...musical 'flat-tappet' oils

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hey peeps - so I've spent several hours scanning the lab results from 540rat and I'd like some confirmation about what the 90,000 psi 'magic number' really means. Is that the 'requirement' for flat-tappet cam engines? I own several 'flat-tappet' hot rods, including my mighty Cummins 5.9 (solid cam), and so I've got a couple questions... I talked with the tech folks at Shell and they claim their Rotella T4, 5 and 6 all have the 'flat-tappet' package, so I've been running Shell Rotella T4 10W30 in my hot rods, but alas the info from 540rat does not specifically list the 10W30, so I don't know how it rates. It does list the Shell Rotella 5W30 Gas Truck oil with a nice rating of ~96,000 psi, which I am now leaning towards for my hot rods. It also lists both the new and old Rotella 15W40 diesel oils, both of which rate in the low 70,000 range - not at/above the 90,000 number...which was very disheartening considering it's what I've been running in my solid cam Cummins. So, looking at the results there seem to be three local off-the-shelf contenders of 'normal' oil that I'm leaning towards for my hot rods, all of which are above the 90,000 magic number: - Quaker State Ultimate Durability 5W30, ~133,000 psi rating - NAPA 5W30, ~105,000 psi rating - Shell Rotella 5W30 Gas Truck oil, ~96,000 psi rating All of these are full synthetic, and all of them list "Dexos" on the bottle - wonder what that means... I also have a fresh 440 that needs to be broken in, and I am VERY curious about the Lucas Break In Oil I bought for the initial break-in - it only rates at ~49,000 psi - not even worth saying how low it rates...and this is a 'break-in' oil? Meanwhile...I am still trying to determine what to run in my Cummins - none of the local 'off-the-shelf' contenders are rated above 90,000 psi; not Rotella, not Delo, so I may have to resort to the expensive mail order oils like Amsoil...and maybe they are worth it...? Would appreciate any thoughts/recommendations. Cheers - Sam
 
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I'm sure there will be a lot of preferences and technical info coming your way. I can only speak from experience. My 1967 396 was broken in and ultimately ran with Valvoline VR1 10w40 (Not street legal) conventional oil. I assembled this engine with a flat tappet cam for street performance with .520 lift - 224 @ .050. Not terribly hard on valvetrain components but stronger valve springs than stock none the less. Used GM EOS oil supplement in the oil for initial camshaft break in then dumped that oil & filter and went back again with fresh Valvoline VR1. Never a problem. Ran the dog sh*t out of it.... Go with real world experience rather a blogger's opinion. I imagine most over the road truckers' tractors are using Rotella, Delvac, Valvoline Premium Blue or Delo. They are very attentive to longevity. It's their livelihood.
 
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There are many long and detailed threads on here about Rat, please do what Overkill posted and read them first. Many, many threads. Long ones. Many of them. The short answer to "I am still trying to determine what to run in my Cummins" is that you use an oil, any oil, that meets the specification or approval your engine requires and has a winter rating appropriate for your expected starting conditions. You find this specification or approval in the owner's manual and once you know that information, Walmart likely has several excellent choices. Somehow though I think you might already know all of this.
 

Mad_Max_Sam

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I appreciate the fast replies. I had done the recommended searching and came up with more hits than I could count. I am using the Rotella T4 because Shell says it has the correct stuff in it for flat-tappet cams, including a solid lifter Cummins, and is also what the bottle states, so I thought I was (might still be) fine. Just after reading the lab results from 540rat...which might be crap(?)...I was just wondering about the 90,000 psi rating, and the fact that the Rotella 15W40 rates under that. And even though the Lucas break-in oil clearly states it's specifically for flat-tappet' engines the very low psi rating really got my attention... Is there any validity to the 90,000 psi rating...which I presume is directly related to proper flat-tappet use? Maybe not?
 
