Race vs. Street Oil and Lubricants: The Great Zinc Debate Continues - Engine Builder Magazine

Race vs. Street Oil and Lubricants: The Great Zinc Debate Continues

In racing applications, it’s not usually so serene. Engines live on the edge. Engine builders and racers are always fighting and scratching for more power, more torque, just that little something extra, even 100 rpm off the corner more than the next guy – but it comes with a price. About the only protection these fire-breathers have from grinding to a halt and destroying your customer’s chance for glory is the quality you’ve built and the thin layer of lubricant that rides in between the metal parts.

While some engine builders may moan that changes to passenger car oils are old news, many camshaft companies tell us that there are still people who don’t know about the lowered levels of zinc and phosphorous. The American Petroleum Institute (API) sets minimum requirements for oil performance parameters such as oxidation resistance, rust and corrosion protection, wear protection, viscosity, and many more. Recent API ratings have reduced the maximum-allowable content of some elements usually found in anti-wear additives, which has caused something of a zinc dialkyl-dithio-phosphate (ZDDP) panic among engine builders and car enthusiasts.

Other than the reduction in anti-wear additive, each new API classification usually requires a higher minimum performance level. Experts say this creates an improvement in lower quality engine oils, but usually does not in premium oils because they routinely exceed the minimum performance requirements anyway. We talked to several top racing oil and lubricant companies to get the latest on the great oil debate.

APIs and Race Oil

“Because oil formulated for racing applications does not generally carry an API rating, the oil manufacturer is freed from API restrictions on formulation, and ingredients and additives,” says Chris Barker, Royal Purple. “In general, racing engine oil will be a more robust formulation than engine oil intended for street use in a modern engine. The racing oil can be formulated to whatever performance and protection level desired or attainable by the oil manufacturer.”

API oils are designed to protect catalytic converters and to lubricate stock engines. Race cars typically don’t have catalytic converters, and race engines see more rpms than stock engines. “The higher rpms of race conditions increase the sliding friction in the valvetrain, and this requires higher levels of anti-wear protection than API oils offer,” says Lake Speed Jr., Joe Gibbs Driven Racing Oil.

“While some API licensed oils may provide adequate protection in a race engine, no API licensed oil can provide the higher levels of anti-wear protection true racing formulations offer. The amount of anti-wear protection in API oils has been reduced to extend the life of three way catalytic converters. The phosphorus in ZDDP (aka Zinc) creates a protective film inside your engine. This film prevents metal to metal contact, but the phosphorus also degrades the effectiveness of three way catalytic converters. As a result, the API has reduced the amount of ZDDP in API licensed oil (specifically, 10W-30 and lower grades).”

Can you ever use an API oil for racing? Most experts say API-rated oils CAN work for racing but it depends on the specific application. “API oil can be used in some sportsman racing, but typically most racing utilizes a purpose specific race oil. Generally speaking racing oils have higher amounts of zinc and phosphorus and a lower viscosity,” says Brian Reese, Comp Cams.

Richard Glady, Brad Penn Oil agrees, “In some cases you can use a street oil that meets an API classification. The older API specification oils, such as an SJ oil typically contained higher levels of zinc than the new API specification oils. The most important part of the oil is its viscosity and a select balance of additives required to protect critical engine parts. Our high performance oils incorporate a unique cut from Pennsylvania Grade Crude Oil that has tremendous ability to cling to critical engine parts and provides outstanding shock load characteristics.”

Royal Purple’s Barker also agrees that an API oil can be used in racing applications, but the engine build, fuel type, and level of competition should dictate what you use. He says a premium oil should be used and you should tell your customer to expect frequent oil changes.

Racing oil formulations must meet the requirements of the racing market which, as we all know, is not a static target. Racers and engine builders are always looking to make more horsepower, turn more rpm. But with each increase in power and rpm, the loads increase, and the oil must be formulated to handle these increasing loads. “As a race team and engine builder ourselves, we are developing oils that can carry higher loads so that we can use thinner, more powerful oils that can handle the higher loads without increasing wear, says Joe Gibbs Racing’s Speed.

Shell Lubricants’ Mark Ferner says that API standards guarantee that the oil meets the demands of modern engines and will also work in stock flat tappet applications as long as there are no modifications to cams, heads, etc. He agrees that for some racing applications, API is okay but the lowered anti-wear protection will create problems for high-powered race engines and street performance engines and a specialty race oil is then recommended. “I used to own a ’69 Firebird,” says Ferner. “If I still had that vehicle and it had the original engine in it in stock condition with flat tappets, then using today’s GF-4 API/ILSAC oil would not be a problem and offer enough wear protection. However, as soon as you make any modification such as an aggressive cam and stiffer springs to reduce valve float, and it’s still a flat tappet, then you’ve probably started to cross over that line where you should be looking at an oil with higher levels of wear protection.”

