Howdy folks, Does anyone use any type of a ZDDP Oil Additive in their pre-powerstroke 6.9 or 7.3 engines? If so, how much do you use, and why do you use it?

I was thinking of using some with my next oil change, but not sure if I should...I use Ford 15w-40 motor oil for powerstroke engines and a powerstroke oil filter on my 6.9 n/a...

Thanks for all your comments & suggestions & insights to the ZDDP question.

BeerCan500

 

These engines run roller lifters and cams. zddp is needed for flat tappet cams. Good for a old ford gasser but not needed for these diesels.

 

That's what I have always thought...really no need...however, recently I have been reading that about 1000 to 1200 ppm of zddp may in fact help our 6.9 and 7.3 pre-power strokes by helping to keep the oil pressure up a little and by "cushioning" bearing surfaces due to our engines using wider bearing tolerances...

It could be that I am reading "bunk" articles by the manufacturers of this additive...or I may be completely and totally wrong in my thinking. I really don't buy into "oil additives" at all since as far as I know...most engine oils are already full of additives to the base stock and others additives are not needed.

So then, why can't I find the chemical make-up for Ford's 15w-40 diesel oil. I have searched everywhere and cannot find that info...It would be nice to know...short of calling em and even then...not get it. It seems that Delo and Rotella have it in some of their diesel oils...Why?

Just asking...I guess inquisitive old brains like mine just want to know...

BeerCan500

 

Everything i've heard is zddp is a high pressure additive. It provides a film on metal surfaces. But roller cames put minimal stress on the cam unlike flat tappets. Now if you own a cummins I'd run a whole ton of zddp. Those things have solid tappets o_0.

Check out bob is the oil guy forums. Those guys know their stuff.

You may be right. Its got to help bearing surfaces.


*edit*
http://www.bobistheoilguy.com/forums...Number=1049812

 

what intrigues me about ZDDP and flat tappet cams..is why do people recommend to run them in old FT blocks (my mustang hasa FT cam actually), yet every single import with overhead cams is technically a flat tappet, and no one worries about cam lobe wear? Is it because of the rocker length? Stang rockers are 1.6 so say i have 300# open, x1.6 id be looking at 480# at the tappet?

 

I hear ya...as best as I can figure...and I am probably wrong...is that by using x strength springs (high strength) multiplies rocker length strength like a fulcrum to hold intake valves open longer for use with long duration high lift cams...thereby increasing torque & horsepower at whatever rpm range one is looking for...which in turn puts more wearing stress, galling, and scoring on not only the lifter/cam lobes wearing surfaces but also lower end bearing...rod and crank and mains...yet like you...I wonder...

Do the newer oils or is it better metals/materials preclude the need for zinc and phosforous as a sacrificial layer for long term use...Who knows without dyno trials and teardowns? Hence, my question? Is ZDDP additive another "snake oil" for "old school" engine builders to make them think they need it?

I remember when...60's and 70's engines would need rebuilt at less than 100k...So, better oils, materials, and design have allowed the older stuff to be phased out in conjunction with cleaner air standards and higher mpg vehicles while horsepower has increased. All I know is I used to build a lot of 289's and 340's in my day and have rebuilt 2 6.9's of late. None of which I ever used any additives, but regardless of all the hype...if ZDDP additive can extend the life of my engines I will use it...but to this day I have yet to see the proof.