If running a flat tappet cam you will always want an oil with a higher level of ZDDP. There are synthetics out there with the additive, as stated above Amsoil, Royal Purple HPS, Joe Gibbs Driven Racing oil to name a few.

Last edited by Rsmach1 (2/21/2016 5:11 PM)

One more reason to run a roller cam. 

Oil formulated for Diesels still have a decent amount of zinc in them, though that might be changing too. Shell Rotella T6 is a great full synthetic 5W40 oil.  I run that in my F250, and it really made a huge difference with cold starts in the winter.  It pours like a much lighter oil, but that has always been my experience with synthetic.  I know some guys are running this oil in their gas engines because of the higher levels of zinc. 

Can't remember where, but I read an article about why you should NOT run oils formulated for diesel engines in your gas engines.  Wish I had saved that article!!
 

Hey guys n gals,there is a oil with a high zinc content already in it! It's made by Lucas and is called " high zinc-hot rod and classic high performance motor oil". Comes in a 5 qt jug or reg qt bottles. I use 20-50 all year long in a 68 289 coupe, and a 67 390 gt fastback. It's on the expensive side to me but worth it! It's about 35 bucks for the jug, but I like Lucas stuff. I also use hyper lube, both motors are happy! I live on long island in NY, and we get every type weather possible, and 20-50 us fine! I wish I could send the picture of it, but I don't know how to do it here! Any way, google it, I think you'll be happy!

terry wrote:

Do yourself a favor and use an oil with the zinc already formulated into it.  IF you use a regular oil and ad zinc, you are in essence changing the chemical makeup of that oil.  In turn that could cause serious damage to your engine.
 ASK ME HOW I KNOW!!
 

 
I'm going to have to call a Point of Order on this statement. Lubricating oil for automotive engines is already a witches brew of additives, so adding a bottle of ZDDP is unlikely to create a condition that would harm an engine. Anyone that tells you otherwise is probably in a position where they are trying to disclaim responsibility. The chemical companies and the auto parts stores would not sell the antiwear additives if there was any credible evidence that those produces could cause harm to engines. After all, the purpose of the additives is to protect engines. However, the best technique is to mix the ZDDP with the new oil before putting it in the engine. That assures that all the lubricant is uniform and the oil pump is not asked to suck up alternating thick and thin fluids.

As others have stated, there are several sources for oil with the anti-wear additives needed to protect flat tappet camshafts.

Hornman wrote:

terry wrote:

Do yourself a favor and use an oil with the zinc already formulated into it.  IF you use a regular oil and ad zinc, you are in essence changing the chemical makeup of that oil.  In turn that could cause serious damage to your engine.
 ASK ME HOW I KNOW!!
 

 
I'm going to have to call a Point of Order on this statement. Lubricating oil for automotive engines is already a witches brew of additives, so adding a bottle of ZDDP is unlikely to create a condition that would harm an engine. Anyone that tells you otherwise is probably in a position where they are trying to disclaim responsibility. The chemical companies and the auto parts stores would not sell the antiwear additives if there was any credible evidence that those produces could cause harm to engines. After all, the purpose of the additives is to protect engines. However, the best technique is to mix the ZDDP with the new oil before putting it in the engine. That assures that all the lubricant is uniform and the oil pump is not asked to suck up alternating thick and thin fluids.

As others have stated, there are several sources for oil with the anti-wear additives needed to protect flat tappet camshafts.

You can call it what you want Hornman.  The auto part stores could care less what you do with what they sell.  And of course the oil manufacturers are going to tell you one thing and the Additives companies another.  the fact remains you are altering the chemical make up of that particular oil!!!!!!

TKO,  If I could still pull threads off the old FYI site I'd point you to a discussion about where adding a ZDDP additive was involved in an engine failure.  There were 2 things in the crankcase of my 289 when I was driving down the highway and the oil light came on. OIL and ZDDP additive.   Long story short, when I pulled the drain plug out of the pan the oil wouldn't run out it was too thick.  I sent a sample to the oil company and their analysis determined it was not their oil!  go figure!!  

