M1 15W-50 Silver Cap HT/HS

Messages
1,158
Location
USA
Hello, I have a dozen quarts of M1 15w-50 silver cap of unknown age...API SM, SL/CF I don't want to just throw it away but its a much heavier viscosity than my gasoline vehicles call for. I am trying to get a better understanding of shearing and HT/HS. I have read that it shears quickly in a motorcycle and in a race application down to a 40-weight QUICKLY but can't find UOAs to support it. It has an HT/HS of 4.5 (based on M1 website) 100*C is 18.1 cSt (based on M1 website) It is 100% PAO (based on personal statements but I can't find definitive proof). I have read that dino oils have more VIIs than synthetics and the VIIs shear and this is the reason Synthetics of equal weight are more shear stable. One of the vehicles I am considering using this oil in a BMW 650 which has a ROTAX single cylinder and a wet clutch. BMW recommends a 10w-40 but some of their bigger wet clutch bikes are now getting filled with 15w-50 when being serviced by BMW. I will be using this in the hot FL summertime. Is this product a shear stable oil? If it is likely to drop to a 40-weight then I would be inclined to use it in the BMW 650gs. Is this a bad idea? Thanks
 
Messages
10,926
Location
Jupiter, Florida
All oils will shear in a motorcycle transmission, even the very shear stable M1, 15W-50. That's why we change motorcycle oil more frequently than automotive oils. I don't think you will find a better oil for all around use. It's not "too thick" as the 15W-50 has excellent cold viscosity, has a great additive package, and it's a great choice for Florida. In fact, I'd go as far as to say you will have to look long and hard to find a more shear stable oil for your BMW single application. I use it in my South Florida Turbo Honda S2000 with great results. An engine normally spec'd for 5W-30, but now making 407RWHP. Want to guess why my engine, and in particular the connecting rod bearnings, has held up well, and others with the exact same turbo setup as me, have not? Hint: It's the oil!
 
Last edited:
Messages
13,613
Location
Frisco, TX
I doubt it's 100% PAO. All synthetic oils these days are a blend of various basestocks. It might be a higher percentage than the regular Mobil 1, but it's not 100%. I think you could use it in the bike, and as Cujet wrote, you just need to change those oils more often.
 
Messages
3,402
Location
BC, Canada
Back in the day I used Delvac 15W50 in just about everything. I still have a 5 liter jug that has in felt pen "good used SAE 50 2500 km from Benz" written on it. (It didn't blow up as predicted.)
 
Messages
10,015
Location
Waco, TX
You can always blend a little if it makes you feel better. OTOH, WHY would you even consider "throwing away oil"?!?!?!?!!?
 

ArcticDriver

Thread starter
Messages
1,158
Location
USA
Originally Posted By: Linctex
You can always blend a little if it makes you feel better. OTOH, WHY would you even consider "throwing away oil"?!?!?!?!!?
Poor choice of words. In fact, on BITOG possibly a word choice that could quickly end in being Banned...or atleast shunned for blasphemy grin I would just give it to a friend of mine with who is a hoarder of cars and trucks and whose yard looks like a parking lot. A good friend to have but would make a terrible neighbor !
 

ArcticDriver

Thread starter
Messages
1,158
Location
USA
Originally Posted By: Dyusik
I would use it in my bikes without a second thought.
The Rotax is just a small 652 cc compared to your bikes...would that make a difference? Thanks
 

ArcticDriver

Thread starter
Messages
1,158
Location
USA
Originally Posted By: BrocLuno
Naw, the motorcycle will be quite happy. Go for it smile
Thanks! I am now confident running this in my bike. My neighbor won't be getting these 12 quarts.
 

SR5

Messages
5,990
Location
Down Under
That M1 15W50 would make an excellent motorcycle oil, it should be fairly shear stable and has a HTHS of 4.5 cP with 1300 ppm Zinc. Spot on if you ask me. It's the M1 5W50 that is more shear prone, but I had a mate run the 5W50 in his Yamaha 600 cc single for years, no problem, and when the gear change got a bit notchy, he just changed the oil, which is what every motorcycle rider does. I think motorcycles like thick oil, especially low revving single cylinder bikes with wet clutches. In my old Yamaha air cooled singles I always ran Penrite HPR 20W60 mineral and in my more modern water cooled in-line fours (Honda CBR) I ran Castrol Edge 10W60 full synthetic. I would have happily run M1 15W50 in any of my bikes.
 

ArcticDriver

Thread starter
Messages
1,158
Location
USA
Originally Posted By: SR5
That M1 15W50 would make an excellent motorcycle oil, it should be fairly shear stable and has a HTHS of 4.5 cP with 1300 ppm Zinc. Spot on if you ask me. It's the M1 5W50 that is more shear prone, but I had a mate run the 5W50 in his Yamaha 600 cc single for years, no problem, and when the gear change got a bit notchy, he just changed the oil, which is what every motorcycle rider does. I think motorcycles like thick oil, especially low revving single cylinder bikes with wet clutches. In my old Yamaha air cooled singles I always ran Penrite HPR 20W60 mineral and in my more modern water cooled in-line fours (Honda CBR) I ran Castrol Edge 10W60 full synthetic. I would have happily run M1 15W50 in any of my bikes.
Yep...thats the stuff alright. 1300 Zinc 1200 Phosphorus 0100 Moly Cheers
 
Top