Motor Oil, ZDDP and Yesterdays Engine - Part 2

Time saving tips to keep your Cub running smooth
cubguy's dad
10+ Years
10+ Years
Posts: 556
Joined: Sun Jan 04, 2009 5:41 pm
Zip Code: 49265
Tractors Owned: 1938 John Deere A
(owned 38 years)
1953 Cub
(owned 21 Years)
1963 Olds Cutlass
1970 Ford F-350
(Cub Hauler)
Location: MI Onsted

Motor Oil, ZDDP and Yesterdays Engine - Part 2

Postby cubguy's dad » Sat Oct 17, 2009 8:38 am


John *.?-!.* cub owner wrote: Thanks Mark. That was a well thought out article. I do have one question. Since the old tractor engines we normally work with, run at much slower rpms than the older car and truck engines, and from what I have seen, have lower strength valve springs, does this affect the need for the amount of ZDDP needed in the oil?

In answer to your question about lifter load, I was able to find an SAE report on the subject. Additive ZDDP at .02% (200PPM) phosphorus, provided protection from lifter scuffing up to 200 lbs lifter load. At .04% (400PPM) phosphorus lifter scuffing was prevented up to 240lbs, at .06% (600PPM) phosphorus lifter scuffing was prevented to 480 lbs. At .08%( 800PPM) phosphorus lifter scuffing was prevented up to 600 lbs lifter load. Some, but not all current API grade SM contain up to 800 PPM Phosphorus in the form of zinc additive. I have not been able to find out which ones though. It would be helpful to know what the lifter load on the Cub camshaft is, maybe we could get away with less additive.

While some phosphorus (contributed by ZDDP) more is not better, break in scuffing is severely reduced by the addition of more phosphorus up to .014% (1400PPM) However long term use of more than .014% actually increased engine wear. At levels of .0.20% the phosphorus attacked the iron properties and caused camshaft spalling.

The correct ratio for phosphorus would be 1400 to 1600 PPM for engine break in. While the minimum of 800 PPM would the limit for a engine that is past its break in period and had the lower lifter/camshaft load (Cub?) The newer engine oils have different EP additives and anti-oxidants that take the place of the need for additional ZDDP to provide this protection.

Engine oil manufactures obviously know of the need for ZDDP protection in older flat tappet engines as many of them are steering there owners towards their ZDDP diesel line of oils. This tells me that they acknowledge the need for ZDDP in these engines. Unfortunately, the characteristics and available viscosity ranges may not be suitable for all older engines.

What can be done, I would argue to supplement one of the new and very good base stock engine oils of the correct viscosity with additional ZDDP to bring the oils EP (extreme pressure) characteristics to that for which the engine was designed.
ZDDP has been shown to be compatible with all base stocks and other additives including the Boron EP additive. The trick would be to know at what levels of ZDDP your oil has (if any) and add enough ZDDP to bring the phosphorus up to 0.12% !200PPM phosphorus a level similar to SF or SG oils.

These are the oils that contain the correct amount of ZDDP that I have found so far;

Valvoline racing oil comes in 10w-30 and 20w-50 and each contain Zinc at 1400 PPM and Phosphorus at 1300 PPM well within the range needed for older engines

Valvoline Racing Synthetic oil ... otor-oil/8

Shell Rotella T is a 15w-40 diesel oil and it contains 1200-1400 PPM 0f ZDDP, the viscosity may limit its application.

Redline and Royal Purple both produces a break-in additive

Royal Purple XPR oil line has a high ZDDP content. I have not found any specs yet

RedFox wrote:This was a real eye opener. I guess in my case, having a '77, I wonder if the "tappets" were redesigned compared to engines built prior to the 70s.

I have found the additive for less online, but be careful, because many of the online "GM" dealer parts stores charge handling fees and inflated shipping...some don't. Below are two to consider and there is a cross part number as well 88862586. I've bought from the second one a few times and have been satisfied: ... er=1052367 ... eid=214533


Bob in CT wrote: I think I would make it a point to use an oil with zinc at break in and the first few oil changes. As I read it, the zinc does not disappear but coats everything so it has some staying power so periodic use after break in may be enough.
If you open up an old engine that has been sitting for years and it is not rusty, you can thank the zinc additive for that too. it is an effective corrosion inhibitor, which is another reason folks with classic hardware that may not run all that often would find it to be a benefit.
This was among the very first additives developed for motor oil and was considered to be a major breakthrough at the time (1930's). Considering how long it has lasted, it is one of the more successful ones too.


