Dr Jay’s Tech Topic - Oil #2

Synthetic vs Petroleum oils- Motor Oil is Motor Oil right? 

So last time we discussed Oils and Viscosities and as promised, this time we will discuss Synthetics versus Petroleum lubricants.

Anyone who has purchased oil lately knows there is a bewildering array of oils on the market. Besides all the viscosities available, there are Petroleum oils, Semi-Synthetic and Pure Synthetic oils out there. One of the myths is that Synthetic oils are better than Petroleum oils, and that is not always the case. However, to understand why, we have to start with the question “How are Synthetic based oils different than Petroleum based oils?”. As we discussed last month, most of the “oil” in a bottle of oil is actually chemicals, things like dispersants, detergents, friction modifiers, viscosity modifiers and some other stuff. The thing is, the chemicals are always added to a base oil. That base can be petroleum oil- like a refined bright stock oil (decayed Dinosaurs and other biological material that died millions of years ago pumped right from the ground) or it can be a molecule made in a laboratory-thereby the name “Synthetic”.

The basic difference in simple terms, between Synthetic Base oil and Petroleum Base oil is: Synthetics are attracted to heat and Petroleum’s are displaced from heat. Now some might immediately assume that synthetic bases are better BECAUSE they are attracted to heat. Remember the old commercials with the frying pan? The demonstration was to heat a frying pan on the stove and then into the pan a guy with a white lab coat would put some synthetic oil and it would flow very quickly to evenly cover the bottom (hottest part) of the pan. Then he would repeat the experiment with a petroleum base oil and the oil would instantly vaporize, the implication being that a synthetic was therefore better. But here is the reality. The hottest parts of an internal combustion engine are the domes of the pistons, the domes of the cylinder heads and the valves. Now what happens if our lubricant is attracted to heat is that we can get an unreasonable amount of “attraction” to these areas of the engine, which by the way do not require lubrication, and therein we can get an enormous buildup of the byproduct of attracting lubricants to heat: CARBON. Carbon build up, particularly at the valve face and stem of the valves can really kill the efficiency of the engine and thereby the power it can produce.

There is no doubt that Synthetic based oils are the future and despite their shortcomings are much better in very hot environments like racing and high performance engines (like our motorcycles) and offer a longer service life. But some basic precautions are needed to ensure they work as expected.
1. NEVER use a synthetic oil as a break-in lubricant. Synthetic based oils can prevent the piston rings from seating properly. Always wait about 4000 miles before switching to a synthetic.
2. NEVER mix the two types of oils. When switching to a synthetic, always warm the engine and drain the oil completely and change the filter too. NEVER top off petroleum oils with a synthetic or Vice versa.
3. If you use synthetic oils, always run the best gasoline available. I prefer Chevron fuels because of their Techron additive which helps to clean the deposits the synthetics can leave on the valves and combustion chamber. If you don’t use Chevron Fuels (or even if you do!), Yamaha has a fuel additive called “Engine Med RX” which is actually almost 100% Techron. When added to your fuel, it will help to remove these buildups.
Check your oil more often. Because synthetic oil is consumed in the combustion chamber due to it's heat attraction properties you will use it up rather quickly. The last thing you want is to run the engine out of oil- Trust me when I say those commercials where they drained the oil out and ran the engine without oil are a complete joke...


Next month we will discuss Tires.....

 Have a safe ride!

Dr Jay