I'm the new owner of a 80 Rx7, the engine will not make idle and had a loud noise. Will this be my problem?




The manifold does not cover the hole on the center iron under the intakes. It makes a noise comparable to a piston engine with a bad rod.

 

I just checked my spare mani. You are missing a section, which leads me to believe you have an older manifold. Not sure on the specifics. I'll pm someone that might be able to calrify this for you.

 

yeah i'm pretty sure you got an older manifold.

 

Here is a shot of a 79 manifold (ignore 83 carb on top) - note ! the ports have been enlarged on this, so just use the OUTside shape as a guide. I see there is NO rectangular opening on my manifold either, so it looks like the manifold should block that hole on your center housing...
Stu Aull
80GS
Alaska

 

blackdragonauto shows 3 different manifold/gaskets 79-80 doesn't have the rectangular opening, 81-85 12a manifold and of course 84-85 13b...so what i'm guessing is that you actually have a newer 12a in your car.

 

Thanks for the reply, I will install a newer manifold , or cap that hole.

Is theres a link of how to cap that hole? I'm hoping that the loud noise was caused by the manifold not covering that hole.

 

Does it sound like an exhaust leak? That's what an open ACV port basically sounds like.

There are two ways to block it.

1. make sure it is carbon and oil free, then stuff it full of quicksteel or some other epoxy-like putty.

2. use a manifold with the correct casting there.