86 FC build
 

I recently purchased an 86 RX-7. It has a carbureted Thunderbird v6 swap that I would like to change. It has a 4-speed auto which has to change to a manual. The battery has been relocated behind the passenger seat. Where does the battery go under the hood? I think I see the spot where it used to be, but it is rusted out (the only rust under the hood). It is on the driver's side, very front of the car. Could it be from battery acid leaking onto it? The current battery is fine BTW. The only other rust I found on the car is a small hole in the drivers side floor pan. I plan on getting those 2 spots welded up soon.

Also, this is probably the wrong forum to ask this, but does anyone know if the Ford 302 block has the same mounting points as the Thunderbird v6?

I will try to get pics up soon if I can figure out how.

that would be where the battery tray was, they break and go away.
Does the car have a Granny's mount?

No Granny's mount. The engine feels secure. no vibration or anything.

It has some starting problems though. Usually it will start up fine, but sometimes it won't unless I jump across one of the starter relays (it has two). I am going to take one out and see if this fixes the problem. Any suggestions before the operation?

Did you get it figured out?

Not yet. I have looked at it some, but I traded my Focus for my brothers Durango, and I am working on that to fix it up and sell it. That would give me some extra funds for the engine swap, and I could get rid of both relays and skip this step.

I believe I have figured out the starting issue. I think the relay is bad. I will replace that soon and see if I experience the problem anymore. If that isn't the problem then it is the key switch.

It may not be the relay itself. Make sure you test the wires with either a test light or multimeter before spending any money on a new relay. You may be getting hosed by the neutral safety switch wire.

A good multi-meter is a tool you will never stop needing if you know how to use it correctly! Voltage, Amps, Ohms!

This is how the starter is wired (attachment). I jump the top post to the empty post and it will start when I turn the key to start, and once the engine starts the starter wont stop turning over until I disconnect the jump. It turns over immediately when I jump the top post to the switch? post or the top to the bottom. But once it starts, if I turn it off and wait a short length of time, it will turn over fine the next time. If it sits to long I have to jump the wires again. Short time = about a day or less. Long time = 2 or more days.

The attachment is a quick 3d model I made in Autodesk Inventor just for illustration, edited in paint for clarification.

I replaced the starter relay and it sounds like it gets more power at the starter. I believe that problem is fixed now.

Well you may not be a rotary fan but anything else in an Rx7 is sad... only because it subtracts from the feel of the car. With that being said, I would like to see a Ford 5.0 in the car instead of all the chevy 350's. Let me know what you do.

What size v6?

It's the 3.8 V6. It was in there when I bought it. I would have liked the rotary in there. I have never driven a rotary...

And supposedly the mounting points are the same for the V6 and v8 from Ford. That might be the best thing to do (swap to 5.0) if the points are the same.

Priceless

A v8 7 and rotary 7 are completely different. You may want to see how hard it is to go back stock and what model you have. If you have a base model and nasty v8 it may not turn out so well and with that being said, same for the rotary.