Jump to content

New oils in flat tappet engines - ZDDP

Recommended Posts

the simple answer to your question is "no" - "new" oils will not cause any problems for cars with "slider" / flat tappets. Remember, earlier oils served us well without the "high pressure" anti-friction additives that have been a part of consumer-grade motor oils for the past few years.

Remember, the so called "anti-friction" oils were added to improve gas mileage - not to solve any problems unique to so called "sliding" or "flat tappet" cam followers.

True, high quality engines have had roller cam followers since at least as far back as World War One. True, "lesser" quality (meaning low and medium price car engines, where no-one ever thought they'd be run much past 100,000 mi, were not equipped with rollers.

These days, even the lower-price motors now seem to have roller tappets. I am curious - even my Toyota now has roller tappers - does anyone know of any major manufacturer today who hasnt yet adopted roller tappets.

Again, we consumer-grade motor operators ran up an awful lot of mileage on the ore-anti friction" additive oils.

Now, let me qualify the above - SOME engines, such as the 300 and 500 series Lycoming aircraft engines, have a special problem where the so called "anti friction" additives seem to help a little. The reason for this is the location of the cam-shaft - very high in the engine, where they dont get the kind of oil bath that a cam-shaft in the standard location gets. If you happen to have a motor with the cam-shaft way high in the engine, you might be wise to use an "anti friction" additive.

Link to post
Share on other sites

6686L In reply to your statement about modern engines all having roller tappets, I agree with you that they all do. The reason is because a roller tappet allows you to use a cam profile with a much steeper ramp angle therefore opening the valve sooner and keeping it open for longer. This can translate to more power and efficiency from a smaller engine, which translates to more profits.

Link to post
Share on other sites

RE : the question was - will the "new" oils cause harm to "slider" (meaning non roller equippeed) tappet/camshaft systems.

C'mon..guys..you are missing the point. The anti friction additives that are no longer being put into consumer-grade motor oils, WERE NOT PUT IN THERE BECAUSE OF CAMSHAFT ISSUES ! The petrol industry and the auto industry dreamed them up to hopefully get a bit more mileage out of cars.

We had a long history of non-additive oils. Cars ran fine with them and gave good service life (remember, good service life in the old days was about 30,000 miles between valve jobs...MAYBE 60,000 miles between overhauls). But that was in large measure because most cars did NOT have air or oil filters.

The insistance on the addition of anti friction additives to oils, by the makers of small piston-powered aircraft motors, has NOT stopped the epidemic of cam and lifter failure ! The failures are most likely due to 1) corrosion pits from long period of dis-use and 2) bad shop overhaul techniques. Let me explain. "Grinding" cams and surface grinding lifters is BAD PRACTICE. You generally damage or lose completley the thin "hardness" layer. You are lucky to get a couple of hundred hours of operation out of an engine that has re ground cams and lifters no matter WHAT additives you put in your oil. Of course there are exceptions.

But again, the answer to the original question is - GO DRIVE THE THING ! FREQUENTLY ! Change the oil at regular intervals ! There were an awful lot of cars that did not have roller lifters, prior to the 2nd World War. And they racked up a lot of miles on engine oil that was far INFERIOR to ANY "legit" multi-grade oil you can buy today.

Link to post
Share on other sites

Original tappets and camshaft, 480,000 miles in 76 years. Always used Imperial Esso oils, single grade (20 weight now). Tried multi grade several times and was never happy with the oil pressure on long (over 400 miles) highway trips.

Link to post
Share on other sites

This is an interesting article that I found on the internet.


"Oil is Killing our Cars"


Keith Ansell, President

Foreign Parts Positively, Inc.



Oil is Killing our cars Part I

About a year ago I read about the reduction of zinc dithiophosphate

(ZDDP) in the oils supplied with API approval that could affect sliding

and high pressure (EP) friction in our cars. The reduction of these chemicals

in supplied oil was based on the fact that zinc, manganese and/or phosphates reduce the effectiveness and eventually damage catalytic converters and introduce minute amounts of pollutants into our atmosphere.

A month or so ago I had a member of the Columbia Gorge MG Club bring a

totally failed camshaft and lifters back to me that had only 900 miles on

them!! I immediately contacted the camshaft re-grinder and asked how this

could happen. They were well aware of this problem as they were starting

to have many failures of this type. In the past, the lack of a molybdenum

disulfide camshaft assembly lubricant, at assembly, was about the only

thing that could create this type of problem. My customer has assembled many engines and had lubricated the camshaft properly and followed correct

break in procedures.

