Most of you read­ing this will know enough about en­gine oil. You’ll un­der­stand enough about oil vis­cos­ity, zinc con­tent, and API rat­ings to know the dif­fer­ence be­tween what goes into your daily-driver and what goes into your V8. The tradies among you who drive a late-model diesel ve­hi­cle ev­ery day may know more than most — af­ter all, you can’t just run any old oil if you’ve got a diesel par­tic­u­late fil­ter (DPF). How­ever, be­yond the surface-level stuff, the world of oil is largely a mys­tery. And, we’ll be the first to ad­mit, it sounds aw­fully bor­ing. Who re­ally wants to know more about oil? Well, as it turns out, it’s not that bor­ing. We were able to chat with Lake Speed Jr, a re­spected US-based ‘tri­bol­o­gist’ — an oil tech­ni­cian, if you were wondering — who was brought to New Zealand by Craig Hyland from En­gine Dy­nam­ics. Lake Speed Jr works ex­ten­sively with the Joe Gibbs Rac­ing Nas­car team and has had a long and in­ten­sive ca­reer in the mo­tor­sport in­dus­try, and he is the brains be­hind the pre­mium Driven Rac­ing Oil range of lu­bri­cants. We made the most of his enor­mous knowl­edge of lu­bri­cants to find out more, and dig into some myths, about en­gine oils.

Hi, Lake Speed Jr. Thanks for tak­ing the time to do this. We’ve got a few ques­tions for you. First of all, do oil ad­di­tives re­ally work, or are you bet­ter to start with a good oil and elim­i­nate the need for ad­di­tives? The STLE [So­ci­ety of Tri­bol­o­gists and Lu­bri­ca­tion En­gi­neers] have an­swered that ques­tion with a ‘no’ — you should never put an af­ter­mar­ket ad­di­tive in any crank­case. If you feel that the oil you are us­ing in in­suf­fi­cient for the job it is do­ing, you should get a dif­fer­ent oil, not put some­thing in. In fact, on the exam to get [STLE] cer­ti­fi­ca­tion, that ac­tu­ally was a ques­tion — ‘when is it ap­pro­pri­ate to use an af­ter­mar­ket ad­di­tive in a crank­case?’ — and the an­swer’s never.

Would that ex­tend to oil flush? I’d say so. Some of the oil flushes avail­able do re­ally weird things, and you re­ally ought to be think­ing about it. Even if you’ve got this old en­gine — say, it hasn’t been run for 15 years, and you’ve got no idea about the con­di­tion of the in­ter­nals, then drain out what’s in there and put in a lighter weight of min­eral-base oil. Let it run for 20–30 min­utes, get heated up, then drain it out and re­place it with, say, HR oil [15W-50 min­eral base]. The key is in chang­ing the oil when it’s hot — if the oil is not hot, then you’re not drain­ing it all out. You’ve got to get it hot enough so the vis­cos­ity thins and it all flows out. Play­ing with ad­di­tives is like play­ing Rus­sian roulette. One guy might say, ‘I used XYZ en­gine treat­ment and I picked up 5hp’; well, the other guy might say, ‘I used XYZ en­gine treat­ment and I lost five main bear­ings’. Which one’s ly­ing? Well, nei­ther of them is — the re­al­ity is that, in one case, the XYZ ad­di­tive did not blend well with the ad­di­tives in the oil al­ready and had a bad re­sult; in the other case, they worked to­gether and it’s OK. Un­less you’re a chemist and you know 100 per cent what you have and what you’re adding it to, it’s just a gam­ble. There’s a lot of guys out there with a lot of money tied up in their mo­tor — is it worth tak­ing that risk?

