Part 7: My 76 Mazda RX-5 Cosmo Restoration - Intake and Exhaust Porting
Has it been nearly a month since my last episode? Wow, time does indeed
fly. I've been quite busy preparing to build the engine. So in part 7, I
cover the intake and Exhaust porting.
The engine is being built with GSL-SE 6 port plates and the Cosmo rotor
housings as the basis for a 6 port turbo
setup. This port job is fairly conservative, only opening up the primary
ports a little and bringing the Exhaust ports close to 2nd gen RX-7 specs. The
goal is to maintain fuel economy, low and midrange torque, and idle
quality. This episode covers everything involved in porting including:
marking out the new ports, grinding the port shape, smoothing the bowls,
smoothing port to runner transitions, smoothing the runners, grinding and
blending the Exhaust ports.