Mazda R100 History from Down-Under

Story by David Morris of


Testing the waters

The most disarming feature of the R-100 was its ordinariness. 30+ years ago the Australian public simply wasn’t able to fathom the sort of performance this small car was offering. Initially, Mazda Australia considered the little car to be a technical adventure, which broke new ground thanks to the uniqueness of its revolutionary rotary engine. In reality the R-100 was able to enjoy an above average level of media attention which helped its sales along well enough to establish its marketing success in Mazda Australia history.

Mazda Japan first showed the car at the 1967 Tokyo motor show along with the newly released L10 Cosmo. Badged the RX-85 (Rotary experimental) It was based on the 1200 coupe which had been on sale for a year prior. However, in place of the tiny 4 cylinder was a revised 10A similar to the 0813 version found in the Cosmo. Code named the 0820, its differences with the Cosmo were manly in cost cutting & making the engine a volume production reality for the export market. Rated at 100 bhp, a change from cast aluminium side plates to cast iron where going to save considerably  as was a chrome steel shaft in place of the chrome molly design. After all, there was a heavy development penalty to pay for & Mazda wanted the money back as soon as they could.

In July 1968, the Familia rotary coupe was released into the Japan streets. Immediately, Mazda Australia imported several for evaluation purposes & gave the car a thumbs up releasing it onto an unsuspecting Aussie public 11 months later in June 1969. When our motoring journalists got hold of the test models they reported not wanting to return them such was the enthusiasm & fascination for the engine. Mazda Japan where quoting a 16.4 ET for the car but the best time reported here was a 17.8@74mph. Perhaps they where not yet used to the rotary engine character, or perhaps the Japanese factory drivers where a little optimistic. Inevitably, the little Mazda white washed all opposition in its class & had to move upscale to find bigger fish. Remembering that back in 1969, a car from the R-100 class was pushing to crack a 21second ET with a tail wind. Comparison stories against the 6 cylinder Monaro, Pacer & Capri where the only way to find equal competition.

As for the racing, Mazda went into the field with blind ambition. They where after all very proud of there new exportable rotary engine. In July 1969, Mazda entered two factory prepared R-100 racers in the famous SPA-frankcorchamps 24hr. The SPA R-100’s ran with their Cosmo type all aluminium 10A engines. By this stage Mazda Peripheral Port engines where capable of 200+ hp but the SPA engines where held to 187hp for endurance reasons. Still the R-100’s put in a giant killing performance to finish a very respectable 5th & 6th place overall, behind the factory backed Porsche 911’s. For the 1970 SPA an R-100 again came 5th outright.

Locally R-100’s where tried at Bathurst & a few touring car rounds but didn’t do all that well. At this stage unfortunately, only the factory understood all the performance secrets. Officially, all was not lost for the Aussie privateer. In late 1970, a series of sports kits where offered by the factory in 5 different grades. Starting at a 10% power upgrade A1 kit through to a 100% power upgrade B2 kit. The A grade kits consisted of varies bolt on goodies such as carbies, manifolds & exhausts. Whilst the B grade kits required engine porting such as the recently developed bridge port.

All kit variations had suspension & brake mods available aswell. Potential buyers would have broken into a sweat when they found the pricing of the upgrade kits. Whilst the A1 kit drained your wallet of only $290 (10% sale price of car), the B2 kit almost doubled the cars value at $2500.Ouch ! Nobody is sure if any of these kits wherever sold in Australia as many dealers can’t recall ever hearing about them. Within another 12 months the R-100 was of the new-car sales list with the sports upgrade kits fading into memory.

In April 1971, Mazda’s competition division was ordered to scale down activity due to impending Japanese emissions & safety regulations. Whilst the companies engineering resources where to concentrate on the new laws they still lent technical assistance & support. What this meant to the man in the Mazda showroom was no more over the counter go-fast goodies for future rotary models. Or at least for the foreseeable future...

...For the Japanese market an April 1970 release of the 4 door Familia rotary SS gave buyers the choice the Japanese family man wanted. Now the Familia was to make its mark as a mainstream vehicle matching the newly released Capella rotary sedan & coupe offering. In an attempt to update the Familia into the 70’s, a marketing name change around 1972 to Familia Presto rotary with minor updates held the cars for the remainder of its lifespan.