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Do yourself a favor. Take that 540rat blog, close the tab, and never open it again. There is absolutely nothing useful about that pseudo-science. The flat tappet lifter to lobe interface operates in boundary lubrication. Hydrodynamic oil film is already out the window. What you need is a tribofilm formed from activation of anti-wear additives (ZDDP in particular) to minimize abrasive wear of the cam lobes and lifters as much as possible. The amount of anti-wear (ZDDP) necessary is largely dependent on acceleration or "jerk" in the valvetrain, the weight of the valvetrain, valve spring pressure, and rpm. Higher lift cams with more aggressive lobes using high spring rates and turning more rpm need more ZDDP to cushion the blow. Your hot rods... do they use stock cams or aftermarket? Are they driven hard and frequently or casual cruisers that never see more than 3k rpm? What engines specifically? The Cummins I'd just put Rotella T6 5w-40 in and not worry about it.
 
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Originally Posted by Mad_Max_Sam
Is there any validity to the 90,000 psi rating...which I presume is directly related to proper flat-tappet use? Maybe not?
None, zero. When that data is properly analyzed and presented no oil tests better than any other oil. They all test the same. Besides that, the test he performs is not applicable to motor oils. There is absolutely nothing "directly related" to anything out of that website. All the work that... guy has done isn't even worth the bandwidth it consumes.
 
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Originally Posted by Mad_Max_Sam
Is there any validity to the 90,000 psi rating...which I presume is directly related to proper flat-tappet use? Maybe not?
Nope. It's a figment of 540rat's imagination. It has absolutely no meaning whatsoever. His "testing" is no more relevant to engine oils than testing which color of Prius can tow easier.
 

Mad_Max_Sam

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with all respect, I would be delighted to continue to use what I have been using in the real world that has been working - I am simply curious about what seems to be a significant amount of research that was done specifically about oils, and it sounds like while the research is extensive it may not have a direct correlation to the real world, and that is based on what 'info from someone on a thread' says, so again with all respect I take pretty much everything with a couple grains of sugar (salt is no fun...unless there's tequila involved smile ). I would be more than delighted to keep using the oil(s) I have been using, which were chosen based on the manufactures specs. I also don't want to be foolish just because a company says 'yah it's got all that stuff - now how many would you like to buy from us?'. Granted - I've never blown out a cam, but I also know that with the change to roller cams oils have also changed, so I'm just trying to keep up with the times...sift through the nonsense...and keep the proper oil in the pan(s). - Sam
 
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The proper way to sift through the nonsense is to know what specification or approval your owner's manual requires for your engine and then pick an oil that carries that specification or approval. There is no "test" on the Internet that judges an oil for higher quality, and there's no need to ask the manufacturer or spend hours reading through truly irrelevant data on some site to try and divine an outcome.
 
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Originally Posted by RDY4WAR
Do yourself a favor. Take that 540rat blog, close the tab, and never open it again. There is absolutely nothing useful about that pseudo-science.
Good advice!
 
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Originally Posted by Mad_Max_Sam
hey peeps - so I've spent several hours scanning the lab results from 540rat and I'd like some confirmation about what the 90,000 psi 'magic number' really means
The Brits have a term - 'fock-all'. Ask your engine builder what he recommends. Most of the 40 grade diesel oils have a good slug of ZDDP in them, but if you need more, there are plenty of other oils with more. Some that won't really break the bank (e.g. VR1), some that might (boutique oils like Red Line, etc.).
 
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Kingston
Originally Posted by kschachn
The proper way to sift through the nonsense is to know what specification or approval your owner's manual requires for your engine and then pick an oil that carries that specification or approval. There is no "test" on the Internet that judges an oil for higher quality, and there's no need to ask the manufacturer or spend hours reading through truly irrelevant data on some site to try and divine an outcome.
What "owner's manual" covers the spec required when you upgrade your 1960s or 1970s hot rod engine with a monster flat tappet camshaft? My engine calls for API SE. It will be fine on basically any oil because it's the original 1976 low lift camshaft, but if I upgraded it with a big camshaft that changes things drastically. There is no spec that the car calls for that will protect it from possible camshaft failure.
 

MolaKule

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Yes, the 540RAT info has been beaten to death so we close this thread. The General consensus is the 540RAT info fails the relevancy test.
 
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