Exhaust port crack.... need help!

M

Matts30coupe

Member
So I found my culprit that has been feeding my exhaust antifreeze... I took down my model "B" block today to find an old repair. Someone stitched the crack and them threw a weld over the top. The stitch was not overlapped and was never properly sealed. So with what I had here in the garage, I tried to preheat, braze, and postheat only to find more cracks... I was able to cover most of the cracks and smooth it out with a bur-bit, but I am not totally confident with the fix...

Does anyone out there know of a product that I can use to coat over the top of this. (Epoxy/Sealer???) They are hairline cracks that don't deal with a lot of pressure, I just want to run this motor till I upgrade to something later down the road.

***** I can't stitch where all of the cracks are.. so if it can't be brazed, I'm wondering if a epoxy or sealer will hold up to the temp.

Anyone have luck with this, or can recommend a product??

Thanks,
Matt
 
use some head gasket in a jar---I have seen the results on engines with blown head gaskets, seen it make 1/2 inch of missing gasket
 
Matts30coupe said:
So I found my culprit that has been feeding my exhaust antifreeze... I took down my model "B" block today to find an old repair. Someone stitched the crack and them threw a weld over the top. The stitch was not overlapped and was never properly sealed. So with what I had here in the garage, I tried to preheat, braze, and postheat only to find more cracks... I was able to cover most of the cracks and smooth it out with a bur-bit, but I am not totally confident with the fix...

Does anyone out there know of a product that I can use to coat over the top of this. (Epoxy/Sealer???) They are hairline cracks that don't deal with a lot of pressure, I just want to run this motor till I upgrade to something later down the road.

***** I can't stitch where all of the cracks are.. so if it can't be brazed, I'm wondering if a epoxy or sealer will hold up to the temp.

Anyone have luck with this, or can recommend a product??

Thanks,
Matt
Click to expand...
do you have photo of area?
 
I have had good luck with KW Ceramic Block seal. Just follow the directions exactly.


Cracks in the exhaust ports are not very common.


Good luck.


Chris W.
 
Clean the cooling system real well, and use some type of ceramic sealer as above suggested
or some type of glass sealer. I have seen some high temp epoxies used in exhaust port
That I never thought would work but they did. I Don’t remember what it was though.
If you could find some I’d use both.
When you try and braze in an area like that you can cause the crack to run further if the whole block is not heated and then cooled down properly.
 
Dodge said:
Clean the cooling system real well, and use some type of ceramic sealer as above suggested
or some type of glass sealer. I have seen some high temp epoxies used in exhaust port
That I never thought would work but they did. I Don’t remember what it was though.
If you could find some I’d use both.
When you try and braze in an area like that you can cause the crack to run further if the whole block is not heated and then cooled down properly.
Click to expand...

Thank you for the reply. This is true. I want to avoid more damage.. I will look into it!
Matt
 
Dodge said:
Clean the cooling system real well, and use some type of ceramic sealer as above suggested
or some type of glass sealer. I have seen some high temp epoxies used in exhaust port
That I never thought would work but they did. I Don’t remember what it was though.
If you could find some I’d use both.
When you try and braze in an area like that you can cause the crack to run further if the whole block is not heated and then cooled down properly.
Click to expand...

That looks like my next move. Rather not apply more heat
Matt
 
Pictures
 

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Who ever did the pin installation must not have known the procedure. I don't know if it would work to finish the process now. A person would have to drill & pin between all those old pins to lock it.

Water glass (sodium silicate) of any brand will generally fill in cracks as long as they don't open up too wide. Corrosion pin holes can also fill as long as they are very small but pressures in certain areas may not allow a good seal. A person has to follow the instructions for whatever water glass is used. I use Bar's leaks myself.
 
Last edited:
Matt,
this is a good candidate for the block sealers available in a bottle.
the active ingredient is sodium silicate, or also known as liquid glass.
being this is a low pressure area and in the hot exhaust it will seal quite well.

depending on the water pump you have, you may need to reseal it if it starts to leak.

John
 
One of the valve-making companies makes epoxies, one for intake and another for exhaust. The Co. name has slipped out of my ancient mind.
 
Any sealer or epoxy repair will be severely tested in an exhaust port or exhaust valve pocket location. The area is subject to the highest temperatures of any part of the Model A block as well as to internal pressure exerted by exhaust within the port.

Cracks in this area are rare in a Model A but may be less rare in a Model B because the "B" casting walls are thinner, especially in the #2 and #3 exhaust ports. Cracks will result in coolant leakage into the exhaust manifold and, if the crack is large enough - or there are pinholes, the result will be exhaust leakage into the coolant as the engine is running.

I have a "B" block that is crack-free except for a 1/16 inch pinhole that is open to the mid-block coolant chamber. The pinhole is about an inch below the deck in the upper valve pocket. I have pondered some solutions, such as pinning the pinhole or hogging out the port and pressing in a sleeve. Any suggestions?
 
Here you go...flipped
 

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