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About Crosley engine oils ...

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  • LouRugani
    Some modern motor oils may have a negative effect on our flat tappet camshaft engines. Important anti-wear additives have been reduced from most of today s
    Message 1 of 1 , Jul 30, 2012
      Some modern motor oils may have a negative effect on our flat
      tappet camshaft engines. Important anti-wear additives have been
      reduced from most of today's oils, leading to camshaft lobe and lifter failures. Comp Cam Camshaft Break-In Oil Additive may help for breaking in rebuilt engines and in continuous use.

      This is a cause for concern. The reformulation of engine oil to meet modern emissions requirements was causing problems for vintage car owners It seems that many oil companies are aware of these problems and have begun to address them.

      AMSOIL was the first company (in 1972) to market fully synthetic motor oils for all types of engines. AMSOIL says "We offer a full line that contains an extreme pressure additive package that has a proven history. Products like our (AMO) 10W-40 and (ARO) 20W-50 gasoline-engine oils contain high ZDDP levels, and are perfectly suitable for flat-tappet cams. We're very committed and are
      actively pursuing ways to specifically market these lubricants to classic car hobbyists.'

      Shell Rotella T is a high-quality lubricant with high levels of the desirable anti-wear additives. Current ZDDP levels are 1,200 ppm.
      Shell was asked if there are any negative effects when using ROTELLA T, and replied: "For older gasoline engines that are no longer under warranty, and emissions aren't a concern, there are no major negative effects when using ROTELLA T. In fact, it carries an API S series
      rating. The only possible concern I see is viscosity, 15W-40 will not circulate as quickly during initial start up in extremely cold weather. In these harsh situations 5W-40 synthetic is then an option. A point to remember is that zinc not only protects flat tappet camshafts against wear, but also any high pressure metallic surface that relies on pressurized oil for lubrication, such as the piston rings, cylinder walls, and rocker arms/pushrods. When oil can't carry the load, zinc steps up and creates a chemical barrier, and the high levels of zinc in commercial grade oil contribute to the fact that some diesel engines run a million miles or more. I don't see us reducing the zinc content in ROTELLA T unless an organization like API imposes a lesser chemical limit on a subsequent category."

      On the ZDDP Additive:
      After 70+ years of troublefree metal-to-metal engine protection, the E.P.A. is forcing ZDDP (Zinc Dialkyl-Dithio-Phosphate, the chemical term for zinc and phosphorus) from domestic motor oil. Our Crosley engines require the friction modifier ZDDP in the engine oil to
      avoid premature deterioration. ZDDP is a surface modifier that alters bearing and journal surface characteristics to prevent metal-to-metal contact. Under 3000+ rpm, heat and pressures quickly increase, and the ZDDP molecule quickly plates over the contact surface with an extremely thin glass-like film and provides a sacrificial coating. As soon as engine conditions return to normal, the film dissipates back into the oil solution. This action prevents the lifter and cam from making contact and greatly reduces the tendency of parts to scuff under the heavy-load boundary lubrication situations.

      These high-load conditions also exist in piston wrist pins. Before 1988, normal amounts of ZDDP could be found in domestic engine oils. The API grade "SG" oils contained in excess of 0.12% ZDDP by weight. The API grade of oil prior to this was "SF" with concentrations in excess of 0.15%.

      For over 38 years it was possible to buy E.O.S. {Engine Oil Supplement} from GM in a 16-ounce bottle, but E.O.S. was withdrawn in the second quarter of 2007. However, E.O.S. may be making a comeback at GM dealers.

      More to come on Crosley engine lubrication ...
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