WHAT ENGINE OIL DO WE USE AND RECOMMEND FOR DUCATI BEVEL ENGINES YOU ASK?
Well, lets open up that old can of worms!
It is a common question we receive and thought it might be a good time to put together some information that will answer these questions and more.
Is brand of oil important?
No, if the Brand is a recognised brand and the grade of the oil is correct, then use it.
The following points are more important than brand.
Is weight/viscosity (SAE Grade) important?
Yes, and here is a bit of a dilemma. A Bevel engine along with lots of other (motorcycle engines) has the same oil in the gear box as it does in the engine.
Problem is that the engine has particular requirements as does the gear box. There are not a huge number of oils that can satisfy both parameters.
The engine and more importantly the piston rings and cylinders do not like thick heavy oil. The rings are not designed to control such oils. A heavy weight of oil can make its way past the oil control rings and get into the combustion chamber causing other issues. Having said that the gear box does not like thin oil and requires what is called an EP (Extreme Pressure) additive. This is because of the shearing action of the gears when under load. Some motorcycle oils that are Multi Grade actually state on the container that they contain these EP additives to protect gear box components but also are of a viscosity that enables the rings to control the oil on the cylinders.
The above is a statement of engineering fact not an opinion.
For this reason, I recommend to anyone who asks what is a suitable oil in their Bevel? Use a Multi Grade oil designed for engines that use the same oil to lubricate the gearbox and have an EP additive or meets JASO MA.
In years past people used 50 weight oil. Not sure of the rationale behind the Mono 50 grade oil thinking, but I can tell you from looking inside 100’s of Bevel engines over the past 45 years the engines that have run Multi Grade oils with EP additives are in far better condition all round compared to engines using straight 50. Also, the sludge traps in those using Multi grades are by far a lot cleaner.
The factory hand book for a 750 GT recommends Agip S 50 Racing oil and recommend changing it every 2000K’s. The SD 900 Darmah hand book recommends Agip Sint 2000 20/W50. These engines are identical in most ways. The factory obviously changed their minds on the Mono grade oil.
There is also another reason Multi Grade oil looks after a Bevel engine more than the heavy Mono grade oils. Bevel Twins are an air-cooled engine.
The oil not only lubricates, it is also the medium in which all the heat generated by the engine is transported (conducted) from the component generating the heat to the aluminium of the engine and ultimately into the cooling fins via heat transfer and then from the fins into the air passing over the fins.
Again, the above is an engineering fact not an opinion.
Thick Mono grade oils do not conduct heat anywhere near as well as thinner oils.
Over the years I have done a huge amount of experimenting with oil types and variations in my race bikes. The difference between engine temperature in the same conditions between Mono Grade 50 and Multi Grade 20/40 was in the vicinity of 20 degrees C. Heat is the enemy in any engine when it is not controlled. There are optimum temps we should aim for. However, exceeding these are extremely detrimental to performance and reliability.
Because our Bevel Twin engines are air cooled and can struggle at times in some conditions to dissipate the heat they generate. A thinner oil will assist in this due to the properties of thin oil in comparison to the thick oil. A good quality Multi Grade with an EP additive is in my opinion the best choice.
Should I use full synthetic, semi synthetic or mineral based?
Synthetic oil can have some extremely good advantages over mineral oil. However, in most cases it is not suitable in any way for Ducati Bevel Twins.
Again, I have experimented with this in my Race bikes.
An advantage of Synthetic is that it is made in some very wide ranges of viscosity. 10/60 or 0/60 is not uncommon. This thin oil has incredible heat transfer properties and make remarkable reductions in engine temps especially on a race bike.
There are two major draw backs that prohibit us using it in STD Bevel engines. Our Bevels have a wet clutch that is at best only just capable of transmitting the power the engine makes to the rear wheel. These lightweight Synthetics are not compatible with 1960 technology in clutch plate materials and cause clutch slip in a big way. Once the friction plates come in contact with the Synthetic oil it is almost impossible to remove it and get the clutch to grip again. So, our 60’s style Bevel clutches do not like Synthetics.
More importantly there is an issue in the way our Bevel gear boxes are designed in the fact that some of the gears on both main shaft and lay shaft free wheel on these shafts. They do not run any bearing as such they just run directly on the shaft itself.
Synthetic oil is not suitable for this type of high shear load and if Synthetic oil is used in most cases the free wheel gears will simply seize on their respective shafts.
I have experienced this situation on may occasions. I have seen Bevel engines changed to synthetic oil and only managed 10 Kilometres before locking the gearbox solid.
Current technology and post the 6 speed Ducati twin gear box, the use of needle roller bearings and pressure fed oil to both main and lay shafts in the gear box keep these free wheel gears well lubricated. They also use dry clutches or wet clutches with a suitable friction material as std. Both these changes allow the use of lightweight synthetic oil in these engines.
My last versions of our Race engines also used lightweight Synthetic oil.
To do this firstly I was running dry clutches but more importantly I manufacture the layshaft of the gear box with an oil feed up the centre which helps feed oil up the shaft and out into the free-wheeling gears. This gives oil flow to the gears and stops them seizing on the shafts. I do offer this modification to customer engines.
