For my old trucks and motorcycles I like to let them warm up awhile before I use them. Straight weight oils and old tech metallurgy aren't the best recipe for "start it and go" in my way of thinking. I also like the oil to thin out some multi viscosity or straight weight with the rise of temperature to know it's flowing freely through all the galleries and bearings Secondly the cylinder head heats quicker than the block and I like to give the block a chance to catch up a little first before I give the engine any combustion stress keeping the head gasket from taking up the slack between the hotter and colder parts of the motor.
