Adding Zinc to Oil?

[DAVID GAGNARD]

Originally Posted by Steve Gallegos

I just got off the phone with an Amsoil rep regarding oil changes. I use 20-50 with Zinc. He told me that with this type of oil that I can go 15 to 20,000 miles without an oil change. Just change the filter about every 2 to 3,000 miles. any comments

The reason for oil changes is the oil gets contaminated over time/miles,not that it wears out per say......once it reaches a certain level of contamination, it is not doing it's job...

With that said,a buddy of mine used to work on an offshore rig for Shell Oil, they had 7,6000 hp gas turbine engines and 6, V-12 diesel engines. he would take oil samples at certain hourly intervals and have them checked, that's how they determined when to change the oil... One year he began doing the same thing with his daily driver, a late 70's Ford Ranchero with a very mild 351-W he built.....He was using Shell Rotella T 15/40 in the Ranchero and he kept it well tuned, mostly highway miles, he found that he could go 12,000 miles between oil changes....He didn't like going that long between changes, but he would go 7,500 miles........

I would guess the way most folks use their Cobra's, they would have the same level of contamination in 4,000 miles, condensation from sitting is the worse type of contamination as is short drives.....On long extended highway/interstate drives, the condensation has time to "boil off" the oil,thereby keeping the oil cleaner for longer periods.....

David