Jim Becker wrote: There are other EP additives that don't contain zinc. Not clear to me that a zinc content chart would be helpful.

Thanks, You are right it appears that we need to look at the phosphorus content also


by Gary Dotson
There's a lot of great info. in this thread. That's some great research, Mark. While this forum is dedicated to the Cub, many of us have other older engines to be concerned about, so although a Cub, with it's lighter valve spring load & lower RPM may not be as much of a concern, other engines we own may be. I have been suggesting Rotella to my muscle car buddies, for a while now. Rotella T is also available in 10W30, but not as easy to find. I stock up on when I find it and have used it in several engines.


Thanks for the update!!!

I did not know that Rotella came in 10w-30, this would be a very good option to the 15w-40 that you normally find. I will certainly look into this.


By Eugene ... -01-08.jpg

Valve spring test load is 23 pounds.
by dirtyred
so if i read the previous reply correctly with the valve spring load at 23 lbs you could use the 200ppm additive to get the protection needed?


I have been unable to find specs on Mobil 1 oils but I was able to come up with some specs for Texaco Havoline engine oil

Texaco Havoline engine oil API SM, SL, SJ, SH with the 10w-40 and straight grades showing good levels of zinc and phosphorus

10w-30 contains 780 PPM phosphorus and 1100 PPM zinc
10w-40 contains 990 PPM phosphorus and 1100 PPM zinc
Straight 30Wt contains 990 PPM phosphorus and 1100 PPM zinc

Havoline Synthetic is also good with the 5w-40 having the most amount of zinc and phosphorus

SAE Grade 5W-20 5W-30 5W-40 10W-30
Phosphorus, wt % 0.075 0.078 0.100 0.078
Zinc, wt % 0.080 0.088 0.110 0.088

I assumed more doom and gloom when looking for current oil specs. And while I am surprised by how good some of the oil looks, it appears that research needs to be done on your favorite oil to see how it stacks up. The range from little to no ZDDP to acceptable levels for a broke-in engine is really surprising. As vintage engine enthusiasts we still need to be wary consumers.

Thanks for the help and comments


Eugene wrote:
The Cub’s 23 lbs spring compression rate is rather low.

In comparison, Chilton, GM, lists valve spring compression test loads of:
59 lbs for a 1970, 6-230 engine. 140 hp @ 4400 rpm.
200 lbs for a 1985, 6-262 engine. 130 hp @ 4400 rpm.

Chilton, Ford, the valve spring compression test loads are from 80 to 229 lbs.
IH range is 23 to 147 lbs. for tractors listed in I&T, IH-8.
Allis‘ range is 13 to 65 lbs. for tractors listed in I&T, AC-11.

The forces present at the cam/lifter interface are the sum of the inertia force and the valve spring force. At low engine speeds the inertia force is very small so almost all of the force on the cam is due to the valve spring.

Thanks for your input and the data. There are certainly varying amounts of load placed on the cam by the different models of engines that you highlighted.

The data you present makes sense as the Cub valves will stay closed simply by gravity and by being a mechanical tappet/lifter and having to operate with a small amount of clearance the pressure or force is only exerted on the cam lobe itself. The Cub engine operates at low RPM and that exerts less pressure as well. Also the Cub engine only has one of the sliding friction areas to deal with, the cam to tappet area, unlike some of the other engines that also have the valve rocker to valve and the timing chain/gear as sliding friction surfaces as well.

Summary so far,
It would appear that with careful research about the particular brand of engine oil that you wanted to use, that off the shelf oil is still available for your vintage stock engine and Cub engine as well. By keeping up on the oil changes good results could be expected.

The addition of a ZDDP additive, high ZDDP engine oil or ZDDP break-in oil would be in order for a fresh rebuilt engine to break the camshaft in. Continued follow up with the same additive package for the next couple of oil changes would be prudent before switching to a lower ZDDP content oil.

Thanks for your input, this has been interesting


by Bob in CT
There are plenty of oils, like Shell Rotella and several other "high mileage" blends that still have levels of zddp comparable to levels that have been used since the 30's and considered sufficient for corrosion protection and tappet wear by those that believe that after 80 years zddp still offers benefits.

by DanR
This is a very informative thread. Thanks to all that have done the research. I do not want to change the original topic but I do have a question. Why was ZDDP % change in the first place? Is this a pollution issue?

by Bob in CT
It is fouling catalytic converters. They are warranted to last a 100,000 miles by federal law. it is the phosphorous & zinc that is shortening their life.

