| | | quote | | Just saw this thread and didn't see any mention of zinc additive needed for flat tappet cam motors... The only off the shelf oil that has it is diesel/ truck oil. |
|
Not True...but
Yes, 'What' Engine Oil
Really MATTERS and in my world, I
never use "additives" in my engines.
Of course, the Fiero V6 has flat-tappets and
needed "Zinc" or ZDDP to protect the cam/lifters from metal-to-metal contact in the '80's.
Unfortunately, ZDDP {zinc and phosphorus} also creates a film inside of catalytic converts which "poisons" the CAT and the API SF rating is now considered
obsolete.
So, MANY '
modern' motor oils have
less ZDDP now to extend the catalytic converter life,
however, many use moly and in some cases titanium to prevent wear.
The API SJ rating is current for 2001 and older automotive engines.
Regrettably, it is very hard to get the 'true' amount of the ppm quantities of zinc, phos, moly and titanium to prevent wear,.......
As an example, which I use in my V6 is conventional Castrol GTX 10W-40.
900 PPM Zinc or 610 PPM?
700 PPM Phosphorus or 750 PPM?
{BTW - in the link below, some Castrol GTX oils are shown in the OUTSTANDING section, however 10W-40 isn't included on their list.
}
FACT: ZDDP is consumed/sacrificed A LITTLE AT A TIME as needed by the heat and load on mating parts.So, I change my engine oils more often than waiting...
--------------------------------------------
PS| | | quote | Zinc Myth and Test Data
Oil's "wear protection" capability that was tested here; the higher the psi value, the BETTER the wear protection. And this applies to ANY engine, including High Performance flat tappet engines.
*Over 90,000 psi = OUTSTANDING wear protection
*75,000 to 90,000 psi = GOOD wear protection
*60,000 to 75,000 psi = MODEST wear protection
*Below 60,000 psi = UNDESIRABLE wear protection |
|
This list in the link below shows nearly one hundred oils tested!https://www.speed-talk.com/...o%20metal%20contact. ------------------
Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles
[This message has been edited by Vintage-Nut (edited 10-26-2025).]
