500 Miles in the 3-Cylinder, Two-Stroke Scott-Engined Morgan 4/4
Complete reliability and ability to average very high speed.
The excellent meeting at Cockfosters last July offered us an excuse to test the Scott-engined Morgan 4/4 over a big mileage, whereas previously the car had only been tried round the Saltaire houses, as it were. That visit to the Scott works and brief trial of the car had endeared us to the idea of three cylinders and the two-stroke cycle, as envisaged by Mr. Cull, Scott's chief engineer, and we had no compunction in asking whether we could take the car down to "Cockfosters." Once again Mr. Cull reminded us that it had been hacking all through the war, but that if we wanted to chance it, we could do so. We did. The first hot day of the year saw us off to Bradford in the Austin to collect our unusual mount. On the journey back to Harrogate we took things steadily and looked around. Oil pressure was noted to remain steady at about 8 lb./sq. in., and the water temperature at about 65° C. Had we but known it, these figures were to remain static throughout a hard and hot 500 miles, save just before we put in a quart of XL, when the oil indication fell away a bit on bends. The first surprise was the way in which the Morgan, as engined by Scott; took Humphrey Bank, outside Harrogate, in top gear, whereas many 4-speed moderns call for 2nd speed to negotiate this notorious hump. The engine seemed disinclined to accept much ignition advance, but, as we noted before, ran beautifully evenly and refused to four-stroke even at idling speed. It commenced commendably on the starter and, indeed, behaved just like any well-mannered Otto-cycle unit.
Starting the long run about mid-day, we got on to A1 after a long holdup at Spofforth level-crossing and, stopping for lunch, and for tea in congested Stamford, we were in and across London early that evening. The Morgan hadn't been pushed very hard, but had cruised happily at around 50 m.p.h., and we had already noted how its seemingly unburstable engine would run up to the same speed in 3rd gear and how astonishingly well the little car — three up, and luggage — pulled up long hills on the highest ratio. Incidentally, gearbox and axle are, we understand, standard Morgan 4/4, in which ease the ratios are 5.0, 6.7, 11.95 and 19.3 to 1.
Next morning the H.215 plugs oiled up in London traffic, so the " softer " C.14s were substituted. These not only stood up to low-speed pottering, but also to subsequent prolonged high-speed cruising, so that the 3SM Scott cannot be considered sensitive about plugs. Incidentally, a record cloudburst proved the practicability of the Morgan hood.
So to Cockfosters. Thereafter the real test commenced. Tea was taken in Barnet, and the Morgan pointed north, still three up, at 6.30 p.m. So fast did it run without effort that the plan of arriving home about midnight seemed unworthy of the car, and the driver decided to improve on this schedule. The engine humming grandly, with that exhaust purr which had led the paddock marshals at Cockfosters to query: "Is it blown?" we devoured A1 with the speedometer on the "70" mark along all the straights. Aided by high-geared steering, a low-hung chassis, Morgan coilspring i.f.s., and Girling brakes, an unexpectedly good time was made.
In the first half-hour 20 miles were disposed of, and 7.30 p.m. saw us nearly at Eaton Socon., 46 miles out of Barnet. Another half-hour and another 24 miles were gone, while, as the driver's watch showed 8.30 p.m., we were at Grantham, 98 miles from where we had started. Exactly 24 miles went by in the next 30 minutes' spell, after which we had a quick drink and rapidly consumed some sandwiches. So consistently did the Morgan make for the North that 24 miles again went by in the next half-hour, and in 60 minutes' running time after our self-imposed stop we had covered 40 miles, which included negotiation of the straight, but congested and signal-controlled main road through Doncaster. A curious phenomenon had by now been experienced. As the oil pressure became unsteady, indicating a falling sump level, the engine "pinked" less and became able to accept rather more ignition advance. The solution appears to be that oil is metered into the fuel by means of a special engine-driven combined fuel and oil pump and, as the oil supply drops, less oil enters the combustion spaces and the full anti knock properties of the fuel are temporarily restored. This is borne out by the sudden violent "pinking" which is experienced as the float chamber empties when fuel is exhausted, allowing an excess of oil to be momentarily injected into the engine. This latter happening occurred just beyond Wetherby, after we had left the Great North Road for Harrogate, and so, instead of getting home from Barnet in about four hours, we spent a difficult hour in the dusk, trying to prime a seemingly unprimable pump. However, the fuel tank was found to possess a sensible tap and we were thus able to fill the float chamber, whereupon the engine started easily, and primed its own pump — the C14 plugs were quite happy after the excess-oil trick.
Working things out the next day, we became more and more impressed. Even allowing for the absence of full peace-time traffic, an average of 48 1/2 m.p.h. for three hours' running up the Great North Road calls for a very good car, especially when its capacity is a mere 1,108 c.c. The Scott engine poured out 70 m.p.h. on the "clock"— say, something over 60 — for mile after mile, and not only felt quite unburstable, but didn't overheat or show any sign of distress at all. After a night in the open in heavy rain, a lot of which came through the bonnet, it started straight away on the starter and was driven rapidly back to Saltaire on those same C14 plugs. If ever it didn't want to start an easily-reached cock in the crankcase was opened, the engine spun on the starter to clear out excess fuel and oil, the cock closed and — off she went. The quart of oil went in after some 450 miles — a consumption of 1,000 m.p.g. from a well-worn two-stroke ! Going down, fuel consumption came out at approximately 27 m.p.g., cruising at 40-50 m.p.h. Including London driving, plenty of stopping and starting, and the very hard drive home, the overall consumption of "Pool" was 23 1/2 m.p.g., on an S.U. carburetter adjusted for all-round running and not expressly for economy. As an amusing exercise, before returning the car, we tried a 0-50 acceleration test, using very rough timing, and got 17 sec., including a longish dwell between the change from 2nd into 3rd gear at around 45 m.p.h. In all we covered 510 miles and no water was added throughout.
All of which has convinced us that the 3-cylinder, crankcase-compression two-stroke, 3 SM 78 by 78 mm. Scott engine is a very fine little unit. It develops over 40 b.h.p. at 4,000 r.p.m., but the firm's intention is to obtain more power lower down in the speed range, while offering 30+ b.h.p. at peak speed. The engine will probably be supplied in this form after the war, and it should be excellent for competition work. Those interested, especially from the latter viewpoint, should contact Scott Motors, Ltd., Shipley, Yorks.