Hi my name is Jacob I have a 1985 Rx7 Fb GS with the 12a and it has been have a weird idling weird and choppy sound ever since I bought it. And I thought it might have been the fuel so I rebuilt the carb put brand new spark plugs and checked all the wires to see if it was the ignition coils and it had bad gas in it so put new gas and it didn't fix the issue. So I compression tested it and found out that the rear rotor is bad with about 60 psi and the front rotor with about 90 psi. And the speedometer says 230,000 miles on it so I knew the engine was either replaced at some point or close to being done for. But I came here to ask how much is the estimated cost to get a 1985 12a rebuilt and streetported since it's gonna get disassemble I wanna get it rebuilt with the Intentions of making it a streetported 12a. And now that I know It needs to be taken it apart it gives me a reason to start looking into it and I wanna know how much the estimated cost it would be to get this done and tips from people who have done it or have experience with it. Also my intentions with the car is to have nice sounding streetported 12a with a little more power than stock but nothing to crazy I do like the car stock but it has been a big goal of mine to get it streetported. Brigdeporting just seem a little much for me. Sorry for the long post if you could help me out that would be great thank you.

 

A rebuild kit by itself will cost ~$1000-1200. The unknown here is what hard parts on the current engine are reusable. If the rotor housings are toast, there's another ~$800 for used one if you can find decent ones. If you hire someone to rebuild it, theres another ~$1500. Porting would be an extra cost.

There are more aspects but this will give you a rough idea what is in store.

 

Yeah I'm not completely sure what components are causing the low compression. But I don't own a rotary compression tester and I know that piston compression tester are not very accurate. But the general psi for the front rotor was around 90 PSI and the rear rotor was around 60 PSI. But I'm not seeing any signs that it is a catastrophic failure. So it may just be shaved down apex seals, weak springs, maybe weak side seals I'm not sure. I wanna give it to someone to rebuild it but I'm not sure who can rebuild it and street port it together. And do I take it apart myself to diagnose what's damaged then send it knowing what I need to rebuild it. I'm not sure just wanted to know since this is where I'm thinking I wanna go with this engine.

 

Finding shop/builder that you can trust is the hard part. I've never had Banzai Racing do a rebuild, but he is a member and sponsor of this site. I myself would trust him. I'm sure there are others, but at least ask around on this forum about their recommendations.

Engine Rebuild

 

Yeah I will ask around and do more research on this. thanks for the advice and tips.