This got me on the phone to Delta Camshaft, one of our major

suppliers. Then the bad news came out: It's today's "modern" API

(American Petroleum Industry) approved oils that are killing our engines.

Next call: To another major camshaft supplier, both stock and

performance (Crane). They now have an additive for whatever oil you are

using during break-in so that the camshaft and lifters won't fail in an

unreasonably short period of time. They also suggest using a diesel rated

oil on flat tappet engines.

Next call: To a racing oil manufacturer that we use for the race cars

(Redline). Their response: "We are well aware of the problem and we still

use the correct amounts of those additives in our products". They

continued to tell me they are not producing API approved oils so they don't have to test and comply. Their oils were NOT the "new, improved and approved" ones that destroy flat tappet engines! "We just build the best lubricants possible". Sounds stupid, doesn't it, New-Approved but inferior products, but it seems to be true for our cars.

To top this off: Our representative from a major supplier of performance and street engine parts (EPWI) stopped by to "warn us" of the problem of the NEW oils on flat tappet engines. This was a call that the representative was making only because of this problem to warn their engine builders! "The reduction of the zinc, manganese and phosphates are causing very early destruction of cams and followers". They are recommending that, for now at least, there must be a proper oil additive put in the first oil used on new engines, beyond the liberal use of molydisulfide assembly lube.

They have been told that the first oil is the time the additives are

needed but remain skeptical that the first change is all that is necessary.

Their statement: Use diesel rated oils such as Delo or Rotella that are usually

available at auto stores and gas stations.

This problem is BIG! American Engine Rebuilder's Association (AERA)

Bulletin #TB2333 directly addresses this problem. I had a short

discussion with their engineer and he agreed with all that I had been finding.

Next phone call was to a retired engineer from Clevite, a major bearing and component manufacturer. First surprise was that he restored older British Motor bikes. The second surprise was that he was "VERY" aware of this problem because many of the old bikes had rectangular tappets that

couldn't rotate and are having a very large problem with the new oils. He

has written an article for the British Bike community that verify all the

"bad news" we have been finding.

Comp Cams put out "#225 Tech Bulletin: Flat Tappet Camshafts". They

have both an assembly lube and an oil additive. The telling sentence in

the bulletin was "While this additive was originally developed specifically

for break-in protection, subsequent testing has proven the durability

benefits of its long term use. This special blend of additives promotes proper

break-in and protects against premature cam and lifter failure by

replacing some of the beneficial ingredients that the oil companies have been

required to remove from the off the-shelf oil".


Oil is Killing our cars Part 3

Last month's report on this subject is turning out to be just the tip of the iceberg! Many publications have had this subject of zinc-dialkyl-dithiophosphate (ZDDP) covered in varying depths over the last few months. Some publications have even had conflicting stories when you compare one month's article with their next month's article! They are all ending up supporting our report.

I have had the good fortune to have the ear of quite a few leaders in

the industry including some wonderful input from Castrol. We have been

very reluctant to "dump" Castrol, as it has been such a great supporter of our cars and industry over the years. Castrol hasn't really abandoned our

cars, just shifted to a more mass marketing mode. Many Castrol products are not appropriate for our cars today, some still are.

Now for the latest report:

#1 Castrol GTX 20W-50 is still good for our cars after break-in!

10W-40, 10W-30 and other grades are NOT good. Absolute NOT GOOD for any oil (Any Brand) that is marked "Energy Conserving" in the API "Donut" on the bottle, these oils are so low with ZDDP or other additives that they will

destroy our cams. Virtually all "Diesel" rated oils are acceptable.

#2 Castrol HD 30 is a very good oil for break-in of new motors. This oil has one of the largest concentrations of ZDDP and Moly to conserve our cams and tappets.

#3 Only an unusual Castrol Syntec 20W-50 approaches the levels of

protection we need when we look to the better synthetic lubricants. We

are attempting to get this oil but will be using Redline 10W-40 or 10W-30 as

these are lighter weights for better performance, flow volume, less drag

and has the additive package we need.

#4 The trend today is to lighter weight oils to decrease drag, which

increases mileage. Most of these seem to be the "Energy Conservation"

oils that we cannot use.

#5 Redline oil and others are suggesting a 3,000-mile break-in for new

engines! Proper seating of rings, with today's lubricants is taking that

long to properly seal. Shifting to synthetics before that time will just

burn a lot of oil and not run as well as hoped.

