oil again

[William F.]

Duke, Williams,
A very long treatise on oil, found at www.540ratblog.wordpress.com with much self congratulatory back patting by author was brought to my attention. The author(name?) claims to be a mechanical engineer. He states he has tested 100's of motor oils for wear protection, using film strength load carrying capacity as criteria at ALS Tribiology in Sparks Nevada. He concludes that the need for ZDDY to prevent wear in a flat tappet engine with sliding friction to contend with is a myth. I don't buy this. I began using Rotella T in 1999 after reading an article in Nov 1999 Car and Driver where Ed Kollin, previously a research chemist in engine testing for Exxon, recommended diesel oil as best for collector cars. He did touch on need for ZDDP as an anti wear additive but his main point for diesel oil was for its anti corrsion protection in collector cars that sit for long periods without running. I have also read your article on oils many times.
I ask that you read and give your thoughts on "rat 540's " article I would also like for you to give the actual engineering tests that show the need for a reasonable amount of ZDDP to protect against wear so we'll have ammunition to refute the aforementioned "test."Thanks

[Dick W.]

Re: oil again

Opinions are like belly buttons, everyone has one and they are usually full of fuzz.

Rest assured that if ZDDP was not needed the oil companies would not still produce oils such as Rotella but all the new oils would be similar to the new FA-4 spec oil which has VERY little ZDDP in it.

[Joe R.]

Re: oil again

Opinions are like belly buttons, everyone has one and they are usually full of fuzz.

Rest assured that if ZPPD was not needed the oil companies would not still produce oils such as Rotella but all the new oils would be similar to the new FA-4 spec oil which has VERY little ZPPD in it.

Dick, you are just too practical for a Corvette owner!

JR

PS. You just gotta do some (research)

[Robert B.]

Re: oil again

been running mobile one 10- 30 in my 61 270 HP for over 20 years ??

[Joe C.]

Re: oil again

For those unfamiliar with what is being discussed, it is "ZDDP" zincdialkyldithiophosphate

[Dick W.]

Re: oil again

Part of my job beginning over 50 years ago was to evaluate and purchase fuel and lubricants. Back then there were not the plethora of oils out there. Mostly CC, CD, MIL Spec 2104, etc. I still keep up with modern oil and the applications. The quality of the lubricants today is a large part of the long engine life we experience with modern engines.

[Duke W.]

Re: oil again

That individual uses a single criterion - film strength - as a sole measure of protection. Film strength is a factor in boundary lubrication situations, but most internal engine components see hydrodynamic lubrication. One guy versus the entire worldwide automotive and petroleum industry. Who do you thing is right? My oil article references the API 1509 document that references all the various tests used in the API certification process, and there's a whole lot more to it than film strength.

[Dick W.]

Re: oil again

And all oils that meet API specs do not always perform as some expect. Just because it is the latest and greatest, or some highly promoted boutique product, it may not be what you need. The uproar about ZDDP created an opportunity for many snake oil salesmen to come out of the woodworks, re-bottle another manufacturers oil with their label and add $5.00 a quart to the cost

[William F.]

Re: oil again

Duke,
Not really disagreeing with you, except, as I understand it "hydrodynamic lubrication" would apply to oil in relation to spinning crankshaft in it's bearings but not to the pressure load of lifter on cam lobe. Maybe I missed it, but where in the reference in your oil article does it address what type of wear additive is best for sliding friction? All I'm saying is that this "540 rat" guy can say, "Look, I've done tests on all these oils, where are you guys's facts to back up that ZDDP is needed?" Would like to see tests or articles form oil engineers or quote from a Shell or other oil company chemist or engineer, not just from "help line" to be able to counter the "ZDDP is a myth" argument. I know some cam companies say ZDDP is important to prevent cam and lifter failure, but some say this is figure pointing when problem lies with low quality lifters or cams.
In same vein, Dick W, we should be able to back up our argument with facts, so it won't be just another "opinion." Hope it's not.

[Dick W.]

Re: oil again

Duke,
Not really disagreeing with you, except, as I understand it "hydrodynamic lubrication" would apply to oil in relation to spinning crankshaft in it's bearings but not to the pressure load of lifter on cam lobe. Maybe I missed it, but where in the reference in your oil article does it address what type of wear additive is best for sliding friction? All I'm saying is that this "540 rat" guy can say, "Look, I've done tests on all these oils, where are you guys's facts to back up that ZDDP is needed?" Would like to see tests or articles form oil engineers or quote from a Shell or other oil company chemist or engineer, not just from "help line" to be able to counter the "ZDDP is a myth" argument. I know some cam companies say ZDDP is important to prevent cam and lifter failure, but some say this is figure pointing when problem lies with low quality lifters or cams.
In same vein, Dick W, we should be able to back up our argument with facts, so it won't be just another "opinion." Hope it's not.

