Judge Ito

When using a short block from 89 to 91 on a 1986 to 88 Rx7, do not forget to block off the exhaust passage on the center side housing. since the 86 to 88 lower intake manifold does NOT have the passage to except the exhaust flow into the manifold. If the exhaust port is not blocked off, you will have an exhaust leak right under the intake manifold.. and your going to go crazy trying to figure it out.. If members don't understand I'll post pictures of this. I usually use epoxy to fill in the port in the center side housing..

the exhaust passage is right under the primary intake port runners.. on 89 to 91 N/A engines. 86 to 88 did not have this passage.. the problem arises when using the 86-to 88 lower intake manifold..on the 89- to 91 n/a block...

j9fd3s

yep. easiest way to deal with it is to keep the lower intake matching the engine. its only off by 1 stud.

BigTurbo74

i just switched the front and rear rotor housings when building my engine.

j9fd3s

that will never ever pass smog.

GMON

ooops, you shoulda though of that one Nick, now your gonna hafta pull the whole engine apart

j9fd3s

we've seen a bunch of engines like that, and living in CA it needs to pass smog. a lot of times we end up rigging the acv to blow only into the exhaust ports anyway to get em to pass.

BigTurbo74

if i had to pass smog i would have bought piston engine a long time ago..

alaskarotorhead

this is to block off the egr port correct?I have usually tapped the egr holes under the exhaust ports(7/16) and cut a stud to the proper length (locktite) and viola,no exhaust escapes the port.This method of course would only work if a motor is apart.I believe both of these methods accomplish the same thing.Good thing to point out though,I almost missed this very thing on my first engine build.



Nick