Is more ex­pen­sive oil al­ways bet­ter? Nope. We get this ques­tion fre­quently — I think I’ve an­swered this one twice to­day, al­ready. Race oil is more ex­pen­sive, but it’s not bet­ter. Say I have a car that I drive to work, drive to the odd car show, then take to the track for drags or a drift do. I may think I have a race car, but I don’t, and I don’t main­tain it like a proper race car. Race oil is low de­ter­gent, low dis­per­sant, and needs chang­ing ev­ery 800–1000km — that level of main­te­nance is not hap­pen­ing with that car. So, while race oil is more ex­pen­sive, it is not ac­tu­ally the right choice for the ap­pli­ca­tion. A good way to know if you should run a race oil or a high-spec syn­thetic is this: if you use pump petrol, use a high-spec syn­thetic like Driven’s LS30; if you use race fuel, use a race oil.

How about zinc con­tent — is there only one type ofZDDP( zinc di­alkyld it hio phos­phate )? Nope, there’s al­most 50. There are three classes of ZDDP — pri­mary, sec­ondary, and aryl. Within those three, there’s both short chain and long chain, as well as high molec­u­lar weight and low molec­u­lar weight, so there is a wide va­ri­ety in ZDDP chem­istry. If you do the math, it works out to around 49 pos­si­ble com­bi­na­tions, and that’s not even with mixing. You can get some ZDDPs that are mixes be­tween two. So, I could mix a short­chain pri­mary with a long-chain sec­ondary to try to get a mix­ture. You can say, ‘I’ve got ZDDP’, but what type? Some are proven to be more cataly tic­converter -friendly and less so for anti-wear. Some are re­ally good for anti-wear, and not so cat-friendly. Is there a spe­cific type of ZDDP that we should be look­ing at for our type of cars — older, pushrod­type stuff? Yes. Older pushrod-style en­gines have very high con­tact forces in the val­ve­train, so the ZDDP ac­tiv­ity re­quire­ment is higher. You see, the ZDDP doesn’t know what the spring pres­sure is; it doesn’t care. It just knows con­tact load. So, if I have a four-valve en­gine that only has 80 pounds on the seat, but my con­tact area is su­per small, it could still be as high as a two-valve mo­tor that has 140 pounds on the seat but has a much wider con­tact surface. Now, with the pushrod mo­tor, you have more dy­namic weight be­cause of all of the val­ve­train’s mass. That’s where the over­head-cam en­gines gen­er­ally have a lot more lee­way, be­cause they don’t have the mass, so some of the in­er­tia forces don’t do the weird things that pushrod en­gines do — the higher your rpm, they start do­ing funny things. The sec­ondary ZDDP is the one that has the bet­ter anti-wear prop­er­ties, so, any time you have a per­for­mance en­gine or a clas­sic flat-tap­pet en­gine, the sec­ondary ZDDP is your bet­ter anti-wear. In the clas­sic and per­for­mance cars, they’re not so much wor­ried about whether they’re go­ing to get 75,000 or 125,000 miles out of a cat­alytic con­verter, so go­ing with an oil loaded with sec­ondary ZDDP like HR1 is a great op­tion for out­stand­ing wear pro­tec­tion. And that’s a re­ally im­por­tant point to make, be­cause too many peo­ple have this fear that if they use a high ZDDP oil, their cats are go­ing to go bad — that’s not gonna hap­pen from the ZDDP. The ZDDP is never go­ing to do that; the cat may not work as well, but it’s not just go­ing to clog up. That only hap­pens when you have, say, stuck rings and are us­ing oil — like a quart ev­ery 100 miles. Some guys have cars that only see a trailer. They fire it up, roll it on a trailer, and go to a show, and it sees less than, say, three miles a year, and they only do one oil change — OK, the oil you bought at the parts store is probably OK. Yes, by now the valve springs are probably only a frac­tion of the spring rate they were ini­tially, but if he doesn’t do any­thing dif­fer­ent to that car, then it’s probably fine. The prob­lem is when that guy jumps on the in­ter­net and says ZDDP is all rub­bish and that he doesn’t have any prob­lems, and the guy that ac­tu­ally drives his car gets a flat cam be­cause he lis­tens to bad ad­vice.

