I see a lot of topics on engine break in, but not a lot on the differences on classic vs modern cars.
Modern cars are filled with fully formulated synthetic at the factory and driven off the assembly line.
If you do this after rebuilding an old engine, the piston rings won't seal properly, so you need to run a break in oil, or at the very least conventional oil. Synthetic oil is actually too good at preventing wear.
Why are modern cars able to do this, but classic cars can't? Is it the surface finish of the cylinder walls? Is it special materials like Alusil or Nikasil? If break in is the final step of the honing process, do modern engines just have this step already completed? Is it the assembly lube they are using?
Is it actually beneficial to dump the factory fill? If you run the factory fill for the full OCI, maybe the extra metal have an abrasive effect and mimick the effect of break-in oil?
Modern cars are filled with fully formulated synthetic at the factory and driven off the assembly line.
If you do this after rebuilding an old engine, the piston rings won't seal properly, so you need to run a break in oil, or at the very least conventional oil. Synthetic oil is actually too good at preventing wear.
Why are modern cars able to do this, but classic cars can't? Is it the surface finish of the cylinder walls? Is it special materials like Alusil or Nikasil? If break in is the final step of the honing process, do modern engines just have this step already completed? Is it the assembly lube they are using?
Is it actually beneficial to dump the factory fill? If you run the factory fill for the full OCI, maybe the extra metal have an abrasive effect and mimick the effect of break-in oil?