Using Silicone Sealants
Since I do technical service for Valco Cincinnati I figured this would be a great place to add some tips. As a personal gearhead first for me its not about sales but about doing it right. The Number one cause of engine failures that leads to core engines for rebuilders is the misuse of silicone engine sealants. When over application of sealants is done you get squeeze-out….Well you also get Squeeze-in….Oil in direct contact with silicone over a large surface area makes it swell. Once it swells it will break off and float around in the oil for awhile. Then at the worst time usually it will plug up a oil galley or hold a pressure relief valve open etc. Valco made a tool to help people use the right amount of sealants when assembling their motors. The Tube-Grip tool was invented and allows the tip that is supplied with your silicone to be cut to the absolute smallest size. You can put down such a fine line of sealant with it that it looks like a robot did it! For a experiment take a regular sheet of notebook paper and put down a average size bead of sealant like you currently use. Now fold the paper over and squeeze it…..Watch how wide your bead becomes! Most engines never use a flange big enough to use that much sealant! So even if your careful you tend to use too much sealant without a Tube-Grip tool. Most of the time you dont need more than a “Dab” or fine line like a sharpie marker produces… As for automotive silicones…There is several kinds. I am familiar with them all, Oxime cure, Acetic acid cure, Amine cure….Different viscosity etc. What they have in common is they all use “Humidity” from the air to cure. That is why you give them time to cure for a few minutes before assembly. During that time Humidity from the air is absorbed causing them to Crosslink & Cure. Without air silicone will never cure or will cure over months or worse. Squirting water on it wont speed it up….But a air conditioned garage can slow it down. So basically silicone in Arizona will cure slower than silicone from Ohio… When removing a silicone seal…You dont have to remove every last trace! If you are replacing the part and it fairly clean all you have to do is add more…Silicone loves to stick to silicone!A unique product that Valco Cincinnati Consumer Products has is a Aluminum Silicone that actually has 5% powdered aluminum content and will give 100% heat transfer abilities and allows it to be used with headers and high heat areas with little effect to the silicone at all 600 degrees is shaken off real easy. The Aluminum silicone is also perfect for intake manifold end rails because it blends in with aluminum intakes and you dont hardly even notice it. Blue silicone is a NO-NO….Sorry Ford guys….But the blue mineral that makes silicone blue also tends to attack silicone and make it cure slower and hold up for less time….We no longer offer any blue silicone for that very reason. If you have questions feel free to ask me. I have done tech support since 2001 and I have a great understanding of auto sealing needs.
Thanks, Brian Santefort