Motor oil info

[Seattle Sam]

The Pennzoil 25-50 GT has NO zinc listed on its data sheet, and claims to be compliant with the current API SJ standards.

[Salvatore]

So what oil is good for us to use in our street motors. I have always used Castrol 10w-40. No good anymore?

[Belair62]

This is supposedly a real concern on engine/cam break in...but I use Valvoline Racing all the time which has a good amount in it..GM engine oil supplement also is supposed to have plenty of zinc but don't quote me on it.

[tirebird]

All the research I've read so far indicates that this is a break in problem,..not a running problem with already broken in engines. For my recent rebuild, we used Castrol 10-40 with moly lube and GM break in additive. Changed the oil at 500 miles to plain Castrol 10-40, and at 3k to Mobil 1 10-30. No cam problems and no oil burning.

My question still is if the oil marketers can't use zinc and phosphate, what are they using to reduce wear and are these substances just as good as ZDDP?

[tirebird]

I wrote to Mobil 1 about zinc/phosphorous levels in it's motor oil and received the following response.

"Mobil1 MX4T 10W40 and Mobil1 V-TWIN 20W50 motorcycle motor oils, Mobil1
15W50 Extended performance and Mobil1 5W40 diesel motor oils contains
the higher levels of zinc and phosphorous for your cams. The new energy
conserving motor oils do have reduced levels of zinc/phos however, they
typically do not have any adverse effects on cams unless you are
running
higher valve spring pressures. I would suggest you stick with the
product listed above if you are concerned about the phos/zinc issues."

[Mr70]

I wanted to add this link onto this topic as I found it useful and informative.
More Than You Ever Wanted To Know About Motor Oil

[Chevy454]

There's also a good article in one of the latest Hot Rod magazines...they talk to oil mans and cam mans...pretty interesting...