I'm toying with the idea of getting a new DD and may have the opportunity to get a clean 1979 RX7 for dirt cheap. The catch is that it doesn't have a motor.
What this car will be used for??? To be honest it will mostly be used as my all year round DD. I currently DD a 2002 4.0 TJ and it gets about 16-17 MPG no matter how I drive. I'm keeping the Jeep. While I'd like to say I am going to rallycross and autocross the RX7, but I'm not going to lie, my life and schedule limit the amount of car stuff I get to do. I would like to keep my budget under $201X in the hopes that I would eventually get to make a Challenge one day.
With the thoughts of mostly DD in mind and looking at motors for the roller I'm not really sure where to go or what to do. My wrenching experience is air cooled VW, Jeep, aircooled Porsche, Mazda3. In that order. I know nothing about rotoray motors, other than something about triangles and apex seals...
I'm looking for an easy swap, that hopefully has been documented. I'm also fine with going with a stock motor if it will get me the MPG numbers for a DD. As always more powar would be great. In the end, I'm open to suggestions.
I tried doing some research on these threads:
http://grassrootsmotorsports.com/forum/grm/rx7-engine-swaps/42222/page1/
http://grassrootsmotorsports.com/forum/build-projects-and-project-cars/rx50-project/33672/page1/
http://classicmotorsports.net/forum/grm/rwd-swap-optionsrx7/57148/page1/
http://classicmotorsports.net/forum/grm/learn-me-fc-rx7-v8-swap/54114/page1/
I have heard of people swapping in Chevy V6s and V8s.
The rotary MAY get you those mpg numbers, but I am not really confident that it will.
I know miata engines are not too difficult to swap in and they will probably get you that MPG with a slight bump in hp.
If you are looking cheap, I have an engine (spins but I have never had it in a car to prove it works) that is dirt cheap. I believe it is out of an 84 GSL.
Rob R.
I made it more difficult by modifying every thing.
However with the Tremec manual and the loooong overdrive the RX5.0 gets a solid 26mpg
A friend just bought the Granny's kit for $100 on eBay
You will also need a GSL-SE crossmember. Turn the crossmember 180 degrees then bolt it in.
The electrics were not difficult if you have the wiring loom and computer, just needs a ground, full time power and switched power to the computer
7 quart pans means you have to modify the crossmember.
My RX7 GSL-SE rear end is holding up with Moser axles
I'd be tempted to drop in a 13B, but IIRC you'll need the front plate from either the 12A or 13B that came in the FB. A decently set up 13B can get decent mileage if you don't rev the nuts off it. Which of course you will 
.
79-80 have the better styling of the 1st gens IMHO.
Also, I can build you an engine that will get you around no problem :)
I have almost enough extra spare parts to do so, again.
BoxheadTim wrote:
I'd be tempted to drop in a 13B, but IIRC you'll need the front plate from either the 12A or 13B that came in the FB. A decently set up 13B can get decent mileage if you don't rev the nuts off it. Which of course you will .
Also will need the GSL-SE 13B crossmember for this swap
I love spinning triangles, but I vote v8!
I too, love spinning triangles.
I too, vote V8.
There is a thread on RX7 club in the Race section of a guy who swapped in a Miata motor. If you are going to use the car in a DD type situation, I'd probably do something similar. A nice, fun 4 banger with a good trans would probably provide the kind of MPG you want.
I vote cheapest V8 you can find.
Besides AussieMG what other MPG numbers are we looking at here? I know that is a weird question to ask on this board, but if looking at it from a DD standpoint I'm curious.
Will the rotoray motors see 20? 25?
Also in my readings I see people mixing oil with their gas like a two stroke motor. Is that common for rotorays as well?
wvumtnbkr said:
If you are looking cheap, I have an engine (spins but I have never had it in a car to prove it works) that is dirt cheap. I believe it is out of an 84 GSL.
How cheap is "dirt cheap"? You can contact me in private if you want. I have some family up in PA
amg_rx7 said:
A nice, fun 4 banger with a good trans would probably provide the kind of MPG you want.
I do too, but it doesn't look like there is a lot of info out there for a setup like that.
I understand most people that go through the hassle of doing a motor swap usually do so to increase performance. I did the same thing when I swapped a later 911 motor in my car.
I don't like the looks of many cars on the road today. The RX7 I like, but the stock motor might not make it conducive as a DD. I think the argument was made in one of the threads I attached that, "great car + bad motor". I'm not saying rotarys are bad, I'm more saying why didn't Mazda make a peppy 4cyl RX7. And if Mazda had put a MazdaSpeed3 motor in the RX8, this whole thread would probably be pointless because I would have bought one.
I think you should just tell me where this car is, and skip the whole idea of buying it. I vote that the 79-80 models are the best of all the generation one cars. I also think you should stick with the magic spinning triangles. I didn't really read what you wante dto do with said car, but I love my rotors. Therefore you will too.
Couple of things....
NA rotary engines have been known to last several hundreds of thousands of miles. The problem comes in when people try to double the horsepower without the knowledge of how to do it properly.
Next, the rotary is a glorious thing. It is light weight, revs to the moon, and is extremely reliable when beat upon. There are few engines that feel as "zippy".
Last, I could do about $150.00 on the engine. It is mostly a longblock. I will need to verify what is on it right now.
Adding oil to the gas is referred to as Pre-Mixing. It is because there is no way for oil to naturally get inside the engine and lubricate the various seals. Therefore, Mazda has an oil metering pump (OMP) that meters oil into the combustion chambers. The generation of RX7 you are talking about has a mechanical OMP. It is very reliable. However, if it does fail, you have ZERO way of knowing until your engine is toast.
For that reason, people usually block off the OMP and run premix. The other reason to run pre-mix is to have a more consistent mixture of oil and gas. Plus, it has shown to make the engine internals "cleaner" than the OMP.
Hope this helps.
Rob R.
octavious wrote:
I do too, but it doesn't look like there is a lot of info out there for a setup like that.
Some links to get you started:
http://www.lamanracing.com/
http://www.rx7club.com/race-car-tech-103/first-gen-race-car-build-mazda-bp-engine-1011458/
octavious wrote:
if Mazda had put a MazdaSpeed3 motor in the RX8, this whole thread would probably be pointless because I would have bought one.
I hear ya. That would have made a great DD type 3 series killer.
In reply to octavious:
with no cats/emissions. EFI properly tuned with no wild port. yeah
or even a stock 86-91 13b with stock EFI bits in a 1st gen gets mid 20s. Friend has a piggyback on his EFI S4 powered 1st gen and gets about 27 highway.
Knurled runs some crazy ports and gets similar mileage but hes him.
