Getting Exhaust/Heat Exchangers Loose

1982911SCTarga · 11-23-2007, 12:58 PM

I've been searching and haven't seen what I'm looking for in terms of how to get the exhaust system to loosen up from the engine. I've removed the barrel and regular heat exchanger nuts, and the muffler straps, on my project cabriolet SC engine and the exhaust/heat exchanger unit (the entire system) doesn't want to come off.

Before I start hammering away, does anyone have some guidance? Do I need to gently tap with a rubber mallet or wooden block on the heat exchanger flanges? What else?

By the way, I didn't suffer any broken exhaust studs as part of the exhaust removal. Thanksgiving was a day late for me this year.

Brian

Oh Haha · 11-23-2007, 01:10 PM

It's probably just "welded" with exhaust gunk from the years of use. I would try to spray some PB Blaster or equivalent product around the attaching points. If you have all of the bolts/nuts removed, there is nothing really holding it on. A mallet/wooden block would be ok to use to get it loosened up. They are pretty stout so short of denting the metal you really shouldn;t hurt anything. I think a couple of good whacks should knock it loose.

1982911SCTarga · 11-23-2007, 01:12 PM

Good points, and I have sprayed PB Blaster on the flange-head joints.

Brian

john walker's workshop · 11-23-2007, 01:37 PM

pry with a big ass screwdriver or the like, over the exchanger with the tip under the cam tower. a little in front, then do the back, then the same on the other side. some nuts are helicoiled and can leave the helicoil on the stud when the nut is removed so check for that.

1982911SCTarga · 11-24-2007, 03:25 PM

The good news is John's advice was dead on (as always). I did take the muffler off first (broke the one bolt I could get onto with an impact wrench and used my air cutoff tool for the other two). Then, with some careful prying with a long pry bar, the headers/heat exchangers/crossover pipe/catalytic converter could be lifted off as a unit.

The bad news is I don't like what I see so far in the exhaust ports of the heads. It looks like there was rich running going on for a long time and there's a lot of wet-carbon-soot buildup. I'm thinking I should probably send these heads out for reworking. Anybody want pics?

Brian

Jascha · 11-24-2007, 05:16 PM

Please post pictures...

1982911SCTarga · 11-24-2007, 05:44 PM

These pics show the exhaust ports in order (from cylinders one through six).

Any thoughts?

Brian

preston_brown · preston_brown's Garage

Yup. Mine looked much worse. I chose to rebuild (150K 3.2L motor).

1982911SCTarga · 11-24-2007, 06:54 PM

Hey, Preston. Thanks again for the recommendation on the engine yoke.

Yep, it's a bit of a close call to make. I've seen worse. No. 5 is the only one showing the beginnings of a stalactite formation. But then again, if I take care of this now, the engine should be good for a long time. The top-side intake ports look good except for some carbon on No. 2. I'm going to have to noodle this one over for a while.

At least I've got the engine down to the bare bones now. It's so much easier to rotate on the stand once you're down to Shorty McShortblock.

Brian

1982911SCTarga · 11-25-2007, 08:32 AM

Spent this morning with the cut-off wheel and assorted tools removing all of the nuts and bolts holding the heat exchangers, crossover and catalytic converter together. What a fuch'n mess -- some of these nuts were extremely well done in the cooker known as a 911 engine bay and were not even recognizable as a fastener.

The idea here is to re-assemble with new hardware liberally treated with high-temp anti-seize to make my life (or a future steward's) easier the next time one has to venture down this path.

Brian