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.


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.

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