All Lubed Up!
But what makes a good one? We all know two stroke oil’s important Silkolene to find out. Stan chats with the boffins at FUCHS
Silkolene boffins answer our direct and frank questions, to bring you the answers you want to know.
With a lifetime in the oil industry and an obsession with two-stroke motocross, there are few people in the UK better qualified to talk to about two-stroke oil than Andy Brown, UK automotive technical manager FUCHS Silkolene. On a recent visit to the firm’s headquarters, I took the opportunity to pose the questions that appear on every forum and gain insight into what makes a good two-stroke oil.
“The biggest problem with engine lubrication is the bloke down the pub,” begins Andy “They’re a mixed blessing. On one hand they may have run an engine on a certain type of oil for years and that’s good knowledge to have; on the other, two-stroke riders tend to be more concerned with whether they’ve seized than about the long-term effects on an engine. It’s usually in the long term that differences between oils become apparent.”
SC: Because it has to do so many things, is two-stroke oil a complex product?
AB: “It’s no more complicated than four-stroke engine oil, the main difference is that four-stroke oil tends to hang around longer. The difficulty in formulating an engine oil is that it has to lubricate in many different aspects.
There are three main types of lubrication: boundary, hydrodynamic and mixed (a combination of both the other two). A simple slow-moving bearing may experience only one of these, whereas components in an engine will experience all three and some components experience different types of lubrication at different points in the cycle. A good example of that are piston rings which exhibit hydrodynamic lubrication for the majority of the stroke but then undergo both mixed and boundary lubrication as they reach the top and bottom of the stroke.
“On its own that’s an easy problem to deal with, but then add components which combine elements of both and ask a lubricant to deal with them all and it becomes quite a complex problem.”
SC: Be honest, aren’t all two-stroke oils the same?
AB: “The answer to that is both yes and no. There are six oil refineries in the UK and every producer buys their base oil from one of those sources at a set market price. So yes, in its raw form all oil’s the same. The difference between brands comes from the specific blend of these base oils and more importantly the performance additives used.”
SC: How can I spot a good oil?
AB: “From the packaging, you can’t. Although base oils are subject to an industry wide standard there’s no obligation for manufacturers to say which one was used. Many people rely on ratings such as JASO but these are only a minimum specification and were set over a decade ago.
As a starting point I’d advise users to look at the label for a contact number. If there isn’t one, walk away from it there and then. There’ll be a reason they don’t want contact and it’s not usually overconfidence in their product!”
SC: You’ve mentioned ‘base oil’ a couple of times, what does that mean?
AB: “Oil comes in one of five types, imaginatively numbered 1-5. One is basic mineral oil, four and five are fully synthetic (but different). Despite the naming all of them are derived from mineral oils, ‘fully synthetic’ simply denotes the petro-chemical processes used to create them. Although these grades conform to an industry standard there’s no definition of what constitutes ‘synthetic’ or ‘semi-synthetic’. For synthetic most of the world classes Group 3 but it’s different in Germany – don’t ask me why! For semi there is no definition of the amount of synthetic so be careful what you choose! The exceptions to this are castor oils which are different products entirely.
“Human nature says that armed with that knowledge riders will start to look for Group 4/5 oil but that number is only part of the story, there are times when a higher grade can actually be harmful.”
SC: If all base oil comes from the same source why does two-stroke oil vary so much in price?
AB: “It’s due to the cost of additives. Show me an oil recipe and I can tell you, within a few pence, what it cost to manufacture. All my experience tells me that the only way to produce cheap oil is to reduce the number of additives. A good two-stroke oil will be formulated for a specific purpose. Depending on the brief we can create an oil that will increase bhp, an oil that will extend engine life or an oil that will reduce emissions. It depends on the application.”
SC: Most two-stroke scooters are based on 1950s/60s technology, surely a cheap oil will be enough?
AB: “A Group 1 base oil is very close to the old two-stroke oils (except castor). However remember that back in the 1960s two strokes were dirty things that fouled plugs routinely and needed de-coking on a regular basis, a lot of that was down to oil quality. We’ve recently re-launched our Classic Two Stroke oil which is perfect for heritage machines but has all the benefits of a modern formula. It’s taken a lot of work but I’m very pleased with the result.”
SC: Can you give me a simple example of additives likely to be missing in a cheap oil?
AB: “A good example are the additives which control how oil burns and how it’s cleaned from the engine. Oils formulated
I’d never given much thought to how two-stroke arrived in my toolbox but was surprised at how complex the process is.
for garden machinery tend to omit these as they’re unnecessary given how the machinery’s used but they’re essential for road use. Without these additives, unburnt oil tends to stick underneath the piston crown. Because this layer forms unevenly it causes hot points on the piston crown. At best these hot points create a buildup of carbon on the piston’s crown, at worst they can contribute to a holed piston.”
AB: “There are so many but I’ll go with micro-welds, which are an issue in any engine, particularly affecting piston rings. In simple terms no matter how polished a surface looks to the naked eye at a microscopic level there’ll be peaks and troughs. As the high points pass one another they heat rapidly and for a fraction of a second weld together. This isn’t a heat seize, it’s a true weld that breaks within milliseconds of being formed. Of course this leaves another uneven surface which creates the next micro-weld and so on. The broken weld has to go somewhere and most of it ends up in oil residue, creating what’s effectively an extremely fine grinding paste.
We can tackle that by effectively polarising the oil particles, creating a chemical bond between oil and metal. This coats the peaks and troughs, decreases friction and as a consequence reduces the likelihood of micro welds occurring. That’s of little interest to a racing team as they’ll strip their engine after ever meeting and probably sacrifice a set of piston rings in the process. Wear simply isn’t an issue for them. However for a rider who covers lots of miles the extra cost would be more than offset by increased engine life and longer periods between maintenance.”
AB: “Our website has a search facility for the most common engines but the starting point should always be the owners’ manual. Finding one of these for classic machines used to be a problem but almost everything’s available on the internet. If the oil listed is no longer available our technical support team can advise on the modern equivalent.
AB: “The process is the same, contact our technical support team, they provide excellent technical advice. Whether selling five litres or a thousand litres, the level of customer/technical service offered is exactly the same. We understand how important selecting the correct lubricant is and believe
that supplying the correct advice is an important part of our business.
“Many questions have been asked before and they can often give a very quick answer. For example a lot of the more unusual classics shared engines and it’s simply a case of cross referencing. For tuned engines be prepared to answer some questions and please answer them fully. A classic car club, who will remain nameless, caused us a lot of problems as they insisted they were racing standard engines. It took a while for us to work out they meant standard engine blocks, almost everything else had been changed. Clearly that affected our advice!”
Everyone’s an expert…..
When I arrived at FUCHS Silkolene I’d expected a hard corporate sell, nothing could have been further from the truth. Yes, everyone’s proud of their product and there’s a genuine belief that they’re the best but I couldn’t have met a more open bunch of people.
As I said my farewells Andy smiled and said: “I’m always amazed how little consideration people give to oil. I’d bet any money that the rider who’s spent thousands on an engine didn’t buy components based simply on what was the cheapest or which came to hand first yet that’s what most people do with oil. The most frustrating part of this interview is knowing that people will read it and then ask the advice of their mate down the pub.”
If you’re not paying attention to your oil maybe this winter’s the time to think about it. Just remember that the only bloke down the pub worth listening to is probably Andy Brown…
Stan