"classic" oil - is it?

[steve00136]

Well started engine out job today and made good progress. Thinking about all the replacement oil I'm going to need for engine, gearbox and over drive - is it really necessary to buy the expensive so called "classic" 20/50 or will the standard 20/50 mineral oil at half the price say from comma do the same job. Both made to various standards. Tempted to go for the cheaper option as only doing about 500 miles a year and don't race it. Any ideas?

[Paul Hollingworth]

The important thing is does it contain ZDDP, which is a zinc additive which protects against cam and tappet wear in older engines. Some posters on this and other forums have suggested that Comma and Halfords 'classic oil' are the same, but I wouldn't like to say. I've found a cheap source of Morris's classic oil, so am running on that. Its made in Shrewsbury and was mentioned in a recent review in Safety Fast. I contacted their technical department to ask if it contained ZDDP but all they would say is "it contains everything your classic MGB needs". To be sure I add half a bottle of STP when I do an oil change. You can get STP for about £3 for 500 ml so its as cheap as engine oil and it makes my old engine a little less rattily. The hot oil pressure is good at about 65 psi on the Morris's, but I think that's controlled by the relief valve anyway. Its always above 40 psi at idle.

[Ian F]

Hi Steve. Not sure about prices but I use Castrol XL 20/50 which I buy from Opie Oils in Cornwall.
I get the 20 litre containers which I decant into Castrol 1 gallon tins (this size is also available from Opie but is more expensive per gallon as you might expect). Delivery is free (I live in Scotland), and I think the price is quite competitive - check their website.

Ian F

[Paul Hollingworth]

Funnily enough a similar question cropped up on the MG enthusiasts forum. Paul Hunt has written a piece on his brilliant Bee & Vee site all about it.

www.mgb-stuff.org.uk/enginetext.htm#oils

(cant get it to hyperlink so you might have to paste it into your browser)

Basically he says that we should not be using oil with an API rating higher than SJ. (not SL or SM) The Morris Golden film I'm using is SF rated so should contain ZDDP. It was taken out of more modern oils because it damages Catalysts.

[Peter Cresswell]

More info here from a past thread:
viewtopic.php?f=4&t=460

[Mnripley]

I normally buy my oils from OPIE in Cornwall

Just been on the web site and I normally look for 20/50W classic oils to check on prices and offers. Today I put my registration Number in for a search the correct car came up MGB 1978 but all oils listed were semi-synthetic 5/40W

[Ian F]

I would just ignore these "smart" search engines and get your usual 20/50 !!!

Ian F

[Mnripley]

Ian

Normally i do, it was just one of those things you do.
Have emailed OPIE to advise of the error.

Michael

[Ian F]

That's good Michael! I am sure it was worthwhile flagging this up to fellow MGB owners.
I have found similar poor advice on other web based retailers, I guess it is just because our cars are rather old and not well understood.

Ian F

[steve00136]

Found Duckhams Q20-50 Good stuff but expensive at https://mymgbinfo.wordpress.com/2019/01 ... -its-back/.
Spec sheet doesn't actually say how much zinc other than confirmed that it contains sufficient?