Oil Question

[webbd]

Hello,
So today I was at Walmart and I came across an oil that claimed to be good for 1989 and older cars. It was SF rated. It didn't have all the new ratings. If I remember right, that's what the owners manual in my 86 said. I heard something about modern oil not being ok for flat roller tappets. I have a perfectly stock 305 by the way. So would this oil have more zinc and would it be better for my engine that the new stuff or would I be better off getting what i usually get? This oil was only like $2.25 a quart, too.
Thanks,
David

[steelybill]

You mean flat tappets. If your Elco has roller tappets (don't know for sure what year they started using those) you don't have to worry. If it has flat tappets, the oil with the zinc additives ZDDP is likely a good idea.

[Rix85]

High levels of zinc are rather important when breaking in a new flat lifter cam. After that, not quite so. Depending on the milage, you probably have a bit, most SAE oils will be fine for regular use. As previously written, the higher zinc levels won't hurt you at all in a daily driver. For the most part, Chevy went to a roller cam in 1987, but that's not an absolute. To be sure, pull the intake manifold and have a look. Stay slick.........

[Marv D]

All oils sold over the counter for highway use have reduced levels of ZDDP,, SF included. Anything with the API starburst had to follow the guidelines or be sold as a 'OFF ROAD ONLY' oil.

I would agree 100% with the Rix in break-in is EXTREMELY important and the chance of loosing a cam at break-in without a good oil / additive is 20fold more likely without, rather than with.
But in 'non stock' applications with higher spring pressures and more aggressive cams (as most of us build in our older cars) the anti-wear properties of the API regulated oils are SORELY lacking to support a flat tappet cam with higher than stock spring pressures. The 170psi OPEN spring pressure at .4" lift of the mild smogger cams of the 70's may not require a buttload of anti wear additives such as ZDDP). But the 130# on the seat and 300+ open of spring pressured necessary to support today's "XE" and 'Thumper" grinds are VERY dependant on oils that have high anti wear properties.

Here's a link to CompCams recommendation of running a bottle of their 'break-in additive' with every oil change.

Myself, oils have gotten so bad at supporting a flat tappet cam that I decided it's just not worth messing with. Every motor I've built in the last 3 years (since the ZDDP levels of Delo and Rotella fell) is a roller cam. There is more than good reason for the rollers. More aggressive valve action than is possible from a flat tappet, less wear and friction, and,, no start-up break-in. You simply start the motor and let her idle. That 20 minutes of a screaming new baby is rather un-nerving isn't it! And the added $500 - $700 of a roller cam package will pay for it's self over the life of the motor in more efficient fuel economy IF you can keep you foot out of the throttle

But,,, that's just my 2¢

[CoyoteOn2]

Originally Posted by Marv D

But,,, that's just my 2¢

AND worth a pennies change !! l.o.l.