Is there any way to tell what type of ZDDP you have in your oil, so that if you’re shop­ping, you can lean to­wards a more prefer­able type? Some­times you can tell by oil anal­y­sis, but off the shelf — no. You can tell what’s not in it, though. Any­thing with an API SN grade has to use the new phos­pho­rous re­ten­tion ZDDP, which is a less ac­tive form of ZDDP. So, any­thing that’s an SN will not have the older, more ag­gres­sive type [of] ZDDP, and most of what you’re go­ing to get off the shelf is SN.

Is there any guar­an­tee that older grades, such as SG or SJ, will meet a par­tic­u­lar ZDDP con­tent? No, but typ­i­cally if it has an SG or an SJ on it, then those oils — and the fact that they’re even dis­play­ing that rat­ing — means that they’re probably buy­ing a pack­age that has been ac­cepted as that. Those are ob­so­lete stan­dards, so you can’t go and cre­ate and


test an oil of that stan­dard and get approval — you can’t even run those en­gine tests. So, to main­tain that, the ad­di­tive sup­plier is selling the pack­age they sold back then, and you can claim it. With those older oils, is there such thing as a shelf life? If you found an older pack­age from 10 years ago, could it still be OK to use? The ba­sic rule of thumb in the oil in­dus­try is that the man­u­fac­tur­ers will typ­i­cally stand be­hind the oil for at least 24 months from the date of man­u­fac­ture. There should be zero is­sues within 24 months. The next 24 months af­ter that, you should be OK as well. That gives you four years. Any­thing past that, you might want to shake it up re­ally good, but it re­ally de­pends on how you store it. There are cer­tain com­po­nents that do lose their po­tency over time, so that can po­ten­tially be an is­sue.

What’s the deal with de­ter­gents be­ing added to oils? Think about mod­ern en­gines and emis­sions; pis­ton de­sign, for ex­am­ple. On old-school en­gines, your top ring land used to be fairly far down. You had all this crevice vol­ume, and all this crevice vol­ume doesn’t burn. The low speed pre-ig­ni­tion is­sue with DI [di­rect in­jec­tion] en­gines, what they were find­ing is that the crevice vol­ume is where it ac­tu­ally ini­ti­ates the mega-knock event. So, one of the pis­ton man­u­fac­tur­ers worked with one of the test labs, and ac­tu­ally patented a crown de­sign where the crevice de­sign is ac­tu­ally ta­pered — it’s not a 90-de­gree an­gle; it ac­tu­ally runs a re­ally odd­ball ra­dius. The idea is that you can ac­tu­ally get the flame front to travel all the way down the top ring. That way, there is no place for it to build up and then light up from. The point be­ing, with the ring land way down, that was push­ing emis­sions. And with low-qual­ity fuel, oil would build up in the ring lands, ring lands would start to stick, and the en­gine would start to use oil, im­pact­ing emis­sions. To run tighter pis­ton-to-wall clear­ances, you run a higher ring land. So, to keep the [top] ring land clean, they had to run more de­ter­gent in the oils. The other thing was the gov­ern­ment push­ing fac­to­ries to get longer ser­vice in­ter­vals, be­cause used oil is an en­vi­ron­men­tal hazard. They want less waste oil, so they push the OEMs to man­date longer ser­vice in­ter­vals, and they get credit for their emis­sions re­quire­ments — some of the things they say, like Porsche rec­om­mend­ing 20,000km drain in­ter­vals. They pay a very high penalty, at least in the US, be­cause of their fuel econ­omy, but they ac­tu­ally get cred­its by other things.

So, gov­ern­ment in­ter­ven­tion has had a big im­pact on oil man­u­fac­tur­ing? That’s the pri­mary rea­son that mo­tor oil is dif­fer­ent to­day than how it was 10 years ago, than it was 20 years ago. Those 20 years of changes have all been driven by gov­ern­ment in­ter­ven­tions, not be­cause of any­thing the oil com­pa­nies or OEMs felt like they needed to do dif­fer­ently per­for­mance- or pro­tec­tion-wise. But if you were in Los Angeles in 1994, com­pared to to­day, you’re def­i­nitely thank­ful for some of the things that have been done — you can ac­tu­ally see! They have made a dif­fer­ence there, but it has come at a cost. There is a trade-off, and as long as peo­ple are aware of what that cost is, then it’s all good. Take E85 — it’s not a bad fuel, but don’t think that it’s the mir­a­cle come from heaven with no strings at­tached. Every­thing that you do has some side ef­fect, there’s some con­se­quence or trade-off, but, as long as you’re aware of that trade­off, then you’re fine.