I found this from an article written by Keith Ansell:

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 friction. 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.

by Larry Dotson
For those that are building/rebuilding their cub engines (and especially those building their puller cubs) Comp cams has a special break-in oil that is available at many auto parts stores. With the use of engine assembly lube and this high ZDDP break-in oil, there is probably nothing else needed. Maybe some of the puller engines and especially the ones with high lift cams and multiple valves springs (like mine) may need racing oil. While running my 180 MPH dragster I asked my oil sponsor if I needed any additives for my oil. Their reply was that if it was needed, it was already in there.

by BigBill
The bottom-line is oil isn't what it once was it has changed and will continue to change in the future. So its up to us to find a solution to the wear problem were going to see now and in the engines of the past to keep them running great.

My point is "WE" need to add something to our oils and what you use is up to you. But don't be fooled by the labels too. I have a certain ritual I go thru rebuilding any engine whether its a lawn mower engine, a dirt bike engine or a race engine the pre-lube is still the exact same operation.

I'm also getting some feed back about these newer car engines too like the Chrysler and Dodge engines. These engines are built with very close tolerances and they use a very light motor oil. The people who own these cars/trucks need to follow the maintenance manual very closely about when to change there motor oils. The lighter wt oils break down very quickly and they lose there lubricating qualities if not changed by the recommended schedule. One mechanic I talked with says he is changing these engines all the time because of this lapse in oil changing timing. With the talk about the oils additives being removed I think this is the tip of the ice berg of what’s happening right now there's proof already and its not just our old equipment.

Now does removing the additives in the motor oil make the oil film less overnight for the cold start up in the morning? I think there are more unknowns yet we don't know about.


I as well have had numerous vehicles with over 200,000 miles on them and the decision concerning motor oil was certainly a lot simpler back when.

Like, what brand oil to use and how often do I have to change it. Unfortunately the same is not true in 2009.

2010 model year autos can easily go well past the 200,000 mile with the correct routine maintenance along with the correct oils, coolants and lubes. Does one size fit all anymore?

Today the engineers at Ford Motor Co. are putting the finishing touches on the 2016 model year automobile. That means that this model year car (2010) has long been yesterdays news, concurrently your 1999 Ford pickup that you love and drive to work everyday has long been an antique in their eyes.

Technology is now on a pace to double itself in less than ten years and it is picking up speed. Ten years ago the pace was a little less than twenty years. The majority of car manufactures have not produced a flat tappet cam engine since 1999 so why would the motor oil not change as well? API service SM oil was introduced in 2004 in response to some of the additives needed for flat tappet cam engines were poisoning the catalytic converters. Because there was no need for the additive in that high of concentration because flat tappet cam engines were yesterdays news, the motor manufactures reduced these additives by half and the resulting thought is that it will suffice for the older engines for now.

Now I am not saying that the sky is falling, that everything will turn to dust over night. or that the latest magic elixir is needed. What I am saying is that things are rapidly changing in the new auto technology and that is what the Motor oil Manufacturers largest consumer base is and the newer auto engines are what their products will be designed to work with and for.

To some it may seem strange but since 2006 Auto manufactures are actually specifying the oil to use in their engines by other than SAE viscosity or API service classification.

General Motors
GM6094M (for many GM vehicles
GM4718 (synthetic Corvette
LL-A-25 (gasoline engines) or LL-B-25 (diesel engines) for vehicles equipped with European engines ( i.e. Cadillac Catera)

WSS-M2C153-H (SAE 5W20 GF3
WSS-M2C929-A (SAE 5W30 for 4.0 and 2.0 Liter engines
WSS-M2C930-A (SAE 5W20 GF4

MS-6395 for 2005 + Vehicles
MS-10725 for 2004 and older vehicles

All approved O.E. Spec oils have to have the ILSAC Starburst symbol on the container. The Starburst Symbol is always displayed on the front
ILSAC (International Lubricant and Standardization Committee) adopted
1993 with GF-1
1997 with GF-2
2000 with GF-3
2004 with GF-4
2010 with GF-5 for use with the 2011 model year engines
(GF means Gasoline Fueled Engines)

Many 2007 and newer Chrysler/Dodge vehicles are equipped with an oil pressure viscosity sensor mounted in the oil galley in the left cylinder head. If you change the oil and use a viscosity oil other than 5W-20 the “Check Engine Light” will set before you get out of the garage and CODE 504 will set “Oil pressure not reaching spec @ 1250 RPM” Your engine probably will be in derate or limp home mode to protect the engine internals and you will have to replace the oil with the correct viscosity AND clear the diagnostic code. These engines require the correct oil and nothing else even an oil additive like STP will set a Check engine light in these vehicle.