When the first imports started arriving down under in mid 69, early stock was noted  to be of 1968 vintage. Apparently this was due to lhd versions going down the line at the time in preparation for the (more important) U.S release soon after. This reduced the numbers needed for our initial sale requirements thus the earlier versions. Mixed amongst the first shipments were a few with the 1200 piston versions 8.8-gallon fuel tank. Mazda recognized this fault straight away & took steps to ensure no further tiny tanks where mounted in the rotary coupes. After all with an average fuel economy of 23 mpg, the 13.5 gallon (60litres) tank was a definite part of its motoring life.

On sale for just 2.5 years down under, a lot happened to the car in that time. Whilst its piston powered counterparts remained unchanged month after month the R-100 went through a great deal of mechanical upgrades during its production cycle. Factors behind this must have been the factories still unfamiliar direction with their rotary powered vehicles as they struggled to find their feet. Casting back to around 1969, if a new idea or design for the car was thought of, then Mazda simply placed it on the R-100 immediately. By the 80’s, manufacturers had learnt it was more cost effective to wait until the next update, e.g.....series-1 to series-2 RX-7.

The R-100 still found itself going through a major update around the mid 1970 era. Again showing the learning stages of the company at the time. Some series-1 cars will have series-2 parts & visa versa. Production uniformity didn’t really start until the RX-2 series. It is also well known that Mazda did the R-100 only as an interim “test the water” model before the official rotary sedan was developed (RX-2)

As for the differences from the series-1 to the series-2.... The major factor you will find is that the series-1 is mechanically the same as the piston powered 1200 version where the series-2 was given unique suspension and brakes when compared to its piston powered 1300 model. When looking for a genuine R-100 the VIN prefix will be M10A. The piston powered 1200 version will be STA with the 1300 starting with STB. Notable rotary differences are.........

Rotary grill is painted black in colour with a small rotor emblem in the centre. The bonnet has a raised dummy vented section in the centre. The well known taillights will be round. Brakes are 9.6” Girlocks hence the need for 14” wheels.  The interior differences are obvious. If you can’t imagine an aircraft type cockpit then you are sitting in the piston version.

When Mazda first offered the car for sale down under the starting price was $2790 & only inflated by another $100 when its showroom days where over. Today an original condition R-100 will be around the $10,000 & rising each year. With modified versions of the car getting around as genuine & piston converted racers, it’s very difficult to find an original example these days. Back in there early days Mazda Australia failed to catalog records of vehicles sales as a lot of the Australian distribution was through importing houses aswell as Mazda. Thus the exact numbers of cars sold down under is unavailable. After questioning some of the earlier Mazda people a figure of 1500 to 2000 sales is the general consensus. A respectable figure for Mazda Australia’s sales at the time. Remembering that this was a technical adventure

In December 1971, the R-100 was dropped from the Aussie sales lists, the RX-2 had been in the showrooms for over 12 months & was only $200 more expensive. The Familia rotary was kept in Japan until the end of 1973 for a total production of 95,800 units. By then Mazda where selling the RX-2, RX-3 & RX-4 leaving the R-100 looking outdated & under performing. Its purpose was achieved & Mazda had gained the export reputation they wanted without the cost of an originally designed rotary model.


Fast fax

Vehicle Familia rotary coupe / R-100
Engine 10A twin distributor.
Capacity 491cc x 2
Compression 9.4 - 1
Power 100 bhp    @ 7000rpm
Torque 98 lb/ft @ 4000rpm
Gearbox 4 speed floor mount
Differential 4.0 - 1


Weight 805 kg (1775lb)
Steering Recirculating ball, variable ratio
Wheelbase 2.26m  ( 7’  5” )
Length 3.83m  (12’  7”)
Width 1.49m  (  4’11”)
Height 1.34m  (  4’  5”)
Weight distribution 56.5 = front - 43.5 = rear
Fuel tank 60 Lt  (13.5Gal)
Wheels & tyres 14 x 4.5 - 145 series tyres


Top speed 170 kph
0 - 100 kph 13.5 sec.
400m 17.8@74
Economy 23mpg (average)

David Morris