How does op­er­at­ing rpm af­fect vis­cos­ity choice? The higher the rpm of the en­gine, the less vis­cos­ity, which is counter-in­tu­itive to most peo­ple’s think­ing; ‘I’ve got a high rpm en­gine, I need a 10W-60’ — no, you don’t. Tighter tol­er­ances in en­gines also re­quire lighter vis­cos­ity. So, take your current BMW or Porsche mo­tors, even the mod­ern Ford Coy­ote V8, that has VVT [vari­able valve tim­ing], and set them aside, be­cause they’re a dif­fer­ent beast al­to­gether. What you’re do­ing with VVT is ask­ing the oil to not just be a mo­tor oil but also a hy­draulic fluid. All those sys­tems have one thing in com­mon — they use oil as a hy­draulic fluid to ac­tu­ate, at some point, the VVT sys­tem. Whether it’s Honda’s VTEC or BMW’s VANOS, there are dif­fer­ent meth­ods, but they all use oil as the hy­draulic force to ac­ti­vate the unit they have. So, in hy­draulics, you have to have oil pres­sure, be­cause it’s fluid force. Typ­i­cally, high-horse­power race en­gines do not need a lot of oil pres­sure. A non-hy­draulic all-out race mo­tor doesn’t need too much oil pres­sure; it needs oil flow. High-vol­ume oil pumps don’t make pres­sure, they in­crease pump vol­ume. If you’re not care­ful, your high-vol­ume oil pump will drain your oil pan dry and then you blow up your mo­tor. How did that hap­pen? You’ve got an en­gine that’s built to run eight gal­lons of oil per minute, and your pump runs 14 gal­lons per minute, so all the oil gets pumped out of the pan! Now, in a VVT en­gine with a hy­drauli­cally op­er­ated val­ve­train, pres­sure does mat­ter, as it’s the fluid force that moves the part. Some of them use a spray­ing mech­a­nism, some­thing with a coun­ter­bal­anc­ing force, so you have to gen­er­ate enough force on one side to over­come it. Thus, you have en­gines that call for a 10W-50 or a 0W-40, some­thing with very wide splits in vis­cos­ity. The oil’s got to go through th­ese very tight clear­ances, but they’re also typ­i­cally alu­minium-block en­gines, which means that they get hot­ter, and those clear­ances ex­pand. So, when the en­gine gets hot and the per­son steps on the throt­tle, there must be enough vis­cos­ity to make this thing work.

How about syn­thetic bases? Is it true that you shouldn’t run a syn­thetic oil in a flat-tap­pet cam en­gine?

