Is there any truth to the rumor that regular oil doesn't have the wear additives necessary in an older engine? Some say that only Shell Rotella has the additives, and others say to add Comp Cams break in lube on every oil change. What's your take on this issue, and what oil do you use in your classic car(s)?
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June 3, 2008 6:55 a.m. bravenrace HalfDork
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June 3, 2008 7:57 a.m. wcelliot New Reader
There is a lot of info out there at various sites... most of it agrees in concept if not in detail.
Here is a writeup done by a Corvair guy who is also an oil dealer.
http://www.widman.biz/Corvair/html/oils.html
Rotella was once a very good option, but with the oil companies changing specifications constantly, what's a good option today might not be tomorrow...
Bill
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June 3, 2008 1:15 p.m. foxtrapper SuperDork
Most of the sites screaming this also make the comment that no modern engines use flat tappets. That should quickly tell you something about the knowledge of those making the claim.
Where I have found good information is from Rouch and other racing teams. They had (past tense) problems with extreme ramp angles on camshafts and quick destruction of the lifter and cams.
After much research, they learned the new oils had reduced zinc (and a few other wear metals). When they either added these additives, or switched to different oil formulations, the problem went away.
Since then the story has grown to encompass all old engines, which was never actually the case.
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June 3, 2008 2:28 p.m. bravenrace HalfDork
Okay, but "what" additives and "what" different formulations? IOW, what should I be running in my older cars? Thanks for the info!
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June 3, 2008 2:59 p.m. DneprDave New Reader
The additive is ZDDP. Mobil oil's website has a good explanation:
http://www.mobiloil.com/USA-English/MotorOil/Car_Care/AskMobil/Zinc_Motor_Oils.aspx
The "attached table" at the end of the link is a pdf file that gives the ppm of the phosphorus compounds and a lot of other interesting information.
Dave
