I am considering going with a full bridgeport, (sv-j-bridgeport according to mazdatrix) but I was unsure about the modification to the rotor housing to accomodate the extra port. From the pictures I've seen the rotor housing has been cut back all the way to the o-ring groove. So what happens to the water seal? Surely it's not just left exposed on the one side to the combustion chamber. Is there really that much benefit to cutting the rotor housing and water seal groove compared to a bridgeport that leaves them intact. Sorry if I've confused anyone here. Thanks for the time,
Evan

 

Reliability. If you don't cut the waterseal it's a little more reliable recommend for street use. Race use cut it back to the waterseal you'll gain way more port timing this way. The waterseal is not exposed to the combustion chamber per se. The only thing passing through the port right there is air and fuel. You will have to cut that portion of the seal that is exposed and then use a sealant around the surrounding areas to keep it from leaking. The reason this is a race only port is simply that a bridgeport cut past the seal will leak. It will only be a matter of time. I've ran bridgeports on the street with no problems just don't cut into the waterseal. The reliefs are there to help with airflow and even with small bridges you can still cut the reliefs without compromising the waterseal.

 

most j-ported engines dont last more that 30,000 miles, i would recomend a normal bridgeport.