is page 455 of an MGB competition/special tuning reference. It covers a lightened flywheel (C–AHT 86, 16¾ lb.), steel timing chain sprockets for high-rpm use, and an extensive Suspension Tuning section explaining understeer and oversteer with numbered lists of factors that promote each. A Road Springs section explains spring rate and working load, followed by a table of nine coil and leaf spring part numbers (AHH 6451, AHH 5789, C–AHT 21, AHH 7080, AHH 6453, C–AHH 8343, AHC 31, AHH 7346, C–AHT 20) with rates, working loads, deflections and fitted heights, plus footnotes on MGB Tourer/GT applicability by car number. Anti-roll bar options (9/16 in., 5/8 in., 3/4 in.) with part numbers and installation kit C–AJJ 3306 are listed, along with competition shock absorbers and stiffer valve assemblies. The right column covers Dunlop tyre advice, the Stage 4 distributor (C–BHA 4415, Lucas 40943A), Champion spark plug grades (N–9Y, N3, N62R, N57R), dynamo pulley notes, free-flow exhaust manifold (C–AHH 7103), fly-off hand brake conversion parts, Sebring Perspex headlamp cowls (C–AJJ 3307), and detailed instructions for baffling or deepening the engine oil sump for 18G/18GA and 18GB engines, including modified sump and packing-piece part numbers.
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Frequently asked questions
- What road spring rates were available for the MGB?
- Coil springs: AHH 6451 (348 lb./in., 1030 lb. working load), AHH 5789 and C–AHT 21 (480 lb./in., 1193 lb.). Leaf springs: AHH 7080 (93), AHH 6453 (99), C–AHH 8343 (100), AHC 31 (99), AHH 7346 (124), and C–AHT 20 (124 lb./in.).
- What anti-roll bars are listed for the MGB and what part numbers?
- 9/16 in. (14·3 mm.) AHH 7329 (2 off bearing AHH 6541 also required), 5/8 in. (15·9 mm.) C–AHH 7593 (includes bearings), and 3/4 in. (18 mm.) C–AHH 7924 (includes bearings and locators). Installation kit C–AJJ 3306 is required if the car had no anti-roll bar previously.
- What factors tend towards understeer on the MGB?
- Stiffer front springs; fitting a front anti-roll bar or increasing its diameter; lowering the front suspension (premature contact of front bump stops); increasing rear tyre pressure above recommended figures; decreasing front tyre pressures (must equal at least recommended figures).
- What spark plugs are recommended for competition MGB use?
- The standard plug was Champion N5, now N–9Y. For competition, N3 is recommended; if a colder grade is needed, use N62R or the colder N57R.
- What is the Stage 4 distributor for the MGB?
- Part No. C–BHA 4415 (Lucas 40943A with 32-oz. spring). It has no vacuum advance; automatic advance is 24° crankshaft degrees, giving 30° maximum with a 6° B.T.D.C. static setting.
- How is the fly-off hand brake conversion done?
- Fit pawl C–AHH 7223 and operating rod C–AHH 7222 for early cars, or C–AHC 551 from Car No. 115596 and on all GHN/D–4 cars.
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