i have a 86 13b it sat for a while and now when it starts it runs but blows coolant. what causes this? how involved is it to fix?
i have a 92 turbo 13 b i would swap it with but not sure it worth the effort. i have everything to convert it, ecu,wireing ect.

 

One or more failed coolant seals causes that. It requires complete disassembly of the engine to replace. Cost of the seals is relatively minor, but typically other wear components will be out of spec and require replacement as well. If it's "sat for a while" with failed coolant seals the irons may be corroded and unusable. All of which will increase cost.
I'm have very limited knowledge on the S4 and S5 cars, but not certain the S5 13bt engine will mate up to the rest of your S4 13b NA drive-train.

 

S4 to s5 should be a direct swap as long as you transfer the engine wireing harness and the computer

 

I stand corrected...your right. But looks like transmission carries a caveat. And sounds like he might also need the starter and fuel pump.
https://www.rx7club.com/2nd-gen-arch...etails-813825/

 

it wont be going to a rx7 its a custom build for a vw chassied sand rail i will build a adapter plate if neccesary i have the complete harness, starter will be vw type. ive just begun to sort out the wireing for the uneccesary things. i bought a wrecked 92 for 300 with the hope i can use it so im jumping in with both feet. but to be honest ive never done anything with a rotary my sand rail came as is but sat for the winter i hadnt had amy issues till now. i appreciate the input hopefully it all goes well.