Planning an engine conversion....

[Gavin J]

Hi Guys,
Just wondered if any of you can you help me,
I'm planning on doing a rotary engine conversion on my 1968 Vw Beetle, and the engine i will be needing is a Mazda RX-7 1200 engine i believe these come out of 1982-1984 mazda RX7's? can anyone confrim this for me?(needs to be carb and not injection) also i will be using a radiator out of a 81/82 Mazda rx-7 radiator as i have been told this will ensure enough cooling...
Just wondered how much 2nd hand engines go for? including all the wiring/pipework etc

Also what sort of performance would i be able to get from that engine ? as i gather rotary engines are quite efficient.


Any info would be great,
Gavin

just to show it can be done, http://www.geocities.com/zenjoe/Zenjoes6503.JPG

[MikeLMR]

You can pick whole cars up pretty cheap, keep an eye out for one thats got terminal rust and a good engine and you'll be OK

Engine rebuils on the 12a engine are around £1000

as for performance, as standard the 81-85 engines kick out 115hp at the flywheel as standard

change out the exhaust and that can net you another 15 -20 hp, change the carb and you can expect around the 150ish mark

then you can get into porting, and or turbo charging with 680hp being about the maximum I've heard of from a 12a

oh and don't forget the larger rotaries ... the 13b and the 20b(triple rotor)

[Gavin J]

Cheers for the reply Mike,
Whats the crack with 13b engines is there much difference size wise to a 12a?
also what sort of power would the 13b be able to produce? are these still carb engines? or injection?

Thanks alot,
Gavin

[Glenn Butcher]

Hi Gavin,

Go for a 13B engine, they are much easier to find parts for and you will be able to get more power out of them (even without a turbo). Yes - you can run on a carb, give Tim a call at www.rxmotors.co.uk, I'm sure he'll have something lying around.

Here is a video of a 13B Turbo Beetle (VIDEO IS LARGE @ 33MB) http://www.be-4-you.com/Sitefiles/Movies/Elsewhere/boble_med_wankel_dougnut.avi (Video link thanks to Fish!)

Quite a bit of power there!

[Gavin J]

What would the wiring be like on this engine though as the wiring is quite straight forward on a 12a? is it much bigger? and does it have injection or is it still carb?
Would there much more cost involved in getting a 13b?
Cheers for the video mate!!!

Sorry for all the questions aswell......

[Glenn Butcher]

Don't worry about the questions - that's what we are all here for :)

Yes - I think the wiring would be quite straight forward.

You would need to use the Mazda Ignition system, if you can - get the coils, leads, distributer/crank angle sensor, alternator, it will all help.

13B by the way is 1308cc.

I don't know how the gearbox and all that area works, but I'm sure there would be some info. out there on the web.

If you can - fuel injection is lovely, but more fiddly.

[Gavin J]

Thanks gbutcher,

To see how it all workshave a look at this site,
it makes an interesting read.....
http://www.geocities.com/zenjoe/VW.html

[Glenn Butcher]

Excellent stuff - some lovely work there!

How heavy is your beetle? they are pretty light I think, so would make a great rotary conversion.

[Gavin J]

Beetles weigh roughly, 870kg
How does this compare to a mazda?
What do you think of the conversion? its fairly straight forward as soon as the radiators has been installed at the front ain't it?

Cheers
Gav

[Glenn Butcher]

Hi Gavin,

Some of the early Mazda's are around 760kg, so with 500hp which many of them do in Oz - you can see why they are so popular! :)

Honestly, I don't know how difficult it would be. But as a number of people have done it I would imagine it shouldn't be too bad.

You would need to obvioulsy mount the engine somehow, then have an adapter plate of some sort made up for the gearbox (don't know how strong/what type of gearbox would be used?).

Radiator shouldn't be too bad, but rotaries tend to run hotter than piston engines - simply because of the way they work. So cooling needs to be good.

[MikeLMR]

you'll need a good exhaust sytem too, no glasspacked silencers as they melt :D and they tend to be very noisy so you want plenty of silencing

oh yes don't forget the oil cooler ... up to 1/3 of the cooling is via the oil

as far as the wiring goes for a 12a or any rotary with a distributor all you really need is to feed the twin coils with 12volts and keep the standard wiring between the ignitors on the dizzy and the coils .... if you can sort out the wiring on a boinger its basically the same

[Gavin J]

Cheers
For the all the advice guys, I won't be doing the conversion for a another few months yet as i have another project on the go,
Dunno if you are interested but heres some current pics of my project,
http://www.btinternet.com/~fatony1/gavbug1.jpg

http://www.btinternet.com/~fatony1/gavbug2.JPG

And finally a pic of the bug i have the rotary conversion planned for;)
http://mig.lathwood.co.uk/uploads/DSCF0033111resize.jpg

Cheers
Gav'