#6 The "Energy Conservation" trend was first lead by automakers to

increase mileage numbers and secondly because the ZDDP and other

chemicals degrade the catalytic converter after extended miles, increasing


We don't have catalytic converters (mentioned to a specific group) and the mileage gains are not that significant for most of us.

For you science buffs: ZDDP is a single polar molecule that is

attracted to Iron based metals. The one polar end tends to "Stand" the

molecule up on the metal surface that it is bonded to by heat and


This forms a sacrificial layer to protect the base metal of the cam and

tappet from contacting each other. Only at very high pressures on a flat

tappet cam is this necessary because the oil is squeezed/wiped from the

surface. This high pressure is also present on the gudgeon pin (wrist

pin) in diesel engines, therefore the need for ZDDP in diesel engines.

Second part of the equation is Molybdenum disulfide (Moly). The moly

bonds to the zinc adding an additional, very slippery, sacrificial layer

to the metal. I found out that too much of the moly will create problems;

lack of this material reduces the effectiveness of the ZDDP. The percentage,

by weight is from .01 to .02%, not much, but necessary.

Latest conclusions: Running our older, broken in engines on Castrol

20W-50 GTX is ok. Break in a new engine for 3,000 miles on HD 30 Castrol.

New engines (after break-in) and fairly low mileage engines will do

best with the Redline 10W- 40 or 10W-30 synthetic.

Link to post
Share on other sites

please dont blame me personally for all these nonsensical stories about many many people driving cars around for many many miles prior to the Second World War, on oil that HAD NO ANTI FRICTION ADDITIVES. I was just a child, too young to drive, too young to be an accurate observor.

Of course these new oils will immediately cause your cam-shaft to uncam, your drive-shaft to un-drive, unless you RIGHT NOW run out and buy these expensive additives.

Seriously, guys, I just spent a fortune going thru the engine in my aircraft - an ordinary garden-variety Lycoming "360" series (translation - ordinary over-head valve cam-shaft with "flat" tappets).

The cam and lifters ground themselves to "nubs" !. (and the thing still ran fairly well..!) As many of you know - we have no choice; we MUST use "legal" aircraft engine oil THAT MUST CERTIFY IT HAS THE ANTI FRICTION ADDITIVES ! So, clearly - the anti-friction additives that aircraft oils still have, did not prevent cam "spalling".

My best guess on my own cam failure is the typical failure caused by "grinding" the camshaft and "surface grinding" the lifters during a previous overhaul.

Again, there is overwhelming evidence the vast majority of the cam and lifter failures on "flat tappet" engines is caused by bad shop practice during overhaul, i.e. "re-surfacing" that removes the "hardness layer" on the cam and tappet bodies. Add to that engines that may sit idle long enough for microscopic "pockets" of corrosion on surfaces subject to extremes of pressure, and you get cam/lifter failure.

So - again, the 'anti-friction" additives of course MAY help the cam-shaft issue, but not much. And again, the anti-friction additives were not put in for guys with older design "flat-tappet" engines - they were there to increase mileage.

Now - I admit I am a snob - I like, for my collector car, the biggest, most expensive, most powerful cars. Someone refresh my memory - was there ANY really expensive, really powerful luxury car made after the early 1920's that did NOT have roller tappets..?

Now, on this oil-additive issue - if you like "conspiracy" theories, it is a free country and that is your "right". Personally, my favorite "conspiracy theory" is the one where President Roosevelt is accused of hiring the Japanese to bomb Pearl Harbor. See...he wasnt really a wheel-chair bound paraplegic...he snuck out of the White House one night..broke into a Radio Shack, where he bought a radio he used to call up the Japanese Navy...and..and..

Link to post
Share on other sites

regarding your question about oil additive technology in the 1930's

To my knowledge, what we now know as "anti friction" additives in motor oils did not exist until the "ecology/mileage" issue hit about 15-20 years ago. Let me qualify that below:

This is admittedly an over-simplification; let me repeat as briefly as I can what has been well-discussed over and over again elsewhere in these forums. Hopefully this info. will be useful to our fellow car-buffs.

There were three major improvements in consumer-grade motor oils following World War II, meaning "detergent" , multi grade" and "anti friction" oils.

So called "multi-grade" and "detergent" oils came in around the same time, in the early 1950's. Both terms are just plain advertising nonsence. Here's why. SINGLE grade oils are actually "multi-grade", since they only have to pass a flow test at a "standard" temp - believe it is 210 0r 212 degrees F. At any OTHER temp, they need not meet any standard, because there isnt any. When cold, single grade oils get so thick, they cant get thru all the places they are supposed to go, which explains why cold dry starts cause so much wear. Multi grade oils are in fact a SINGLE GRADE, meaning they flow well when it is very cold, but retain their "film" strength when hot.

