Does assembly lube go bad? Whats the longest you can leave an engine on the shelf before you would need to disassemble it and add new lube?

When you build the engine, and you use assembly lube or good oil, it can have a fairly long shelve life. (I prefer oil)

However, before you start it, fill it with oil and use a drill in the dist shaft and prime the engine. This will move oil throught the engine and to the bearings. Also, move your crank to make sure you get the oil to the rocker arms.

I have had them sit for a couple of years, primed them and then started them - no problems.

I have used white litheum assembly lube for years with no problems, others have used STP/Oil mix, staight STP, straight 30 oil. It is all in what you want. Engines were rebuilt and fired on assembly lube. for years without priming. Very few problems ever resulted - now doing this is a big NO-NO. What ever turns your crank.

Suppose the engine was assembled with white litheum assembly lube, and sat on a shelf in a shop for 5, 10, or even 15 years? would there be any chance of the lube drying out or would it be perfectly ok to just prime it up and fire it?

Personally I would prime it and fire it.

Ok, thanks