exhaust bowl crack/leakage

[HopRod]

I have an 8BA block that has had previous exhaust bowl crack repair by pinning. I performed a pressure test on the water jackets and bubble checked for leaks. I found some small weepage leaks at the sites of the pin jobs in cylinders 6 & 7.
I tried to read all the posts on crack repair here and it seems Sodium Silicate comes up quite often. Would this work for sealing up the seepage in the exhaust bowls? Any advice appreciated. Thanks

[HopRod]

One more time around. Anyone?

[Planojc]

I'm no expert on this but I've heard that sodium silicate repairs are used only on water jacket cracks. Check with Richard at Antique Engine Rebuilding in Skokie Illinois. He only works on Model A engines but could answer your question on the sodium silicate process.

[wga]

Used these products on my 8BA. Ceramic / silica based product.


https://www.amazon.com/Irontite-Thor...99359825&psc=1

https://www.amazon.com/Irontite-All-...18738641&psc=1

[Ronnieroadster]

Originally Posted by HopRod

I have an 8BA block that has had previous exhaust bowl crack repair by pinning. I performed a pressure test on the water jackets and bubble checked for leaks. I found some small weepage leaks at the sites of the pin jobs in cylinders 6 & 7.
I tried to read all the posts on crack repair here and it seems Sodium Silicate comes up quite often. Would this work for sealing up the seepage in the exhaust bowls? Any advice appreciated. Thanks

Every type of sealer sold contains sodium silicate in various amounts the difference's between the brands sold are simply how much water is added and what coloring has been added to the water. The best way to seal the leaking pin job would be using the sodium silicate non diluted. I find it on ebay usually I buy the one gallon container size.
I find it works best when there's only water in the cooling system.
Ronnieroadster

[HopRod]

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Thanks for the replies. I was concerned with the direction of pressure asserted from the exhaust side into the cooling system, rather than the water being at a higher pressure than say an intake leak. I am imagining the molecules of the sodium silicate being forced into the cracks by pressure exerted on the cooling system. In an exhaust port leak I was worried the "molecules" would be pushed away from the crack by the higher pressure of the combustion process. Maybe I am over-thinking this.

[Ronnieroadster]

Originally Posted by HopRod

Thanks for the replies. I was concerned with the direction of pressure asserted from the exhaust side into the cooling system, rather than the water being at a higher pressure than say an intake leak. I am imagining the molecules of the sodium silicate being forced into the cracks by pressure exerted on the cooling system. In an exhaust port leak I was worried the "molecules" would be pushed away from the crack by the higher pressure of the combustion process. Maybe I am over-thinking this.

You may be overthinking this. The exhaust is exiting at various pressure pulses unlike the cooling system which is working under a constant pressure.
I do know of a few individuals who had water flowing out their exhaust pipe due to crack issues in there flathead blocks. They all experienced complete sealing using the Sodium Silicate. At the time they purchased it at the local drug store since its also a food preservative also know as water glass.
Ronnieroadster

[HopRod]

Thanks Ronnieroadster, I really appreciate your real world knowledge and help.