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| P Type Profile |
Not long after the J series cars were put on sale, the MG Car Company realised that the two-bearing four-cylinder engine was nearing the end of its development life. The steady request for replacing broken crankshafts, forced the Company to issue a Service Sheet, specifically pointing out that J crankshafts should not be re-ground, as this was likely to induce a fracture.
During 1933, the six-cylinder Magnette engine had demonstrated that high crankshaft speeds could be maintained, even on touring engines, without undue stress so a four-cylinder version was designed, essentially removing cylinders four and five from the block and retaining a single centre main bearing. The camshaft was also strengthened in line with the six-cylinder engine design. The resulting engine, still at 847cc was very smooth running and was fitted to a chassis, one and a half inches longer than the J type with side rails made from thicker steel and slightly deeper in section. The 3' 6" front and rear track was retained as were the 12" drum brakes, cable operated, as fitted to the later F types, J3 and J4. The new car was designated P type and came in two body styles. The two-seat body was similar in style to the later J2 with flowing wings and a short running board but an inch and a half wider across the seats. The four-seat body, however, was quite different with enclosed petrol tank at the back and very pleasing lines. The only down side to the whole car was its Wolseley four-speed gearbox which was fitted with low ratio 1st and 2nd gears, leaving a wide gap to third but the new ‘box was favoured by trialists! No saloon version was offered but an attractive Airline Coupé body was produced in small numbers. The same Airline body was available on an N chassis and it has to be said that the six-cylinder chassis carried the Airline body better than the P on account of the wider track. Performance of the new P type was not as good as the older J as the extra weight of body and engine took its toll. To rectify this, later in 1935, a larger engine version of the P was produced with the bore increased to 60mm giving 939cc and the result certainly restored some of the performance. This new version was designated PB and the earlier P types became known as PAs. Another welcome change on the PB was a reversion to the closer gearbox ratios as found on the J types. For customers wanting even more power, MG sanctioned the use of supercharging the P engine and, providing the boost pressure did not exceed 6 psi, fitting one did not invalidate the guarantee.
The P types were the last of the OHC Midgets. In 1936, after William Morris sold MG to Morris Motors, the design team at Abingdon was disbanded and all subsequent MG products were designed at Cowley, the Morris main works. While many regret the passing of the OHC engines it should be noted that rationalisation and the forced use of standard Morris parts ensured MGs survival, otherwise it was quite likely the MG factory would have ceased to exist by 1946.
P type specification
Wheelbase
Track
Steering - early PA
Steering - late PA PB
Brakes
Wheels
Tyres
Chassis weight
Weight of Complete Car:-
two-seat
four-seat |
7′ 3½″ (2.22m)
3′ 6″ (1.07m)
Marles Weller
Bishop Cam
12″ drums, cable operated
2.50″ x 19″ side laced wire, Rudge type
4.00″ x 19″
10 cwts 84 lbs (546 kg)
14 cwt 28 lbs (724 kg)
14 cwt 84 lbs (749.3 kg) |
Bore - PA
Bore - PB
Stroke
Capacity - PA
Capacity - PB
Power output - PA
Power output - PB
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57 mm
60 mm
83 mm
847 cc
939 cc
36 bhp
43 bhp |
PA 31st January 1934
PB 22nd July 1935 |
to 22nd July 1935
to 13th February 1936
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| Cars Produced: |
Total 2500 |
PA two-seat sports
PA four-seat
PA Airline Coupé
PB two-seat
PB four-seat
PB Airline Coupé
Chassis only |
1396
498
28
408
99
14
57 |
P type pictures:
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