hey guys, gals,

im in marfa tx and ran into a mercedes guy who told me to run pennzoil 10w-30 (sl) in my block based on zinc?

he also said it had to be black label pennzoil instead of yellow label(sm or sadomasochism, as he termed it).

the reason he said is that the (sm oil) will play havoc with the rockers....

note- the sl/sm is on the back of the bottle in a small circle.....

is this good information or horse hockey....

lyle

As long as you are running approved oil you should not have a problem.

Lyle, what are you driving?... what is the tappet design of the engine?... flat tappets or roller followers?

SL oil has more ZDDP (zinc) than SM oil, which is better for tappet designs, but not necessarily a "must-have" unless the engine is running a hot cam with high spring tensions, such as an altered engine. SM oils have enough ZDDP content for most engine applications.

Though there is a smidgen of truth to what he said, he was throwing his weight around more than anything else. Spend some time on bobistheoilguy.com and you'll get details on this issue.

Yeah, at some point, in the early eighties I think, MB changed the composition of the cam lobes and rocker arm surfaces to be more tolerant of the lower-zinc, emmissions-friendly oil formulations. I'm sure some of the guys on here have better memories of the timeframe than me. But, any engine less than 20 years old should certainly not be affected by the current low-zinc oils.

DG

There's a lot of hoopla surrounding Zinc, ZDDP, etc... especially when it comes to breaking in new (non-stock) flat-tappet motors.

You can either take a class from a triboligist like Kevin McCartney, or just use what the manufacturer tells you to; simple as that. If you want to use something different, forget the SAE and ILSAC standards and look for ACEA certifications on the bottle.

Also, while bobistheoilguy.com has a lot of good info, it's not the end-all-be-all. If you really want to compare oils, just go to their websites and get the MSDS/tech sheets. You might also try out blackstone-labs.com and get your oil analyzed to see what's actually going on instead of just guessing.

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.