I'm pulling the heads on my '90 LB9. Biggest job I've ever tried, and I'm wondering if I've bitten off more than I can chew, but whatever.

I'm trying to remove all the smogger stuff over the heads on the passenger side. It is attached to a bunch of metal lines coming off of the exhaust manifold. What is this system called?



The lines have nuts on them that are almost impossible to get a wrench on (arrows). Is there a trick to getting them off? Or a special tool?

 

Those are the air injection manifolds, screwed into the exhaust manifolds. Yours are surprisingly clean, but after 24 years of heat cycling that are well baked in there. PBBlaster or Liquid Wrench on the threads AND on the tube-to-nut joint will help break it free. Use a flare wrench, not just a plain open end wrench.

The better news: the AIR manifolds do not HAVE to be removed from the exhaust manifold to remove the exhaust.

Since you are pulling the heads, all of the accessories have to come off. Remove the hose from the check valve, and the exhaust/air manifold can come off as a pair.

Then replace with Dyno Don shorty headers.

 

Don't try and remove the air tubes, really unlikely you will get them off. No need to, just remove the whole manifold.

 

Thanks for the advice. I found it in my Haynes Manual under a chapter I'd never noticed before called "Emissions Control Systems". I'll stop trying to get these off and just remove the exhaust manifold. Thanks for the advice.

And as for the short headers - time and money, never have enough of either.

 

Well, that didn't go so well.

 

Oops! Don't worry about it, these are low pressure pipes carrying reg air. Even tape would make an adequate connection.