I heard some aluminum heads benefit from an epoxy sealant to prevent porosity in the water jackets. Anybody know whats best to use, and what the process is? GM may have some over the counter product??
You're gonna love this: Liquid gl***. Yes, the exact same stuff they killed the Cash For Clunkers engines with. I've spent a lot of time down at Lamar Walden's shop in Georgia... Lamar used to race Pro Stock from its beginnings until about 1980, and has built a helluva lot of engines since then too. They used it to seal everything from Pro Stock iron heads that had been hogged out, to hogged and welded aluminum heads, to restore aluminum heads, to my iron double hump heads when they developed cracks around the exhaust seats. "We'd have never been able to go racing if it wasn't for that stuff." he told me. Dyno Don also used to work out of Lamar's shop when he was in this part of the country, and used it on his Fords. If the heads are on the engine, drain the water, plug the water pump ports (pump off), mix up a batch as per instructions, dump into the thermostat housing, cap it off, apply a few pounds of pressure with an air port, let it sit for a little while, drain, let dry over night (or longer if you want), and you'll be good to go. I watched the leak in my exhaust seat go from a stead stream, to a steady drip, to a slow drip, to nothing in about a minute as the stuff was forced into the seam. Walden said it's just about mandatory after a set of aluminum heads has been welded on, because the welds will almost always have some porosity. Interestingly, Sodium Silicate can also be used to "clean" concrete (how, I don't know), seal concrete floors, and preserve eggs! Dip the eggs in the stuff, pull them out and it will seal them completely, preserving them. It's cheap, too. Call a really well-equipped farm store or hardware store. -Brad
Brad, Thanks for the comprehensive answer and suggestions. I'll do some research on liquid gl***. I know loc***e has a casting sealant that requires an impregnation process (I think you need to pull a vacuum). It's used on stuff like compressor housings, not sure about cylinder heads. Eric
My told my Son to buy a Quart of food grade Watergl*** at the Drugstore just for this use on my old '80 C/10, 250 6-banger that isn't done even yet. (It's in my beadroom closet now).... You probably need to flush the heads as good as you can get them unless you have them hot tanked. Then pour the stuff in them like pouring latex paint in the water port's and drain, catch for reuse and let dry in a kitchen oven at say a couple a 100 degree's or maybe a schosh higher? To set the stuff and repeat until you get the water jackets covered thick enough to do what you want done! pdq67
Brad54 is right about the liquid gl***. It's used for many reasons on racing engines. I'm in school right now at The School Of Automotive Machinists in Houston Tx. Judson told us about the loc***e process you mentioned, but I think it was expensive. He said it was needed on some cylinder heads from the factory because they were so porous water would soak through them, but I can't remember which ones. I beleive he also said some cleaning processes can remove the sealant.
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