Weegie Posted May 29, 2020 Posted May 29, 2020 I hope on here that oil threads are a bit calmer than on WG where everybody goes NUTS with illl informed opinions I had overheating on a HiCam which resulted in low oil pressure and I'm guessing, no more than that, that a combination of these engines running very hot in traffic and possibly the relief valve behaviour, it starts to leak around 50psi and yes most of them seem to do that, is contributing to the dropping pressure. At the time bike overheated, I was running a Motul 15/50 full synthetic and just wondered opinions regarding upping viscosity to a 20/50 or even 20/60 weight oil. That won't stop the overheating but might help allleviate the plummeting oil pressure. AFAIK the recommended weight is 20/50. Do some of the later bikes not run a 10/60? Really I'd rather run a lighter rather than a heavier viscosity but when my oil sump temp reached 120C the oil pressure had dropped to under 10psi although that was a circa 2k RPM At the moment it's just a thought, I'll probably try a 20/50 first. Anectodally I've also seen some people posting that changing oil vendors can even have a marked difference 1
80CX100 Posted May 29, 2020 Posted May 29, 2020 For now I'm still running 20w50 dino in my round heads, I don't know if I want to tempt the oil leak gods by running a full synth in them just yet,lol ;~) But I'm running the recommended 10w60 synth in my Griso & CalVin, and planning to use it as well in my V11. I don't want to put words in his mouth, but iirc Chuck has shared the opinion that any bike worth taking care of is worth running 10w60 in it. I can definitely see the merits of quick full lubrication when cold with the 10w aspect,,, and the heavy durable 60w aspect when it gets real hot and the engine is working hard. If the seals, gaskets and breathing are up to it, I wouldn't hesitate to use 10w60 synth, Fwiw ymmv Kelly 2
Lucky Phil Posted May 29, 2020 Posted May 29, 2020 9 hours ago, Weegie said: I hope on here that oil threads are a bit calmer than on WG where everybody goes NUTS with illl informed opinions I had overheating on a HiCam which resulted in low oil pressure and I'm guessing, no more than that, that a combination of these engines running very hot in traffic and possibly the relief valve behaviour, it starts to leak around 50psi and yes most of them seem to do that, is contributing to the dropping pressure. At the time bike overheated, I was running a Motul 15/50 full synthetic and just wondered opinions regarding upping viscosity to a 20/50 or even 20/60 weight oil. That won't stop the overheating but might help allleviate the plummeting oil pressure. AFAIK the recommended weight is 20/50. Do some of the later bikes not run a 10/60? Really I'd rather run a lighter rather than a heavier viscosity but when my oil sump temp reached 120C the oil pressure had dropped to under 10psi although that was a circa 2k RPM At the moment it's just a thought, I'll probably try a 20/50 first. Anectodally I've also seen some people posting that changing oil vendors can even have a marked difference If you look on the German forum for these things everyone seems to run 10W-60. The xxW number should always be as low as possible for a full synthetic oil. By that I mean a true group 4 oil. The only reason for a 20W-xx oil was in the days of mineral based oils which sheared down relatively quickly and the base 20W oil was insurance for those that didn't do oil changes. Full synthetics dont break down like that so a heavy base oil isn't necessary. For those that think a 0W-40 as an example is too thin have a think about this. At engine operating temperature say 90-100 deg C where the engine is designed to produce peak torque, in other words to be at maximum load the 0W-40 oil is around 1/3 the of viscosity that it is at room temperature. So the argument that its too thin doesn't stack up. It's still more viscous when cold than at operating temp and at operating temp its a 40 weight oil. I would run a -10W-40 full synthetic if they made such an oil. I've run my V11 on Mobil1 0W-40 for ten years with no seal leakage, no oil at all in the airbox, no oiling issues at all period. It also has adequate ZDDP levels of 1000ppm for flat tappet engines. You want to be aiming at ZDDP levels of 1000-1400ppm. More isn't necessarily better. For the Daytona I'm inclined to go heavier say a 10W-50 or 60 full synthetic only because they tend to run hot in traffic and could use the extra viscosity at idle to maintain oil pressure. A std Daytona/Centauro engine doesn't really in the real world put any more load on the critical load carrying components such as main and rod bearings than a 2 valve engine either. The power outputs of both are within reason pretty much the same So from my first hand experience and a little basic knowledge about oil I'd say for any of the old generation big block engines the choice would be a full group 4 synthetic in the 0W-40, 10/15W-50 or the 10W-60 depending on the ambient temps you ride in and traffic conditions. For the later 8 valve engines i'd go with the recommended 10W-60. Ciao 3
footgoose Posted May 30, 2020 Posted May 30, 2020 I have nothing to contribute likely due to various oil threads over the years leaving me wanting. I default to what the engine was designed for. I'm slow to convert to synth but have begun the switch with my autos since my F150 Ford calls for semi synth. I will follow this and as I usually do, will pilfer knowledge from those with more expertise. TIA
Weegie Posted May 30, 2020 Author Posted May 30, 2020 9 hours ago, Lucky Phil said: If you look on the German forum for these things everyone seems to run 10W-60. The xxW number should always be as low as possible for a full synthetic oil. By that I mean a true group 4 oil. The only reason for a 20W-xx oil was in the days of mineral based oils which sheared down relatively quickly and the base 20W oil was insurance for those that didn't do oil changes. Full synthetics dont break down like that so a heavy base oil isn't necessary. For those that think a 0W-40 as an example is too thin have a think about this. At engine operating temperature say 90-100 deg C where the engine is designed to produce peak torque, in other words to be at maximum load the 0W-40 oil is around 1/3 the of viscosity that it is at room temperature. So the argument that its too thin doesn't stack up. It's still more viscous when cold than at operating temp and at operating temp its a 40 weight oil. I would run a -10W-40 full synthetic if they made such an oil. I've run my V11 on Mobil1 0W-40 for ten years with no seal leakage, no oil at all in the airbox, no oiling issues at all period. It also has adequate ZDDP levels of 1000ppm for flat tappet engines. You want to be aiming at ZDDP levels of 1000-1400ppm. More isn't necessarily better. For the Daytona I'm inclined to go heavier say a 10W-50 or 60 full synthetic only because they tend to run hot in traffic and could use the extra viscosity at idle to maintain oil pressure. A std Daytona/Centauro engine doesn't really in the real world put any more load on the critical load carrying components such as main and rod bearings than a 2 valve engine either. The power outputs of both are within reason pretty much the same So from my first hand experience and a little basic knowledge about oil I'd say for any of the old generation big block engines the choice would be a full group 4 synthetic in the 0W-40, 10/15W-50 or the 10W-60 depending on the ambient temps you ride in and traffic conditions. For the later 8 valve engines i'd go with the recommended 10W-60. Ciao Thanks Phil All these contributions are very much appreciated. I reckon a 10/60 it is for the HiCam and I'll just continue with my 15/50 in the 2V bikes for now. In Scotland max ambients tend to be mid 20s and when I'm out in the Summer lows probably mid teens. John
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