If you are interested in more information on the current state of motor oil and other topics go to

How does this impact the majority of us? unless you own or maintain a 2006 or newer vehicle, perhaps not much at all, at least not yet. The current SM motor oils in my opinion have enough additive for a well broke in flat tappet cam and lifters. If you install a new cam and lifters you will need an assembly lube just as you have done in the past. Motor Oil is slated for a change again in the summer of 2010 with the adaption of ILSAC Spec GF-5, how will this effect older engines? I do not know yet. But as one engineer put it “The time will be here soon that motor oil can not be grandfathered to work in all earlier engines”

Next time you go to Walmart, go to the motor oil aisle and look for motor oil that meets your O.E. Spec, has the starburst symbol in the front and has the right SAE viscosity index and the correct API service class for your vehicle. There will be some among the dozens that you look through but if you did not know what to look for how would you make the right choice?.


By Bob in CT
Mark, Larry,

2 excellent posts. I think the point was well made that just because your 2001 whatever is doing fine, it is important to keep in mind that the oil that broke it in was designed for your flat tappet engine and the oil you get today, unless you do some due diligence, is not. Time will tell what the long term impact will be. I am more inclined to think someone is credible when they say they are "not sure" rather than people that state it will NEVER be a problem, with no evidence to back it up, or the doomsday faction that says the sky is falling. I'll probably continue to run a 15-40 diesel oil in my Cub in the summer which has plenty of zinc and that should be fine for me even if my winter oil has zero. The protection the zddp provides is a coating that does not vanish overnight as i understand it.

Oil analysis has been used for years on fleets of big trucks and construction equipment to manage oil changes where the sumps may hold 10 gallons or more of oil. That is an expensive oil change. it will also tell you a lot about the condition of your engine and confirm a coolant leak.

I remember when 100,000 miles was a mark of longevity. It was a big deal when Volvo began using a million mile odometer- i remember a lot of people laughing at that as foolish at the time. We sure have come a long way in quality of engineering and manufacturing. i am no longer impressed by anything less than 300,000 miles anymore.

Buzzard Wing wrote: Apparently diesel motor oil (Motocraft 15W/40) has zinc in it, 1331 and 1273 (PPM?) were the 2 readings. Probably too thick for a Cub?

Buzzard Wing
Shell Rotella is a good choice as it comes in 10w/30, 15w/40 and 30wt. Most places do not carry the 10w/30, but it is available. My local Auto parts carry all three as there are quite a few people my self included that use the 10w-30 in their old vehicles and equipment.
Buzzard Wing wrote: But I still have never heard of an engine fail because of the oil itself, only the lack of it.

Buzzard Wing
Engines of the last five years are asking more of motor oil besides lubricating and cooling. For example the engine in the Honda CRV requires that the motor oil is changed at every 3000 miles and should not be operated if the oil level is down by 1/2 quart or more. Why? this engine uses a hydraulic cylinder operated by oil pressure to keep the dual overhead cam timing chain tight. We had a 2004 CRV in the shop with engine performance problems, several misfire codes set, and the problem? It was 1 quart low on motor oil, which was affecting the camshafts timing via the chain tension provided by the hydraulic (motor oil pressure) tensioner, allowing the too much slack in the chain By the way if the cam timing gets too far off, valves start to hit pistons and things get ugly real fast. (Honda has a huge technical service bulletin regarding motor oil on this engine)This is just one of a dozen or so engines currently out there that depend on motor oil quantity and quality to operate the camshaft timing correctly, the Ford dual variable camshaft engine is another.

Recently I was called out to an auto shop to look at a 7.3 diesel Ford pickup that was not running right, (in fairness to them they are not diesel people) they had changed the fuel filter and other things put were not having any success. I pulled the dipstick and found that it was 6 quarts low on motor oil (it has a 14 qt crankcase capacity), there were no other problems and the engine had good oil pressure. We topped off the crankcase and the engine ran just fine. This engine has HUEI (Hydraulic Unit Electronic Injectors) they operate off of high pressure motor oil which has to be in sufficient quality (viscosity and no aeration) and quantity to operate the injectors. One of the Ford recommend diagnostic procedures for engine performance problems with this engine calls for inspecting and or changing the engine oil.

