MGB GHN5/GHD5 18V Engine General Data - Valve, Starter & Spring Specs

This is page 65 of an MGB workshop manual, titled 'General Data (GHN5/GHD5 Cars, 18V type Engine)'. It provides supplementary specifications applicable to GHN5 (Tourer) and GHD5 (GT) series MGBs from Car No. 258001 fitted with the 18V engine, to be used in conjunction with earlier specification pages. Engine type codes are listed by transmission: 18V 581F–581Y (synchromesh gearbox), 18V 582F–582Y (synchromesh with overdrive), and 18V 583F–583Y (automatic transmission). Inlet valve data includes a 45½° seat angle, head diameter 1.625–1.630 in., stem diameter 0.3429–0.3434 in., and stem-to-guide clearance 0.0008–0.0018 in. Valve spring specs give free length 1.92 in., fitted length 1.44 in., and loads of 82 lb (fitted) and 142 lb (top of lift). Electrical data covers the Lucas 2M100 pre-engaged starter motor: brush spring tension 36 oz, minimum brush length ⅜ in., commutator thickness 0.140 in. minimum, lock torque 14.4 lb ft with 463 amps, torque at 1,000 rpm of 7.3 lb ft with 300 amps, light running current 40 amps at 6,000 rpm, armature end-float 0.010 in., and solenoid winding resistances. Front suspension spring data (from Car Nos. 293446 Tourer / 296196 GT) lists coil diameter, free height, static lengths under load, and number of free coils for each body style.