Every engine rebuild we do at Vee Two is test run in our workshop. We run these engines on a run-in oil which is a straight Mono grade 30 weight. The reason for this is so that the rings get the opportunity to bed properly into the cylinder. We do not assemble the rings and bores with any oil. The gudgeon pin is assembled with a Moly lube however the cylinders and pistons are assembled with DWF. IE CRC or WD40. Again, we have done a huge amount of testing on this with race and road engines. The method we have developed for assembly allows the rings to seal on the bores and stay sealed for the life of the engine.
I learned this procedure from looking at F1 engine assembly technology. Prior to adopting this method, I was finding engines assembled with oil on the bores and rings suffered oil consumption from day one and although did not blow smoke from the exhaust they just continued to consume oil. Up to 500mm per 2000 ks or less.
So thus, the reason we assemble cylinders with DWF and run the engines for approx 20 to 50 Ks on the 30 weight and then go to a 20/50 Multi Grade.
If the customer wants a middle of the road oil and is going to change it around 2 or 3000 Ks then a run of the mill motorcycle oil from any reputable brand like Shell or Castrol in a 20w50 is perfectly acceptable. For something higher end we use Motul Mineral Classic 20W/50. This is around twice the price however it will do more than twice the mileage while still being acceptably close to the standard of the time of our engines.Manufacturers are changing and developing oils all the time. Hard to keep up sometimes. For example, in 1998, the Japanese Automotive Standards Organisation (JASO) introduced the MA specification. This is for multi grade oil in motorcycle engines with a wet clutch and gearbox using the same oil as the rest of the engine. This has become the more commonly advertised and OE required spec on oil bottles and in owners manuals. The oils we recommend today may be superseded tomorrow. We take our quality control and continual improvement seriously.
Also worth a mention is the use of chrome cylinders (Nikasil Plating)
This process was used on the last of the Bevel engines both 900 and Millie.
There is varied instruction for running in these Chrome cylinders. I have used these cylinders extensively on my later version Race bikes. We also run them in our Ritorno Engine. I have used Italian OEM Ducati Chrome Cylinders and I have had my own cylinders plated in Australia, New Zealand, England and the USA. In regard to running them in I have used recommended lubricants from the manufactures. They all recommend a “light engine oil” for assembly. Interestingly, one recommends neat two stroke oil? They claimed it was better protection than normal engine oil. I have never done any comparisons on this.
Chrome cylinders are becoming normal in pretty well all engines these days. They are a very good thing and have huge advantages over cast iron.
More on that in the near future.
Do you make a high flow oil pump?
Yes. We do manufacture high flow/pressure oil pumps however, these are for use in our Ritorno engine and plain bearing conversions in factory bevel twins only. They are not for use with a needle roller big end.
Your Bevel engine uses a Roller Bearing Big End Assembly. Roller Bearing Big Ends are not designed to run high flow and high-pressure oil pumps. Many Roller Bearing big ends only have a splash feed oil supply. Over Supplying oil to these big ends is very detrimental to their operation and longevity. The oversupply of oil causes the rollers to skid and not rotate as they are designed to do. When the rollers skid, they develop small flats on them and the big end will fail prematurely.
Roller Big Ends have been around in motorcycles for many years. They are also used in many of the late model 4 stroke Moto X engines. Many of these later engines do not have pressurized oil feed to the big end. They rely totally on oil mist and oil splash to supply oil feed to the big end.
Laverda Triples have never had a direct oil feed to their roller big ends. Again, they rely on what is called an oil slinger. This is a method of collecting oil and oil mist from what is floating around the crank cases. The oil is collected within a thin metal disc fixed to the side of the crank shaft and then directed into the big end assembly. There is no pressure or direct oil feed at all. Interestingly, Laverda crank shafts and big ends do huge milage before requiring any attention. As a comparison Ducati Bevel big ends do not do any where near the same milage before failing. The Laverda Tripple engine was one of the most reliable engines in endurance racing of that time. Interesting fact since they only rely on a splash and mist feed to the big end.
I have had Bevel engines arrive in my workshop seized or locked up. On inspection I have discovered an issue with the oil pump drive gear being either broken or come off the oil pump. These engines failed because the oil feed to the rear head was zero and the rockers and camshaft simply melted and destroyed themselves. On inspection of the engine and big end assembly the big ends had no damage or showed any sign of overheating even with zero oil feed from the oil pump.
I suspect that people hear talk or discussion about high output and high flow oil pumps that are fitted to various engines for whatever reason. These improved output pumps are all for Plain Bearing big end assemblies. Plain bearing big ends are a completely different mechanical component and none of the mechanical properties of these two bearing types are remotely the same.
We manufacture a replacement oil pump for both Square and Round case Bevel Engines. They are made to exacting tolerances and there has been a huge amount of R&D through racing and Dyno testing to develop these products. They do not cause the Big End Rollers to skid and they supply the correct pressure and volume for the clearances built into our big end assemblies. They are also compatible to the STD Ducati Roller Big End.
Roller Bearing Big End design and development over the years is another and a very interesting subject for another time.
The comparison between Plain Bearing Big end and Roller Bearing Big End systems is complex.