Originally Posted By: Building3
So it seems like I can't go wrong with Rotella, Valvoline VR1 or Valvoline Max Life. One further question, there seems to be a so called "common wisdom" in the collector car world that you should not use synthetic oils in older cars because it will cause the engine to leak for a variety of reasons. No one here mentioned that. So I should file that under "old wives tales" and move on?
There is some truth to it, synthetic oils are very good at cleaning, so often they might dissolve the "gunk" that has built up on the cooler parts of the crankcase like around seals and gaskets, and then you might get an oil leak, you say your engine has sludge, so i wouldn't use a full synthetic oil for now.
Take the rocker covers off and post a few picture on here so we can evaluate how much sludge it has.
What you should definetly NOT do is an engine flush, i know a person who did an engine flush on an engine which had some sludge and it basically dislodged all that sludge and it went straight into the oil pump pickup tube, blocked the screen, lost oil pressure, and the engine was toast and needed a full rebuild, thankfully he caught it early, otherwise the engine would have to have been junked completely.