motor oil

schrader7032 · Post by **schrader7032** » Tue Aug 25, 2009 7:51 am

I would think that the straight weights would be acceptable to use...you just have to manage your oil changes more frequently for the changes in temperatures. Part of the issue with multi-vis oils is that the viscosity enhancers can break down over time, so you won't have the full range of viscosity the longer you run the 20w50. But probably at the frequent change intervals that these bikes require, that really shouldn't be a problem either.

The important thing to do is to use a quality oil. I attended an oil seminar the BMWMOA National rally in July. It was given by a Spectro oil engineer and while some of what he said might be sales hype, Spectro tries to make their oils at the top levels of the various specs. He said that if one of the tests requires a reading of say 55-68 (for whatever the test was), they made sure that the oil read as high as possible, nearer the 68. This way as the oil quality degrades due to use and combustion products, it remains within the oil grade for as long as possible. BMW's oils are made by Spectro...that is what I use in all my bikes and my '73 Firebird.

The other thing you should make sure of is that the oil is an SG grade oil. This will have more than adequate amounts of ZDDP which helps protect the old engines and is good for flat tappet type top ends.

Kurt in S.A.

VBMWMO · Post by **VBMWMO** » Mon Feb 15, 2010 2:53 pm

I have been using Castrol 20-50W in my 68 R-60 US for a while, but have noticed that my auto shop is now selling straight 30W and 40 W in castrol too. Does any one think there is a difference in say running the 40 for summer and 30 for cooler temps or just stick with the 20-50W. The bike has 37K on it , and I change the oil frequently. Thanks.