I'm glad to see people becoming informed about ZDDP. I thought I would add what I have learned.



The ZDDP used in diesel engines is not the same stuff found in gasoline engines. Rotella might be protecting your engine, but you are better off using the ZDDP for gasoline engines.



The ZDDP for gasoline engines bonds to the iron oxide of the surface of the cam and builds up layers like fish scales. That would imply that a large amount of car ZDDP is needed at break in, and then lower amounts are needed thereafter.



The zinc in ZDDP is a carrier and it is lost when ZDDP bonds to iron oxide. The lost zinc will form a sludge in the bottom of the pan. Change your oil after break-in to help remove the extra zinc.



The 4 cyl STP Oil Treatment has high amounts of ZDDP. The motorsickle sumsabitches have done all the research about the various amounts of ZDDP in EOS, STP, etc., and they use the STP 4 cyl stuff. That's good enough for me.



Good luck.

Best regards,



Paul Menten

Meridian, Idaho

Pcmenten,



While oil with the higher gas-type Alkyl ZDDP ratios may exhibit better wear protection than diesel-type Aryl ZDDP ratios (see: the LNE link Y-blockhead provided), the Alkyl additive is not as stable. Since I don't feel like coughing up the $ for SAE reprints, I am not really sure what it is about diesel engines that warrants higher detergent levels, and trading maximum wear protection for ZDDP stability (soot/heat/extended fleet drain intervals)?

I THINK the problem may be that if drain intervals are pushed too far in an attempt to cut fleet costs, and the less stable Alkyl ZDDP breaks down, you end up with severe sludge/acid bearing damage that more than cancels out the wear reduction characteristics.



P.S. I was also surprised to discover (LNE site) that changing oil too often actually INCREASES wear!

6 VOLTS/POS. GRD. NW INDIANA

Read the below tech article-

http://www.hughesengines.com/general/techArticleDetail.asp?articleID=1000039

Very interesting. I noted that Hughes denies that the zinc additives sticks to metal parts (which would negate high detergent/Rotella concerns). Though they DO have a vested interest (selling alternate additive formula), it still seems like a pretty bold contradiction to accepted science.

6 VOLTS/POS. GRD. NW INDIANA

I found this very interesting and informative,but must take it with a grain of salt after seeing the date of it's  publication.A lot has changed in the almost 8 years since.There is also the fact that they are more or less using this info to tout their own products.

 

Paul,

Boonville,MO

Paul,

I think the date you are referring to must be when the site was established, not the specific posting.

6 VOLTS/POS. GRD. NW INDIANA

Daniel,

You may be right.I just noticed the date printed at the bottom of the article and thought that was the date that it was written.

 

Paul,

Boonville,MO

seems to me that to use their own words all that reading is just to sell their own crap. how many cars from the 50's have catilytic converters all i saw through the whole article was how zinc destroys converters which is irrelevant to us y blockers ive been running stp since day 1 & i saw my cam at 3000 miles & it still looked like new.

moz. geelong victoria australia.

graduate 1980, bus, truck, car, hot rod, boat, submarine, hovercraft, hydrafoil, firetruck, mobile home, jet, helicopter, cruise ship, motorcycle, bicycle, santa's sleigh, clock, alloy bullbar, alloy fuel tank, lens, dr who's tardis, matter - anti matter warp drive buffer & y-block lover

Kultulz, Thanks for sharing.  The article reads to be resonably up to date or at least within the last couple of years.  Some of the info would appear to be pertinent while other parts makes it sound like a sales pitch.  Unlike a bad load of fuel, the reduction or removal of zinc from the oil is not the type of thing that will be instantly noticed within the engine and other factors such as cam and lifter hardness and valve spring pressures will also come into play.  The key here is to have minimal wear at 100K miles and not suddenly discover catastrophic wear at 40K miles or less.

Lorena, Texas (South of Waco)

After reading much about the zinc issue on this and other forums, I chose to go with Hughes additive. Haven't had any problems, but it's much to early (1000 miles) to tell.

My name is Greg and I am addicted to Y's.