oil's aint oil's 2006 jts

[t-rev]

if a lot a of cam wear happens on cold start-up,wouldn't a "sticky" oil work well because the parts would already have a'coating'?,or does it work the other way around?

[Steve S]

if a lot a of cam wear happens on cold start-up,wouldn't a "sticky" oil work well because the parts would already have a'coating'?,

Its not just the cams, but all engine components suffer metal to metal contact on cold start until the oil starts flowing. Oil is formulated to be "sticky" or polar and it will not totally drain off, residue will remain for a very long time. The design of some engines will also leave the cams in a bath of oil so there is little problem at all.

Anti wear additives in the oil "activate" with the heat created during metal to metal contact and coat surfaces with a layer. This coating is continuously being worn off and relaid.  During cold start up this coating should be there from when the engine was last running to do its job until an oil film can be establish. Cams will however always operate in a state when there is metal to metal contact so they should have a good coating of anti-wear on them. Anti-wear additives work on a molecular level, not in a "film" of oil. The large volumes of oil that flow over the cams are not to provide extra lubrication, it is needed to cool the components and of course to provide a constant supply of additives to wherever they are needed.

[colcol]

Cam wear happens on a JTS when the oil is contaminated with by products of petrol which is like a solvent, which isn't good for lubricating the bearings, cams and such, for city running where the oil doesn't get hot and burn off the solvent, change your oil sooner, say at 5,000klms, i have used Shell helix 10-60 ultra racing, as it was on special at Supercheap and i found that my engine didn't blow up which is good, will give the Fuchs GT1 10 - 60 oil, because it has German Technology, just like Volkswagons, so that must be good as well, Colin.