WHEN YOU SEE THAT SLIDING ... IT’S GOT SO MUCH LOAD ON ITSELF THAT IT’S TRYING TO WELD ITSELF
Do all modern API-rated oils require lower ZDDP levels, or only those of lower viscosities? The current API ratings use specific viscosity grades. So, anything that’s a 10W-30 or lower is required to be a maximum of 800ppm [parts per million] of ZDDP; 20W grades and higher can be up to 1200ppm, but the higher grades are still limited to 1200ppm max.
Could you, theoretically, run a car on running-in oil indefinitely? You can, you’d just have to change the oil very regularly — the drain interval becomes very short, around every 1000km. The idea of breaking-in oil is no different to painting something — it’s establishing a more tenacious base. If you decide to paint a car without primer, your paint job may look good, but it won’t last very long. In an engine, it’s about establishing an anti-wear film — you’re not worried about having the oil in there for a long amount of time, because, during break in, you’re going to have the highest amount of wear metals. Around four times the amount of wear metals are created during break in compared to any other time in the engine’s life. That goes back to one of the causes of the rollercam synthetic myth, because people that typically have roller cams and run synthetic oils, what don’t they do? Change their oil very often, because the synthetic oils are marketed as having longer drain intervals. So, if I’ve got this brand new roller-cam and run synthetic oil, I don’t need to run breakin oil, and end up running this synthetic oil for 10,000 miles, or however long the oil pack says, then I wonder why the lifters and needles are crap. It’s because the number-one reason for rollerbearing failure is contamination, and what didn’t you do? Keep the system free of contamination. Low detergent, low dispersant oils are used for that reason — it establishes an anti-wear film and then removes contaminants from the system. You’re looking at two things: reducing wear, and then removing what is wearing, so that it is not continuing to move through the engine.
Are friction and wear directly related? Nope. That is the most difficult thing to really comprehend, but reducing friction does not necessarily reduce wear, and reducing wear does not necessarily reduce friction. A reduction in friction and wear can occur at the same time, but the two things are independent, and you can never make the assumption that reducing friction to improve horsepower will also reduce wear. We’ve seen it over and over again, and you cannot relate the two. ZDDP is a classic example; if you put the right type of ZDDP in the engine oil at a higher level, you will reduce wear in the engine, but also increase friction — because ZDDP is not a low-friction coating. You can replace it with a lower friction coating that doesn’t prevent wear as well, and you can improve your economy and all that, but wear increases.
Is more ZDDP always better? Nope, it’s a balance. The whole thing about all of this is balance, which strikes against the whole racer mentality of ‘a little is good, so more must be better’. That’s not the case with oil — more oil pressure is not better, more oil flow is not better, too little flow is not good, too little pressure is not good. Same with viscosity, it has to be just right. Most oil conversations start at the wrong point, by talking about oil. We do not make engines to put oil into; we make oil to put into engines. So, the starting point of every oil discussion should not be the oil; it should be the engine — it’s motor oil, not an oil motor. Someone will say that a certain oil is better because it’s got this and this and this and this — no, no, no. Understand the application first. It could be a 289 in a classic car, or a 289 in a track car. Same engine, same components, different application, and you’re going to get two different oils. Understand your application first — do I have a flat-tappet cam, am I running ethanol, etc.? Then select a product that has the right viscosity, the right chemical characteristics for the application, then pick the brands you trust to deliver all of these things. People typically start in the opposite direction — they’ll start with the brand and then they try to find the best oil [that] that brand offers, and then shoehorn it into their application. And then you try to justify your rationale for doing so. You’re wrong, and just because it didn’t blow up, [it] doesn’t mean you’re not wrong. Engines that
blow up do not equate to bad lubrication, just as engines that don’t blow up don’t equate to good lubrication. Just like every doctor graduated from medical school, but not every doctor got an A in medical school.
What effect does camshaft profile have on oil life? More aggressive ramps on flat-tappet cams are going be more demanding on the ZDDP anti-wear package in the oil. Think about a low-lift, low-duration cam profile as like a small carburettor. It’s not using a lot of fuel. Whereas your big-lift, really aggressive cam profile is like an 850 Double Pumper — it’s going to use a lot of fuel. The fuel in this analogy is the consumption of the ZDDP. In low-lift, low-duration, ‘low-use’ camshafts, you can get by with low-ZDDP oil in some applications, but the moment you try to take that low-ZDDP oil and put it in a ‘high-use’ situation, it’s going to fail. It’s not about how much ZDDP is in your oil — that’s the wrong question. It’s about the application.
