Re: Another oil thread
Oh man I hate oil threads....they really get emotional (and slippery!)
Being a person that had a Big block OMC (Ford) 460 with a cam that went flat in only 300 hrs or so I started investigating camshaft failures and what oil might have to do with it. (My brother used theSLICK50 type of snake oil in it!!.......Maybe that caused it!!)
Anyway, I found that since most automotive oils for gasoline engines have reduced ZDDP (to protect the cat converter) the camshaft makers like COMP, ISKY, and cam grinders etc have been suggesting that people use oils that have higher levels of ZDDP compounds to prevent cam lobe wear in flat tappet cams.
They say that one should use diesel type oils because they seem to contain more (much more) ZDDP than any of the current crop of gas engine type oils including all of the synthetics.
To that end they recommend using oils like Shell Rotella 15W40, Chevron DELO 15W40 and any other diesel rated single or multi-grade oils.
I suppose if you HAD to use a synthetic oils like Shell Rotella 5W-40 synthetic, Chevron 5W-40 SUV, or Mobil Delvac 1 5W-40 etc would be good too.
Some of those camshaft manufacturers also suggest using GM EOS or equiv for camshaft lubrication.
Here's a couple of articles that reference several major camshaft makers suggestions on what oils/additives to use to protect your flat tappet cam (I suppose those with a roller cam don't have this problem)
nullhttp://www.minimania.com/web/Displa...isplayType/Technical Information/ArticleV.cfm
http://www.hotrod.com/techarticles/engine/flat_tappet_cam_tech/oil_summary.html
Now, I suspect that since there's no marine engine catalytic converters available (yet!!) Mercurys 25W40 and other NMMA FC-W oils probably HAVE the increased levels of ZDDP necessary to protect the marine camshafts out there.
This seems to be a big enough problem nowadays and the people who race and motorcyclist types are all talking about the new oils and how they DON'T lubricate well enough to protect camshafts.
There's also a new oil for diesels that is supposed to be better for cat converters (diesels now have cat converters and particulate filters that are sensitive to older oils). These new oils have reduced levels of ZDDP but I don't know what they did to replace it.
Anyway, if you have an older engine with a flat tappet cam you might consider using a diesel type rated oil to protect it.
All the old engine rebuilders that I talk to tell me to use Delo 15W40 or similar.
Cheers,
Rick
