Mineral Oil

[Alimacdee2]

recently purchased a non detergent oil on ebay, https://www.ebay.co.uk/itm/373537080204
thought it good value,  usually buy their semi synth 10-40 motorcycle oil.
excuse my ignorance, but I see its a SAE40 anyone used sae40 in their SOHC?  any perceived problem using this oil? I’ll refrain from asking which is the best oil for the sohc..Castrol gtx.



 

[McCabe-Thiele (Ted)]

It looks as if it's not a Multigrade so imho not suitable.

Whats you reasoning to not want a detergent oil?

My understanding of detergent oils is they keep particles such as carbon & other combustion products  in suspension so they do not clog up the engine parts or corode delicate parts ? It will always look nice & clean.

[K2-K6]

A bit thick at 40 as Honda (i think) give notes to use 30 viscosity if single grade over 59 F ambient.

That won't damage it, but warm up is the penalty by being essentially too thick by some margin. For UK temperature range and generally more summer, then 30 viscosity would be ideal in single grade.

Nominal oil spec for these is Mineral 15w40 which is effectively a 20 viscosity native oil, plus pour point supresant (making that 15w spec) with "multigrade" polymer to give flow characteristics of 40 viscosity @ 100 degree C.

[Athame57]

Nominal oil spec for these is Mineral 15w40 which is effectively a 20 viscosity native oil, plus pour point supresant (making that 15w spec) with "multigrade" polymer to give flow characteristics of 40 viscosity @ 100 degree C.

Does this mean I'm to be told the 10w40 mineral oil I use is wrong? 

[K2-K6]

Nominal oil spec for these is Mineral 15w40 which is effectively a 20 viscosity native oil, plus pour point supresant (making that 15w spec) with "multigrade" polymer to give flow characteristics of 40 viscosity @ 100 degree C.

Does this mean I'm to be told the 10w40 mineral oil I use is wrong? 

No, it has slightly more range at lower temperature than originally specified in reality. Thst won't hurt you, it'll flow better at cold start which will help with longevity.

The original spec was PROBABLY  inhibited slightly by the base oils and polymer materials available when contemporary, likely improvement in current oil blends is probable.

[Athame57]

No, it has slightly more range at lower temperature than originally specified in reality. Thst won't hurt you, it'll flow better at cold start which will help with longevity.

The original spec was PROBABLY  inhibited slightly by the base oils and polymer materials available when contemporary, likely improvement in current oil blends is probable.

Aaah---sooo..... I can sleep in peace again! That is good. 

[K2-K6]

Yup, all good and generally the ambient temperature "up the smoke" are a little up on out in the sticks too. Quite snuggly for an air-cooled engine 

Its funny the numbers they use on oils anyway, both the 10w and 15w are thicker in effective viscosity than the 40 

There's a lot hidden in those specs on the can.

[McCabe-Thiele (Ted)]

Nominal oil spec for these is Mineral 15w40 which is effectively a 20 viscosity native oil, plus pour point supresant (making that 15w spec) with "multigrade" polymer to give flow characteristics of 40 viscosity @ 100 degree C.

Does this mean I'm to be told the 10w40 mineral oil I use is wrong? 

That looks more suitable to me, multigrade & has detergent.

[Alimacdee2]

thanks for that,  always thought mineral oil may be more suitable for these air cooled engines, anecdotal but  synthetic oils always look very thin to me when really hot, semi synth I suppose is giving you the best of both worlds. Looks like the sae40 is a non starter then, I’ll have to find a use for it, unless I buy an Austin 7 at Mathewsons!

[Bryanj]

Got a lawnmower?

[Alimacdee2]

Yes lawnmower and vintage rotovator will both benefit,

[taysidedragon]

The oil filler cap/dipstick on my 400f has "Use 10w40 oil" cast into it. That's what the manuals say for UK climate as well.

[K2-K6]

Yes lawnmower and vintage rotovator will both benefit,

Its only got to be 15c and above ambient temperature to be in range of using it in the Honda. It wouldn't be a problem at all. If summer use were the aim and then change it'll be fine.

[Athame57]

The oil filler cap/dipstick on my 400f has "Use 10w40 oil" cast into it. That's what the manuals say for UK climate as well.

My gosh, I never noticed that in seven years, been for a look at my own and ditto .... answer hiding in plain sight! 

[Martin6]

Regular changes are important. Two chains (primary and cam) and a gearbox, quickly reduce oil viscosity by shearing the oil's polymer chains. The viscosity you start with isn't what you drain out.