Modern Engine Oil

Although our hobby is built on tradition, it certainly benefits from modern automotive technology. Street rodding is and always will be a unique blend of historic automotive architecture and contemporary mechanical components. Alternators, electronic ignitions, computer-controlled fuel injection, and disc brakes are only a few of the improved components that street rod builders have embraced. There have also been advancements we have taken advantage of almost without realizing we were doing it; specifically we're speaking of modern engine oil.

The longevity of all engines, including our beloved vintage designs, has increased dramatically compared to the lubricants available just a few decades ago as a result of lubricant improvements. And the best part of that particular technology was that no effort was required to use it because, while there were many brands of oil to pick from, we could be confident that any that met the latest API standards (see "A Slippery Subject" in the February '07 issue of SRM for a complete explanation of API standards and SAE designations) would provide more than adequate lubrication for the majority of engines found in street rods. The latest oil was indeed the greatest, and all we had to do was pour it in to provide our street rod's engine all the protection it needed from premature wear. Unfortunately, that's no longer the case, as technology has thrown us a curve.

The Problem
Ironically, one of the latest advancements in automotive technology has turned out to be a step backward for aficionados of early iron. In a nutshell, the issue is premature cam wear in some engines with flat-tappet cams, and it's due to the reduction of an important anti-wear compound, zinc dialkyldithiophosphate (ZDDP), in many of the latest engine oils. A combination of zinc and phosphorous, ZDDP is unique in that it bonds to the camshaft as a result of heat and friction and actually creates a sacrificial coating between the lobes and lifters (pushrod ends, valve stem tips, wrist pins, and other parts also benefit from ZDDP). At one time, zinc levels in most motor oils were around 1,400 ppm (parts per million), but due to stricter government-mandated standards that require extended emissions control warranty periods, it was decided that lower ZDDP levels were necessary to prevent degradation of catalytic converters and oxygen sensors. As a result, the levels were reduced in SL oils to 1,000 ppm and were dropped even further with the SM-rated oil that auto manufacturers are now requiring to meet warranty requirements. These oils have a maximum 800-ppm of ZDDP. To properly protect flat-tappet engines, particularly the performance variety, most experts agree that 1,000 ppm is the absolute minimum, and some prefer 1,100 to 1,200. At this point, the obvious question is why don't new cars have problems with cams going flat if ZDDP is so crucial? The simple explanation is just about all of them are equipped with friction-reducing roller lifters.

The Solution
Now, before you run out to the garage and drown your sorrows in a quart of 10W-40, for those who are old enough, let's think back to the days when unleaded gas was introduced and the fear was that every old engine was going to grind to a halt (if you're too young to remember that, trust us, it happened). This is a similar situation. In some cases, engine modifications will be called for to cope with changes in formulations; in others, little or nothing will have to be done other than selecting the proper product.

As we've said, this issue impacts engines with flat-tappet cams; new engines that are not broken in, and new and used performance engines with greater-than-stock valve spring pressures are most susceptible to damage (mild, stock engines that are completely broken in seem to tolerate the reduced zinc levels with little or no adverse effects). Let's take a look at some of the things that can be done to prevent problems in those engines that are susceptible to damage.

Improved Parts
If there was ever a case of getting what you pay for, lifters are a prime example. There was a big shakeup in the flat-tappet business a few years back-buyouts and bankruptcies resulted in two of the four companies making them halting production, and there was lifter shortage as a result. Offshore manufacturers cranked up to fill the void as a response to the situation; unfortunately these lifters were poor at best, their failure rate was high, and the worst part is they're still out there. If you're going to run flat tappets, buy from a reputable source and make sure you're getting quality parts by asking questions. The best bet is to buy lifters from the cam supplier-they don't want problems any more than you do.

While quality parts are important, your choice of quality parts is critical as well. Talk to the cam manufacturer and follow their recommendations for related parts; pay particular attention to installed spring heights so open and closed valve pressures are correct. In some cases, there are modifications to the engine that can prevent problems. Rod side clearances on the loose side will help, as the oil tossed off the crank as it rotates is the cam lobe's/lifter's only source of lubrication; if the engine came with a windage tray, leave it out, and additional oiling to the cam/lifer interface can be provided by special lifters such as those offered by COMP Cams that have oil supply holes to the lifter face/cam, or by grooving the lifter bores (full-floating piston pins are also a wise choice to prevent problems in that area). Then, of course, if there are retrofit roller tappets and rocker arms available for your engine (or if they're an option on the crate engine you're considering), they are definitely the way to go.