The term "detergent" is also nonsence. THERE IS NO SUCH THING AS 'DETERGENT' MOTOR OIL. Again, an advertising term to show the motor stays clean. Simply means the molocules cant "link up" to form sludge. "Detergent" oils CAN NOT DISSOLVE SLUDGE ! I got into a big argument about this around 1957, when I pulled my Packard Twelve apart for an overhaul. I cleaned out all the sludge, except for some "test sections" in the crank-case. One "test section" I left on the inside wall of the crankcase is where oil thrown off from the crankshaft hits it directly - the other is behind the webbing of the main bearing supports. I "pull" my oil pan down every few years as a good maintainence proceedure just to check things out; THOSE SLUDGE SPOTS ARE STILL THERE, DESPITE USING 10w30 EVER SINCE 1957 ! Well over 100,000 miles since then, under all kinds of driving conditions, including MANY years of Los Angeles traffic (yes...I am crazy enough to STILL be driving the same Packard Twelve.)

Again, "detergent" oil simply means that the engine wont make MORE sludge. Will not effect EXSISTING sludge. CANT ! Chemically wont happen! No solvents in "detergent" oils !

Oils for use in gears, such as the hypoid axle gears, DID have anti-friction additives as early as the late 1920's. Again, if any of these sulpher-based anti friction formulas were used in MOTOR oils, I am not aware of it.

Link to post
Share on other sites

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">To my knowledge, what we now know as "anti friction" additives in motor oils did not exist until the "ecology/mileage" issue hit about 15-20 years ago. </div></div>

Do you consider zddp an anti friction additive?

Link to post
Share on other sites

In anwer to your question, let me first assure you I personally am not competent in oil technology and certainly no expert on chemistry!

Best I can do for your question, is give you the following "layman" comment - you have given us the chemical abbreviation for the "family" of zinc-based anti-friction additives used in consumer-grade MOTOR oils in recent years. Motor oils containing these additives bear the API designation "energy conserving" ( I only see this now on 5W-20 oils specified for the latest cars-cant seem to find it in the 20W-50 oil I like to use when I plan to REALLY "tear" up the desert during summer heat extremes).

If engine oil from before the war had zinc-based anti-friction additives of this nature, again, I am not aware of it, and I find no mention of it either in the literature I have access to, or recall seeing it advertised or on oil containers of before, oh..say...hmmmm 1985 ?

Similar anti-friction additives have been required in recent years of motor oils for piston AIRCRAFT in order to meet "Lycoming Service Bulletin 446C.

If you know something I dont, by all means share it with us.

Link to post
Share on other sites

From what I have read zddp "anti friction" additives have been used in motor oils since the late 30's. I'll try to post some references if you would like.

Link to post
Share on other sites

yes - that would be very interesting ! But even if so, it would not change the answer I gave to the fellow that started this particular "thread" with his question.

The indisputable fact is, and at the risk of repeating myself, long before the end of the 1930's, there were LOTS of cars being driven LOTS of miles with ordinary "flat" tappets (meaning non-roller cam followers) that gave good service for far more miles than most of us car buffs would use our collector cars for today.

Link to post
Share on other sites

I know of several enignes that have had cam failures with BRAND NEW camshafts not reground. One of those engines belonged to my former boss who was a disturbtor of Mopar Performance parts and former drag racer/engine builder.

At the Trade show at the AACA Annual meeting, those there that sell camshafts had infromation on what what's been changed in the oil and what you should do. unfortunely I didn't have the chance to stop and talk to them and pick up the info.

Link to post
Share on other sites

"NEW" OILS...?

NONSENCE - we are just going back to the "old" oils !

The problem of random cam failures is not a new one. Down thru automotive internal combustion engine history, random failures have occured. Random failures continued to occur AFTER the introduction of the so called "anti-friction additives" introducted (in aviation motor oils ONLY a dozen or so years ago).

If we accept the fact that there have ALWAYS been random failures of cam-shafts, even brand new ones, down thru the history of the internal combustion engine, the next question is "what can we do about it".

A review of automotive technical literature, beginning during World War One, provides the answer. For example, using improperly heat-treated cam followers, or used / re-surfaced "re-ground" cams and/or cam folowers, and/or mixing cam followers that have been in service, on top of a "new" cam-shaft, WILL provide a higher incidence of random cam failure. Again, this is REGARDLESS of the time period, meaning, before, during, and after the introduction of so called "anti-friction additives".