Ferner says some engine builders turn to a diesel oil. “Because it’s a diesel oil it has higher levels of wear protection, about equal to what it was before we started reducing the phosphorous levels several years ago at the car manufacturers’ request. For street oils at the lower viscosity grades with the API starburst, the phosphorous has to be between 600-800 ppm. Before we started drilling these down it was in the 1,200-1,400 range – no one knows for sure because no one talked about it then; it’s not an industry-recognized number. But to put it in perspective, today’s diesel engine oils are capped at 1,200 ppm.”

Ferner continues: “We’ve had enough experience over the last several years to provide enough protection for most modified performance engines except for those at the very highest levels of professional racing such as a NASCAR engine. The diesel oils probably come in at just under that 1,200 ppm number, and the purpose built racing oils could be all over the place: some could be as high as 1,900 ppm of phosphorous.”

Ferner admits that 1,200 ppm may be on the edge of an engine builder’s needs, depending on who you talk to and what you are running. But for most of the grassroots racers and even World of Outlaws and others, he says research has shown that diesel oil will suffice for most of these applications. He says the only concern with the diesel engine oils may be when you are truly trying to squeeze out every last horsepower. “Some of the additives that go into diesel oil so it can do its job and keep the soot in suspension may actually cause you to leave some power on the table vs. a racing oil. If you are really trying to get everything from the engine you may be a candidate for a true racing oil: you’ll get the wear protection and a formulation optimized to reduce internal drag.”

Role of Synthetic and Mineral Based Oil

The majority of each bottle of motor oil is made up of a base-stock taken from five groups of base-oil classifications. Group I base stock is the least refined base oil from crude oil. These are typically straight-weight, conventional motor oils. Group II base stock is more refined with fewer impurities, often used to create multigrade conventional motor oils. Group III base stock is even more refined to perform at the level of other synthetic base stocks and therefore is categorized as synthetic. Group IV base stocks are PAOs (Polyalphaolefin) synthetics and Group V is essentially anything that will not fit into the previous four categories such as esters and polyolesters.

Racing oil experts say that racing itself hasn’t necessarily changed in a substantive way because of synthetic oils. Royal Purple’s Barker says, however, that the performance and protection offered by superior quality synthetics have allowed a shift to lighter viscosity oils that reduce parasitic power losses (oil pumping, friction, etc.) while maintaining long-term protection of the engine.

“There are very good conventional oils available and there are some over-priced, sub-par synthetics available,” says Barker. “Additive chemistry and over-all formulation are more important than base oil type alone. Though Royal Purple oils are built on synthetic base stocks, our additive chemistry, especially our proprietary ‘Synerlec’ additive technology, is really what provides the performance and protection. No oil should be judged by one or two components.  The performance of the resulting formulation is what is important. With that said, we believe the best synthetic motor oil is better than the best conventional.”

Synthetics may allow for higher temperature operation and longer drain intervals but mineral oils have a place at the table, too, according to David Willis, Spectro Oils. “Mineral oils have made significant gains in the past several years and in some applications provide adequate lubrication at a more reasonable cost. Synthetics will outperform mineral oils in extreme heat and cold, but are not always the best choice.

Brad Penn’s Glady agrees: “Mineral-based oils, especially oils blended with Pennsylvania Grade Crude Oil provide tremendous ‘wetability,’ sticks to engine parts and offers better shock load characteristics than synthetics. On the other hand, synthetics provide better heat dissipation characteristics than mineral-based oils, especially with industrial applications.”

Just as in nearly every other aspect of the engine builder’s world, there’s no single answer. While synthetic oil has many benefits over conventional oil, Joe Gibbs Racing’s Speed says in applications where contamination levels are very high (i.e., dirt or heavy fuel dilution), a conventional oil may be a better choice. “Synthetic oils cost more, so there is always a temptation to go longer between oil changes. In most cases synthetic oils can provide extended drain intervals over conventional oils, but in the case of high contamination, the drain intervals need to be shortened – regardless of using  synthetic or conventional oil. In these cases of high contamination, conventional oils can provide adequate protection at a lower cost.”

Break-In Oils

Break-in oil has two primary jobs: 1) protect the camshaft and lifters; and 2) allow the piston rings to seat to the cylinder walls quickly. “Current API oils may not have sufficient anti-wear protection and a superior quality synthetic can extend the time needed for the rings to seat, says Royal Purple’s Barker. “Break-in oil should fill this requirement. They are generally high–quality conventional oils with a high anti-wear additive content.  Until API CJ-4, conventional diesel oil was a fine break-in oil.”

“We have race teams that break in their engines on synthetic oils,” says Shell’s Mark Ferner. “I don’t see any benefit or disadvantage to it. Whether conventional or synthetic, the way the other parts of the formulations are built, in our opinion, if you want to break in with synthetic or conventional it’s not going to cause a problem, as long as you have the the wear protection you need.»

