topped off with PZ 10-30 conventional

[HTSS_TR]

Originally Posted By: 06VtecV6
Originally Posted By: aquariuscsm
Originally Posted By: 06VtecV6
but full synthetic keeps a film between starts
Not true whatsoever. Probably the biggest oil myth out there.
Then what is the benefit of synthetic oil? It is simply a more robust additive package for longer OCIs to the exclusion of everything else? If that is the case, PYB 10-30 or 5w-30 etc. conventional is all we need for 3-5k OCIs!!!

True. Synthetic is good for longer OCI up to 10-12k or longer. For OCI of 5-7k or shorter conventional of appropriate grade is all you need.

 

[Garak]

Originally Posted By: 06VtecV6
Then what is the benefit of synthetic oil?

There are a few other ones, but that's the primary one. The other is being able to make an oil in a very good grade for cold flow. You're not going to be finding a 0w-XX in a conventional. You might in a blend, but more commonly in a synthetic.

For most applications, yes, PYB is all anyone needs for short OCIs.