Engine protection during storage
What is the best product to introduce into engine cylinder heads for protection during long-term storage? Suggestions vary but Marvel Mystery Oil seems to be suggested most frequently. Your opinion would be appreciated.
First, I would not limit the protective steps taken to preserve the well-being of an engine to just the cylinder heads. All of the internal parts, from the cylinder walls to the crankshaft journals, are vulnerable to corrosion. My preference is to coat all surfaces with oil.
While Marvel Mystery Oil is a fine product that serves various useful purposes, I would not use it as a primary tool to protect an engine that’s going into long-term storage. This is because Marvel Mystery Oil has a relatively thin viscosity and it seems logical to me that oil with a considerably heavier viscosity will cling to surfaces longer and provide a less permeable barrier. Though it costs more, I think the added expense of fully synthetic oil is worth it, especially given that it takes only a couple of quarts to thoroughly coat the internal surfaces of an engine.
Besides coating the engine’s components with oil, it also is important to store the engine in a friendly environment, if possible. That means a dry space with moderate temperatures.