Ferner points to the OEMs as support. “Corvettes come straight off the line with synthetic oil and so does the Viper. It can be done and doesn’t take any special procedure. Decades ago there were compatibility issues between synthetic and conventional oils. Today, some pure scientists may suggest you shouldn’t mix the two because each was optimized individually, but I’ve been in the business since 1988 and since that time if you want to mix synthetic and a conventional oil there’s not a chemical compatibility problem between the two.

Brad Penn’s Glady says that the purpose of break-in oil is really to control the wear process. “A well-balanced break-in oil with unique base oils and a select balance of additive concentrate helps to seat the rings quickly and completely; too much zinc in a break-in oil is not a good thing and may deter the rings from seating properly. The benefit of a specially formulated break-in oil will help to ensure the long and useful life of the engine.”

Assembly Lubes and Additives     

Most oil experts say that for true racing applications, anti-wear additive products are a compromise. Ideally, a racing oil is designed specifically with the correct amount of anti-wear and other friction modifiers and things so you don’t need to use an additive in those situations. However, in street performance and break-in where you aren’t as concerned with optimizing the formulation, an anti-wear additive product can be good insurance.

Any time there isn’t a catalytic converter involved, you will benefit from a proper level of zinc, says Comp’s Reese, emphasizing the word proper. “Keep in mind, TOO MUCH zinc causes additive blocking – in other words, too much zinc will get in the way of the other additives from doing their respective jobs. The market has gone overboard with the zinc fixation. Don’t OD on zinc.”

Engine Pro’s Don Weber says his group offers a variety of  additives and assembly lubes that fit most engine builder’s needs. One of these is a traditional zinc additive, which contains some of the highest concentrations of zinc and phosphorous of any brand of additive. It is compatible with any oil, whether it is synthetic or mineral based so that engine builders and their customers can choose their favorite brand of oil to use with the additive.

Another option is an assembly lube that contains moly. It adheres well to metal surfaces and has a compound in it that makes it sticky and comes in a squirt bottle to make it convenient to lubricate the parts thoroughly. One product Engine Pro offers contains no zinc and is safe to use in vehicles with catalytic converters. “There are many vehicles from 1975 until the 1990s that had both a catalytic converter and flat tappet cams. With its re-engineered calcium petroleum sulfonate complex, this is an alternative to zinc and phosphorous. It’s more for the weekend racer with a car or truck that has a converter.”

Steve Mugerauer from Howards Cams says, “We, like many others, offer a few different brands of racing and break-in oils, and they do a really good job, depending on your brand preference. The reason we decided to offer our own lube is because it got to be really confusing with the various bottle sizes. We found out that the majority of the big guy’s break-in formula was mostly mineral oil. So we have several reasons why ours is a good choice for engine builders. One, is the concentration of ZDDP and Phosphates. Max Z has 60,000 ppm of ZDDP and 42,000 ppm of phosphates. It comes in a four oz. bottle, which will treat six quarts, so it’s the additive and not the mineral oil you are paying for. It’s one of the highest amount of those additives that you can put in an engine. The second reason is we are the only ones who put 10,000 ppm of moly in our formula. It’s a real fine molybdenum disulfide. The third reason we think engine builders will choose Max Z is the price. It’s very affordable and you get the maximum amount of protection.”

Royal Purple offers Max-Tuff, an ultra-tough, synthetic lubricant designed for use in reassembling repaired equipment. Barker says Max-Tuff utilizes durable synthetic molecules that adhere to metal surfaces and create an extremely strong barrier between surfaces. This minimizes the possibility of metal-to-metal contact while providing excellent protection against rust and corrosion to both ferrous and nonferrous metals.

New GF-5 Oil Standards

In the Fall of 2010, a new oil spec called GF-5 is being introduced. The new standards will increase fuel economy and emissions as well as make it more compatible with E85 ethanol. Because experts say it will not have been tested in race applications, however, it’s critical that the engine building community is aware of the changes. The wear protection has not been lowered but the types of zinc and phosphorous may be altered to meet the new requirements.

“The current oil classifications are API SM/ILSAC GF-4 for spark ignited gasoline engines,” says Joe Gibbs’ Speed. “For the 2011 model year, GM is introducing dexos 1, a global engine oil specification for all GM cars and trucks. The new dexos 1 oil standard will require the use of synthetic base stocks, and it requires increased protection for catalytic converters compared to API SM. As a result, API is introducing a new oil standard – API SN / ILSAC GF-5. These new standards require improved engine cleanliness (more detergents and dispersants), improved fuel economy (lower viscosity base oils) and increased protection for three way catalytic converters (restriction on the type of ZDDP used).”

If your engines aren’t ready for retirement yet, it pays to pay attention to what keeps them running smoothly and efficiently.Here
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