mobil 1 oil

[Mike N.]

1957 vette-

What's the take on using sinthetic (MOBIL 1 30 weight oil) on a newly rebuilt '57 283 engine?????

Would the motor leak profusely??

Thanks in advance
Mike

[Joe L.]

Re: mobil 1 oil

Mike-----

Whether the use of Mobil 1 is a worthwhile investment for an engine is a matter of considerable debate. I like synthetic oils even though I admit that the only real benefit that they provide is higher temperature capability which may or may not ever come into play. However, as far as the propensity to leak, that's either an "old wive's tale" or a legitimate rap for EARLY synthetics that's not a problem today. Your engine is no more likely to leak using a synthetic 10W-30 than using a conventional 10W-30.

The base oil for any multi-viscosity motor oil is the LOWEST weight of the range. Temperature-sensitive viscosity improvers make the oil act like a higher weight oil at higher temperatures. So, a 10W-30 oil is, basically, 10 weight oil, whether it's a synthetic or conventional.

[Duke W.]

Re: mobil 1 oil

The primary advantage of synthetic base oils is greater resistance to oxidation. This provides both higher resistance to oxidation in applications that run very high oil temperatures (like racing without and oil cooler) or longer service life. Also, synthetics flow better at arctic temperatures, so a 0W-40 is a suitable year round oil if you winter in Fairbanks and Summer in Phoenix.

What few ever think about is the additive package - the detergents, dispersants, anti-wear, and anti-corrosion additives that engines need to provide long term protection. The level of these additives has been reduced over the years in motor oils designed for spark ignition engines. Because modern engines warm up faster and have more precise fuel control, blowby dilution is less of an issue with modern engines, so they don't need as much additive concentration, and the combustion byproducts of some additives are believed to contribute to catalyst aging.

Current heavy duty diesel engine oils have a higher concentration of these critical addtives, which will likely benefit the longevity of vintage engines that have more crankcase dilution and more sliding surfaces. They are available in both mineral oil and synthetic base, and if you only drive a few hundred to a few thousand miles a year, an annual change with a mineral base oil should be perfectly adequate.

Motor oils are rated by API service catergory. The current service category for spark igntion oils is "SM". The current HD diesel engine service category is "CI-4". That's all you need to know. Brand names are not important - the API service catergory is what counts.

The only other thing you need to select is viscosity based on the expected ambient cold start temperature range you expect during the oil service interval. CI-4 oils are commonly available in 15W-40, which covers the range of about 15F to 100+F.

To learn more about motor and gear oils visit www.api.org

Duke