S4/S5 Center iron incompatibility? ACV exhaust leak issue...
 

When I rebuilt my '88 Vert's engine, I had to replace a number of hard parts due to the damage that caused the rebuilt- somehow a large flanged bolt got ingested by the engine and destroyed a rotor and housing and damaged the center iron. I ended up with a S5 center iron instead of an S4, since it was what was handy and I figured it meant being able to eliminate the EGV block-off plate.

However, now that the engine is together and on the car, I CAN NOT get the ACV to seal against the LIM- I get a fairly strong exhaust leak at the bottom of it. I'm concerned that if I tighten the nuts any further that I'm going to break one of the studs (can someone remind me what the official torque spec is for those again too?).

Before I go the next step and just get a block-off plate from Banzai Racing and ditch the ACV entirely (Kentucky has no emissions to worry about), I wanted to check and make sure that the problem wasn't some incompatibility that I wasn't aware of between the S5 center iron and the rest of the S4 setup. Thanks!

uh your issue isn't the ACV... it is the big rectangular hole that now resides below the center of the S4 lower intake manifold.

remove the LIM and get a piece of "U" shaped aluminum trim that is about the same size as the slot, trim it to length and hammer that sucker in there, reassemble, done.

the S4 n/a irons had a round freeze plug pressed in at the same location.

Ah, so it IS due to the S5 iron. I'll have to take the LIM off over the weekend and see what I can do about plugging it up like you said.

Thanks!

Some pictures showing the port air path differences on S4 and S5 LIMs: http://homepage.mac.com/carldavis/intake/mod.html.

wow i didn't know that great info guys!!!