I receive regular emails from a Porsche development website, located in California. As one might expect, everything
"LN Engineering, LLC", sends is top-notch.
Their opinions on modern oil usage caught my eye. We don't hear of "break-in oil" nowadays, but with today's modern engines, the importance of break-in oils has actually risen.
Here's a partial quote with
synthetic oil highlighted:
Quote:
"...Both the cylinder walls and piston ring faces would wear into each other, hence where the term breaking in an engine came from. Cylinder bores in modern engines are for the most part all plateau honed and use harder carbon steel piston rings, many of which use coatings like CrN (chromium nitride) to provide increased durability. This results in less wear during break-in but can also mean engines can take longer to break-in and can be more sensitive to tuning issues during initial run-in. Likewise using the wrong oil during this period can extend the amount of time it takes to seal up the piston rings or even prevent them from seating at all. That is why a break in oil is used and synthetics or any oils with friction modifiers should not be used during the break-in period.
"As the engine oil is often referred to as the gasket between the piston ring and the cylinder bore, what oil is used for break-in and afterwards is critical. We all know never to use a synthetic or semi-synthetic oil in a new engine, however using any engine oil with friction modifiers can also negatively affect the ability of the piston rings to break-in, resulting in poor ring seal and increased blow-by. Remember, we need there to be some wear between the rings and cylinder bores to allow everything to seal up properly during this period."
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Their recommendation for all engines is a motor oil with the brand name of "
Driven".
Forty years ago, engine rebuilders were advised
not to use
STP when re-assembling their engines. Because of the above quote, I suspect even the small amount of
STP used would mix with conventional break-in oil, thereby affecting the length of time piston rings would take to "wear-in".
I disregarded that advice when rebuilding my occasional Porsche 911 engine (among others), thinking the benefits would outweigh any negatives. Fortunately, unbeknownst to me, everything worked out well.
LN Engineering also brought up the oil measurement markings on Porsche dipsticks. It turns out, Porsche revised their dipstick lengths, even providing replacements.
When I rebuilt my first 911 engine, it was to replace valve guides, seals, and gaskets because of excess oil leaks and oil consumption. Little did I know until having the exact same problems,
that dipstick had broken off at the end about ¾-inch!