A friend of mine (a three time Ford recognized Master Tech) said (when we were discussing the new Ford engines), The new engines have changed so much that it is not about how long the rods, mains or rings will last as 200,000 miles+ is almost a given. The camshaft, chain and all these hydraulic actuators are the now critical components to engine performance and long trouble free life, stress to your students the importance of recommended oil and oil change intervals.

Mrs Jones, we have run a series of diagnostic tests and we have found the engine performance problem with your car, we recommend a oil and filter change using the recommended motor oil Funny? This is actually true; the real trick is selling this to Mrs Jones as something other than snake oil.

Our choices of motor oil today seems almost endless and do not count on the oil companies to make it any easier. I commented to one oil company rep that their 75,000 mile motor oil did not meet any O.E. Manufacturers Spec or have an ILSAC approved symbol on the bottle. “You are right” he said “However, this is still our best selling product overall and we do not have plans to change that any time soon”

As Bob said it is up to us to exercise due diligence as no one else will.


By Bob in CT
Rick Spivey wrote: As for today's oil being less capable than oil of yesteryear, that's nuts. I used oil of yesteryear, and it would either form sludge in you oil pan, or coke up on your valve train. I never see that with today's oil. Technology really is moving forward for the most part.

Rick, i don't think anyone is talking about "oils of yesteryear". Even though zddp was the first and one of the most successful additives ever in motor oil, it is still being used in some oils and dropping it had nothing to do with coking or sludge build-up or as a performance improvement. Zddp fouls catalytic converters and manufacturers need to warranty emissions for more than 100,000 miles. I thought of a good analogy and I'll share it here. Once in a while I get sinus headaches. i used to get them frequently and they were like migraines. The only way to get rid of them was with pseudoephedrine which get things draining to relieve the pressure. Sold under the popular name Sudafed among others. the same drug was being used by meth labs so to stop people from buying shopping carts full of the stuff they put it behind the counter and required a signature and ID. Trouble is, is that you can still buy an over the counter drug with the same or similar name but without the effective ingredient. took me a few minutes to figure that out when I was looking for my discount generic version and none of the packages on the shelf had the right stuff. How many people shelled out 6 bucks for some stuff that looked and cost the same but did not perform as expected? the oil on the shelf today looks like the same bottle and has the same numbers, but is probably does not have what lubrication engineers have considered to be 'the right stuff" for over 70 years. They did not take it out because they found something better or cheaper. it was done to protect catalytic converters on new cars sold today with an extended emissions equipment warranty. it was judged to be a fair trade-off because new cars have roller cams which do not need the Extreme Pressure properties that flat tappet cams do. So are we buying a package that looks the same and costs the same but will GIVE us a headache in the future? time will tell. there is 70 years of zddp data out there. No where near as much on the new formulations and auto manufacturers are not going to care about vintage performance as there is no warranty on old equipment. This could be another y-2-k and amount to nothing. A lot of smart people thought that would be a problem just as a number of cam manufacturers have released cautionary bulletins about this. I like to use a 15-40 diesel formulation oil in the summer anyway so i don't have to change my buying habits as they have higher zinc levels. This entire topic makes for some interesting discussion so I am glad it came up.


By Bob in CT
RedFox wrote: Can you really put in 15w40 diesel formulation in a Cub? I believe Bob wholeheartedly, but I have never even seen that viscosity mentioned anywhere in my Cub manual.

I use it in hot weather, especially when I am mowing which really works the tractor hard. That weight was recommended to me a long time ago when I had a diesel car as being very stable in maintaining its viscosity. You won't find many modern oils recommended in the original manuals. The first time I recall seeing 15-40 was in the early 80's and even then I had to go buy it right from the Kendall distributor as it was not stocked by retailers. Diesel oils have high levels of zddp still to protect the wrist pins (according to what I read and referenced in an earlier post) so it can't hurt our engines to have the same protection available that the engine designers counted on way back when.


By BigBill
RedFox wrote: Can you really put in 15w40 diesel formulation in a Cub? I believe Bob wholeheartedly, but I have never even seen that viscosity mentioned anywhere in my Cub manual.

Depending on where you live its 10/40wt, 10/30wt or 5/30wt for the winter. Running any thicker oil will cause bearing problems because the thicker oil takes too long to get thru the filter and in the oil galleries to the moving parts. Its in the cub manual to run what oil wt for what outside temps.

Experiance is knowing what NOT to do the next time.......
1937 John Deere A (Big John)
1953 Farmall Cub (LiL Red)
Lots of projects.

  • Similar Topics
    Last post

Return to “Engine, Clutch, Transmission and Hydraulics”

Who is online

Users browsing this forum: No registered users and 0 guests