This is my beloved 1983 mazda RX-7. It has a 12a rotary engine. I bought this car in 2004 from a scrapyard. I needed this car, because at that time the matra (which was my daily driver) was in the proces of a previous engine conversion. The matra's original 1600cc engine was replaced by a peugeot 1900cc engine. During this project i was driving very happily in the mazda. I realy liked the character of the engine. The way it revs and sounds and the smoothness And then the matra's engine conversion was completed. The new 1900 engine was more powerfull than the original 1600 engine, but i was not satisfied. Now i was used to the rotary engine, the 1900 engine couldn't please me.
	The mazda's M.O.T. did expire, and the car was in a too bad condition for a new MOT. It had bad brakes, wheel bearings, tyres, steeringcolum, rust, exhaust and more. But the engine was fine! The mazda was put to rest in a shed. A little thought popt in mind: Rotary engine in the matra? A rough measure with a tape measure told me the engine would fit.
	My brother Hans helped me to get the engine out.
	Well, here it is.
	The rest of it is no longer needed, so return to scrapyard. Note the flower pot on the wall.
	The thing is, the rotary engine is a longitudinal engine, but it needs to go transversal in the matra. It needs a transversal gearbox. But there is no transversal gearbox for the rotary engine. So i have to fit an "alien" gearbox, using an adapterplate. Which gearbox to use? There are a few requirement of the gearbox: The bellhousing must be big enough for the large mazda flywheel and the position of the starter motor. That must be positioned next to the gearbox, instead of next to the engine. Original matra gearbox and the peugeot gearbox can't be used for those two reasons. I found two gearbox options, Citroen CX 2.5 or toyota celica 3gse. I prefered the citroen, because it is mainly the same as a matra gearbox, but it has a bigger bellhouse. However, the clutch mechanism and the position of the startermotor makes it too complicated to use. So toyota gearbox it was.
	Citroen gearbox: scrap metal.
	I got this toyota gearbox for free (thanks celica forum) It was old and worn. Ideal to "sacrifice it to science" I opened the gearbox (never done such a thing) and discovered that the gearbox was actualy in good condition!
	I need to make something to line up the gearbox with the engine. Normaly on the primairy shaft there is a little pilot shaft which goes in a little bearing in the flywheel. But this primairy shaft doesn't have such a pilot shaft. So i got this shaft made. This shaft comes in place of the primairy shaft, and it has the pilot shaft.
	Like this.
	A supplier from my work has a waterjet cutter. He made me a steel ring which will act as an experimental adapterplate. Engine and gearbox are now bolted together.
	Say "hello" to your future shell. We are still in "investigating stage" There are 100's more things to sort out and at this point i'm not sure if this project will succeed. I don't start the actual engine conversion until i am sure it will work. So the matra stays on the road as long as possible with the current engine. As long i am not sure how this will end, i try to keep things as cheap as possible. Keeping in mind there might be a dead end.
	This is the 1600cc engine, which was originaly fitted in the matra. The rotary engine must be positioned exactly the same way as how the original engine was fitted. That way i am sure the driveshafts are positioned OK (i had loads of troubles with the driveshafts after the first conversion, caused by a badly positioned engine) I don't want any welding or grinding on the chassis to receive the rotary engine. It MUST be suspended on the original chassis engine mounts. On the original engine i made a jig which point to all engine mounts and the dif. The dif will be the reference point. So this jig gives me the position of the dif according to the engine mounts.
	The jig is now positioned with the dif reference point to the dif. Alligning the frame level and square. It now tells me where the engine mounts must be. Next to the alternator, next to the starter motor and in front of the rear exhaust port comes the mount points.
	This gives a idea where the righthand side mount must come. The only "beef" to attach this are the 4 bolds at the bottom. So i have to make a very beefy bracket to these bolds. This bracket has to curl around the pulleys.
	This lefthand side mount is easy. It is close to the gearbox's suspension point.
	The bottom engine mount (white) is about 10 cm aside of the adapter plate.
	The drive shaft will be very tricky. It runs close to the exhaust ports, leaving little space for the header. Even more tricky will be the support bearing of the drive shaft. It must be in front of the oil pump. But there is nothing there to fit a bearing bracket. Shifting the drive shaft so the bearing will be in a better place is a option, but i don't want to do that, because i want to keep the driveshafts in the original lenghts.
	With autocad, chipwood and a jigsaw i start to design the engine mount. The big hole on the right is for the drive shaft to stick trough.
	Option 1 of the bearing: an industrial bearing unit. Denied because too lump and it was touching the oil pump.
	Option 2: an other industrial bearing unit. Denied because it should be bolted with spacersn and that would by too weak.
	Option 3: A bearing in a custom housing. The housing is mounted to an extra bracket. This bracket is on one side bolted to the engine mount and on the other side it must be bolted somewhere to the engine's front iron. The bracket must curl around the oil pump and ité lever. Bolting it to the front iron will be very tricky. I have to drill and tap in it. There is also a bearing option 4, which is a custom bearing housing directly on the engine mount. (for this i have to shift the drive shaft) And there is even a option 5, which involves the bearing housing from the original engine.
	Here is the result of a few evenings autocad. It includes an adapter plate, the lefthandside enginemount, an exhaust flange and the 5 options of the bearing. All this will be lasercut from 12mm steel.
	A few pounds of steel.
	I drilled the holes myself in the adapter plate. The dent in the plate under the oil filter is to accommodate the clutch cilinder.
	The left hand engine mount with option 4 of the bearing housing....
	...And option 2, 3 and 5. I want to use option 3, but to be sure i also made all the other options. You never know.
	The adapter plate must be bolted to the engine with countersink M10 fine tread bolts. I couldn't get these from any supplier, so i have to make them myself.
	This is a toyota clutch plate, which have about the same size as the mazda one.
	The clutch lever pivots on this pen. I had to move this pen a bit out (using some washers. Now the toyota clutch lever is in the right position for the mazda clutch cover.
	And now it is time for trail fitting the engine in the car! At this point the matra is still on the road. All the rotary engine prepare work is done separate from the matra. I tried to keep costs as low as possible, keeping in mind the project could fail.