While there are tons of reasons why you can destroy a cam, one of the more recent hot topics has to do with
zinc content. Having lost a cam myself while running Mobil 1, I have been thinking of a change. Nothing against Mobil 1... I have used it for years in my other cars with great sucess... but those cars did not have a flat tappet camshaft. My Cobra does.
I have been considering switching to Rotella T
synthetic 5W-40 partly because of the
zinc content. Plus it is available at darn near every truck stop in the country and at $13 a gallon (Wal-Mart), the value is hard to agrue with. So, I contacted Shell, told them of our issue and asked them for their advise. Here is their response:
"The Rotella T oils, both the conventional 15W-40 and the
synthetic 5W-40, are formulated primarily for diesel engines. Although exact additive concentrations are proprietary, the Rotella T oils have a robust anti-wear additive chemistry and contain substantially more
zinc than a dedicated gasoline engine
oil that must meet the ILSAC GF-4 requirements for concentration of metallic and phosphorous based additives because of their effect on catalytic converters. While we have no data exclusive to flat tappet camshaft designs, we would expect the Rotella T
Synthetic 5W-40 to perform well in these engines."
If you care to see what the zinc content of the
oil you are using is, a quick search on Google should give you the information you need.
I have also contacted Crane Cams to get their input and will post it here once received.