Most major Japanese manufacturers had a small minibus in their lineup in the 1960s and 70’s; Toyota’s Coaster, Nissan’s Civilian, Mitsubishi’s Rosa, and Isuzu’s Journey are good examples. These were small forward-control buses built on a truck chassis – front engined – seating anywhere from 22 – 30 passengers. Mazda had one also, the Parkway, but could boast its bus had something the others didn’t…
The Parkway Rotary 22/26 was fairly similar to these other models – it was front engined, was the same size, and seated either 22 or 26 passengers. What made the Parkway unique was its engine – a version of Mazda’s 13B rotary.
Toyota 2B 3.1 Liter Four Cylinder Diesel
Other minibuses used mostly four and six cylinder diesel engines, in sizes from 3.0 to 4.0 liters, to maximize torque and fuel efficiency. The Toyota 2B four cylinder diesel being a good example; 3.1 liters pushing out 90 hp and 160 ft lbs of torque.
For the Parkway, the two-rotor gas 13B put out 135 hp at 6500 rpm and 132 ft lbs of torque at 4000 rpm. Like most pre-fuel injection rotaries, a big Hitachi four-barrel carburetor (missing in the photo above) fed gas to the rotor cavity.
Those who have owned rotaries know they are great engines, but have two big shortfalls; they’re thirsty and they have a dearth of low end torque. One has to wonder why Mazda would offer the 13B rotary in this application, when they already had perfectly acceptable, more fuel efficient gas and diesel engine options. I couldn’t find an official answer but I’ll hazard a guess – by the early to mid-70’s, Mazda had built a strong, enviable reputation as a purveyor of rotary engines – and perhaps they wanted to market themselves as “having a rotary in every model”. The other reason being that maybe they assumed there were some efficiencies in scale with regards to engine production.
There were advantages for using a rotary in a bus. Rotaries are very compact, and the intrusion into the interior, and subsequent engine cover “hump” between the driver and passenger, was much smaller than with ordinary engines. They are also much smoother and less noisy (forward of the muffler), resulting in a quieter interior.
But those pluses likely couldn’t overshadow the poor gas mileage and lack of torque. Perhaps this was why the rotary engined Parkway was manufactured for only two years – with just forty-four made.
I’m still glad Mazda gave it a go – they created a very unique bus. Four currently survive in Japan with one on display at the Mazda Factory Museum in Hiroshima.
Maybe some intrepid soul will pull this one out of the shed and get it back on the road too…