Nah, that’s crazy. Ev­ery Nas­car en­gine out there uses flat tap­pets and all run syn­thetic oil. That’s one of those myths that came be­cause, when they first started re­duc­ing the ZDDP in the oil, the first ones to have lower ZDDP were the syn­thet­ics, be­cause they were the pre­mium oils for the new­est, lat­est, and great­est. So, there probably were some guys who looked at this new 10W-30 syn­thetic oil and thought it’d give them more power, dropped it in their old 289, and wiped the camshaft — be­cause they went from a 1200ppm zinc oil that had lots of sul­phur in it nat­u­rally, to one with zero sul­phur in it, be­cause it’s syn­thetic, and lower ZDDP. ‘Oh, it’s the oil’s fault’ — no, it wasn’t the syn­thetic oil that was bad; it was the chem­istry that wasn’t right for the en­gine. Even if you had a min­eral-base 10W-30, you wouldn’t be too keen to run that in an old Mus­tang, would you? Oh, I would to­tally put a 10W-30 — just not an off-the-shelf 10W-30 but a high-zinc one — in a Mus­tang. Be­cause of where the pickup tube is rel­a­tive to the oil pump, it’s a rel­a­tively long pickup tube, th­ese Ford mo­tors ben­e­fit — es­pe­cially at cold start — from a lighter weight oil. It’s very easy, in Fords with a wet sump, to put in a re­ally heavy oil, and the en­gine won’t get enough oil mov­ing through it. One of our cus­tomers is a guy in the UK who is a Ford spe­cial­ist, and he had a re­ally high­end Cobra — a real Cobra, not a kit car. They were run­ning a dry-sump sys­tem, where they could ob­vi­ously prime it re­ally eas­ily; well, FIA came out with a rule that the en­gine had to run an oil­ing sys­tem as per fac­tory. They’d al­ways run 20W-50 with the dry-sump sys­tem, went out to Donington early in the spring, it was a cool day, and they filled it up with 20W-50. So, they fired it up and went off, with 20W-50 in the wet-sump mo­tor, and threw the rod bear­ings. They did it twice be­fore they started ques­tion­ing what was go­ing on. We told them that, for the en­gine they’re run­ning, they need to run a 5W-20. Well, they were scep­ti­cal but, by that point, he was two re­builds in and had noth­ing to lose, so went with the 5W-20. He had to try some­thing to fix it, so they put in our 5W-20 Joe Gibbs Driven XP1, went out, won the race and went all sea­son with­out look­ing back. The higher the oil vis­cos­ity, the less flow you have upon start-up, and the more wear that oc­curs in the en­gine — 70 per cent of the wear that oc­curs in the en­gine oc­curs on start-up. As long as you don’t run an oil that’s too thin for the en­gine, then you’re good. The right vis­cos­ity for the clear­ances is the right choice.

It’s a com­mon be­lief that syn­thetic-base oils cause roller lifters to slide on cam lobes — is this true? It’s ba­si­cally the same vari­a­tion of the flat-tap­pet deal — it’s not that it’s syn­thetic; you need the ex­treme-pres­sure ad­di­tive. With flat tap­pets, you have this slid­ing ac­tion, where it’s try­ing to wipe away the oil, and you have that con­tact load. With a roller, you don’t have the slid­ing, but you have this rolling, this line con­tact, es­pe­cially with nee­dle roller bear­ings. So, if you don’t have enough vis­cos­ity to keep all those parts sep­a­rated, and you don’t have the ex­treme-pres­sure ad­di­tives, you will have a prob­lem. When you see that slid­ing, that’s be­cause it’s got so much load on it­self that it’s try­ing to weld it­self — it’s like a pot­hole; that ini­tial lit­tle rip­pling is what causes it to slip and start ham­mer­ing lifters and the val­ve­train. Run those en­gines on a high-zinc syn­thetic oil, and they’ll run for a very long time with­out any roller-lifter is­sues.

The val­ve­train de­sign in­her­ent in mod­ern over­head­cam con­fig­u­ra­tions (right) gen­er­ally im­plies a lower val­ve­train mass, when com­pared with tra­di­tional over­head-valve as­sem­blies (left). The rough rule of thumb to be ap­plied here is that older-style pushrod en­gines are more likely to re­quire oil with su­pe­rior anti-wear char­ac­ter­is­tics.

Some older en­gines have pistons with lower top ring lands. The flame front from the com­bus­tion event may not be able to clear this crevice be­tween the pis­ton crown and up­per ring land, caus­ing a build-up of oil, which could then cause the ring to stick, lead­ing to even fur­ther oil con­sump­tion. TO KEEP THE [TOP] RING LAND CLEAN, THEY HAD TO RUN MORE DE­TER­GENT IN THE OILS ...

A di­rect in­jec­tion sys­tem sees the fuel in­jected straight into the com­bus­tion cham­ber. As there is no fuel to wash the in­take valve, an ef­fi­cient crank­case ven­ti­la­tion sys­tem is of the utmost im­por­tance to elim­i­nate the risk of con­tam­i­na­tion build-up, which can pre­vent the in­take valve from seat­ing prop­erly.

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