How can two 10w40 mineral oils be different?

[Athame57]

I recently ordered my oil of choice, Westway's 10w40 4T  mineral oil for classic motorcycles on eBay.  But this was not before I spotted something and cancelled in time the first order. I had noticed the smaller writing on the illustration that said it was merely engine oil, it turns out for the likes of stationary engines like diesel/petrol generators and plant equipment. Would I have been in much trouble if I'd to have gone on and used it?

[McCabe-Thiele (Ted)]

I have noticed a lot of cut and paste description errors when it comes to items on eBay.
That's why I used to go to a parts retailer, talk to the person at the counter, look at the tin of oil etc.

I have ordered items then realised in my rush to buy now I've ended up cancelling an order like you have

Even the photos often do not match the item listed except in a generic sense.

[Athame57]

I have noticed a lot of cut and paste description errors when it comes to items on eBay.

Same here Ted. On this occasion it was on Westway's own eBay outlet so it was down to me swooping for the cheaper listing, I should have looked closer, but as with the question, I never counted on two 10w40 mineral oils being different! 

[Bryanj]

Dont just look at the grade look at the full spec and compare to the manual, dont forget these engines are designed to oil that was common 40 years ago not this wattery sythetic crap that modern cars and bikes use plus it is supposed to be changed every 1500 miles, in all honesty i think the small petrol/diesel oil may well be fine, when was the last time you changed the oil in your lawn mower, if ever!

[Athame57]

Bryan, the last time I used a lawnmower it was one of those contraptions with an engine that sweats, ie one man power! 

[Bryanj]

If thats all thats available the grass gets a reprieve!

[Sesman]

…”watery synthetic crap…”. Do tell. 😳

[exvalvesetdabbler]

Worth keeping an eye on once it's back in stock

https://www.sportsbikeshop.co.uk/motorcycle_parts/content_prod/2443472

I have a store not too far away, just wait for the right price and swing by and stock up. 

Currently have this in my bike
https://www.sportsbikeshop.co.uk/motorcycle_parts/content_prod/238309

Postage is free over £25

Good old Castrol gtx is as good as anything for these old engines. Used their 15/40 for many years when most placed sold it at reasonable prices.

Regards
Dave

[K2-K6]

As noted by Bryan, looking at the more detailed specifications should clarify what they are offering.

I buy a very specific transmission oil (fully synthetic for ZF auto) that is well categorised, identified for a number only for type as it can be used in place of very high cost car manufacturer bottles. 

Westway seem quite good technically, but some products may superficially look the same on initial approach, especially where plain viscosity is replicated for different manufacturer specs.

[McCabe-Thiele (Ted)]

The same issue about specification comes into play with modern fully synthetic oils.
Our car specifies SAE 0W/20 VCC-RBSO-ZAE at over £20 a litre.
There are a variety of Shell or Castrol SAE 0/W20 oils but they have different letters in the specification with some at half the price.
At one time you could buy Asda branded mineral oils at bargain prices in our local store. Now it's synthetic or part synthetic at much greater cost.

I've used this site in the past
www.opieoils.co.uk