vyv_cox
Well-Known Member
I use a standard 15W-40 semi-synthetic in my 3YM30s which is rated API CF so that still looks like a good choice for a "synthetic" adherent like me.
Richard
Which one?
I use a standard 15W-40 semi-synthetic in my 3YM30s which is rated API CF so that still looks like a good choice for a "synthetic" adherent like me.
Richard
Which one?
I've been putting together spares etc and the oil I was recommended for the Yanmar was Motul 15w40 4t.
https://www.motul.com/gb/en/products/oils-lubricants/inboard-4t-15w40
Hoping I've not brought the wrong stuff now![]()
That stuff seems to be for petrol engines.
That stuff seems to be for petrol engines. Have a look at Vyv's website and pick the appropriate grade (if you can get it).
Iv been using 15/40 mineral oil for ages , I read that synthetic oil wasn't recommended for these comparatively low tech engines , Iv been using mineral oil for 15 plus years in our yanmar engines with no problems .
It's very easy to find a synthetic oil that 'meets' 15W40. Something like a 10w50 will have a lower cold viscosity and a higher hot viscosity. I.e. it will have a more constant viscosity over the temperature range.It's not so easy to obtain a 15W-40 synthetic oil and they seem to be expensive. Synthetic oils are heading in the opposite direction and 0W-5 oil is now available and it wouldn't surprise me if some car manufacturers soon start to recommend it for new engines. I'm using 0W-20 in one car but OW-5 seems a bit too radical even for cars.
I've not heard of a 0W-0 oil yet but I'll bet it's in development. I guess after that they need to change the rating system or go -ve! :ambivalence:
Richard
It's very easy to find a synthetic oil that 'meets' 15W40. Something like a 10w50 will have a lower cold viscosity and a higher hot viscosity. I.e. it will have a more constant viscosity over the temperature range.
This might raise a giggle or two?:
http://www.apriliaforum.com/forums/...-oils-all-OK-oil-experts-come-and-have-a-read!
Of course, you've put meets in inverted commas because you are aware that that is not what I meant. 10W-50 is not the same as 15W-40 and if it's not in my local Halfords, which it's not, it's not easy to find.
Now, let's get back to the serious stuff ......
Richard
It's not so easy to obtain a 15W-40 synthetic oil and they seem to be expensive. Synthetic oils are heading in the opposite direction and 0W-5 oil is now available and it wouldn't surprise me if some car manufacturers soon start to recommend it for new engines. I'm using 0W-20 in one car but OW-5 seems a bit too radical even for cars.
I've not heard of a 0W-0 oil yet but I'll bet it's in development. I guess after that they need to change the rating system or go -ve! :ambivalence:
Richard
These ultra-low viscosity grades may be OK for modern cars with hardened crankshafts and hard aluminium-tin bearings but it must be remembered that their only purpose is fuel economy. I have seen too many research reports of older engines running on oils with viscosities higher than these blowing up on the dynamometer. My opinion is that 15w-40 is the lowest to go to with an older engine, although I have no idea whether newer Volvo or Yanmar engines do have hardened shafts. The most recent engine I have stripped was a D2-40 that had copper-lead bearings, which suggests the shaft is unhardened. I run my old BMC 2.2 litre on 20w-50 and the Yanmar 3GM30F on 15w-40.
I remember as an apprentice and motorcyclist (over 50 years ago!) reading a book which was along the lines of designing a race motorcycle engine, it talked about the "porcupine" engine, manx nortons etc! It even gave details on making a new conrod with precise details as to where to tack weld the bits before full welding! Going back to one of your earlier posts about 0 weight oils, this book made the bold statement that water was as good a lubricant as anything as long as there was enough of it pumped through the bearing!Indeed. My relatively recently designed 3YM30 (well, designed in the last 15 years anyway!) is still 15W-40 recommended so that's what I use.
Richard
Going back to one of your earlier posts about 0 weight oils, this book made the bold statement that water was as good a lubricant as anything as long as there was enough of it pumped through the bearing!
Stu
I don't think sae 0 exists.? SAe hot viscosities seem to go down to 20?It's not so easy to obtain a 15W-40 synthetic oil and they seem to be expensive. Synthetic oils are heading in the opposite direction and 0W-5 oil is now available and it wouldn't surprise me if some car manufacturers soon start to recommend it for new engines. I'm using 0W-20 in one car but OW-5 seems a bit too radical even for cars.
I've not heard of a 0W-0 oil yet but I'll bet it's in development. I guess after that they need to change the rating system or go -ve! :ambivalence:
Richard