My '87 3.4pr swapped failed smog pretty miserably a couple weeks ago, and I *thought* I hit the easy button and replaced the cat, but that didn't about nothing. My gut was telling me the exhaust leak in the front manifold had gotten pretty bad, and the guy at the smog shop told me straight up "You have a big exhaust leak, it's going to wreck your smog." Well, he may have been right.
I've been avoiding doing the work because of all the horror stories about broken off bolts & studs, and pulling a head off is *not* something I really want to do, but I had no choice. I soaked everything in Aerokroil for a couple days, and was pleasantly surprised when the rear manifold came right off. Zero issues! Then things went wrong.
The challenge with the rear manifold started with the heat shield. Someone replaced the sheetmetal nuts with actual full size nuts, and THOSE fused to the heat shield. First turn of the wrench and the fused nut just twisted and ripped the heat shield. Two of the three went down that way, so the heat shield is trashed. I left the studs & bolts in place to remove the crossover pipe and then things went REALLY wrong. The bottom bolt came out fairly easily, the top bolt might have, but before it could it literally
twisted the manifold in half. Check it:
I gotta believe it was in bad shape, but that's crazy!
After the manifold basically twisted 180 degrees the crossover bolt came right out. All six bolts 'n' studs came right out too. There was some thread damage on one of the studs, but I ran a thread chaser up and down the hole in the head and those threads seem fine, so I think I'm in good shape for a reinstall.
I'm pissed that I lost a manifold, but
real happy there are no fastener or thread issues. Could have gone worse.
I called WCF this morning to order their "replica" manifolds. I'm not messing around with welding given this failure - who knows where else the manifold is weak?
Anyway, as part of this project I'm just going through everything - replacing all the sensors, gaskets, EGR, etc. The ignition system is only a year old, so I think with this work done I'll be in good shape.
But, does anyone know a part number for the gasket that sits on the crossover pipe below the EGR valve 'adapter?' I know Fiero Store (IIRC) stocks one, but I was hoping to get one quicker than that... Looks like this:
If not, no worries...