 

An additive doesn't alter the oil, they may enhance certain characteristics of the oil for example viscosity, oxidation resistance, anti-wear, etc.  The additive package is actually just suspended in the oil.  There is no chemical interaction (covalent bonding, oxidation/reduction reaction).  ZDDP (zinc dialkyldithiophosphates) were first used in the '30s and '40s as antioxidants.  It was found that they worked in that respect by suppressing the formation of peroxides, and reducing corrosion of lead/copper bearings by reducing organic acids.  It was also discovered that ZDDP also worked as an extreme pressure additive and anti-wear additive.   Under heat ZDDP breaks down and forms smaller molecules that will bond with metal and provide a layer of protection between the boundary layer of the lubricating oil and the metal part.   This layer can tolerate tremendous pressure and temperature, while greatly reducing direct metal to metal contact.  Once this was discovered it became the most widespread anti-wear additive in lubricating oils.  But, nowhere in this process does the ZDDP affect the lubricating oil, it merely acts as an agent to enhance pressure handling, thermal loading, and reduce wear by acting directly on the metal parts in the engine. 

Now, where things could go awry is that I have no idea what was in the ZDDP additive you put in your engine.  If it was straight ZDDP and blended properly in the oil I remain convinced that it was incapable of doing harm.  But, if there was something else in that chemical stew God only knows what it was and what it could do. 

The best course would have been to send an oil sample to someone like Blackstone Labs, who do independent oil analysis.  Then you'd have gotten an answer you could believe in rather than always wondering if the oil company was just covering their butt. 

I use Shell Rotella T, usually on sale for $23 a gallon.  I called the 1-800 number and spoke with a Shell  engineer who did confirm Rotella T has ZDDP and even gave me the levels in the mixture them.  He deemed then as safe levels for a traditional flat tappet engine.  I've used Rotella exclusively for 4 yrs.  Even use it in my 8N flat head tractor!

The concern with ZDDP, and why it was removed from gasoline branded oils is that it can damage the catalytic converter.  Manufacturers are now required to warranty the converter for 100k, as part of the emissions warranty. 

Diesels first had converters starting in the '03 model year (Dodge was actually installing them in the late '90s before it was required).  So, by '03 the link between ZDDP and converters was well known, as converters had been used on gasoline engines since 1975.  The emissions standards for Diesels (levels of allowable pollutants) have been reduced by the EPA at least twice since widespread Diesel emissions started in '03, but those reductions have had nothing to do with catalytic converters, instead they were aimed at particulate matter (requiring Diesels to run particulate filters in the exhaust system), and NOx levels (higher in Diesels due to the incredible compression ratios they run).  Meeting the NOx standard has been accomplished with EGR systems, and on some engines with the use of DEF (Diesel Exhaust Fluid, a fluid containing urea used to reduce the NOx levels). 

From everything I've read about Shell Rotella it contained 1200ppm of ZDDP in its original formulation.  But, Rotella is now meeting the CJ-4 API spec, which has a reduced amount of phosphorus, likely reducing the ZDDP content down to 600-800ppm.  But, I cannot find exact information from Shell or anyone else to verify this.  It must have a maximum of 800ppm, but it could be lower, and how much I cannot say. 

So, I would still run a ZDDP additive in the Rotella for a flat tappet engine, however, the key to ZDDP additives is to get the amount right.  ZDDP levels should be between 1200 and 1400ppm.  Too little doesn't do enough to protect the engine, but too much can cause zinc pitting of bearings and engine damage.  Consequently, I'm inclined to agree that buying an oil with the ZDDP already in it at the right content (1200-1400ppm) is the safest course of action.  Those oils cost more, but I've always said that in the grand scheme of things oil is cheap and engines are expensive.

must be the same article I read about using Rotella!!

I was doing some searching for more info on this subject, most of the articles I found were written by various oil companies.  Of course they are not Biased!   Maybe some one should write one, seems to be enough knowledge in this thread

From what I've read, if you have a flat tappet cam you want 1,200ppm minimum, so I'd opt for the racing oil.  1,300ppm is right in the middle of the optimum range (1,200-1,400ppm)

Lubricating oils are different than fuel.  I would not try to run Diesel in a gasoline engine or vice versa.  Its important to know your classifications, which is why API specs are so useful.  When a "Diesel" oil, or maybe we should say "Diesel branded oil" meets the CJ-4 API spec then it is perfectly acceptable for use in gasoline engines as well.  Unfortunately, as it pertains to our conversation here, when they obtained the CJ-4 spec it also required them to reduce the ZDDP content to meet that spec, making this conversation rather moot.  Prior to the switch, many, many enthusiasts ran Rotella in their classics with very good results.