Figured I would highlight some things for my rally car seperate of the build thread for the 1.6 swap from a Miata. Car currently is running and driving on a Megasquirt.

i swapped to an FC subframe, which allowed the stock oil pan to work without any issue. Now, for a regualr FB... not sure how that would work out.

Engine mounts were custom pin type, and the mount was off the frame. which is nice for dropping a subframe easily, and very strong.

 

pretty cool. how come you went with the 1.6 and not the 1.8? i ask cause i have a 1.6 miata and the 1.6 is just really lacking in power.

 

two reasons, 1. the 1.6 was cheaper at the time, and 2. the 1.8 being longer hit the steering rack

 

I can't figure out what I am looking at here. Are you showing parts of two different cars? Is the car initially normal aspirated, then converted to a turbo?

In any case, I don't know the tube diameter or wall thickness for the motor mounts, but next time I would make the mounts longer on the frame side, so those tubes are shorter to reduce the bending loads. And there is a reason most motor mounts are at a 45 degree angle, more or less. The right hand mount in particular would be in less bending and more in direct compression loading under full torque if the bolt were lower and the tube were angled more. With that little Miata motor, you are probably fine. I can't help being **** - I am an aero engineer.

Looks like you are doing a good job on this installation, seems like you have lots of room with the Miata motor. I would be interested to know how you like driving it. I just did one in my FB that was a really tight fit, shown here:

http://www.cardomain.com/ride/3936025/1984-mazda-rx-7/

 

she drives great actually! with the FC subframe, i have it close to the steering rack. like about as close as i would want to go. So i have to shorten the driveshaft just like 3/4" (damn it) but aside from that, ive been loving it with the 4.78s. Little low on power, a 1.8 would be better yea, but would have to go even farther back towards the firewall OR raised up like two inches.

the car had a turbo on it, but i opted to run NA since the turbo was pooped and an old Isuzu thing that i couldnt get parts for easy.

The mounts i basically modeled after cast 909 ford racing mounts for the sierra which are straight like that but granted, they are cast with some better support at the base. I didnt want to mount to the subframe, so that was about as good as it would get.

 

so after some consideration, i MAY be swapping to a 1.8 engine. Since i went to coil-on-plug, all i need to do is change to a trigger wheel for the megasquirt, and i can push the extra length of the 1.8 back towards the firewall.

I can also change a couple things i didnt like at this time too.

This 1.8 will likely get turbocharged.

 

If only it were easier to get a strong transmission behind the bp.

 

yup. and more power in NA.

frankly, ive considered ditching the engine for a rotary. OR a duratec 2.3 / T5