The exhaust heat riser on my 1962 292 still works (surprisingly), but the butterfly pivot entry to the casting on the engine side of the riser has blown through (hopefully that makes sense). As such, hot exhaust gases are venting out the hole onto the valve cover (definitely not ideal). So I was thinking of pulling the heat riser and replacing it with a spacer, but then I thought could I pull the heat riser, pull all the butterfly valve and pivot parts out and braze the pivot holes shut (or blocking them off somehow). Has anyone done this, or see any issues in doing it? Brazing seems like a cheaper option but want to confirm it is a viable avenue. I’m in Australia so a spacer is a relatively expensive option once I factor shipping in to the equation.I don’t need the heat riser to work either fyi.

I’ll need to replace the gaskets on the heat riser whichever avenue I take. Does anyone know the part numbers for these? I understand they are different on either side of the heat riser (one is flat, one has a donut?). I haven’t pulled the riser yet; I’m trying to get everything in hand before doing so.

Oh, and what are the odds the I can get it off without breaking the studs?! I am thinking soaking them with WD-40 fora while before hitting them with heat and working the nuts slowly is the best approach.

Appreciate any input into the above.

 

Yes, when they malfunctioned - often rusted shut - it was VERY common to remove the valve mechanism and reinstall the non-moving metal portion back into the system to act as a spacer. Brazing the holes should be fine.

I have an NOS valve and just pulled it and took a look. Both sides are completely flat. It came with one gasket as shown. I don't believe they used any donut.

C0TE-9A427-A - VALVE ASSY. - EXHAUST THERMOSTAT CONTROL



I believe the gasket is the following, but as always do your research.

C1SZ-9450-A - GASKET MANIFOLD

You can look on eBay for that number and get a visual. I don't have any of those yet as a separate part so can't confirm.

Soaking them and some heat are not bad ideas. But WD-40 is not what I'd use. I use a 50/50 mixture of ATF and Acetone - shake well before each use. It's been proven to work better than Kroil, PB Blaster or Liquid Wrench. WD-40 doesn't even make the short list. I disassembled my entire exhaust system from manifold bolts to tailpipe and didn't break any on a 1964 truck that's sat outside for years.

 

That is very clear, thank you for pulling your part from your extensive collection; always love your NOS part shots. Only one gasket is interesting and good to know both would be flat. Thanks once again.

 

An update: I hit the bolts with Cyclo Break-Away Penetrating Oil every day for several days, used heat, but no dice when wrenching on them; they wouldn't budge. I was being very patient, but I'm pretty sure these bolts have never been loosened, ever. Then today I thought I was getting somewhere, only for one to shear off. I suspect the other (lower) one will have a similar fate, but we'll see. The upper one has ok access for retapping, but if the lower one breaks I assume I'll then have to pull the manifold out to retap (I assume I can retap them and install new studs?). I would much prefer to not take that route, but I guess I'd better hit those bolts with the penetrating oil in anticipation. The joys of old trucks... TA455HO, you did well not breaking any bolts!

In other news the penetrating oil worked a charm on the rear leaf spring mount bolts. WD-40 was useless for this application as I hit them with it for days on end, but they did not move. the Cyclo stuff worked after two days of application.