It’s quite ingrained in people who own old vehicles to use mineral-base oils. Is there any particular application where you’d recommend a mineral- over a synthetic-base oil in a flat-tappetcam engine? Well, I would tell people to use a mineral-base oil over a synthetic, but there’s only two reasons why. One is the age of the seals, and the type of the seals in the engine. Original seals, rope seals, etc., were all developed around mineral oils with higher viscosities. These were solvent refined. Trace MEK [methyl ethyl ketone] solvent that’s still left in some of these oils causes these seals and O-rings to swell up, which keeps them sealing. You put in a synthetic oil that’s not solvent refined, they tend to just dry; shrink; crank; and, subsequently, weep. So, if you’ve got an old engine that has been run on mineral oil its whole life, then just stick with mineral oil. Secondly, if the car is not used very much, only goes to car shows, and is driven less than, say, 1000 miles in a year, why waste your money on synthetic? Synthetic is designed to perform better under extremes, and if the car is not being put under any extremes, then why are you bothering? The guy who’s out there drag racing, go for it. You might get that day where it’s crazy hot, the air’s really good, or there’s a lot of grip, and you need that extra little bit of protection.
With regards to the rope main seals and mineral oil, does that only apply to original engine seals, or reconditioned engines as well? Well, if you rebuild an engine and you run the same type of seal in it, then it still applies. If you put in a modern seal, say, neoprene, then it will no longer apply. That said, from an efficiency standpoint, you will always be better off with a synthetic.
How does fuel choice affect oil life; say, E85 over traditional pump gas? There’s two factors that actually influence the life of the oil. One is the operating temperature of the oil, and the other is what we call the ‘oil-to-fuel ratio’. Rule of thumb is, for every 10°C you increase your oil temperature, you cut your oil life in half. You start from about four years if it’s not doing anything, but, as you crank it up and it gets hotter, you start to decrease that oil life. The ‘oil-to-fuel ratio’ refers to how much fuel is run through a given volume of oil. So, a larger oil sump will live longer with the same fuel flow as a smaller volume of oil. Inversely, for a given quantity of oil, the more fuel flow you run through it, the shorter its life is going to be. So, if you’re running 92 octane — you know, pump fuel — at close to stoichiometric, you’re pretty good. When you run E85, you’ve increased your fuel ratio by almost double, so you cut your oil life in half. It’s a reality — the guy who runs race gas is going to have a longer oil life than the guy who runs methanol, because you’re going to run twice as much methanol as race gas, which shortens the life of the oil due to the higher oil-to-fuel ratio.
Does that mean PCV (positive crankcase ventilation) has an effect on oil life? Crankcase ventilation is a good thing. You obviously want to get all of that vapour out. The trick is — let’s say, with a car like a 1965 Mustang versus a Mitsubishi Evo — the old-school car’s PCV vents to atmosphere. That’s super friendly — yeah, maybe not environmentally — for the oil, because it just goes out. In the Evo, it goes back to the intake manifold, so you’re rebreathing all this junk. So, now, your fuel does affect oil life. If your tune is fairly rich, you compound the problem because what you’re running through the oil also goes back into the PCV system, and it comes back in again. If you’re rich in the Mustang, it just goes in and goes back out, and you only have to see it once — that’s why you can smell older vehicles more than you can smell newer vehicles.
So, would PCV to a catch-can tend to be preferable, then? Yes, it works. It is a mechanical device that works. Now you’re not putting those vapours and those chemicals back into the engine, [and] you can safely drain them off. So, if your car’s got a catalytic converter in it, it’s going to work better and last longer because of the catch-can keeping that stuff from getting to it. They’re actually a really good idea — especially when you start making performance mods and running the car harder. That was one of the first things that GM had to do with the 2014 or 2015 Corvette. It’s a DI engine, and they realized really quick that maybe they should put catch-cans in it. With a DI engine, it’s very important to have a good catchcan system, because there’s no more fuel flow to wash the intake mouth clean. So, they built the PCV oil separators into the valve covers; in each bank of the valve covers, there’s a PCV valve sitting in there, and the oil separators built into it. That way, you retain the oil in the engine — that’s the one downside to the remote catch-cans: you are removing that volume of oil and are not putting it back into the engine. If you’re running the car hard and slowly decreasing oil volume, the oil-to-fuel ratio is also going down, so it changes oil life.
So, if you have an external catch-can for PCV, you would not want to reuse that oil simply because of exposure to air? No; you might be tempted to do that, but you wouldn’t want to.
Thanks for taking the time to answer all of our questions, Lake — we sure learned a lot! Special thanks must go to Lake Speed Jr for taking the time to be interviewed, as well as Craig Hyland at Craig Hyland’s Engine Dynamics for helping to bring Lake Speed Jr to New Zealand for an informative seminar.
RULE OF THUMB IS, FOR EVERY 10°C YOU INCREASE YOUR OIL TEMPERATURE, YOU CUT YOUR OIL LIFE IN HALF
An older-style PCV system is likely to vent to atmosphere, as the Holden straight-six does (right). This is better for the engine than a recirculating system, which feeds crankcase vapour back into the intake. Using a catch-can, as shown at left, is a superior variation of this system — not only does it prevent the engine from rebreathing the spent crankcase vapour but it also collects it to be drained in an environmentally responsible manner.