Exhaust leak at rear exhaust port.

[arnold z]

Have some rust and pitting.of the block around the rear exhaust port. Is there a fix that holds a while? The manifold is burnt a little too. I bought a new one, but would like to get it to seal for a while when I change it.
I've been adding a little extra gasket and jb weld extreme heat, but it doesn't last long.

 

[HarryVanderpool]

Here is my solution. Wire wheel both mating surfaces.
Clean mating surfaces thoroughly with MEK or acetone.
Cut a piece of board that can be bolted to both mating surfaces and drill bolt holes so you can bolt the boards tightly to both mating surfaces separately. Cover one side of the board with aluminum foil.
Mix and apply Devcon Ceramic epoxy to the pitted areas.
Bolt the wood with the foil facing the repair tightly.
Allow the recommended time for curing.
Remove wood molds.
Grind away excess flash.
Reassemble with a new gasket.
This repair will last the life of the engine.

 

[Dan]

Harry has the better product, but I have had great luck using JB Weld extreme heat epoxy. Clean the block very good per the above proceedure, smear on the epoxy, place a piece of wax paper over the epoxy and manifold bolts, bolt on the manifold to torque spec, wait a day, remove manifold and wax paper, clean up excess epoxy. Reinstall the new manifold with a new gasket with permatex red high temp gasket sealer on both sides.

You will probably never deal with this exhaust leak again in your lifetime.

 

[Dober_paw]

2x what Harry & Dan say - also search the archives with keyword Thermosteel - you'll find lots and lots of info / caveats on manifold repair at #4 - like don't double up on gaskets and do use brass nuts. See also the 75 hints. Never again in lifetime? YMMV. Probably depends on the extent of original damage - I've done 3 repairs in 34 years - current repair is on year 4 - hey maybe I'm getting better w/ practice.

 

[arnold z]

Here is my solution. Wire wheel both mating surfaces.
Clean mating surfaces thoroughly with MEK or acetone.
Cut a piece of board that can be bolted to both mating surfaces and drill bolt holes so you can bolt the boards tightly to both mating surfaces separately. Cover one side of the board with aluminum foil.
Mix and apply Devcon Ceramic epoxy to the pitted areas.
Bolt the wood with the foil facing the repair tightly.
Allow the recommended time for curing.
Remove wood molds.
Grind away excess flash.
Reassemble with a new gasket.
This repair will last the life of the engine.

When I search Devcon ceramic epoxy, I find a big variety of products. Is there a part number or Item.number for the one you use?

 

[arnold z]

Looks like a thermosteel product will be my choice. Can't buy the Devcon in a small quantity that I can find.