Oil ASI specs?

[Jak*]

Hi, I get roughly what 10w40 etc means and I understand that ASI specs seem to be updated every couple of years. I can see that an older vehicle like my 1959 Norton may have components that react with some of the additives in modern semi synthetic oils. However given that the ASI specs now seem to change so often is there any problem running a vehicle which for arguments sake is supposed to run on SF on SM? Will this cause any damage or cause the engine to run less efficiently? Presumably if there is a problem in a few years time vehicles will become obsolete because the requisite oil is not available.
Cheers Jak

[EarthWorm]

I just make sure I get the correct API spec or a higher one, as far as I know there is no danger with going for a higher (alphabeticly) spec.
the only other considerations are I believe the choices between mineral/synth/semi-synth
I'm not a great believer in fully synthetics, I don't reckon it has the same film strength.
Not au fait with old stuff which might entail finding single weight oils without gear additives if its pre unit
P.S. I assume your worries about reactions to mdern oils are mainmly about seals and such?, if so, can you not get modern pattern seals with more compatible materials?

[Richard Simpson Mark II]

Here you go: http://www.opieoils.co.uk/c-2164-castro ... e-oil.aspx

[threepot]

As above,or Morris?
http://www.morrislubricantsonline.co.uk ... r-oil.html

[92kk k100lt 193214]

There can be issues with seals.

On the Ks, which first came out in 83, some owners report fully and semi synthetic oil as weeping out through some of the rubber O ring type gaskets. Me too. Other than that there are no apparent issues arising from modern oils. But some engine seals also suffer a little. However replacements usually don't.

For wear there generally is no problem using later spec oils but seals and petrol are a problem due to ethanol. That can be relevant if you are getting petrol contaminants into your oil on an older engine. An old wet clutch engine won't like modern car [as opposed to motorcycle] oils with all the additives.

In the end I just went for bulk buying oil at Lidl and at a main dealer who runs discount sales on Total oils.

[Richard Simpson Mark II]

As above,or Morris?

http://www.morrislubricantsonline.co.uk ... r-oil.html

I was talking to a bloke who worked for Morris a couple of years ago. He said they still did a full range of oils for steam engines...and the family that owns Morris Oils tests them in its own steam traction engine!

[bowber]

I think you need to be using mineral oils in old british bikes, they were never designed for synthetic oils and tend to suffer with seizures on rocker shafts etc.
I've seen a massive difference in the oil film left by synthetics though, years ago synthetics used to run off and leave practically no oil film for cold start protection, now they seem as good or better than mineral oils and leave a goo oil film as the motor cools.
Still not as good as Morris R though (Castrol R was crap but Castrol M was good)
Steve

[Richard Simpson Mark II]

I'd have thought a 1959 British motorcycle engine would be happiest on monograde, 20W in Winter and 50W in Summer.
When I worked in the motorcycle shop in the late 1970s there was a bloke who used to come in very regularly on an old Brit single and buy 4 litres of Castrol GP 10W-40.
I wondered what he did with it...and one day I asked him.
"I put it in my bike"
"What, that one out there"
"Yeah, that's my bike"
"Ever wondered why it uses so much?"
"Well, it's old, it's going to burn a bit."
I tried to tell him that the Castrol GP we sold was formulated for modern Hondas etc and had only the name in common with the monograde oil recommended in his bike's handbook. Yes, an old bike would use a bit of oil, but not two litres a week.
I showed him the range of Silkolene monogrades we had in stock, and suggested an appropriate one for the time of year.
"I'm not putting that modern foreign muck in my bike, sonny! I'll stick with Castol GP."
Oh well, I'd tried. At least he was putting money in the till.

[Richard Simpson Mark II]

I think you need to be using mineral oils in old british bikes, they were never designed for synthetic oils and tend to suffer with seizures on rocker shafts etc.
I've seen a massive difference in the oil film left by synthetics though, years ago synthetics used to run off and leave practically no oil film for cold start protection, now they seem as good or better than mineral oils and leave a goo oil film as the motor cools.
Still not as good as Morris R though (Castrol R was crap but Castrol M was good)

Steve

Top tip from no less than Les Williams.

If you are rebuilding a Meriden Triumph, BSA etc, mix up a 50/50 slurry of STP and engine oil and paint it over the piston, bore, rocker arms etc.

The top ends of those engines only gets fed by oil from a spur taken off the scavenge side of the dry-sump lubrication system. For the first few seconds that they run for the first time, that area has only residual lubrication. The STP mix makes a very thick and long-lasting film to protect the engine in those crucial first few seconds.

[Jak*]

Hi, thanks for the replies I do use straight 40w in my Norton it is more the modern bikes I was concerned about. For instance if you have a bike where the owners handbook says you should be using an oil with an ASI spec of SE would you be invalidating the warranty or causing any problems by using SM oil.
Thanks Jak