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The Mazda rotary engine is a good match for Datsun 1200 -- it is light and compact. It makes more power than a piston engine of the same size and weight. The engine weight is down low so it doesn't interfere with good handling.
Contents |
Performance
Also See: Mazda Wankel engineᵂ
Typical engine power in stock form:
- 12A: 100-130 HP, 100-115 lb. ft. torque
- 13B EFI: 135 hp, 133 lb. ft. torque
- 13B-Turbo (1987-1991 "Turbo II"): 185-200 HP
- 13B-REW (twin turbo) 255-280 hp
- 13B-MSP (RX-8) 237 hp USA, 191-250 hp world
Quarter Mile acceleration performance ranges from quick to insanely quick. With a totally stock rotary engine you won't be wanting for power.
- 19.8 secs at 65 mph: Stock Datsun 1200 piston engine (baseline)
- 16.1 at 90mph: bone stock 12A rotary engine tuned by ear
- Ange's 13.7 second 12A bridgeport
- JVML's 8.1 second 13B twin turbo
Rotor Power
Overview
- Modify crossmember & fabricate new mounts
- Oil pan
- Bigger tunnel to fit the Mazda transmission
- Custom gearbox mount
- Custom exhaust
- Custom turbo manifolds (for 13BT)
- Larger radiator (suitable for the HP of the engine)
- Tailshaft, custom
- Shifter relocation forward
- Differential suitable for torque of engine
13BT in Sunny B310
Discussions
- Rotary conversion advice
- Project: SUNNY COUPE GX (13B COSMO TURBO)
- Rota 1200
- Rotary 1200 Coupe, 6 Speed
- Datsun 1000 Rotary
Engine
The Mazda rotary comes in two common sizes: 12A and 13B. In Australia, choose a 10A for street legal swaps. Everyone else, choose the 13B. There are less common versions, the old 10A and the ultra-rare and expensive 20B triple rotor.
Custom Single Rotor rotary engine (pictured in Datsun 1000)
12A (1146 cc, equivalent to 2.4 liter piston engine)
Mazda 13B (1308 cc, equivalent to 2.6 liter piston engine) carbureted
13B Fuel Injected
Mazda 13B Turbo rotary engine
Mazda 13B Turbo Factory EFI
13B Turbo with factory intercooler
20B triple rotor
13B carbureted
Engine Mounts
Cut out about 10mm out of the standard 1200 crossmember and brace it. This allows the engine to sit low enough.
Front Mount
Most swappers use the front-mount engine case.
Fit at front of engine bay
Mount circled in green. Original engine mounts are removed (circled in red)
Topic - Weld or bolt new custom-made brackets to the front of the chassis rails (bolt to bumper support bolts)
If your rotary doesn't have a front-mount case, you can retro-fit it using a 12A timing cover (which fits on 13B).
Side Mount
Mad Dat 13BT Fitting Kit allows the newer-type rotary engine side mount, their crossmember curves down so the top of the cross member is lower.
Datrotor fabricated these for a 13B:
Mad Dat
13BT into 1200 Engine Fitting Kit Product No - FK13B1200 ($1200 in 2012)
Includes custom engine crossmember, custom 13B engine brackets, rubber mounts, gearbox cross member (2 part) and gearbox rubber mount. Adjustable 22mm sway bar includes mounting bushes & saddles and link ends. Suits RX-7 S4 (1985 - 1988) and RX-7 S5 (1989 - 1991) as is. Engine cross member comes with engineers report.
Motor Plate
For racing a hard-mounted motor plate can be used. Not recommended for a street car as it transmit vibration directly to the body.
Oil Pan
Use the Moroso oil pan for Datsun 1200.
Transmission
Use the transmission that comes with the rotary engine (the Mazda transmission).
Driveshaft
A custom driveshaft to mate the Mazda transmission with your differential will have to be fabricated. Any driveshaft shop can make this for you.
Shifter
A new shifter mount hole may need to cut? Look into doing the shifter extension mod otherwise your shifter will be a little bit to far back for comfort (it will sit in between the front seats right in front of the handbrake).
Transmission Mount
Mount the gearbox the with a similar bracket to ca18 one.
or make a new gearbox crossmember.
Tunnel
Some fabricate a large tunnel. Is it necessary, or just used with beefy racing transmissions?
In any cause, you'll have to make the tunnel higher through the middle and make space for the clutch fork, or cut a hole for the clutch fork.
Alternatively you can fit an aftermarket hydraulic throwout bearing to replace the clutch fork.
Differential
The least 12A engine outputs 100 lb. ft. of torque. The stock Datsun 1200 H145 diff can handle that.
But many 12A put out 115 lb. ft. of torque, which calls for a stronger diff. The H150 from a B210 or B310 can handle this.
Stock 13B engine calls for an H165.
Any modified rotary (especially if the turbo boost is raised) will need a stronger differential, such as a Nissan H190. Drag racing versions need the ultra-strong Ford 9".
See: Rear Axle Swaps
Exhaust
For the 13BT, run headers to the rear firewall across to the passenger side.
Wiring
Fit these using the stock 1200 wiring harness. Wires may need to extended.
* Starter + * Starter S * Alternator + * Alternator Earth * Engine earth * Body earth * Coil
For carbureted engine * electric choke (connect to coil 12V)
For EFI engine * ECU relay * Fuel pump relay
Builds
Datrotor's DATYLD
Rotary-Powered Datsun 1200 photo index
Here are some pictures from our club photo album. Click a pic for larger photos, details, and discussion:
Photo Index
Click any thumbnail to see it full size in our Club Photo Album. Read details or post a comment! 
