GUYS,
There are several ZDDP additives on the market and I recommend one of them be added at every oil change. Conventional oils have less than 800 ppm of ZDDP and can be death to flat tappet cams, especially when they get a lot of time below 1000 rpm or with too much spring pressure.
Ron
When I first heard about the removal of Zinc from motor oil I contacted STP and although they would not say how much ZDDP was in their oil treatment I was assured that it would treat 4-5 quarts of oil with enough zinc to protect our engines. I think it's still around $4. Beater
I run 1/2 bottle of STP (blue bottle) in the oil in my plow truck (350 SBC), I run Mobil 1 synthetic in it.
I would run a full bottle, but the oil thickens too much in the cold with that much STP (6 quarts).
Been together now for 2 years (after the last cam went south) so I'm not sure how good that is (as it hasn't been that long).
I had a discussion with the tech folks at Joe Gibbs Racing Oil and they told me the ZDDP additives can be removed by some oil filters. They had blended theirs not to do this.
Joe Gibbs started making their own oil when they had cam failures soon after the corp formed. They now sell "hot rod" oil especially blended for flat tappet older street engines. It is another option...Good Luck
ZDDP has NOT been removed from engine oil. The latest Starburst oil spec (
ILSAC GF-4) limits the amount of phosphorus (antiwear component of ZDDP) to 800 ppm max and 600 ppm min.
Heavy Duty Engine Oils have plenty of ZDDP for flat tappet engines. If you're running an aggressive aftermarket valve train, the 15W-40 CI4/SL oils typically have the highest amounts of phosphorus.
ACCCC recommends the use of the [hot] viscosity recommended in your owner's manual.
ACCCC - Engine Oil Article
On every engine we build we recommend break-in with Joe Gibbs BR break-in oil then run Redline synthetic or Joe Gibbs synthetic of the proper weight (stock 235 Chevy to 1400hp Chrysler) NEVER had a problem (and some of these engine get the crap run out of them).
Ron
Here is Comp Cams take on it.
WIPED CAMS
Excellent article...but Doc always writes well and tells it like it is. A "Must read" for anyone using a flat tappet cam.
I hope his back is getting better.
Ron
I'd heard that zinc is most important in cam break in, once broken in it's a lot less critical. That would be for stock cams, people with high spring pressure/steep cam ramps would know better.
Anecdotally, I've run Mobil 1 synth oil for most of the last 22 years in the AMC 232ci six in my '63 Rambler Classic. Dead stock, and broken in looong ago on dino oil. Zero problems, though I think in the next year I'll send off for an oil analysis just to look-see what's going on down there for wear on the hard parts.
I'm about to break in a brandy-new Rambler 195.6 OHV six, new cam and lifters, stock valve springs (comically soft rate!) but I'm using 4 qts of Joe Gibbs + 1 dino oil. Would rather waste money on needlessly good oil than regret, etc.
The 5th qt of Joe Gibbs will go in the first oil change as an "additive".