Witches tales re synthetic oil:
> Synthetic oil degrades gaskets. False! My engines have cork, paper, silicone composition and copper gasket materials. They have not been affected by synthetic oil;
> Synthetic oil leaks excessively. False! 10W30 and 10W40 synthetic oils have the same flow mechanics as 10W30 and 10W40 non-synthetic oils;
> Synthetic oil is harmful to babbitt bearings. False! I have an engine nearing 50,000 miles of running with synthetic oil, and the babbitt bearings are fine;
> Synthetic oil doesn't keep the engine clean. False! Synthetic oil stays cleaner longer than non-synthetic oil because synthetic oil substantially reduces wear, especially wear of the cylinder walls;
> Synthetic oil is too expensive. False! I use Walmart's Super Tech full synthetic oil costing $17.56 for 5 quarts. On a newly rebuilt engine, I use Shell's Rotella non-synthetic until the piston rings are seated;
> Synthetic oil needs changing every 500 miles. False! My habit is to change the oil once a year regardless of the miles driven. It is a rare occasion when one of my Model A's accumulates over 2500 miles in a year. However, even if one of my Model A's accumulated 10,000 miles, I would only change the oil once per year.