The Mazda R100 was first seen in Japan in 1967 at the Tokyo motor show, and was originally called the RX85. Subsequently it was introduced in Japan in April 1969 (?), where
it was called the Familia Presto Rotary Coupe, and sold in overseas
markets as the R100.
There was also a 4 door version sold from April 1970 known as the Familia
The "original shape" of the R100 was sold April 1969 until 1972.
At this time the shape was changed to the yellow car pictured here (model code
FA3TS), I have heard varying reports that
the Familia Presto Rotary Coupe was sold in Japan until 1973 - but I have never
been able to ascertain if this particular shape was available with a rotary.
R100 coupes and sedans were powered by a 10A twin distributor engine, that
developed 100 BHP and 98 lb-ft of torque.
All markets except the USA used the 0820, (detuned Cosmo sport 0813).
The USA models (sold April 1969-1972) used the revised 3877 with thermal
reactor for lower emissions.
Although I sold it in early 1999, My 1300 was a 1973 model
(I don't know the month exactly because the 'Compliance plate' was removed, but is is the first of the FA3TS models.)
Being a 1973 it was exempt from the pollution equipment required on later
years in Australia.
These cars were only sold in Australia with and 87 BHP 1300cc OHC 4 cylinder
engine, mine had a 13B originally fitted back in 1987 or 1988. (As far
as I am aware this was one of, if not the, first rotary powered 1300 in
Australia. This has since changed with there being several dozen of them
around, as they are cheap and light (around 800kg) and go very fast with
a modified rotary). The car went through two further owners until it got
to me in late 1990. After some minor repairs it was registered in June
The car was fitted with:
13B RX4 street port engine
4 barrell Nikki carburettor w/mechanical secondarys
RX4 Distributor (points ignition)
Enormous headers (2.5 inch from the port collecting into 3 inch)
RX4 automatic (the previous owner put this in due to problems with the
clutch in a manual transmission
RX3 'long nose' differential and brakes and stock (1300) leaf springs
RX3 brake booster
RX4 front disc calipers
RX3 strut with RX3 disc and RX2 strut insert (shock absorber), plus RX2
top mount and RX3 spring
Stock steering components and lower suspension arm
Stock front swaybar
Transmission tunnel needed to be enlarged by about 2 inches. Not mandatory
but makes things a whole lot easier - use a 929/RX4 floorpan cutout.
RX4 radiator and early RX2 oil cooler
RX2 (early) air cleaner
As far as I am aware, the front engine mounts were on
a small cross member that is from an RX4. This simply needs the mounting
holes enlarged slightly and is bolted on under the stock front swaybar
mounts. The original 1300 4 cylinder engine mounts are on a cross member
that passes underneath the engine. These need to be cut/ground off. Also,
the stock 13B oil pan needs to be reversed (front to back). This entails
re-drilling the holes in the pan and fabricating a longer oil pickup.
See the diagram above for a picture of this.
(NOTE: If you ever build one of these cars, use an early
RX2 radiator and oil cooler, because they bolt virtually straight in. The
RX4 radiator is a hassle)
At the end of 1991 the motor was blowing a lot of smoke, so I decided to
have it rebuilt. I helped my mechanic freind build it.
I got a hold of a 1985 13B engine for $150, which was locked up.
When this was dismantled it was apparent that the engine was in the rain and filled
with water, everything was rusted solid. However,
it had only done about 15-20,000 km and once it was cleaned up it was like
The engine was rebuilt with all new seals (except the oil control rings
- which are very expensive for what you get), and new rotor housings. The
entire rebuild cost about $Aus 2000.
It was built using a very large street port on the secondary and a medium
sized port primary. This was done for better low speed torque due to the
automatic transmission. Apart from replacing the differential center with
an RX2 4.1:1 unit and a 1st generation RX7 tailshaft, not much else has been done
to the car apart from replacing worn out bit and peices.
Performance was good, but could be better (Never officially
timed, but 1/4 mile in about 15?). I think the major problems are the carburettor
being too small and the automatic transmission.
Unfortunately when the car never really lived up to it's potential as I did not
have the facilities to fix it properly. It had an annoying drivetrain vibration
that could not be gotten rid of, handled badly on anything but a smooth road (I
span the car around once. Luckily it was a wide street and I was only going 40
km/h). It was noisy and hot. I bought a 13B turbo engine to put into it but I
decided that it would have been too dangerous.
In the end I got sick of the car and sold it along with all the spares and I
bought a much newer car (nothing of particular interest to readers of this
site). I am vaguely considering buying a JC Cosmo (20B motor), but the finances
could prove the downfall of that idea.
The person that bought the car was going to transplant some of the key parts
into a 1300 Wagon, possibly including the 13B turbo engine I sold with the car.
He was going to get back to me but I have not heard from him.
"The Hitman's" 12A powered
Matt 'The Hitman' (from Sydney, Australia)
has a 1976 Mazda 1300 Wagon with a 12A fuel injected engine. He has a website
with more information about this car. See Links section.
Here are a few pictures from his site:
Matt's engine fitting procedure was slightly different
to mine. Here it is:
1. Stock engine cross-member. Mounts are cut off and RX-4 type angled
section welded in. You can use an R100 cross-member , but they are very
rare and expensive.
2. RX-2 Engine mounts. VERY RARE.. you cannot even buy these new from Mazda.
Believe me , I have tried !
3. I used an RX-7 Series 1 5-speed gearbox , with a 626 extention housing.
As you mention, the trans-tunnel needs enlarging. I split mine down the
middle and welded in a 3" strip.
4. An 808 wagon tailshaft went straight up.
5. Stock diff. My engine pumps out a meaty 123KW at the wheels ( about
165HP ) and my stock diff has never even appeared to have problems. It's
amazing how long they last when you don't do burnouts :-)
6. I have an Alloy RX-3 radiator in my car. It fitted right in after removing
excess brackets. the Support brackets on these radiators can be prised
off for easy grinding. It runs pretty cool , and even handles the towing
I do with the car. An R100 Alloy radiator bolts right in but is not up
to the task of a 12A or larger. I tried already....
7. A Series 3 RX-7 Water Cooled Oil Cooler is used for its simplicity.
If you intend to really push your car use a normal air cooled one, but
I have found my type to handle it OK
(Craig's Note - Series 1 RX7 = 1979/1980; Series 3 RX7 = 1984/1985)
I have seen these cars fitted with both 12A and 13B turbo
engines. In both cases the turbo needs to be re-located into a space where
it fits. One of these cars fitted with a good 13B turbo engine would have
as good or better power to weight ratio of just about anything on the road.
Personally I think this model of car would be dangerous with that much power.
Further reading and acknowledgements:
* Special thanks to The Hitman for infomation about his 1300 wagon.
* I have not been able to find any other information about the rotary powered
variants of this model.
Other relevant reading at Craig's Rotary Page (Please go via the INDEX
* No futher reccomended reading at this site.
Other relevant sites on the Internet (Please go via the LINKS
* The Hitman's site (Pics and info about his 1300 wagon).
* There may be further reading at Mazda Japan's history site.
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