Start-Up/Break-In
More than ever before, the procedure used when first starting a fresh engine and breaking in a new flat-tappet engine is critical. The best way to ensure there are no problems is to follow the cam manufacturer's (or engine supplier's) procedures to the letter. If you're building your own engine, use plenty of quality assembly lube on the cam and lifters; with any engine-homebuilt or crate-prime the oil pump, oil lines, and fill the oil filter with oil using an auxiliary pump, operating the internal oil pump with a hand drill or an external pressure tank. If the engine is equipped with stiff valve springs (more that 160/170 lbs of pressure seated, 290/300 open), lighter break-in springs may be necessary (check with the cam manufacturer on this one).

When the engine is first fired, use one of the break-in oil additives available (COMP Cams recommends its PN 159 with the company's 'shafts) and follow the cam manufacturer's/engine supplier's recommendations for run-in procedures. Generally that means running the engine at a fast idle for half an hour, shutting it down, and then re-torquing heads if necessary, checking valve lash and so on. Some engine builders will change oil and filter at that point; others prefer to run the oil and the break-in additives 500 miles before dumping it. We usually change the oil, then add another dose of break-in additive and run that for a few hundred miles. It's also advisable to keep idling time to a minimum until the engine is broken in; again, that's because the cam and lifters don't get much oil at low engine speeds.

Engine Oils
Although we were sworn to secrecy as to the source, a representative of one of the largest engine remanufacturing companies in the country admitted that they break in all their engines with diesel mineral oil. He offered two specific reasons for this. First was that the higher level of ZDDP offers increased protection to the cam and lifters, which was almost a given. The second will come as more of a surprise. They believe that because of the compounding, these oils are, in his words, "slightly less slippery," and promote spinning of flat tappets and biting of the rings to the cylinder walls, both of which help the break-in process. Although quite a few custom engine builders also agreed on diesel oil for break-in, others prefer racing oil and a few still rely on 30W non-detergent.

As we talked to various engine builders, we heard a variety of theories on the subject of oil for flat-tappet engines after the initial break-in period; diesel oil was a popular alternative. However, be aware that diesel oils have particularly high detergent levels. Those detergents "surround" deposits that accumulate in the oil and hold them in suspension, so much of it drains out when the oil is changed. However, these detergents will also stick to the inside of the engine and may result in sludge-like residue inside the engine.

There are other oil options that have been suggested; some have tried marine oil-specified for use in four-cycle, water-cooled outboards-and motorcycle oil. But the fact is, all of these are stopgap measures because technology is closing in on us. Soon, catalytic converters will be mandatory on virtually everything with an internal combustion engine, and diesel, marine, and motorcycle oil will reflect that with lowered levels of ZDDP. We've been told that zinc is mandated to be 600 ppm or less by 2012, but don't panic-there are alternatives and more will likely become available.

For now, keep in mind the oils with the lowest ZZDP levels are those with the latest API SM service designation. Oils that don't meet that standard and are SL rated (check some of the high-mileage varieties), or are not API rated, have more ZZDP.

The fact is there are plenty of options available to provide any engine with the protection it needs (check out the side bar for some specific suggestions), and we'll bet Brennan's roadster that more will become available. As soon as one oil company starts targeting the needs of vintage engines that don't have warranty issues, others are bound to follow. We may not be able to stop technology, but at least we can cope with it.

News From SEMA
Synergyn Lubricants Introduces A Line Of Street Rod ProductsSynergyn is a name that some folks may recognize from the company's 20-plus years of experience in producing high-end racing lubricants that have been widely used in the highest levels of motorsports, including NASCAR and NHRA competition. Recently, Synergyn has ramped up product development by consulting with some of the eavyweights of the industry, such as COMP Cams, Lunati, and TCI Automotive. The result is the creation of a new line of engine oils, transmission fluids, gear lubricant, fuel treatments, and specialty additives specifically made to meet the unique needs of street rodders and performance enthusiasts. Among the list of products to be introduced will be a line of engine oils and additives that specifically address the zinc needs of flat-tappet cams.