a discussion started in Toby's new build thread regarding engine failures and oil. Hopefully we can continue that discussion and avoid hijacking that thread any further.
Byeats, regarding your question about Mobil 1. I've used the stuff that chadx posted the picture of for three years in two different bikes. 17 fx and 18 500 exc. I've had both clutches apart and no sign of burning or slipping. Plate thickness was in spec. So, does it work with wet clutch, I'd say yes. But, I am not the best test subject as I never slip the clutch under load.
Regarding the shell rotella comment about inferior product. Imo, it is not an inferior product for the diesel application for which it is designed. Diesel engines spread loads over much larger areas and therefor the psi load is drastically less than the loads in our high performance light weight smaller is better bike engines. A high film strength oil is far less important in the diesel compared to the heavily loaded big end rod needle bearing in our jap bikes. I believe ktm went to the plain bearing on crank pin for that reason. With two maybe three times the surface area to distribute the load the ktm crank will tolerate an oil with less film strength.
Take a look at this blog, 540ratblog.wordpress.com
Author is mechanical engineer and tested 235 oils including film strength. Rotella 5w40 full synthetic tested at 67,800 psi. Mobil 1 0w-40 tested at 127,000 psi. There were 199 oils that tested better than rotella for film strength. Most diesel oils had far less film strength than gas engine oils. When the film strength is exceeded you have metal on metal contact.
As a 50 yr grease monkey and former auto tech instructor, I agreed with the authors opinions and testing. He also comments on the auto oil in wet clutch debate that I also agree with. Unfortunately, a long read but, very interesting.
Appreciate hearing from those who have had engine failures. It might be possible to see correlation between oil and failure?
Byeats, regarding your question about Mobil 1. I've used the stuff that chadx posted the picture of for three years in two different bikes. 17 fx and 18 500 exc. I've had both clutches apart and no sign of burning or slipping. Plate thickness was in spec. So, does it work with wet clutch, I'd say yes. But, I am not the best test subject as I never slip the clutch under load.
Regarding the shell rotella comment about inferior product. Imo, it is not an inferior product for the diesel application for which it is designed. Diesel engines spread loads over much larger areas and therefor the psi load is drastically less than the loads in our high performance light weight smaller is better bike engines. A high film strength oil is far less important in the diesel compared to the heavily loaded big end rod needle bearing in our jap bikes. I believe ktm went to the plain bearing on crank pin for that reason. With two maybe three times the surface area to distribute the load the ktm crank will tolerate an oil with less film strength.
Take a look at this blog, 540ratblog.wordpress.com
Author is mechanical engineer and tested 235 oils including film strength. Rotella 5w40 full synthetic tested at 67,800 psi. Mobil 1 0w-40 tested at 127,000 psi. There were 199 oils that tested better than rotella for film strength. Most diesel oils had far less film strength than gas engine oils. When the film strength is exceeded you have metal on metal contact.
As a 50 yr grease monkey and former auto tech instructor, I agreed with the authors opinions and testing. He also comments on the auto oil in wet clutch debate that I also agree with. Unfortunately, a long read but, very interesting.
Appreciate hearing from those who have had engine failures. It might be possible to see correlation between oil and failure?