Thoughts on the best performing oil for a classic

Question

Hello folks, I got a r33 nissan skyline GTST manual with 70k US miles.

What is the best performing type of oil for a early 90s turbo model nissan? conventional or synthetic? What brand and viscosity? zinc additive needed?

My first major change was from 5w30 to castrol magnatec 0w20 cause the intelligent molecules combat cold start wear.

Chuck Tobias · Accepted Answer

With a turbo you definitely want to use synthetic. There are some with sufficiently high levels of ZDDP for flat tappet engines. (It's mainly a consideration in performance applications and breaking in new cams.)

https://www.mobil.com/en/lubricants/for-personal-vehicles/auto-care/all-about-oil/ask-our-auto-experts/mixing-motor-oil-to-reach-the-right-zddp-level-for-classic-cars

Justin Shepherd · Answer

I wouldn't deviate from the specified weight oil on the 2nd number, especially with a turbocharger. 0W-30 will probably be fine on that end and help with cold start wear if you're concerned about that, but 0W-20 may be a tad too thin. If Nissan never updated that 20 weight is okay, I would keep the -30. My Ranger is spec at 5W-30, my Mustang is 5W-20 and I mixed up the specs last time around. I found out later that Ford backwards updated that my engine is compatible with 5W-20 oils in a Technical Service Bulletin. My girlfriend's EcoBoost Mustang is also 5W-30. Other than that, motor oil is pretty much motor oil if it has the API seal. Those "intelligent" wear molecules are probably no better than any other oil's additives and a marketing ploy.

motorcycleman [BANNED] · Answer

From what I heard, magnatec stays in the heads instead of draining to the sump. I'm also running a deathly cold mishimoto radiator kept 100% full never drained once don't know if that's an issue.