Just delivered my FD to my tuner after installing my new Turblown 8374 kit to tie up some loose ends, correct any improper installations, basically wrap up my build and put a tune on the car. Car starts ok cold or hot, runs good, but idles rough and has a slight stumble until it gets to about 65-70c indicated on the pfc commander. Car sat for about 1 year while waiting on the turbo kit but now has fresh fuel and premix. Compression test showed mid-90s to 100s on the rear rotor, front showed 85-75-85. Thoughts?

 

Your front rotor is weak, rear is decent

You could try fogging the engine with some water and see if some carbon dislodges and brings the front rotor up, but its hard saying if it will

 

I'm reading as we speak about the atf/sea foam/fogging tricks for stuck seals. These tricks really work sometimes? Think it might be a waste in my case, with all numbers showing slightly low on that front rotor.

 

https://www.rx7club.com/general-rota...-motor-858218/

Post 6, banzai racing gives some good useable info. Bad/stuck side seal is usually more than 10 psi difference, no?

 

Anyone else? I'm 95% leaning toward a rebuild since the motor is an unknown, but don't wan't to just throw away money.

 

just dump some water in it with it running, then go take it for a hard drive

If it runs, enjoy it, don't fret about it

 

Either it's stuck, or it's damaged. Your compression results (85-75-85) may give you a hint on which it might be (stuck or damaged), but I'm not sure. If it were simply worn, you'd see similar (lower) numbers with the other rotor. I'd try the easy/cheap route first and go from there.

 

Tuner has already pulled the motor ahead of schedule. Motor was torn down this morning. Broken corner seal and slightly damaged rotor. Damn. Motor ended up having 3mm apex seals. He said that probably partly accounted for the lower compression numbers.