RX7Rox

Damn...Just what I didn't want to happen. I was trying to free up my stuck 5th/6th ports on my GSL-SE without the hassle of removing the manifolds. Actually the front one was working perfectly, so I figured the rear port (by firewall) wouldn't be that carboned up. I tapped lightly with a hammer and moves fairly easy....so I try to work the lever back and forth and damn it falls off in my hand!
I need suggestions...I can get a stock manifold complete thru ebay for 79.00 or should I re-use my manifold and replace the ports and sleeves with Pineapple racing improved design for 49.00???

LongDuck

You're going to need a new lower intake manifold.

The rotating rods themselves are what actuate the rotary sleeves, but the rods are about 6" long and extend from the actuator side, through the lower intake manifold, through the intake runner for the secondaries, and then attach to the '6'-port sleeves. If you broke a rod, which is likely, the rod can be removed and replaced, but you'll likely have to do this with the lower intake manifold off of the car.

Oftentimes, on cars with high mileage, there will be a lot of carbon buildup on the rods themselves, which will break off when you try to remove the rod. If this cracked carbon buildup gets into your engine, you're going to have problems. Removal of the lower intake manifold is not that difficult (an extra 5x12mm bolts) and then you can get to the sleeves, the rods, and find out where the rod is broken.

Give that a shot and then reply back. $79 for a new lower intake manifold is a steal, IMO. HTH,

RX7Rox

thanks LongDuck, I decided to go ahead and purchase the new intake manifold so I won't have to worry about cleaning carbon deposits and buying the replacement parts I broke... aux. port rods/sleeves etc. Besides getting all new gaskets needed for this swap, is there anything that can be tweaked to the new manifold for better flow/performance before installing it??

LongDuck

I'd leave it pretty much stock - there's not much you can do other than port-match and polish the internal runners, but some have said that port-matching can lead to problems with air backflow that can cause idle and emissions problems.

This is due to the overlap which occurs between exhaust and intake ports, and how this dynamic pulse impacts the intake tract. If you port-match, you run out of the air block that keeps airflow moving into the engine and not back out the intake on the pressure pulse.

Clean it up really well, and you should be fine. HTH,

RX7Rox

Keeping this particular car completely stock is the best way to go. I'm very pleased how this car runs in stock form and it never fails to amaze me. Replacing the lower intake with new, I'll probably still see an improvement since only one aux. port was working.
BTW...keep the weather nice in Phoenix cuz I'll be there over Thanksgiving. Would love to take the RX, but I'm going by air.