From: "Veeduber" Newsgroups: rec.autos.makers.vw.aircooled Sent: Tuesday, December 23, 2003 4:25 PM Subject: Re: Engine Knocks After Oil Change! HELP!
.................Hello Bob,
............I'm still not sure what to think about synthetic oil usage in an aircooled engine. We do know that it has a higher flash point than a mineral based motor oil. Mobil says that Mobil1 is resistant to thermal damage up to
400 deg. F., I think. It's also clear that synthetic oil flows better when it's cold which is a plus for any engine during the initial period following start-up. Having said all of that, I've seen that 20w-50 Mobil1 (V-Twin motorcycle formula) runs at a lower pressure in my Berg full flow 1679 at sustained highway speeds than a 20w-50 mineral oil (RevTech motorcycle formula for Harleys) that I'm running right now. The difference at about 3000 rpms after several miles distance is at least 5 but no more than 10 psi. This must mean that these comparative viscosity ratings are not to be believed, at least not when comparing synthetic & mineral oil formulas. Head & oil temps seem to run about the same. As for your suggestion that synthetic oil might not be suitable for the larger tolerances of an aircooled VW engine, I'm starting to believe that you're on to something there and I'm thinking of buying a single weight mineral oil for winter use here in upstate NY (and possibly a 40 weight mineral oil in the warmer months). I've read somewhere that single weight oil more resistant to thermal damage. Is there a specific 30 weight brand that you've seen that's better than the others? With your experience in aviation, have you seen anything about types or brands of oil that might be useful for us v-dubbers?..........btw.........I've noticed that some of the professional aircooled VW drag racing teams, that aren't getting sponsorship money from an oil company, are using Kendall.Tim Rogers