You will never experience a “dry start” because there will always be a film of oil that stays on all of the internal parts of your engine, even if it hadn’t been started for many years.
I used to think this, too. But I had an experience at work that completely shattered my worldview on motor oil as a preservative.
No secret, I work with the large industrial Cummins engines. A customer of ours has ships they use to service offshore oil drilling rigs. These ships have up to SEVEN of our 50L V16s aboard (at a conservative 2000hp each) and look like this:
They reached out to me because they had experienced several camshaft failures on boats that had come out of drydock. In the course of their own investigation, they managed to document photographically that several of the camshafts on on vessels still in drydock had flashed surface rust between the lobes.
The engines were running fine while at sea and no evidence of internal corrosion was ever documented while in service. The engines weren't touched during drydock, but they did sit for months on end immediately near seawater with just the residual oil film from engine operation to protect them.
The first time you see rust INSIDE an engine that has been running fine for years up until it sat unused for months, you too will probably question just how good a preservative is engine oil film for prolonged storage.
There are engine preservative oils made for the purpose of preventing internal engine corrosion (VP/Royal purple have one. Cummins recommends Tectyl 900 for storage).
These products are necessary because engine oil alone is not a long term preservative. How long is long term? I personally think engine oil is good for maybe 6 months. I wouldn't go longer than that on regular engine oil.