There is one sure-fire way to eliminate cam shaft failure. You can find it in quality motors going back, again, to the First World War. We call that "roller cams". When we say "roller cams" we are referring to the practice of having a roller or needle bearing cam follower that does not "slide" or create excessively high sliding friction on the steel surface of the cam.

When we are talking about consumer grade "throw-a-way" cars for the lower and middle classes, where the car is presumed to be traded in for a new one every three to five years, going to the expense of providing roller cams made no economic sense. The typical warranty on a new car of that nature until relatively recently was "90 days or 4,000 miles, whichever occured first".

In recent years, consumers of ordinary cars have demanded more long term reliability from their engines (typical of what has ALWAYS been demanded by the rich, and ALWAYS provided in the highest quality cars and most inssutrial grade motors).

As such, manufacturer warranties have now been extended, some going as far as 10 years and 100,000 miles (essentially duplicating what better grade motors for industrial purpose and/or the "super luxury" cars of the "super rich" have had since the 1920's).

I am not clear where any of you got the idea that an automotive maker of consumer grade automobiles ever had a duty to provide roller cams, or the degree of long term durability they provided. Where did ANY of you get the idea that a manufacture of auto engines has ANY responsiblity for durability to used car owner-operators ?

I recall seeing an advertisement from the Packard Motor Car Company, which, if memory serves, was from the early 1920's. The ad. said something about the Packard of that era was a "10 year car" that could go fast.

Of course, and at the risk of repeating myself, just about every maker of the highest quality industrial and auto engines from that era foward, provided their customers with roller cams. I do not recall that Fords, Chevrolets, or, for that matter, any other "consumer grade" (translation "use it for three to five years and throw it away") ever had roller cams, until recently.

The bottom line is that a honest and sincere review of automotive technical history, tells us "you get what you pay for"!

In conclusion, I am not convinced that the use of anti-friction additives, that are now being withdrawn from service, were anything more than they claimed to be, i.e. trying to get a little better gas mileage.

As we know, these additives were screwing up the smog equipment; THAT is why their use has been terminated. And, again, since even the manufacturers of cheap cars are now accepting the idea that these cars should last longer, are including roller cams in their products.

I repeat my question - anyone know of a new automobile engine that does NOT come factory equipped with a roller cam ? If there is, I am not aware of it.

So there you are...you get what you pay for. Want to be free of the risk of cam failure ? GET A MOTOR EQUIPPED WITH ROLLER CAM !

Link to post
Share on other sites
  • 3 weeks later...

I should have qualified my above remarks by adding something that might make you breathe a bit easier. Your cam from a 30's era design concept, has a much more gentle profile than the wilder cams that have come about in recent years.

In addition to trying to get a bit more mileage, the zinc-based additives also DO have a protecting effect on the MUCH higher "sheer" streses of the wilder cams of recent years. The relatively gentle profile of your pre-war car, again, DOES not require, and probably will give you NO BENEFIT, from the use of these "slippery" additives.

Again, the best solution to avoiding cam troubles, especially on the much more dramatic "lift" profiles of recent years, is go to a roller cam. But that's NOT YOUR PROBLEM WITH YOUR PARTICULAR CAR !

Fix it, drive it, and enjoy it ! Best of luck to you!

Link to post
Share on other sites

again...your '30 Buick does NOT have anything NEAR the wilder cam lift profiles of modern cars. Until you have an explanation as to how all those millions of cars ran all those miles prior to World War Two, without ruining their cam-shafts, you have no legit explanation as to why you want additives that did not exist then.

Link to post
Share on other sites

I too was concerned about my straight eight valve in head engine, so I wrote directly to Shell. Here is their answer:

Dear Clifford,

API SH and SJ are perfectly compatible. It's part of the API

requirements that later versions be backward compatible. The SJ version

still has considerably more zinc protection than a conventional

passenger car oil and sill more than you need for your application, so

there is no need to add more protection. You will get excellent

protection from the Rotella T in your engine.

Thank you for your interest in our products! If you have any further

questions, you can call us at 800 231 6950.


MaryCarol Boemmel

Lubrication Engineer


Link to post
Share on other sites
  • 2 weeks later...
  • 2 weeks later...
  • 1 year later...

I've been using Castrol GTX 10w-30 for the past 6 years but have decided to switch (and have purchased)Valvoline VR1 10w-30 with much higher levels of zinc and phophorous than most other oils being sold today. Not that more expensive either. $45.00 for 7 quarts (including shipping) from Jegs. $35.00 less shipping.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...