Speeds Secrets November 2007

Switching to Synthetics

A while back the guys from Speed’s Performance Plus told us about the benefits of filling the oil bag, transmission and primary case with synthetic lubricants. Speed’s does it exclusively now. In fact, they’ve added that service to their on-the-road tuning center. The reason? Speed’s found that the Lucas synthetic oils they’ve chosen do a better job lubricating Harley engines than do conventional petroleum-base oils. Synthetics hold their viscosity longer than petroleum-based oil and, critically important in an air-cooled V-twin, those synthetics actually remove the heat.

An air-cooled engine, remember, is also oil cooled. And running a full-synthetic, Speed’s found, can dramatically drop the engine temperature 15- to 25-degrees. That’s a huge benefit, especially in an engine that’s been modified with higher compression, maybe a more radical cam grind, a bigger carburetor or throttle body and a free-flow exhaust. Which pretty much describes many Harleys on the road. Those bikes run stronger than OE, no question about that, but they also run hotter.

On the other side of the coin, Speed’s has seen plenty of bone-stock late-model Harleys delivered with severely leaned-out fuel curves to meet EPA emission requirements. They’re running hotter than ever now, too. Anything you can do to help drop engine temperature is a step in the right direction, and switching to synthetics is an easy move. With worldwide oil prices where they are now, the price difference between a quart of regular petroleum-based lubricant and a quart of synthetic is negligible, too.

So why, and how, do synthetics offer all these benefits--benefits, incidentally, that also can make a transmission shift easier and a clutch engage smoother. The answer, in a nutshell, is chemistry. Synthetic lubricants are manufactured through chemical reactions, unlike standard petroleum-based lubricants, which are distilled and refined. Synthetics can still have some of the same natural-base ingredients found in regular oils, but through the magic of the laboratory formulas, their hydrocarbon molecules are changed and re-arranged, and recombined into “synthesized” hydrocarbon molecule chains with improved uniformity.

All this leads to better lubrication properties and the ability to more efficiently remove heat. Synthetic oils are custom-engineered to deliver all the lubrication properties of premium petroleum-based oil, but do so with none of the cold-thickening or hot-thinning shortfalls found in regular oils. Those re-engineered molecules also do a better job withstanding extreme engine temperatures that can have conventional petroleum-based oil vaporizing or oxidizing. Furthermore, the chemical construction of a synthetic eliminates contaminants, minimizing the trace amounts of sulfur, wax and asphalt found in conventional petroleum-based oils. That’s the stuff that causes varnish and sludge buildup. With a synthetic it’s gone.

There’s more. Start-up is one of the toughest times for an engine and its lubricant. Here synthetic oils help by clinging better to engine parts, coating them uniformly at all times so the parts have a film of lubricant the moment the engine is started. Synthetics are pumped through the engine to all the critical passages and bearing surfaces faster, too. Things just keep looking better and better, don’t they?

And consider this: All oils—petroleum-based and synthetic—contain “additive packages” to help them last longer, stay cleaner and do their job. The amount and quality of additives varies from brand to brand, but synthetics almost always have a superior additive package that actually increase the oil’s life in the engine. Independent laboratory testing has determined that synthetic lubricants can last for 25,000 miles or more without significant breakdown.

Still, myths persist about making the switch to synthetics. One persistent belief is that synthetic oils cause engine leaks. Not true. Bad gaskets and seals cause engine leaks. If an engine is already leaking with conventional motor oil, sure, it’s going to leak with the synthetic, too, but not in a greater quantity. And some say you can’t switch from synthetic oil to conventional oil or vice versa, or that once you start using synthetics you can’t go back to conventional oil. The belief here is that synthetics and conventional oils can’t be mixed because they’ll adversely react with each other and cause catastrophic engine problems. Again not true. As long as both oils meet the viscosity and performance requirements of the engine, they can be interchanged. Why you would want to do that, other than to maybe top off an oil tank during a road trip, is an open question.

The bottom line is that at Speed’s Performance Plus they’ve become true believers in synthetics. These are lubricants that work. And with that full-service/full-synthetic oil change station they’ve set up at the events, they’ve made plenty of converts, too.