sealing engines--

[Baxter Culver #17184]

There is a product for sale (at least at my NAPA store) that could solve a lot of engine leakage problems, particularly if used in the course of rebuilding an engine.  It is an aerosol applied silicone sealant produced by McKanica of Aurora, IL.  (Internet link http://www.mckanica.com which can be used as a gasket substitute or in conjunction with a gasket.  A local club member (Wayne Lyndon) used it as a substitute for the cork seals that are usually fitted in the rear main bearing cap of a flathead Cadillac engine.  Used in conjunction with the Mercedes seal, his engine is now drip-proof.  What the sealant does is similar to those foam seals that can be injected into voids around the house.  When injected, the silicon foam expands to fill the void, then hardens (cures) in about 12 hrs.  It comes in several types.  In the application I am aware of, the "Red High Temp Silicone" was used.  It should be good in applications where temps are up to 650 degrees. It can also be removed if repairs are later needed.  
I will be using it when I assemble my flathead--which should be back from the machinist tomorrow.

[Chris Braun]

Sounds interesting, but I have a few questions...

How do you know that chunks of this stuff wont fall off inside the engine once it "cures"?

When using crack and gap filler in a house, it is often the case that the gap filler over expands, and pushes things apart.  What are the chances that it will bend things, such as an oil pan, valve covers, etc?

And most importantly....  how much does this stuff cost for how many ounces/pounds/etc?

[baxter culver #17184]

Good questions.
As with all gasket sealers, this one should be used judiciously.  It seems to have consistency and resiliance much like the Silicone you buy in a tube.  "Chunks" breaking off would be unlikely if carefully applied, not slathered on.

I see it as a valuable sealant for those instances where sealing is difficult because of a particular design --such as the small rectangular cork seals that are on each side of the main bearing cap in the flathead engine.  The sealant manufacturer does claim it can be used on valve covers, water pumps, front covers, etc.  If it lives up to those claims, it could replace the Blue Silicone tube found in most garages.  The unique design of the tube does give the user a lot of control over how much is dispensed and at what rate.  

As for cost, the aerosol can contains 6.7 fl oz.  The cost was under $10 (cant find the receipt).  So it is probably a little more expensive than a tube of Silicone on a per oz basis.  While I dont intend for it to replace my can of Permatex #2, I will use it on the main bearing cap and experiment with it in other places as a potential substitute for the Blue (or Orange) Silicone I have been using.