Look at oil specs for older HD engines that still use sliding surfaces. All camshaft manufacturers require the use of a camshaft assembly lube for new installs to validate the warranty. I remember the camshaft problems we had in the mid '70's when they started reducing the additive It is not opinion, it is a fact that ZDDP should be used in engines that still have flat tappet camshafts. Sure, most of the time you can get away with running regular oil, but the cost of replacing a camshaft and set of lifters way outweigh the additional cost of Rotella, RPM Delo, Premium Blue, etc.

When the engines were manufactured in our vintage Corvettes the oil had more than enough ZDDP to take care of camshafts. The advent of the catalytic converter required the reduction of the additive in the oils, it was contaminating the converters. Modern engines with roller cam lifters and roller rocker arms require very little of the additive.

[Joe C.]

Re: oil again

Considering that the bottom of the lifter should have a convex profile with the crown being about .001 -002 higher, and the camshaft lobes having a .001-.002 taper with the lobe contact point offset from the lifter centerline then the lifter should rotate in its bore. As such, then would the friction be rolling, sliding, a combination of both, or some other?

Reference the following and correlate:

http://www.brighthubengineering.com/manufacturing-technology/73568-hydrostatic-lubrication/

Thank you.

BTW: AFAIK, the zinc component in ZDDP is what contaminates catalytic converters. According to what I've heard, the component (which is sacrificial) needed for flat tappet cam/lifters is the phosphate in zincdithiophosphate (ZDDP).

[William F.]

Re: oil again

Yes, an assembly lube is required when installing a new flat tappet cam and lifters but that's not same as oil requirement. I'm just being a devil's advocate, but where is reliable scientific based information that proves ZDDP is better at reducing sliding friction than the friction reducing additive packages in modern oils? All I've really seen is "because it used to be in motor oil but it's not anymore."

[Joe L.]

Re: oil again

Look at oil specs for older HD engines that still use sliding surfaces. All camshaft manufacturers require the use of a camshaft assembly lube for new installs to validate the warranty. I remember the camshaft problems we had in the mid '70's when they started reducing the additive It is not opinion, it is a fact that ZDDP should be used in engines that still have flat tappet camshafts. Sure, most of the time you can get away with running regular oil, but the cost of replacing a camshaft and set of lifters way outweigh the additional cost of Rotella, RPM Delo, Premium Blue, etc.

When the engines were manufactured in our vintage Corvettes the oil had more than enough ZDDP to take care of camshafts. The advent of the catalytic converter required the reduction of the additive in the oils, it was contaminating the converters. Modern engines with roller cam lifters and roller rocker arms require very little of the additive.

Dick------


Yes, I agree. If one is using an engine that's equipped with flat tappet lifters, then I recommend using an oil with significant ZDDP content. Shell Rotella and Chevron Delo are two but there are many others. Also, Shell Rotella and Chevron Delo are dual rated for both gasoline and diesel service.

Engines with roller lifters do not require these type of oils. So, if one converts one's vintage engine to a roller cam, then modern gasoline service only oils can be used without concern.

[Duke W.]

Re: oil again

Duke,
Not really disagreeing with you, except, as I understand it "hydrodynamic lubrication" would apply to oil in relation to spinning crankshaft in it's bearings but not to the pressure load of lifter on cam lobe. Maybe I missed it, but where in the reference in your oil article does it address what type of wear additive is best for sliding friction? All I'm saying is that this "540 rat" guy can say, "Look, I've done tests on all these oils, where are you guys's facts to back up that ZDDP is needed?" Would like to see tests or articles form oil engineers or quote from a Shell or other oil company chemist or engineer, not just from "help line" to be able to counter the "ZDDP is a myth" argument. I know some cam companies say ZDDP is important to prevent cam and lifter failure, but some say this is figure pointing when problem lies with low quality lifters or cams.
In same vein, Dick W, we should be able to back up our argument with facts, so it won't be just another "opinion." Hope it's not.

Cam-lifter interface lubrication is likely hydrodynamic under most conditions. The toughest is idle as the less the relative speed between surfaces, the less likely lubrication is hydrodynamic. That's why initial break-in should be well above idle speed.

My article has a link to the API 1509 document and appendices. If they are dead just google. Those docs reference the various API and ASTM tests, some of which you may have to buy if you want to study them in detail.

Additive requirement is not specified. These are pass-fail tests and blenders use what they find to be the required level of additives to pass the tests.

Duke

[Ray C.]

Re: oil again

I know nothing about motor oil, so I will leave the chemical engineering to the experts, however I just got my engine back from Carolina machine Engines where it was completely rebuilt. It has a solid lifter Competition Cam, the paperwork (from Competition Cams) says that it has to be broken in with special "High Zinc" oil or the warranty is void. Also says not to use 21st century oil. After break in always use high zinc .14% (1400 PPM) to protect the cam and lifters from being destroyed which will completely ruin the entire engine.
I am assuming that there is data to support issuing this warning.
And I know what assuming means...